Open-label, controlled, phase 2 clinical trial assessing the safety, efficacy, and pharmacokinetics of INM004 in pediatric patients with Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome

Open-label, controlled, phase 2 clinical trial assessing the safety, efficacy, and pharmacokinetics of INM004 in pediatric patients with Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Open-label, controlled, phase 2 clinical trial assessing the safety, efficacy, and pharmacokinetics of INM004 in pediatric patients with Shiga toxin-producing Escherichia coli -associated hemolytic uremic syndrome Alicia Fayad, Iliana Principi, Alejandro Balestracci, Laura Alconcher, and 24 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4751636/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 12 Nov, 2024 Read the published version in Pediatric Nephrology → Version 1 posted 5 You are reading this latest preprint version Abstract Background Shiga toxin-producing Escherichia coli -associated hemolytic uremic syndrome (STEC-HUS) is a severe condition mainly affecting children. It is one of the leading causes of acute kidney injury in pediatric population. There is no established therapy for this disease. INM004 is an anti-Shiga toxin composed of equine polyclonal antibodies. This study aimed to assess the safety, pharmacokinetics, and efficacy of INM004 in pediatric patients with STEC-HUS. Methods Phase 2, open-label clinical trial with an historical control arm. Patients in the treatment arm received two doses of INM004. The primary endpoints were the safety profile, pharmacokinetics, and efficacy (dialysis days) of INM004. Secondary endpoints included other renal and extrarenal outcomes. Propensity score matching was used for efficacy comparisons between arms. Results Fifty-seven and 125 patients were enrolled in the treatment and control arm, respectively. After propensity score matching, 52 patients remained in each arm. INM004 was well-tolerated. Eight adverse events were considered possibly related, none of which were serious or severe. In the primary efficacy endpoint, patients of the treatment arm presented a non-statistically significant difference of two dialysis days. On secondary endpoints, trends toward a lower number of patients needing dialysis and dialysis for more than ten days, and shorter time to glomerular filtration rate normalization, were observed favoring the treatment arm. Conclusions INM004 showed an adequate safety profile. Efficacy trends suggesting a beneficial effect in the amelioration of kidney injury were observed. These results encourage the conduction of a Phase 3 study of INM004 in pediatric patients with STEC-HUS. Hemolytic-Uremic Syndrome Acute Kidney Injury Clinical Trial Phase 2 Passive Immunotherapy Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction Shiga toxin (Stx)-producing Escherichia coli -associated hemolytic uremic syndrome (STEC-HUS) is a form of thrombotic microangiopathy (TMA) characterized by the triad of hemolytic anemia, thrombocytopenia, and acute kidney injury (AKI) [ 1 , 2 ]. It is one of the leading causes of AKI in pediatric population and a relevant contributor to the development of chronic kidney disease (CKD) [ 3 – 5 ]. Approximately 60% of patients require dialysis during the acute phase of the disease [ 1 , 3 ], and the mortality rate is around 3% [ 1 , 3 ]. Children under five are the most affected group [ 6 ]. In Argentina, STEC-HUS is endemic and exhibits the highest incidence globally [ 7 , 8 ]. STEC-HUS remains an orphan disease without an established treatment. INM004 is a novel therapy composed of F(ab´) 2 fragments from equine immunoglobulins that efficiently neutralize Stx [ 9 ]. These antibodies were raised by immunizing horses with two chimeric protein particles that stabilizes the B subunit of Stx1 and Stx2 in their native conformation and exposes their Gb3-binding sites. Thus, the elicited antibodies would have a strong capacity for blocking the entrance of Stx to their target cells [ 10 ]. In a phase 1 placebo-controlled trial, INM004 was well-tolerated and was not associated with serious or severe adverse events (AE) in healthy volunteers [ 11 ]. Similarly, INM004 showed good tolerance in 11 pediatric patients with Stx-positive bloody diarrhea in a phase 2/3 study for the prevention of STEC-HUS which was early terminated during the COVID-19 pandemic (NCT04132375). The primary objective of this phase 2 study was to assess the safety, efficacy, and pharmacokinetics (PK) of INM004 in pediatric patients with STEC-HUS. The proposed mechanism of action of INM004 is the neutralization of Stx in the bloodstream to block the interaction with its receptor in the target organs. The findings of this investigation aim to provide insights into the safety and therapeutic potential of INM004, in view of a future phase 3 trial. 2. Methods 2.1. Study design and participants A multicenter phase 2, open-label clinical trial of INM004 with an historical control arm, was performed in 16 reference hospitals across Argentina. Eligible subjects were hospitalized patients with STEC-HUS. The study design is detailed in Fig. 1 . Patients of the treatment arm received INM004 in addition to standard of care (SoC) treatment for STEC-HUS, and the control arm only received SoC. Overall, SoC for pediatric STEC-HUS patients was consistent between participant centers in Argentina, following specific guidelines for its management [ 12 , 13 ]. Patients of the control arm were retrospectively selected by a review of all medical charts of patients hospitalized during the recruitment period for this group (Fig. 1 ). The evaluation of the PK of INM004 was part of a sub-study conducted in a subsample of the treatment arm (Fig. 1 ). This study was prospectively registered in clinicaltrials.gov (NCT05569746). Written informed consent was provided by legal guardians of all subjects of the treatment arm. Assent of children was obtained as applicable. 2.2. Inclusion and exclusion criteria The same inclusion and exclusion criteria applied for both arms, except for two specific criteria related to the safety of subjects receiving an experimental treatment. In other to include patients as early as possible after STEC-HUS onset, subjects were eligible for their inclusion with two of three components of the diagnostic HUS triad: signs of kidney injury and at least one of the two hematological signs of the TMA (i.e., hemolysis and/or platelet consumption). Kidney injury was defined by sCr above the upper limit of normal (ULN) for age and sex or hematuria (≥ 5 red blood cells per field or ≥ 27 red blood cells/µl in the urinary sediment); hemolysis was defined by lactate dehydrogenase (LDH) above the ULN for age or presence of schistocytes in the peripheral blood smear; platelet consumption was defined by a platelet count < 150 x 10 9 /L or decrease of ≥ 50% in the platelet count within the previous 24 hours. Other inclusion criteria were age between 1 and 12 years old; history of diarrhea with onset within the 13 days prior to the diagnosis of the STEC-HUS in the participating institution; a negative pregnancy test in subjects of the treatment arm who had had menarche. Patients were excluded from the study if they met any of the following criteria. Dialysis for more than 48 hours at the time of diagnosis of the STEC-HUS in the participating institution; history of chronic/recurrent hemolytic anemia, thrombocytopenia, or CKD; personal or family history of atypical HUS; suspicion of HUS secondary to infectious processes other than gastrointestinal; evidence of clinically significant chronic disease whose symptoms may have interfered with the treatment or diagnosis of STEC-HUS, at the discretion of the investigator; pregnant or breastfeeding subjects; participation in a clinical trial simultaneously or in the previous three months. For the treatment arm, an additional exclusion criterion was the history of anaphylaxis or previous administration of equine serum, or allergic reaction to horse exposure. 2.3. Procedures This study assessed two regimens of one- or two-dose of 4 mg/kg of INM004 administered as intravenous infusions during 50 minutes (Fig. 1 ). While most patients were included in the two-dose regimen, the one-dose regimen was only aimed at assessing PK in a small part of the sample. Study visits were performed for all subjects on the day of diagnosis of STEC-HUS in the participating site (day 0) and on days 1, 2, 3, 4, 7,14, 21, and 28. Hospital discharge was determined by the attending physician according to SoC, and in those cases assessments had to continue as outpatient visits. For outpatients, visits on days 14 and 21 could be done by phone. Assessments at each visit are described in Fig. 1 . A 12-lead electrocardiogram (ECG) was performed in patients of the treatment arm at baseline and 24 h after the second dose. Microbiological confirmation of STEC infection was performed by SoC procedures at each site for both arms (Fig. 1 ). Additionally, IgM antibodies against Escherichia coli O157, O145, O121 and O103 in serum were determined in a central laboratory using commercial Chemtest® kits (CHEMLIS® E. coli Combi Glyco-iELISA) for patients of the treatment arm. Safety and tolerability were assessed by the Data Safety Monitoring Board (DSMB) by monitoring AE and AE of special interest (AESI) (i.e., injection site reactions and hypersensitivity reactions), laboratory values, vital signs, physical examination, and ECG. AE were coded using MedDRA version 25.1. PK samples were collected at 6 different time points (Fig. 1 ). Concentrations of INM004 were determined by ELISA [ 11 , 14 ]. Immunogenicity was evaluated by the presence of anti-product antibodies by ELISA in blood samples obtained at days 0 and 28 [ 11 ]. 2.4. Outcomes Primary and secondary outcomes are detailed in Fig. 2 . 2.5. Sample size considerations The study aimed to evaluate the safety and PK of INM004 and provide exploratory insights into efficacy to guide the design of a Phase 3 trial. One hundred patients were expected to be recruited during one warm season in the treatment arm and 200 eligible subjects were expected for the control arm. This sample size was expected to yield a power of 78% to detect AE with an incidence of 1.5%, and a power of 80% to detect a 50% difference in the primary efficacy outcome. The PK sub-study was planned to include 18 patients (12 and six receiving the two and one-dose regimen, respectively). 