{"paper_id":"014df660-87bb-4034-971a-5d90a581b2e7","body_text":"Evaluation of RC48-ADC in combination with PRaG regimen: An \nopen-label, prospective, multicentre study assessing efficacy and safety \nfor advanced refractory HER2-expressing solid tumors (PRaG3.0 \nStudy Protocol)\nMeiling Xu*, Yuehong Kong*, Junjun Zhang*, Rongzheng Chen, Pengfei Xing, Xiangrong Zhao, \nShicheng Li, Yingying Xu, Liyuan Zhang#\n1. Center of PRaG therapy, The Second Affiliated Hospital of Soochow University, Suzhou, China. \n2. Center for Cancer Diagnosis and Treatment, The Second Affiliated Hospital of Soochow \nUniversity, Suzhou, China. \n3. Laboratory for Combined Radiotherapy and Immunotherapy of Cancer, The Second Affiliated \nHospital of Soochow University, Suzhou, China.\n*Meiling Xu, Yuehong Kong, and Junjun Zhang are co-first authors.\n#Liyuan Zhang is the Corresponding author. Email: zhangliyuan126@126.com\n . CC-BY 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted August 15, 2025. ; https://doi.org/10.1101/2025.08.13.25333549doi: medRxiv preprint \nNOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice.\n\nAbstract\nIntroduction: Combining antibody-drug conjugates (ADCs) with radioimmunotherapy is a \nfeasible and highly promising approach for treating HER2-positive patients, offering a potential \nparadigm for pan-cancer therapy. ADCs have demonstrated significant efficacy in cancers \nexpressing human epidermal growth factor receptor 2 (HER2), independent of the tumor's tissue of \norigin. Preclinical studies suggest that ADCs not only induce immunogenic cell death but also \nselectively enhance tumor radiosensitivity, providing a strong rationale for their integration with \nimmunotherapy and radiotherapy. A combination regimen (PRaG) including hypofractionated \nradiotherapy (HFRT) alongside a PD-1 inhibitor and GM-CSF leverages HFRT to trigger tumor \nantigen release, GM-CSF to stimulate the proliferation and activation of antigen-presenting cells, \nand PD-1 inhibitors to relieve suppression of CD8+ T cells. The trial reported an objective response \nrate (ORR) of 16.7%, with three patients achieving complete remission. Building upon these \nfindings, a next-generation regimen—disitamab vedotin (RC48) ADC combined with PRaG \nregimen (termed PRaG3.0)—may further amplify synergistic antitumor effects in HER2-expressing \ncancers. This precise combination therapy offers an innovative and exploratory approach for treating \npatients with HER2-positive or HER2-low tumors across various tissue types, potentially addressing \nthe unique challenges associated with HER2 expression heterogeneity.\nObjective: This study aims to investigate the effectiveness and safety of RC48-ADC combined \nwith PRaG regimen for HER2-expressing advanced solid tumors. \nMethods and analysis: This study is a prospective, single-arm, open-label, multi-center clinical \ntrial designed as a basket study. Enrolled patients with confirmed HER2-expressing solid tumors \n(IHC 3+, 2+, or 1+) that had progressed after standard treatment or were intolerant to it were divided \ninto three cohorts: pancreatic cancer, gynecological tumors, and others. Patients received RC48 (2 \nmg/kg) via intravenous injection on day 1, followed by subcutaneous GM-CSF at 200 µg from days \n3 to 7 and interleukin-2 (IL-2) at 2 million IU from days 8 to 12. Radiotherapy was initiated on day \n3, targeting one lesion with hypofractionated radiotherapy (2-3 fractions of 5 or 8 Gy). PD-1/PD-\nL1 antibodies were administered within one week after completing radiotherapy. Treatment was \nrepeated every three weeks, and if there were no target lesions, radiotherapy could be discontinued, \nwith RC48 given for at least six cycles. After achieving a complete tumor response, maintenance \ntherapy with PD-1/PD-L1 antibodies continued until disease progression or intolerable toxicity \noccurred. The primary endpoint was the objective response rate (ORR).