2.6. Statistical analysis Categorical variables were described using absolute frequencies and percentages, and quantitative variables were summarized using mean and standard deviation (SD) or median and interquartile range or range. Chi-square test or Fisher's exact test were applied to compare categorical variables, and regression linear models were used to compare quantitative variables between the treatment and control arms. The variable dialysis days was analyzed using a negative binomial regression model to consider the overdispersion of zeros. Cox's proportional hazards regression model was used to estimate the hazard ratio (HR) for time-to-event variables. Due to the exploratory nature of the study, no adjustments were made for multiple comparisons. Safety analyses were descriptive. The estimation of PK parameters by non-compartmental analysis (NCA) methods was performed using Phoenix WinNonlin software (version 8.3, Certara USA, Inc., USA). The following sets were considered for the different outcomes. Full analysis set (FAS): all subjects of the treatment arm who received at least one dose of INM004 and all subjects of the control arm; safety population (SP): all subjects from the treatment arm who received at least one dose of INM004; matched population (MP): FAS subjects selected using the propensity score matching procedure (PROC PSMATCH, SAS 9.4), to address potential selection bias. A propensity score matching procedure (PROC PSMATCH, SAS 9.4) was used to generate a sample matched on its baseline characteristics. The following variables at the day of diagnosis of STEC-HUS (day 0) were pre-established for the calculation of the propensity score: age, sex, days from onset of diarrhea to diagnosis of STEC-HUS, dialysis requirement, severe neurological complication (seizures, coma or brain infarction), invasive mechanical ventilation, patient referred with > 24 hours of hospitalization at the place of origin, estimated glomerular filtration rate (eGFR), hemoglobin, creatinine, urea, bloody diarrhea in the prodromal period, antibiotic requirement prior to day 0, expansion requirement prior to day 0. A stepwise selection of the variables was carried out by means of a logistic regression considering the arm (control, treatment) as a dependent variable and using an entry criterion of 0.8 and an output criterion of 0.3. The variables that remained in the model were finally used for calculating the propensity score. The greedy algorithm was used for the determination of the paired sample of 1:1 by the nearest similar neighbor (greedy nearest neighbor), considering a caliper equal to 0.2. Any imbalance was evaluated by the standardized mean difference (SMD). Covariates with SMD < 0.25 were considered as properly balanced. Safety, PK, and immunogenicity evaluations were performed on the SP. All efficacy analyses were performed on the MP. As a sensitivity analysis, time-to-event analysis was repeated with multiple imputations for missing data using predictive mean matching methods. Statistical analyses were performed using SAS® software version 9.4. 3. Results 3.1. Participants Fifty-seven and 125 patients were included in the treatment and control arm, respectively. Fifty-two patients in each arm were part of the MP. Patient disposition is shown in Fig. 3 . Ten patients were included in the PK sub-study, of which 8 received the two-dose regime and two the one-dose regime. Both arms of the MP were balanced in their demographic and most of their baseline clinical and laboratory parameters, except for a higher platelet count and a higher incidence of some prodromal symptoms in the treatment arm (Table 1 ). Demographic and baseline clinical characteristics of the SP, FAS, and PK population are presented in Supplementary Tables 1, 2 and 3. Table 1 Demographic and baseline characteristics of the subjects of the matched population Demographic and baseline characteristics Treatment arm (n = 52) Control arm (n = 52) Age (years), mean (SD) 2.6 (2.0) 2.9 (2.3) Female sex, n (%) 26 (50) 25 (48) Weight (kg), mean (SD) 15.2 (6.8) 15.9 (6.4) Height (cm), mean (SD) 95.1 (15.1) 96.5 (17.1) BMI (kg/m 2 ) mean (SD) 16.2 (2.4) 16.6 (2.0) Prodromal symptoms, n (%) Diarrhea 52 (100) 52 (100) Bloody diarrhea 41 (79) 42 (81) Abdominal pain 36 (69) 19 (37) Fever 24 (46) 19 (37) Vomiting 41 (79) 33 (58) Therapeutic management of prodromal symptoms, n (%) Pre-admission antibiotics 10 (19) 6 (12) Expansion 23 (44) 23 (44) Days from diarrhea onset to diagnosis, median (Q1:Q3) 5.0 (3.0:6.0) 4.0 (4.0:6.0) Baseline laboratory parameters, mean (SD) Creatinine (mg/dL) 2.4 (1.9) 2.7 (2.1) eGFR (ml/min/1.73 m 2 ) 27.6 (28.2) 26.3 (21.3) Urea (mg/dL) 126.0 (75.0) 136.0 (82.4) Leukocytes (10 9 /l) 18.1 (9.1) 18.5 (11.8) Neutrophils (%) 59.3 (11.6) 58.2 (12.3) Platelets (10 9 /l) 82.7 (57.9) 60.3 (37.5) Hemoglobin (g/dL) 9.2 (2.1) 9.2 (2.0) Hematocrit (%) 26.9 (6.1) 27.1 (5.7) LDH (ratio) a 9.2 (4.4) 9.7 (4.7) Sodium (mEq/l) 131.7 (4.7) 132.2 (5.2) Potassium (mEq/l) 4.3 (0.8) 4.2 (0.6) Bicarbonate (mEq/l) 15.8 (3.9) 15.9 (4.4) pH 7.3 (0.1) 7.3 (0.1) Neurological involvement, n (%) 12 (23) 12 (23) Somnolence 7 (14) 10 (19) Seizures 6 (12) 6 (12) Cardiovascular involvement, n (%) 3 (6) 2 (4) Hemodynamic instability 1 (2) 2 (4) Tachycardia 2 (4) 0 (0.0) Gastrointestinal involvement, n (%) 40 (77) 31 (60) Hemorrhagic colitis 3 (6) 2 (4) Ischemic colitis 1 (2) 0 (0.0) Increased liver enzymes b 40/48 (83) 31/43 (72) Ilium 2 (4) 0 (0.0) Gastrointestinal wall thickening 0 (0.0) 1 (2) Increased pancreatic enzymes 0 (0.0) 1 (2) Rectal prolapse 3 (6) 2 (4) Respiratory involvement, n (%) 4 (8) 2 (4) Pulmonary edema 0 (0) 1 (2) Invasive mechanical ventilation 2 (4) 1 (2) Tachypnoea 2 (4) 0 (0.0) Infectious involvement, n (%) 1 (2) 0 (0.0) Bacteremia 1 (2) 0 (0.0) a Lactate dehydrogenase (LDH) values were standardized according to the upper limit of normal of each center (LDH value / LDH upper limit of normal). b Percentages calculated on the evaluable patients (patients on whom liver enzymes were measured) SD , standard deviation; Q1 , first quartile; Q3 , third quartile; STEC-HUS , Shiga toxin-producing Escherichia coli hemolytic uremic syndrome; eGFR , estimated glomerular filtration rate; LDH , Lactate dehydrogenase All subjects except one complied with the assigned doses. This patient received a dose 5% less than expected due to an error in dose calculation. For both SP and MP, there was a mean (SD) of 0.7 (0.5) days between STEC-HUS diagnosis at the participating center and the first dose, and a mean (SD) of 5.6 (2.1) days between the start of diarrhea and the first dose. Therapeutic management of prodromal symptoms is shown in Table 1 . For the MP, on day 0, 45 (87%) and 49 (94%) patients presented the STEC-HUS triad in the treatment and control arm, respectively. Seven patients completed the triad over the first three days after diagnosis. Overall, 49 (94%) patients of the treatment arm and 52 (100%) patients of the control arm presented the complete triad, during the study. The three patients without thrombocytopenia, presented minimum platelet counts near the lower limit of normal. Forty-six (89%) and 44 (85%) patients had microbiological confirmation of STEC infection performed by local testing in the treatment and control arm, with serotype O157 being the most frequently detected, followed by O145 (Supplementary Table 4). Genotype stx 2 was the most frequently detected (Supplementary Table 4). After the determination of IgM by the central laboratory, microbiological confirmation reached 96% in the treatment arm. 3.2. Safety outcomes 3.2.1. Adverse events (AE) One hundred and three AE were reported in 38 of the 57 enrolled patients (Table 2 ; Supplementary Table 5). No AE resulted in study discontinuation, premature discontinuation of the infusion, or precluded administration of the second dose. In two cases, a reduction in infusion rate of the first dose was required due to the presence of hypotension in one case and vomiting in the other. In the first case, the patient had hemodynamic instability with inotropic requirement prior to INM004 infusion, and STEC-HUS was considered as an alternative cause for the hypotension event. In the second case, the patient already presented vomiting prior to the infusion, and STEC-HUS was also considered an alternative explanation for the vomiting during the infusion. Table 2 Overview of adverse events that occurred during the study Adverse events Safety population (n = 57) Total number of adverse events 103 Subjects with any adverse, n (%) 38 (67) Number of SAE 4 Subjects with any SAE, n (%) 4 (7) Number of related adverse events 8 Subjects with any related adverse event, n (%) 7 (12) Number of AESI 10 Subjects with any AESI, n (%) 6 (11) Number of adverse events with fatal outcome 0 Subjects with any adverse event with fatal outcome, n (%) 0 (0.0) SAE , serious adverse event; AESI , adverse event of special interest Four AE were classified as serious (Supplementary Table 6), and ten were AESI during the study (Supplementary Table 7). None of these events were considered related to INM004, except for one event of rash scarlatiniform (an AESI) assessed as possibly related to INM004, but which could also have been explained by a concomitant COVID infection during hospitalization. There were no cases of anaphylaxis or serum sickness. Of the total AE, eight were considered as possibly related to INM004 by the investigator, none of which was severe or serious, and seven had alternative possible causes (STEC-HUS, other medical conditions, and concomitant medications) (Supplementary Table 8). The DSMB concluded that INM004 showed an adequate safety profile. 3.2.2. Laboratory, vital signs and electrocardiographic finding No clinically significant abnormalities were found in the laboratory parameters, ECG, or vital signs after the first or second dose of INM004 administration compared to pre-administration of INM004 first dose. None of the patients presented QT/QTc interval prolongation after INM004 administration. 3.3. PK outcomes The median (range) C max was 58298.3 (30724.4–84217.4) ng/ml for the two-dose regime, and 56661.4 (46399.4–66923.5) ng/ml for the one-dose regime. Median t 1/2 (range) was 40.6 (31.5–75.1) hours and 56.4 (40.1–72.6) hours for two and one-dose regimens, respectively. All PK parameters are summarized in Supplementary Table 9. Plasma concentration of INM004 as a function of time for both dose regimens is shown in Supplementary Fig. 1. 3.4. Efficacy outcomes 3.4.1. Primary efficacy outcome The median number of dialysis days was four in the treatment arm and six in the control arm (Table 3 ). This non-statistically significant difference of two days was also observed when only patients who received dialysis were considered (Table 3 ). Table 3 Efficacy outcomes – Matched population Efficacy outcomes Treatment arm (n = 52) Control arm (n = 52) p-value Dialysis requirement, n (%) 29 (56) 35 (67) 0.23 Dialysis days in all patients a , median (Q1:Q3) 4.0 (0.0:9.0) 6.0 (0.0:11.5) 0.43 Dialysis days only in patients who required dialysis, median (Q1:Q3) 8.0 (5.0:16.0) 10.0 (6.0:14.0) 0.95 Dialysis duration in classes, n (%) 0.44 0 days 23 (44) 17 (33) - 1–10 days 19 (37) 21 (40) - > 10 days 10 (19) 14 (27) - Dialysis duration dichotomic, n (%) 0.35 ≤ 10 days 42 (81) 38 (73) - > 10 days 10 (19) 14 (27) - Dialysis requirement after Day 0 b , n (%) 15 (40) 23 (58) 0.11 Anuria, n (%) 25 (48) 31 (60) 0.24 Anuria days in all patients, median (Q1:Q3) 9.0 (6.0:12.0) 9.0 (6.0 :12.0) 0.88 Anuria after Day 0 b , n (%) 6 (18) 9 (30) 0.27 Hypertension with medication requirement on Day 28, n (%) 6 (14) 7 (17) 0.81 Hospitalization days, median (Q1:Q3) 11.0 (7.0 :18.5) 13.5 (6.0 :19.5) 0.93 Hematuria on day 28 c , n (%) Detected 14 (27) 1 (2) - Not detected 25 (48) 3 (6) - Missing 13 (25) 48 (92) - Proteinuria at day 28 c , n (%) Detected 18 (35) 3 (6) - Not detected 24 (46) 3 (6) - Missing 10 (19) 46 (89) - a For patients without dialysis during the study, a value of zero dialysis day was imputed b Day 0 is the day of diagnosis of Shiga toxin-producing Escherichia coli -associated hemolytic uremic syndrome (STEC-HUS) in the participating site c Results were not compared between arms due to the high number of missing values in the control arm. Q1 , first quartile; Q3 , third quartile 3.4.2. Secondary efficacy outcomes There was a trend towards a lower number of patients needing dialysis in the treatment compared with the control arm (RR = 0.83; 95% CI: 0.61–1.13) (Table 3 ). Similar trends were observed for the need for dialysis for more than ten days (RR = 0.69; 95% CI: 0.43–1.10), the requirement of dialysis after day 0 (RR = 0.71; 95% CI: 0.35–1.46), the occurrence of anuria: (RR = 0.81; 95% CI = 0.56–1.16), and the onset of anuria after day 0 (RR = 0.61; 95% CI = 0.25–1.50) (Table 3 ). The evolution of creatinine showed a similar pattern in both arms, with values that were overall lower in the treatment arm (Fig. 4 , Supplementary Table 10). eGFR showed an increase during the follow-up period in both arms, which started at day 1 and day 3 for the treatment and control arms, respectively, and was overall higher in the treatment arm (Fig. 4 , Supplementary Table 10). When the time to kidney function recovery was compared between arms, the treatment arm showed a trend toward a shorter time to recovery (HR = 1.83; 95% CI: 0.95–3.50) (Fig. 5 ). No differences were observed in the number of patients in each group who presented hypertension requiring medication on Day 28 (Table 3 ). Presence of hematuria and proteinuria at day 28 are presented in Table 3 . No comparison between arms were made for these variables due to the high number of missing data in the control arm. All patients in both groups achieved platelet counts > 150 x 10 9 /L during the study follow-up period (Fig. 4 ; Supplementary Table 10), with a median time to recovery of 7 (95% CI = 7.0–8.0) days for the treatment group and 9 (95% CI = 8.0–11.0) days for the control group (HR = 1.26; 95% CI = 0.84–1.88). Evolution of hemoglobin is shown in Fig. 4 and Supplementary Table 10. No differences between arms were observed in LDH values during the study (Supplementary Table 10). A similar number of patients required red blood cell transfusions (89% and 87% in the treatment and control arms, respectively) (Supplementary Table 11). A low incidence of neurological, cardiovascular, and gastrointestinal events was observed in both arms after day 0 (Supplementary Table 11). No significant differences were observed in the occurrence of severe extrarenal events (convulsions, cerebral infarction, coma, hemodynamic instability, myocardial failure, myocarditis, hemorrhagic colitis, ischemic colitis, pancreatitis, respiratory distress syndrome, or requirement of mechanical ventilatory assistance for more than 24 hours), with eight patients in the treatment arm and ten in the control arm presenting at least one of these events after day 0 (Supplementary Table 12). No differences between arms were observed in hospitalization length (Table 3 ). No patients in the treatment arm died, and one death was recorded in the control arm. 3.4.3. Sensitivity analyses A similar trend to that of the primary analysis was observed in time to kidney function recovery in the analysis performed with multiple imputations (HR = 1.71; 95% CI = 0.86–3.39). 3.5. Immunogenicity On Day 28, none of the 57 treated patients showed specific reactivity against INM004. 4. Discussion This Phase 2 study aimed to explore the safety, PK profile and efficacy of INM004, a novel therapy for the treatment of STEC-HUS. Its results were expected to provide the first insights on the use of INM004 in pediatric patients with STEC-HUS and to serve as the basis for the design of the Phase 3 study. This study showed that INM004 is a safe therapy for STEC-HUS affected children. INM004 infusions were well tolerated with an adequate benefit/risk profile. There was no evidence of site injection reactions, anaphylaxis, or other severe hypersensitivity reactions associated with INM004 administration. None of the subjects developed symptoms compatible with serum sickness, and no immunogenicity was detected in any of the 57 treated subjects. Overall, safety and immunogenicity findings were consistent with those of phase 1 [ 11 ]. Previously, Inmunova had tested similar equine F(ab´) 2 fragments anti-SARS-Cov-2-RBD (CoviFab®) that showed a safety profile as good as that reported in the present study [ 17 , 18 ]. In the PK sub-study, INM004 showed a profile similar to the one expected, according to the simulated values for pediatric patients with different weights obtained from an allometric calculation based on data from healthy adult volunteers from Phase 1. Two doses of INM004 4 mg/kg separated by 24 hours showed adequate INM004 blood concentrations during five days without significant accumulation despite kidney impairment, as expected for molecules that are not eliminated by renal clearance. Regarding efficacy, this study showed non-statistically significant trends toward a beneficial effect in several efficacy outcomes related to kidney involvement, including dialysis requirement. These findings might be interpreted as a potential effect of INM004 in the prevention of dialysis or prolonged dialysis. Moreover, a shorter time to kidney function recovery (measured through eGFR recovery) was observed in the treatment compared to the control arm. Altogether, these results could be considered as evidence of less kidney injury in patients treated with INM004. Data from observational studies have shown that the requirement of dialysis and its duration, as well as the presence and duration of anuria, are predictors of kidney sequelae in patients with STEC-HUS [ 19 – 22 ]. Additionally, several studies conducted in pediatric and adult populations with AKI showed that its severity and duration are predictors of evolution to CKD [ 23 – 26 ]. During the early stage of STEC-HUS circulating Stx is expected to still be present in the bloodstream. Therefore, even when the disease cannot be prevented, it is hypothesized that Stx neutralization by INM004 can ameliorate kidney injury and reduce acute and long-term morbidity. Regarding extrarenal outcomes, no clinical effect was observed in the present study in hematological parameters and in the incidence of severe clinical events affecting other target organs, but those were of low incidence. When present, most extrarenal events were ongoing on the day of STEC-HUS diagnosis before INM004 administration. The main limitation of this study was the non-randomized design, which allowed for the treatment of a considerable number of patients in a short period, but it could have also been a source of bias. To minimize selection bias, measures were adopted in both the study design (same centers, same seasonal period for enrollment, same eligibility criteria and same SoC for the treatment and the control arm; systematic review of clinical registers for the inclusion of subjects of the control arm) and the statistical analysis (propensity score matching procedure). To address the potential bias introduced by the unblinded design, objective variables were selected as efficacy endpoints. Due to the possibility of attrition bias, as data of the control arm was limited to clinical chart reports, a sensitivity analysis with imputation of missing data was performed for time-to-kidney function recovery. Results were concordant with those of the primary analysis. Additionally, the presence of a higher number of patients with prodromal symptoms and more patients having received antibiotics for the treatment of the prodromal phase in the treatment arm, could be explained by an under-registration of these variables in the control arm. Another limitation was related to the time of the intervention with INM004. Due to its proposed mechanism of action, the prodromic phase (i.e., patients with STEC associated diarrhea) might be the optimal moment to initiate treatment with this product. However, in Argentina, most patients with diarrhea caused by STEC attend health centers of low complexity or are ambulatory managed. Patients are hospitalized at highly complex centers when HUS is already established. For this reason, this study was planned to assess the potential therapeutic effect of INM004 in patients as soon as possible when diagnosis of STEC-HUS was established, with at least two of the three components of the HUS triad. Regarding the PK profile of INM004, the present study provided adequate and relevant information. However, most of the patients studied were under four years, and the results might not be generalizable to the entire pediatric population. This limitation should be addressed in a Phase 3 study, in which the characterization of INM004 is planned to be continued. Finally, as enrollment was lower than expected, it is possible that some potential AE of low incidence (below 1.5%) were not detected. The enrolled sample of 57 subjects yielded a power of 58% to detect AE with this low frequency. As a phase 3 trial with a larger sample size is planned as part of the clinical development of INM004, it will allow us to identify additional events in the case they occur. In conclusion, this study showed that INM004 can be safely administered to pediatric patients with STEC-HUS and allowed the obtention of PK data that confirmed that the planned regime of 2 doses of 4 mg/kg is adequate in this population. The study also showed trends regarding the amelioration of kidney impairment during the acute phase of STEC-HUS. The presented results would allow us to move forward to a Phase 3 study to evaluate the efficacy of INM004 in the treatment of STEC-HUS. Declarations Acknowledgments We acknowledge the members of the DSMB: Dr. Vanesa Castellano, Dr. Esteban Nannini, Dr. Tomás Orduna, Dr. Jorge Ferraris, Dr. Raquel Wainsztein. Author contribution Fernando Goldbaum, Linus Spatz, Santiago Sanguineti, Mariana Colonna Ian Roubicek, Carolina Massa, Marta Rivas, Mariana Pichel and Vanesa Zylberman contributed to the study conception and design. Material preparation and data collection were performed by Alicia Fayad, Iliana Principi, Alejandro Balestracci, Laura Alconcher, Paula Coccia, Marta Adragna, Oscar Amoreo, María Carolina Bettendorff, María Valeria Blumetti, Pablo Bonany, María Laura Flores Tonfi, Luis Flynn, Lidia Ghezzi, Jorge Montero, Flavia Ramírez, Claudia Seminara, Ángela Suarez, and Ana Paula Spizirri. The first draft of the manuscript was written by Carolina Massa, Marina Valerio, Fernando Goldbaum and Ian Roubicek. Alicia Fayad, Iliana Principi, Alejandro Balestracci, Laura Alconcher and Paula Coccia commented on previous versions of the manuscript. All authors read and approved the final manuscript. Ethics approval: This trial was performed following the principles of the Declaration of Helsinki and Good Clinical Practice. The protocol was approved by the local Ethics Committees and the Argentine National Food and Drug Regulatory Agency (ANMAT). Conflict of interests: AF, IP, AB, LA, PC, MA, OA, MCB, MVB, PB, MLFT, LF, LG, JM, FR, CS, AS and APS declare reimbursement for conduction of clinical trial as investigator of the study. MR, MP, VZ, LS, CM, MV, SS, MC, IR and FG report personal fees from Inmunova S.A. Funding: Inmunova S.A. References Boyer O, Niaudet P (2022) Hemolytic-Uremic Syndrome in Children. Pediatr Clin North Am 69:1181–1197. https://doi.org/10.1016/j.pcl.2022.07.006 Fakhouri F, Zuber J, Frémeaux-Bacchi V, Loirat C (2017) Haemolytic uraemic syndrome. Lancet 390:681–696. https://doi.org/10.1016/S0140-6736(17)30062-4 Bruyand M, Mariani-Kurkdjian P, Gouali M et al (2018) Hemolytic uremic syndrome due to Shiga toxin-producing Escherichia coli infection. Médecine Mal Infect 48:167–174. https://doi.org/10.1016/j.medmal.2017.09.012 Ylinen E, Salmenlinna S, Halkilahti J et al (2020) Hemolytic uremic syndrome caused by Shiga toxin–producing Escherichia coli in children: incidence, risk factors, and clinical outcome. 