\nEthics and dissemination: The study protocol received approval from the Ethics Committee \nof the Second Affiliated Hospital of Soochow University (JD-LK-2022-121-02), as well as from all \nother participating hospitals. The clinical trial registration number is NCT05115500 and registration \nDate date is November 4, 2021.\nIntroduction\nAntibody-drug conjugates (ADCs) represent a breakthrough in oncology, offering a highly \nspecific and effective therapeutic approach by combining the tumor-targeting precision of \nmonoclonal antibodies with the potent cytotoxicity of chemotherapeutic agents [1, 2]. ADCs have \ndemonstrated efficacy across a variety of HER2-expressing tumors, extending beyond the \ntraditional tissue-of-origin paradigm [3]. HER2 expression, associated with aggressive tumor \nbehavior and poor prognosis, is not limited to breast and gastric cancers but is also found in \n . CC-BY 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted August 15, 2025. ; https://doi.org/10.1101/2025.08.13.25333549doi: medRxiv preprint \n\ncolorectal, ovarian, pancreatic, and lung cancers [4, 5] . Agents like trastuzumab deruxtecan and \ndisitamab vedotin (RC48) have shown significant anti-tumor activity in these malignancies, \nincluding those with low HER2 expression, underscoring their versatility and broad applicability[6-\n8].\nBeyond their direct cytotoxic effects, ADCs can induce immunogenic cell death (ICD), leading \nto tumor antigen release and enhanced immune system activation. This dual mechanism positions \nADCs as ideal candidates for combination therapies, particularly with immunotherapeutic \napproaches like immune checkpoint inhibitors [9, 10]. Their ability to target diverse tumor types and \nstimulate immune responses highlights ADCs as a cornerstone of pan-cancer therapy, paving the \nway for more effective and precise treatment strategies.\nRadiotherapy, with its well-established safety profile, widespread clinical availability, and \nimmune-activating potential, has gained attention as a valuable partner in combination therapies[11, \n12]. The PRaG therapy—an innovative immunotherapy regimen—integrates hypofractionated \nradiotherapy (HFRT), PD-1/PD-L1 inhibitors, and granulocyte-macrophage colony-stimulating \nfactor (GM-CSF) to create an in-situ vaccine effect, stimulating anti-tumor immunity and \nremodeling the tumor microenvironment. Grounded in the cancer-immunity cycle hypothesis, PRaG \ntherapy addresses three critical stages: (1) HFRT releases tumor antigens, (2) GM-CSF activates \nantigen-presenting cells, and (3) PD-1 inhibitors restore CD8+ T-cell activity by counteracting \ninhibitory signals [13]. Widely implemented in China, PRaG therapy has shown notable clinical \noutcomes in treating advanced, refractory cancers, including esophageal, gastric, colorectal, \npancreatic, lung, and breast malignancies, with demonstrated efficacy in refractory cases such as \ngastric cancer and ovarian cancer. A phase II trial reported an overall response rate (ORR) of 16.7% \nand a disease control rate of 46.3%, including complete remission in select patients[14].\nDisitamab vedotin (RC48), a novel humanized anti-HER2 ADC, incorporates monomethyl \nauristatin E (MMAE) as its cytotoxic payload and exhibits strong HER2 affinity and robust \nantibody-dependent cell-mediated cytotoxicity (ADCC) [15-17]. Beyond its cytotoxic effects, RC48 \ncan induce ICD, promoting widespread release of tumor antigens and enhancing immunotherapy \neffectiveness by activating effector T cells. These properties make RC48 an attractive candidate for \nintegration into multi-modal combination therapies[18, 19].\nThe PRaG3.0 regimen, combining RC48-ADC with HFRT, PD-1/PD-L1 inhibitors, GM-CSF, \nand IL-2, represents a novel, synergistic treatment strategy targeting HER2-expressing cancers, \nincluding those with low HER2 expression. This approach leverages the complementary \nmechanisms of ADCs, radiotherapy, and immunotherapy to achieve enhanced anti-tumor effects. \nTo evaluate the clinical potential of this paradigm, an exploratory phase II, open-label, multi-center, \nsingle-arm study was conducted, focusing on the efficacy and safety of PRaG3.0 in patients with \nadvanced solid tumors exhibiting HER2 expression.