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EClinicalMedicine 34:100843. https://doi.org/10.1016/j.eclinm.2021.100843 Farizano Salazar DH, Achinelli F, Colonna M et al (2022) Safety and effectiveness of RBD-specific polyclonal equine F(ab´)2 fragments for the treatment of hospitalized patients with severe Covid-19 disease: A retrospective cohort study. PLoS ONE 17:e0274796. https://doi.org/10.1371/journal.pone.0274796 Spizzirri FD, Rahman RC, Bibiloni N et al (1997) Childhood hemolytic uremic syndrome in Argentina: long-term follow-up and prognostic features. Pediatr Nephrol 11:156–160. https://doi.org/10.1007/s004670050248 Garg AX, Suri RS, Barrowman N et al (2003) Long-term Renal Prognosis of Diarrhea-Associated Hemolytic Uremic Syndrome: A Systematic Review, Meta-analysis, and Meta-regression. JAMA 290:1360. https://doi.org/10.1001/jama.290.10.1360 Loos S, Aulbert W, Hoppe B et al (2017) Intermediate Follow-up of Pediatric Patients With Hemolytic Uremic Syndrome During the 2011 Outbreak Caused by E. coli O104:H4. Clin Infect Dis 64:1637–1643. https://doi.org/10.1093/cid/cix218 Oakes RS, Kirkhamm JK, Nelson RD, Siegler RL (2008) Duration of oliguria and anuria as predictors of chronic renal-related sequelae in post-diarrheal hemolytic uremic syndrome. Pediatr Nephrol 23:1303–1308. https://doi.org/10.1007/s00467-008-0799-9 Ulrich EH, Hessey E, Perreault S et al (2022) Association of Nonrecovery of Kidney Function After Pediatric Acute Kidney Injury With 5-Year Kidney and Nonkidney Outcomes. Crit Care Explor 4:e0614. https://doi.org/10.1097/CCE.0000000000000614 Hessey E, Perreault S, Dorais M et al (2019) Acute Kidney Injury in Critically Ill Children and Subsequent Chronic Kidney Disease. Can J Kidney Health Dis 6:205435811988018. https://doi.org/10.1177/2054358119880188 Kellum JA, Sileanu FE, Bihorac A et al (2017) Recovery after Acute Kidney Injury. Am J Respir Crit Care Med 195:784–791. https://doi.org/10.1164/rccm.201604-0799OC See EJ, Jayasinghe K, Glassford N et al (2019) Long-term risk of adverse outcomes after acute kidney injury: a systematic review and meta-analysis of cohort studies using consensus definitions of exposure. Kidney Int 95:160–172. https://doi.org/10.1016/j.kint.2018.08.036 Supplementary Files Graphicalabstract.pptx SupplementalMaterialPN.pdf Cite Share Download PDF Status: Published Journal Publication published 12 Nov, 2024 Read the published version in Pediatric Nephrology → Version 1 posted Editorial decision: Major Revisions Needed 20 Aug, 2024 Reviewers agreed at journal 18 Jul, 2024 Reviewers invited by journal 18 Jul, 2024 Editor assigned by journal 17 Jul, 2024 First submitted to journal 16 Jul, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Study design. \u003cstrong\u003eb.\u003c/strong\u003e Visit schedule, procedures, and microbiological diagnosis\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4751636/v1/5f0cb43be557260e7b5d6333.jpeg"},{"id":63054306,"identity":"e2588707-ed04-49f7-aef7-2f6d76a7b64a","added_by":"auto","created_at":"2024-08-22 14:50:17","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":629698,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eStudy outcomes. \u003c/strong\u003e\u003csup\u003ea\u003c/sup\u003eeGFR lower limit of normal for each subject was estimated with the Bedside Schwartz equation\u003csup\u003e \u003c/sup\u003e[15], using the serum creatinine upper limit of normal for age and sex reported by Chuang et al. (2021) [16].\u003cstrong\u003e \u003c/strong\u003e\u003cem\u003eTMA\u003c/em\u003e, thrombotic microangiopathy; \u003cem\u003eeGFR\u003c/em\u003e, estimated glomerular filtration rate; \u003cem\u003esCr\u003c/em\u003e, serum creatinine; \u003cem\u003eLDH\u003c/em\u003e, lactate dehydrogenase; \u003cem\u003eLLN\u003c/em\u003e, lower limit of normal.\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4751636/v1/4e61e01d5361b3a4cf906b23.jpeg"},{"id":63054308,"identity":"e49ca39e-8adc-450d-adda-b5eb2262974b","added_by":"auto","created_at":"2024-08-22 14:50:17","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":185131,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eParticipant disposition. \u003c/strong\u003e\u003cem\u003eFAS\u003c/em\u003e, full analysis set; \u003cem\u003eMP\u003c/em\u003e, matched population; \u003cem\u003eSP\u003c/em\u003e, safety population.\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4751636/v1/67aad338c7fba6c4b48fddcb.jpeg"},{"id":63055259,"identity":"ad2e6549-6bff-41ac-abd2-4b947d2404b2","added_by":"auto","created_at":"2024-08-22 14:58:17","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":268422,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eLaboratory parameters of the thrombotic microangiopathy during the entire follow-up period – Matched population. a. \u003c/strong\u003eCreatinine;\u003cstrong\u003e b. \u003c/strong\u003eeGFR; \u003cstrong\u003ec.\u003c/strong\u003e Hemoglobin; \u003cstrong\u003ed.\u003c/strong\u003e Platelets. \u003cem\u003eeGFR\u003c/em\u003e, estimated glomerular filtration rate.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-4751636/v1/a114e5f8e4f32f859d6679f6.png"},{"id":63054311,"identity":"1bb6d706-aa3f-4c82-ba1f-d1df81f3ed49","added_by":"auto","created_at":"2024-08-22 14:50:17","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":73926,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eKaplan-Meier cumulative incidence of glomerular filtration rate recovery during the follow-up period. \u003c/strong\u003e\u003cem\u003eGFR\u003c/em\u003e, glomerular filtration rate; \u003cem\u003eLLN\u003c/em\u003e, lower limit of normal\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-4751636/v1/6ad1a7c92a77c14acba74333.png"},{"id":69285070,"identity":"9cf1a9d2-4d0d-41e5-913f-246e831850a6","added_by":"auto","created_at":"2024-11-18 19:23:41","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2473072,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4751636/v1/81bf2b15-00ca-4881-8ce7-bffd395214bb.pdf"},{"id":63054305,"identity":"3d23367e-619f-4923-947a-3e31de8ae318","added_by":"auto","created_at":"2024-08-22 14:50:17","extension":"pptx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":116843,"visible":true,"origin":"","legend":"","description":"","filename":"Graphicalabstract.pptx","url":"https://assets-eu.researchsquare.com/files/rs-4751636/v1/619d3b62e66b157993c1a50d.pptx"},{"id":63055260,"identity":"4c3b242f-1305-4e98-b2c6-e94d94e44983","added_by":"auto","created_at":"2024-08-22 14:58:17","extension":"pdf","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":512481,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementalMaterialPN.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4751636/v1/be7963338b7d8fc9d017f2eb.pdf"}],"financialInterests":"","formattedTitle":"\u003cp\u003eOpen-label, controlled, phase 2 clinical trial assessing the safety, efficacy, and pharmacokinetics of INM004 in pediatric patients with Shiga toxin-producing \u003cem\u003eEscherichia coli\u003c/em\u003e-associated hemolytic uremic syndrome\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eShiga toxin (Stx)-producing \u003cem\u003eEscherichia coli\u003c/em\u003e-associated hemolytic uremic syndrome (STEC-HUS) is a form of thrombotic microangiopathy (TMA) characterized by the triad of hemolytic anemia, thrombocytopenia, and acute kidney injury (AKI) [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. It is one of the leading causes of AKI in pediatric population and a relevant contributor to the development of chronic kidney disease (CKD) [\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Approximately 60% of patients require dialysis during the acute phase of the disease [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], and the mortality rate is around 3% [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Children under five are the most affected group [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. In Argentina, STEC-HUS is endemic and exhibits the highest incidence globally [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSTEC-HUS remains an orphan disease without an established treatment. INM004 is a novel therapy composed of F(ab\u0026acute;)\u003csub\u003e2\u003c/sub\u003e fragments from equine immunoglobulins that efficiently neutralize Stx [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. These antibodies were raised by immunizing horses with two chimeric protein particles that stabilizes the B subunit of Stx1 and Stx2 in their native conformation and exposes their Gb3-binding sites. Thus, the elicited antibodies would have a strong capacity for blocking the entrance of Stx to their target cells [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. In a phase 1 placebo-controlled trial, INM004 was well-tolerated and was not associated with serious or severe adverse events (AE) in healthy volunteers [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Similarly, INM004 showed good tolerance in 11 pediatric patients with Stx-positive bloody diarrhea in a phase 2/3 study for the prevention of STEC-HUS which was early terminated during the COVID-19 pandemic (NCT04132375).\u003c/p\u003e \u003cp\u003eThe primary objective of this phase 2 study was to assess the safety, efficacy, and pharmacokinetics (PK) of INM004 in pediatric patients with STEC-HUS. The proposed mechanism of action of INM004 is the neutralization of Stx in the bloodstream to block the interaction with its receptor in the target organs. The findings of this investigation aim to provide insights into the safety and therapeutic potential of INM004, in view of a future phase 3 trial.\u003c/p\u003e"},{"header":"2. Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Study design and participants\u003c/h2\u003e \u003cp\u003eA multicenter phase 2, open-label clinical trial of INM004 with an historical control arm, was performed in 16 reference hospitals across Argentina. Eligible subjects were hospitalized patients with STEC-HUS. The study design is detailed in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003ePatients of the treatment arm received INM004 in addition to standard of care (SoC) treatment for STEC-HUS, and the control arm only received SoC. Overall, SoC for pediatric STEC-HUS patients was consistent between participant centers in Argentina, following specific guidelines for its management [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Patients of the control arm were retrospectively selected by a review of all medical charts of patients hospitalized during the recruitment period for this group (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The evaluation of the PK of INM004 was part of a sub-study conducted in a subsample of the treatment arm (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThis study was prospectively registered in clinicaltrials.gov (NCT05569746). Written informed consent was provided by legal guardians of all subjects of the treatment arm. Assent of children was obtained as applicable.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Inclusion and exclusion criteria\u003c/h2\u003e \u003cp\u003eThe same inclusion and exclusion criteria applied for both arms, except for two specific criteria related to the safety of subjects receiving an experimental treatment. In other to include patients as early as possible after STEC-HUS onset, subjects were eligible for their inclusion with two of three components of the diagnostic HUS triad: signs of kidney injury and at least one of the two hematological signs of the TMA (i.e., hemolysis and/or platelet consumption). Kidney injury was defined by sCr above the upper limit of normal (ULN) for age and sex or hematuria (\u0026ge;\u0026thinsp;5 red blood cells per field or \u0026ge;\u0026thinsp;27 red blood cells/\u0026micro;l in the urinary sediment); hemolysis was defined by lactate dehydrogenase (LDH) above the ULN for age or presence of schistocytes in the peripheral blood smear; platelet consumption was defined by a platelet count\u0026thinsp;\u0026lt;\u0026thinsp;150 x 10\u003csup\u003e9\u003c/sup\u003e/L or decrease of \u0026ge;\u0026thinsp;50% in the platelet count within the previous 24 hours. Other inclusion criteria were age between 1 and 12 years old; history of diarrhea with onset within the 13 days prior to the diagnosis of the STEC-HUS in the participating institution; a negative pregnancy test in subjects of the treatment arm who had had menarche.\u003c/p\u003e \u003cp\u003ePatients were excluded from the study if they met any of the following criteria. Dialysis for more than 48 hours at the time of diagnosis of the STEC-HUS in the participating institution; history of chronic/recurrent hemolytic anemia, thrombocytopenia, or CKD; personal or family history of atypical HUS; suspicion of HUS secondary to infectious processes other than gastrointestinal; evidence of clinically significant chronic disease whose symptoms may have interfered with the treatment or diagnosis of STEC-HUS, at the discretion of the investigator; pregnant or breastfeeding subjects; participation in a clinical trial simultaneously or in the previous three months. For the treatment arm, an additional exclusion criterion was the history of anaphylaxis or previous administration of equine serum, or allergic reaction to horse exposure.