\nMethods \nObjectives\nThe primary objective of this study is to investigate the effectiveness of RC48-ADC \ncombined with radiotherapy, PD-1/PD-L1 inhibitor sequential granulocyte-macrophage colony-\nstimulating factor, and interleukin-2 for HER2-expressing advanced solid tumors. The secondary \nobjective is to assess the safety and toxicity of this treatment. The study also aims to explore a \npanel of T lymphocyte subsets, tumor-associated cytotoxic T cells, activated cytotoxic T \n . CC-BY 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted August 15, 2025. ; https://doi.org/10.1101/2025.08.13.25333549doi: medRxiv preprint \n\nlymphocytes, activated memory T cells, monocytes, dendritic cells, interleukin-2, interleukin-4, \ninterleukin-6, interleukin-10, interleukin-17A, tumor necrosis factor, interferon-γ.\nStudy design and Sample calculation\nThe PRaG3.0 trial (NCT05115500) was a single-arm, open-label, multicentre, phase II study \ninitiated by the Second Affiliated Hospital of Soochow University. The recruitment period for this \nstudy is from November 2021 to April 2026. The trial was designed as a basket study. Enrolled \npatients were divided into three cohorts that were pancreatic cancer, gynecological tumors, and the \nothers. Simon 2 stage optimization design was adopted.\nPancreatic Cancer: The null hypothesis H0 posits an objective response rate (ORR) ≤0.05, \nwhereas the alternative hypothesis H1 posits an ORR ≥0.2. With a one-sided α=0.05 and β=0.2, \nthe calculated total sample size for a single-arm is 29. Stage 1 will enroll ten patients; at least one \npatient must respond positively in Stage 1 to proceed to Stage 2, which will enroll 19 patients. If \nthe total number of positive responses after completing Stage 2 is greater than 4, the trial group is \nconsidered effective. If no patient responds positively in Stage 1, the study will be terminated.\nGynecological tumors: The null hypothesis H0 posits an ORR ≤0.05, whereas the alternative \nhypothesis H1posits an ORR ≥0.25. With a one-sided α=0.05 and β=0.2, the calculated total \nsample size for a single-arm is 17. Stage 1 will enroll nine patients; at least one patient must \nrespond positively in Stage 1 to proceed to Stage 2, which will enroll eight patients. If the total \nnumber of positive responses after completing Stage 2 is greater than 3, the trial group is \nconsidered effective. If no patient responds positively in Stage 1, the study will be terminated.\nOther Tumors: The null hypothesis H0 posits an ORR ≤0.05, whereas the alternative \nhypothesis H1 posits an ORR ≥0.2. With a one-sided α=0.05 and β=0.2, the calculated total \nsample size for a single-arm is 29. Stage 1 will enroll ten patients; at least one patient must \nrespond positively in Stage 1 to proceed to Stage 2, which will enroll 19 patients. If the total \nnumber of positive responses after completing Stage 2 is greater than 4, the trial group is \nconsidered effective. If no patient responds positively in Stage 1, the study will be terminated.\nInclusion criteria \nThe study inclusion criteria will be as follows:(1) Age ≥18 years; (2) Participants with \nadvanced, confirmed HER2-expressing (IHC3+, 2+ or 1+) solid tumors that had progressed after \nstandard treatment, or standard treatment intolerance were enrolled. Patients must have recurrent \nor metastatic late-stage solid malignant tumors with a confirmed pathological diagnosis or medical \nhistory. Furthermore, pathology must show HER-2 positivity (IHC 1+, IHC 2+, or 3+), and there \nmust be no guideline-recommended standard treatment options, or the patient must be intolerant or \nexplicitly refuse standard treatments due to personal preference. Additionally, patients should \nhave identifiable