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Procedures\u003c/h2\u003e \u003cp\u003eThis study assessed two regimens of one- or two-dose of 4 mg/kg of INM004 administered as intravenous infusions during 50 minutes (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). While most patients were included in the two-dose regimen, the one-dose regimen was only aimed at assessing PK in a small part of the sample. Study visits were performed for all subjects on the day of diagnosis of STEC-HUS in the participating site (day 0) and on days 1, 2, 3, 4, 7,14, 21, and 28. Hospital discharge was determined by the attending physician according to SoC, and in those cases assessments had to continue as outpatient visits. For outpatients, visits on days 14 and 21 could be done by phone. Assessments at each visit are described in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. A 12-lead electrocardiogram (ECG) was performed in patients of the treatment arm at baseline and 24 h after the second dose. Microbiological confirmation of STEC infection was performed by SoC procedures at each site for both arms (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Additionally, IgM antibodies against \u003cem\u003eEscherichia coli\u003c/em\u003e O157, O145, O121 and O103 in serum were determined in a central laboratory using commercial Chemtest\u0026reg; kits (CHEMLIS\u0026reg; E. coli Combi Glyco-iELISA) for patients of the treatment arm.\u003c/p\u003e \u003cp\u003eSafety and tolerability were assessed by the Data Safety Monitoring Board (DSMB) by monitoring AE and AE of special interest (AESI) (i.e., injection site reactions and hypersensitivity reactions), laboratory values, vital signs, physical examination, and ECG. AE were coded using MedDRA version 25.1.\u003c/p\u003e \u003cp\u003ePK samples were collected at 6 different time points (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Concentrations of INM004 were determined by ELISA [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Immunogenicity was evaluated by the presence of anti-product antibodies by ELISA in blood samples obtained at days 0 and 28 [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4. Outcomes\u003c/h2\u003e \u003cp\u003ePrimary and secondary outcomes are detailed in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5. Sample size considerations\u003c/h2\u003e \u003cp\u003eThe study aimed to evaluate the safety and PK of INM004 and provide exploratory insights into efficacy to guide the design of a Phase 3 trial. One hundred patients were expected to be recruited during one warm season in the treatment arm and 200 eligible subjects were expected for the control arm. This sample size was expected to yield a power of 78% to detect AE with an incidence of 1.5%, and a power of 80% to detect a 50% difference in the primary efficacy outcome. The PK sub-study was planned to include 18 patients (12 and six receiving the two and one-dose regimen, respectively).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.6. Statistical analysis\u003c/h2\u003e \u003cp\u003eCategorical variables were described using absolute frequencies and percentages, and quantitative variables were summarized using mean and standard deviation (SD) or median and interquartile range or range. Chi-square test or Fisher's exact test were applied to compare categorical variables, and regression linear models were used to compare quantitative variables between the treatment and control arms. The variable dialysis days was analyzed using a negative binomial regression model to consider the overdispersion of zeros. Cox's proportional hazards regression model was used to estimate the hazard ratio (HR) for time-to-event variables. Due to the exploratory nature of the study, no adjustments were made for multiple comparisons.\u003c/p\u003e \u003cp\u003eSafety analyses were descriptive. The estimation of PK parameters by non-compartmental analysis (NCA) methods was performed using Phoenix WinNonlin software (version 8.3, Certara USA, Inc., USA).\u003c/p\u003e \u003cp\u003eThe following sets were considered for the different outcomes. Full analysis set (FAS): all subjects of the treatment arm who received at least one dose of INM004 and all subjects of the control arm; safety population (SP): all subjects from the treatment arm who received at least one dose of INM004; matched population (MP): FAS subjects selected using the propensity score matching procedure (PROC PSMATCH, SAS 9.4), to address potential selection bias. A propensity score matching procedure (PROC PSMATCH, SAS 9.4) was used to generate a sample matched on its baseline characteristics. The following variables at the day of diagnosis of STEC-HUS (day 0) were pre-established for the calculation of the propensity score: age, sex, days from onset of diarrhea to diagnosis of STEC-HUS, dialysis requirement, severe neurological complication (seizures, coma or brain infarction), invasive mechanical ventilation, patient referred with \u0026gt;\u0026thinsp;24 hours of hospitalization at the place of origin, estimated glomerular filtration rate (eGFR), hemoglobin, creatinine, urea, bloody diarrhea in the prodromal period, antibiotic requirement prior to day 0, expansion requirement prior to day 0. A stepwise selection of the variables was carried out by means of a logistic regression considering the arm (control, treatment) as a dependent variable and using an entry criterion of 0.8 and an output criterion of 0.3. The variables that remained in the model were finally used for calculating the propensity score. The greedy algorithm was used for the determination of the paired sample of 1:1 by the nearest similar neighbor (greedy nearest neighbor), considering a caliper equal to 0.2. Any imbalance was evaluated by the standardized mean difference (SMD). Covariates with SMD\u0026thinsp;\u0026lt;\u0026thinsp;0.25 were considered as properly balanced.\u003c/p\u003e \u003cp\u003eSafety, PK, and immunogenicity evaluations were performed on the SP. All efficacy analyses were performed on the MP. As a sensitivity analysis, time-to-event analysis was repeated with multiple imputations for missing data using predictive mean matching methods. Statistical analyses were performed using SAS\u0026reg; software version 9.4.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.1. Participants\u003c/h2\u003e \u003cp\u003eFifty-seven and 125 patients were included in the treatment and control arm, respectively. Fifty-two patients in each arm were part of the MP. Patient disposition is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. Ten patients were included in the PK sub-study, of which 8 received the two-dose regime and two the one-dose regime. Both arms of the MP were balanced in their demographic and most of their baseline clinical and laboratory parameters, except for a higher platelet count and a higher incidence of some prodromal symptoms in the treatment arm (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Demographic and baseline clinical characteristics of the SP, FAS, and PK population are presented in Supplementary Tables\u0026nbsp;1, 2 and 3.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDemographic and baseline characteristics of the subjects of the matched population\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDemographic and baseline characteristics\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTreatment arm\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;52)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eControl arm\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;52)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years), \u003cem\u003emean (SD)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.6 (2.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.9 (2.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale sex, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26 (50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e25 (48)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWeight (kg), \u003cem\u003emean (SD)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15.2 (6.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15.9 (6.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHeight (cm), \u003cem\u003emean (SD)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e95.1 (15.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e96.5 (17.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e) \u003cem\u003emean (SD)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16.2 (2.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16.6 (2.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProdromal symptoms, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiarrhea\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e52 (100)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e52 (100)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBloody diarrhea\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e41 (79)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e42 (81)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAbdominal pain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e36 (69)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19 (37)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFever\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24 (46)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19 (37)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVomiting\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e41 (79)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e33 (58)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTherapeutic management of prodromal symptoms, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePre-admission antibiotics\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10 (19)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (12)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eExpansion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23 (44)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23 (44)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDays from diarrhea onset to diagnosis, \u003cem\u003emedian (Q1:Q3)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.0 (3.0:6.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.0 (4.0:6.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBaseline laboratory parameters, \u003cem\u003emean (SD)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCreatinine (mg/dL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.4 (1.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.7 (2.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eeGFR (ml/min/1.73 m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e27.6 (28.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e26.3 (21.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUrea (mg/dL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e126.0 (75.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e136.0 (82.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLeukocytes (10\u003csup\u003e9\u003c/sup\u003e/l)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18.1 (9.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18.5 (11.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNeutrophils (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e59.3 (11.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e58.2 (12.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePlatelets (10\u003csup\u003e9\u003c/sup\u003e/l)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e82.7 (57.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e60.3 (37.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHemoglobin (g/dL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9.2 (2.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9.2 (2.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHematocrit (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26.9 (6.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e27.1 (5.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLDH (ratio)\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9.2 (4.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9.7 (4.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSodium (mEq/l)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e131.7 (4.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e132.2 (5.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePotassium (mEq/l)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.3 (0.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.2 (0.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBicarbonate (mEq/l)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15.8 (3.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15.9 (4.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003epH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.3 (0.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.3 (0.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNeurological involvement, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (23)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12 (23)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSomnolence\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7 (14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10 (19)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSeizures\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (12)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCardiovascular involvement, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHemodynamic instability\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTachycardia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGastrointestinal involvement, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e40 (77)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e31 (60)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHemorrhagic colitis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIschemic colitis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIncreased liver enzymes\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e40/48 (83)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e31/43 (72)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIlium\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGastrointestinal wall thickening\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIncreased pancreatic enzymes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRectal prolapse\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRespiratory involvement, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePulmonary edema\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0 (0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInvasive mechanical ventilation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTachypnoea\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInfectious involvement, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBacteremia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003e\u003csup\u003ea\u003c/sup\u003eLactate dehydrogenase (LDH) values were standardized according to the upper limit of normal of each center (LDH value / LDH upper limit of normal).\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003e\u003csup\u003eb\u003c/sup\u003ePercentages calculated on the evaluable patients (patients on whom liver enzymes were measured)\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003e\u003cem\u003eSD\u003c/em\u003e, standard deviation; \u003cem\u003eQ1\u003c/em\u003e, first quartile; \u003cem\u003eQ3\u003c/em\u003e, third quartile; \u003cem\u003eSTEC-HUS\u003c/em\u003e, Shiga toxin-producing \u003cem\u003eEscherichia coli\u003c/em\u003e hemolytic uremic syndrome; \u003cem\u003eeGFR\u003c/em\u003e, estimated glomerular filtration rate; \u003cem\u003eLDH\u003c/em\u003e, Lactate dehydrogenase\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAll subjects except one complied with the assigned doses. This patient received a dose 5% less than expected due to an error in dose calculation. For both SP and MP, there was a mean (SD) of 0.7 (0.5) days between STEC-HUS diagnosis at the participating center and the first dose, and a mean (SD) of 5.6 (2.1) days between the start of diarrhea and the first dose. Therapeutic management of prodromal symptoms is shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eFor the MP, on day 0, 45 (87%) and 49 (94%) patients presented the STEC-HUS triad in the treatment and control arm, respectively. Seven patients completed the triad over the first three days after diagnosis. Overall, 49 (94%) patients of the treatment arm and 52 (100%) patients of the control arm presented the complete triad, during the study. The three patients without thrombocytopenia, presented minimum platelet counts near the lower limit of normal. Forty-six (89%) and 44 (85%) patients had microbiological confirmation of STEC infection performed by local testing in the treatment and control arm, with serotype O157 being the most frequently detected, followed by O145 (Supplementary Table\u0026nbsp;4). Genotype \u003cem\u003estx\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e was the most frequently detected (Supplementary Table\u0026nbsp;4). After the determination of IgM by the central laboratory, microbiological confirmation reached 96% in the treatment arm.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Safety outcomes\u003c/h2\u003e \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e \u003ch2\u003e3.2.1. Adverse events (AE)\u003c/h2\u003e \u003cp\u003eOne hundred and three AE were reported in 38 of the 57 enrolled patients (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e; Supplementary Table\u0026nbsp;5). No AE resulted in study discontinuation, premature discontinuation of the infusion, or precluded administration of the second dose. In two cases, a reduction in infusion rate of the first dose was required due to the presence of hypotension in one case and vomiting in the other. In the first case, the patient had hemodynamic instability with inotropic requirement prior to INM004 infusion, and STEC-HUS was considered as an alternative cause for the hypotension event. In the second case, the patient already presented vomiting prior to the infusion, and STEC-HUS was also considered an alternative explanation for the vomiting during the infusion.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eOverview of adverse events that occurred during the study\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAdverse events\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSafety population\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;57)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal number of adverse events\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e103\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSubjects with any adverse, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e38 (67)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of SAE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSubjects with any SAE, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of related adverse events\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSubjects with any related adverse event, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7 (12)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of AESI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSubjects with any AESI, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (11)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of adverse events with fatal outcome\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSubjects with any adverse event with fatal outcome, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"2\"\u003e\u003cem\u003eSAE\u003c/em\u003e, serious adverse event; \u003cem\u003eAESI\u003c/em\u003e, adverse event of special interest\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eFour AE were classified as serious (Supplementary Table\u0026nbsp;6), and ten were AESI during the study (Supplementary Table\u0026nbsp;7). None of these events were considered related to INM004, except for one event of rash scarlatiniform (an AESI) assessed as possibly related to INM004, but which could also have been explained by a concomitant COVID infection during hospitalization. There were no cases of anaphylaxis or serum sickness. Of the total AE, eight were considered as possibly related to INM004 by the investigator, none of which was severe or serious, and seven had alternative possible causes (STEC-HUS, other medical conditions, and concomitant medications) (Supplementary Table\u0026nbsp;8). The DSMB concluded that INM004 showed an adequate safety profile.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section3\"\u003e \u003ch2\u003e3.2.2. Laboratory, vital signs and electrocardiographic finding\u003c/h2\u003e \u003cp\u003eNo clinically significant abnormalities were found in the laboratory parameters, ECG, or vital signs after the first or second dose of INM004 administration compared to pre-administration of INM004 first dose. None of the patients presented QT/QTc interval prolongation after INM004 administration.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.3. PK outcomes\u003c/h2\u003e \u003cp\u003eThe median (range) C\u003csub\u003emax\u003c/sub\u003e was 58298.3 (30724.4\u0026ndash;84217.4) ng/ml for the two-dose regime, and 56661.4 (46399.4\u0026ndash;66923.5) ng/ml for the one-dose regime. Median t\u003csub\u003e1/2\u003c/sub\u003e (range) was 40.6 (31.5\u0026ndash;75.1) hours and 56.4 (40.1\u0026ndash;72.6) hours for two and one-dose regimens, respectively. All PK parameters are summarized in Supplementary Table\u0026nbsp;9. Plasma concentration of INM004 as a function of time for both dose regimens is shown in Supplementary Fig.\u0026nbsp;1.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e3.4. Efficacy outcomes\u003c/h2\u003e \u003cdiv id=\"Sec16\" class=\"Section3\"\u003e \u003ch2\u003e3.4.1. Primary efficacy outcome\u003c/h2\u003e \u003cp\u003eThe median number of dialysis days was four in the treatment arm and six in the control arm (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). This non-statistically significant difference of two days was also observed when only patients who received dialysis were considered (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEfficacy outcomes \u0026ndash; Matched population\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEfficacy outcomes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTreatment arm\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;52)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eControl arm\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;52)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDialysis requirement, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e29 (56)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e35 (67)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.23\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDialysis days in all patients\u003csup\u003ea\u003c/sup\u003e, \u003cem\u003emedian (Q1:Q3)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.0 (0.0:9.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.0 (0.0:11.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.43\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDialysis days only in patients who required dialysis, \u003cem\u003emedian (Q1:Q3)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8.0 (5.0:16.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10.0 (6.0:14.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.95\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDialysis duration in classes, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.44\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0 days\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23 (44)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17 (33)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u0026ndash;10 days\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e19 (37)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21 (40)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;10 days\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10 (19)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 (27)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDialysis duration dichotomic, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.35\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026le;\u0026thinsp;10 days\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e42 (81)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e38 (73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;10 days\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10 (19)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 (27)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDialysis requirement after Day 0\u003csup\u003eb\u003c/sup\u003e, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15 (40)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23 (58)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnuria, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25 (48)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e31 (60)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.24\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnuria days in all patients, \u003cem\u003emedian (Q1:Q3)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9.0 (6.0:12.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9.0 (6.0 :12.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.88\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnuria after Day 0\u003csup\u003eb\u003c/sup\u003e, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (18)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9 (30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.27\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHypertension with medication requirement on Day 28, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7 (17)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.81\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHospitalization days, \u003cem\u003emedian (Q1:Q3)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.0 (7.0 :18.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13.5 (6.0 :19.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.93\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHematuria on day 28\u003csup\u003ec\u003c/sup\u003e,\u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDetected\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14 (27)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNot detected\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25 (48)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMissing\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13 (25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e48 (92)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProteinuria at day 28\u003csup\u003ec\u003c/sup\u003e, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDetected\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18 (35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNot detected\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24 (46)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMissing\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10 (19)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e46 (89)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003csup\u003ea\u003c/sup\u003eFor patients without dialysis during the study, a value of zero dialysis day was imputed\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003csup\u003eb\u003c/sup\u003eDay 0 is the day of diagnosis of Shiga toxin-producing \u003cem\u003eEscherichia coli\u003c/em\u003e-associated hemolytic uremic syndrome (STEC-HUS) in the participating site\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003csup\u003ec\u003c/sup\u003eResults were not compared between arms due to the high number of missing values in the control arm.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003cem\u003eQ1\u003c/em\u003e, first quartile; \u003cem\u003eQ3\u003c/em\u003e, third quartile\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section3\"\u003e \u003ch2\u003e3.4.2. Secondary efficacy outcomes\u003c/h2\u003e \u003cp\u003eThere was a trend towards a lower number of patients needing dialysis in the treatment compared with the control arm (RR\u0026thinsp;=\u0026thinsp;0.83; 95% CI: 0.61\u0026ndash;1.13) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Similar trends were observed for the need for dialysis for more than ten days (RR\u0026thinsp;=\u0026thinsp;0.69; 95% CI: 0.43\u0026ndash;1.10), the requirement of dialysis after day 0 (RR\u0026thinsp;=\u0026thinsp;0.71; 95% CI: 0.35\u0026ndash;1.46), the occurrence of anuria: (RR\u0026thinsp;=\u0026thinsp;0.81; 95% CI\u0026thinsp;=\u0026thinsp;0.56\u0026ndash;1.16), and the onset of anuria after day 0 (RR\u0026thinsp;=\u0026thinsp;0.61; 95% CI\u0026thinsp;=\u0026thinsp;0.25\u0026ndash;1.50) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe evolution of creatinine showed a similar pattern in both arms, with values that were overall lower in the treatment arm (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, Supplementary Table\u0026nbsp;10). eGFR showed an increase during the follow-up period in both arms, which started at day 1 and day 3 for the treatment and control arms, respectively, and was overall higher in the treatment arm (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, Supplementary Table\u0026nbsp;10). When the time to kidney function recovery was compared between arms, the treatment arm showed a trend toward a shorter time to recovery (HR\u0026thinsp;=\u0026thinsp;1.83; 95% CI: 0.95\u0026ndash;3.50) (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). No differences were observed in the number of patients in each group who presented hypertension requiring medication on Day 28 (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Presence of hematuria and proteinuria at day 28 are presented in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. No comparison between arms were made for these variables due to the high number of missing data in the control arm.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAll patients in both groups achieved platelet counts\u0026thinsp;\u0026gt;\u0026thinsp;150 x 10\u003csup\u003e9\u003c/sup\u003e/L during the study follow-up period (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e; Supplementary Table\u0026nbsp;10), with a median time to recovery of 7 (95% CI\u0026thinsp;=\u0026thinsp;7.0\u0026ndash;8.0) days for the treatment group and 9 (95% CI\u0026thinsp;=\u0026thinsp;8.0\u0026ndash;11.0) days for the control group (HR\u0026thinsp;=\u0026thinsp;1.26; 95% CI\u0026thinsp;=\u0026thinsp;0.84\u0026ndash;1.88). Evolution of hemoglobin is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e and Supplementary Table\u0026nbsp;10. No differences between arms were observed in LDH values during the study (Supplementary Table\u0026nbsp;10). A similar number of patients required red blood cell transfusions (89% and 87% in the treatment and control arms, respectively) (Supplementary Table\u0026nbsp;11).\u003c/p\u003e \u003cp\u003eA low incidence of neurological, cardiovascular, and gastrointestinal events was observed in both arms after day 0 (Supplementary Table\u0026nbsp;11). No significant differences were observed in the occurrence of severe extrarenal events (convulsions, cerebral infarction, coma, hemodynamic instability, myocardial failure, myocarditis, hemorrhagic colitis, ischemic colitis, pancreatitis, respiratory distress syndrome, or requirement of mechanical ventilatory assistance for more than 24 hours), with eight patients in the treatment arm and ten in the control arm presenting at least one of these events after day 0 (Supplementary Table\u0026nbsp;12). No differences between arms were observed in hospitalization length (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). No patients in the treatment arm died, and one death was recorded in the control arm.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section3\"\u003e \u003ch2\u003e3.4.3. Sensitivity analyses\u003c/h2\u003e \u003cp\u003eA similar trend to that of the primary analysis was observed in time to kidney function recovery in the analysis performed with multiple imputations (HR\u0026thinsp;=\u0026thinsp;1.71; 95% CI\u0026thinsp;=\u0026thinsp;0.86\u0026ndash;3.39).\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003e3.5. Immunogenicity\u003c/h2\u003e \u003cp\u003eOn Day 28, none of the 57 treated patients showed specific reactivity against INM004.\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThis Phase 2 study aimed to explore the safety, PK profile and efficacy of INM004, a novel therapy for the treatment of STEC-HUS. Its results were expected to provide the first insights on the use of INM004 in pediatric patients with STEC-HUS and to serve as the basis for the design of the Phase 3 study.\u003c/p\u003e \u003cp\u003eThis study showed that INM004 is a safe therapy for STEC-HUS affected children. INM004 infusions were well tolerated with an adequate benefit/risk profile. There was no evidence of site injection reactions, anaphylaxis, or other severe hypersensitivity reactions associated with INM004 administration. None of the subjects developed symptoms compatible with serum sickness, and no immunogenicity was detected in any of the 57 treated subjects. Overall, safety and immunogenicity findings were consistent with those of phase 1 [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Previously, Inmunova had tested similar equine F(ab\u0026acute;)\u003csub\u003e2\u003c/sub\u003e fragments anti-SARS-Cov-2-RBD (CoviFab\u0026reg;) that showed a safety profile as good as that reported in the present study [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn the PK sub-study, INM004 showed a profile similar to the one expected, according to the simulated values for pediatric patients with different weights obtained from an allometric calculation based on data from healthy adult volunteers from Phase 1. Two doses of INM004 4 mg/kg separated by 24 hours showed adequate INM004 blood concentrations during five days without significant accumulation despite kidney impairment, as expected for molecules that are not eliminated by renal clearance.\u003c/p\u003e \u003cp\u003eRegarding efficacy, this study showed non-statistically significant trends toward a beneficial effect in several efficacy outcomes related to kidney involvement, including dialysis requirement. These findings might be interpreted as a potential effect of INM004 in the prevention of dialysis or prolonged dialysis. Moreover, a shorter time to kidney function recovery (measured through eGFR recovery) was observed in the treatment compared to the control arm. Altogether, these results could be considered as evidence of less kidney injury in patients treated with INM004. Data from observational studies have shown that the requirement of dialysis and its duration, as well as the presence and duration of anuria, are predictors of kidney sequelae in patients with STEC-HUS [\u003cspan additionalcitationids=\"CR20 CR21\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Additionally, several studies conducted in pediatric and adult populations with AKI showed that its severity and duration are predictors of evolution to CKD [\u003cspan additionalcitationids=\"CR24 CR25\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. During the early stage of STEC-HUS circulating Stx is expected to still be present in the bloodstream. Therefore, even when the disease cannot be prevented, it is hypothesized that Stx neutralization by INM004 can ameliorate kidney injury and reduce acute and long-term morbidity.\u003c/p\u003e \u003cp\u003eRegarding extrarenal outcomes, no clinical effect was observed in the present study in hematological parameters and in the incidence of severe clinical events affecting other target organs, but those were of low incidence. When present, most extrarenal events were ongoing on the day of STEC-HUS diagnosis before INM004 administration.\u003c/p\u003e \u003cp\u003eThe main limitation of this study was the non-randomized design, which allowed for the treatment of a considerable number of patients in a short period, but it could have also been a source of bias. To minimize selection bias, measures were adopted in both the study design (same centers, same seasonal period for enrollment, same eligibility criteria and same SoC for the treatment and the control arm; systematic review of clinical registers for the inclusion of subjects of the control arm) and the statistical analysis (propensity score matching procedure). To address the potential bias introduced by the unblinded design, objective variables were selected as efficacy endpoints. Due to the possibility of attrition bias, as data of the control arm was limited to clinical chart reports, a sensitivity analysis with imputation of missing data was performed for time-to-kidney function recovery. Results were concordant with those of the primary analysis. Additionally, the presence of a higher number of patients with prodromal symptoms and more patients having received antibiotics for the treatment of the prodromal phase in the treatment arm, could be explained by an under-registration of these variables in the control arm.\u003c/p\u003e \u003cp\u003eAnother limitation was related to the time of the intervention with INM004. Due to its proposed mechanism of action, the prodromic phase (i.e., patients with STEC associated diarrhea) might be the optimal moment to initiate treatment with this product. However, in Argentina, most patients with diarrhea caused by STEC attend health centers of low complexity or are ambulatory managed. Patients are hospitalized at highly complex centers when HUS is already established. For this reason, this study was planned to assess the potential therapeutic effect of INM004 in patients as soon as possible when diagnosis of STEC-HUS was established, with at least two of the three components of the HUS triad.\u003c/p\u003e \u003cp\u003eRegarding the PK profile of INM004, the present study provided adequate and relevant information. However, most of the patients studied were under four years, and the results might not be generalizable to the entire pediatric population. This limitation should be addressed in a Phase 3 study, in which the characterization of INM004 is planned to be continued. Finally, as enrollment was lower than expected, it is possible that some potential AE of low incidence (below 1.5%) were not detected. The enrolled sample of 57 subjects yielded a power of 58% to detect AE with this low frequency. As a phase 3 trial with a larger sample size is planned as part of the clinical development of INM004, it will allow us to identify additional events in the case they occur.\u003c/p\u003e \u003cp\u003eIn conclusion, this study showed that INM004 can be safely administered to pediatric patients with STEC-HUS and allowed the obtention of PK data that confirmed that the planned regime of 2 doses of 4 mg/kg is adequate in this population. The study also showed trends regarding the amelioration of kidney impairment during the acute phase of STEC-HUS. The presented results would allow us to move forward to a Phase 3 study to evaluate the efficacy of INM004 in the treatment of STEC-HUS.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe acknowledge the members of the DSMB: Dr. Vanesa Castellano, Dr. Esteban Nannini, Dr. Tom\u0026aacute;s Orduna, Dr. Jorge Ferraris, Dr. Raquel Wainsztein.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFernando Goldbaum, Linus Spatz, Santiago Sanguineti, Mariana Colonna Ian Roubicek, Carolina Massa, Marta Rivas, Mariana Pichel and Vanesa Zylberman contributed to the study conception and design.\u0026nbsp;Material preparation and data collection were performed by Alicia Fayad,\u003csup\u003e\u0026nbsp;\u003c/sup\u003eIliana Principi,\u003csup\u003e\u0026nbsp;\u003c/sup\u003eAlejandro Balestracci,\u003csup\u003e\u0026nbsp;\u003c/sup\u003eLaura Alconcher,\u003csup\u003e\u0026nbsp;\u003c/sup\u003ePaula Coccia,\u003csup\u003e\u0026nbsp;\u003c/sup\u003eMarta Adragna,\u003csup\u003e\u0026nbsp;\u003c/sup\u003eOscar Amoreo,\u003csup\u003e\u0026nbsp;\u003c/sup\u003eMar\u0026iacute;a Carolina Bettendorff,\u003csup\u003e\u0026nbsp;\u003c/sup\u003e Mar\u0026iacute;a Valeria Blumetti,\u003csup\u003e\u0026nbsp;\u003c/sup\u003ePablo Bonany,\u003csup\u003e\u0026nbsp;\u003c/sup\u003eMar\u0026iacute;a Laura Flores Tonfi,\u003csup\u003e\u0026nbsp;\u003c/sup\u003eLuis Flynn,\u003csup\u003e\u0026nbsp;\u003c/sup\u003eLidia Ghezzi,\u003csup\u003e\u0026nbsp;\u003c/sup\u003eJorge Montero, Flavia Ram\u0026iacute;rez,\u003csup\u003e\u0026nbsp;\u003c/sup\u003eClaudia Seminara,\u003csup\u003e\u0026nbsp;\u003c/sup\u003e\u0026Aacute;ngela Suarez,\u003csup\u003e\u0026nbsp;\u003c/sup\u003eand Ana Paula Spizirri.\u0026nbsp;The first draft of the manuscript was written by Carolina Massa, Marina Valerio, Fernando Goldbaum and Ian Roubicek. Alicia Fayad,\u003csup\u003e\u0026nbsp;\u003c/sup\u003eIliana Principi,\u003csup\u003e\u0026nbsp;\u003c/sup\u003eAlejandro Balestracci,\u003csup\u003e\u0026nbsp;\u003c/sup\u003eLaura Alconcher and\u003csup\u003e\u0026nbsp;\u003c/sup\u003ePaula Coccia commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval:\u003c/strong\u003e This trial was performed following the principles of the Declaration of Helsinki and Good Clinical Practice. The protocol was approved by the local Ethics Committees and the Argentine National Food and Drug Regulatory Agency (ANMAT).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interests:\u003c/strong\u003e AF, IP, AB, LA, PC, MA, OA, MCB, MVB, PB, MLFT, LF, LG, JM, FR, CS, AS and APS declare reimbursement for conduction of clinical trial as investigator of the study. MR, MP, VZ, LS, CM, MV, SS, MC, IR and FG report personal fees from Inmunova S.A.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e Inmunova S.A.\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBoyer O, Niaudet P (2022) Hemolytic-Uremic Syndrome in Children. Pediatr Clin North Am 69:1181\u0026ndash;1197. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.pcl.2022.07.006\u003c/span\u003e\u003cspan address=\"10.1016/j.pcl.2022.07.006\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFakhouri F, Zuber J, Fr\u0026eacute;meaux-Bacchi V, Loirat C (2017) Haemolytic uraemic syndrome. 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Kidney Int 95:160\u0026ndash;172. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.kint.2018.08.036\u003c/span\u003e\u003cspan address=\"10.1016/j.kint.2018.08.036\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"pediatric-nephrology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pnep","sideBox":"Learn more about [Pediatric Nephrology](http://link.springer.com/journal/467)","snPcode":"467","submissionUrl":"https://www.editorialmanager.com/pnep/default2.aspx","title":"Pediatric Nephrology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Hemolytic-Uremic Syndrome, Acute Kidney Injury, Clinical Trial, Phase 2, Passive Immunotherapy","lastPublishedDoi":"10.21203/rs.3.rs-4751636/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4751636/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eShiga toxin-producing \u003cem\u003eEscherichia coli\u003c/em\u003e-associated hemolytic uremic syndrome (STEC-HUS) is a severe condition mainly affecting children. It is one of the leading causes of acute kidney injury in pediatric population. There is no established therapy for this disease. INM004 is an anti-Shiga toxin composed of equine polyclonal antibodies. This study aimed to assess the safety, pharmacokinetics, and efficacy of INM004 in pediatric patients with STEC-HUS.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003ePhase 2, open-label clinical trial with an historical control arm. Patients in the treatment arm received two doses of INM004. The primary endpoints were the safety profile, pharmacokinetics, and efficacy (dialysis days) of INM004. Secondary endpoints included other renal and extrarenal outcomes. Propensity score matching was used for efficacy comparisons between arms.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eFifty-seven and 125 patients were enrolled in the treatment and control arm, respectively. After propensity score matching, 52 patients remained in each arm. INM004 was well-tolerated. Eight adverse events were considered possibly related, none of which were serious or severe. In the primary efficacy endpoint, patients of the treatment arm presented a non-statistically significant difference of two dialysis days. On secondary endpoints, trends toward a lower number of patients needing dialysis and dialysis for more than ten days, and shorter time to glomerular filtration rate normalization, were observed favoring the treatment arm.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eINM004 showed an adequate safety profile. Efficacy trends suggesting a beneficial effect in the amelioration of kidney injury were observed. These results encourage the conduction of a Phase 3 study of INM004 in pediatric patients with STEC-HUS.\u003c/p\u003e","manuscriptTitle":"Open-label, controlled, phase 2 clinical trial assessing the safety, efficacy, and pharmacokinetics of INM004 in pediatric patients with Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-08-22 14:50:12","doi":"10.21203/rs.3.rs-4751636/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major Revisions Needed","date":"2024-08-20T15:18:46+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2024-07-18T20:13:25+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-07-18T17:47:42+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-07-17T08:33:38+00:00","index":"","fulltext":""},{"type":"submitted","content":"Pediatric Nephrology","date":"2024-07-16T11:54:20+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"pediatric-nephrology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pnep","sideBox":"Learn more about [Pediatric Nephrology](http://link.springer.com/journal/467)","snPcode":"467","submissionUrl":"https://www.editorialmanager.com/pnep/default2.aspx","title":"Pediatric Nephrology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"f277185b-b593-4d1f-a72e-e0d5519672c6","owner":[],"postedDate":"August 22nd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-11-18T19:15:54+00:00","versionOfRecord":{"articleIdentity":"rs-4751636","link":"https://doi.org/10.1007/s00467-024-06583-3","journal":{"identity":"pediatric-nephrology","isVorOnly":false,"title":"Pediatric Nephrology"},"publishedOn":"2024-11-12 15:57:59","publishedOnDateReadable":"November 12th, 2024"},"versionCreatedAt":"2024-08-22 14:50:12","video":"","vorDoi":"10.1007/s00467-024-06583-3","vorDoiUrl":"https://doi.org/10.1007/s00467-024-06583-3","workflowStages":[]},"version":"v1","identity":"rs-4751636","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4751636","identity":"rs-4751636","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}