measurable metastatic lesions; (3)No occurrences of congestive heart failure, \nunstable angina, or unstable arrhythmias in the past 6 months;(4) Patient's performance status \nmust be graded 0-3 according to the Eastern Cooperative Oncology Group (ECOG) scoring \nsystem, with a life expectancy assessment of ≥3 months; (5) No severe history of hematologic, \ncardiac, pulmonary, hepatic, renal abnormalities, or immunodeficiencies; (6) One week before \nenrollment, absolute T-lymphocyte count must be ≥0.5 times the lower limit of normal; \nneutrophils must be ≥2.0×10^9/L; AST and ALT must be ≤3.0 times the upper limit of normal \n(for liver cancer/liver metastatic cancer, ≤5.0 times the upper limit of normal); creatinine must be \n≤3.0 times the upper limit of normal;(7) Patients must possess the capability to understand and \nvoluntarily sign the written informed consent form. \n . CC-BY 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted August 15, 2025. ; https://doi.org/10.1101/2025.08.13.25333549doi: medRxiv preprint \n\nExclusion criteria \nPatients who meet any of the following criteria will be excluded: (1)Pregnant or \nbreastfeeding women.(2)Patients with a history of other malignancies within the past five years, \nexcept cured skin cancer and cervical carcinoma in situ.(3)Patients with uncontrolled epilepsy, \ncentral nervous system diseases, or psychiatric disorders, which, in the investigator's judgment, \ncould significantly affect the ability to provide informed consent or interfere with medication \nadherence.(4)Clinically significant (active) heart diseases, such as symptomatic coronary artery \ndisease, New York Heart Association (NYHA) Class II or higher congestive heart failure, severe \narrhythmias requiring medication, or a history of myocardial infarction within the past 12 \nmonths.(5)Patients requiring immunosuppressive therapy due to organ transplantation.(6)Patients \nwith known major active infections, or significant hematologic, renal, metabolic, gastrointestinal, \nendocrine dysfunctions, or other uncontrolled serious comorbidities as judged by the \ninvestigator.(7)Patients allergic to any components of the investigational drug.(8)Patients with a \nhistory of immunodeficiency, including those testing positive for HIV or suffering from other \nacquired or congenital immunodeficiency diseases, those with a history of organ transplantation, \nor those requiring long-term oral steroid therapy due to other immune-related diseases.(9)Patients \nwith active acute or chronic tuberculosis (T-spot positive, chest X-ray showing suspicious \ntuberculosis lesions).(10)Other conditions that the investigator considers inappropriate for \ninclusion.\nTreatment scheme and modalities\nEnrolled patients were treated using the PRaG 3.0 protocol, those received RC48-ADC(2.0 \nmg/kg d1, every 3 weeks), then HFRT (2-3 doses of 5-8Gy) was delivered for one metastatic \nlesion every other day, followed by GM-CSF(200 μg d3-7), sequential IL-2(2million IU d8-12), \nand PD-1/PD-L1 inhibitor was dosing within one week after completion of HFRT. After RC48-\nADC combined with PD-1/PD-L1 inhibitor sequential GM-CSF and IL-2 for at least six cycles, \nthen maintenance with PD-1/PD-L1 inhibitor was administered until disease progression or \nunacceptable toxicity. The specific treatment protocol is shown in Figure1. \nFigure1 Treatment schedule of the PRaG3.0 therapy\nPatients received RC48 (2 mg/kg, IV) on day 1, GM-CSF (200 µg, SC) on days 3–7, and IL-2 (2 \nmillion IU, SC) on days 8–12. Radiotherapy (2–3 fractions of 5 or 8 Gy) began on day 3, followed \nby PD-1/PD-L1 antibodies within one week after radiotherapy. \nObjective endpoints and efficacy assessment\nThe primary endpoint was objective response rate (ORR), which was defined as the \nproportion of participants with partial (PR) or complete (CR) response in evaluable patients in \naccordance with the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 determined by \ninvestigators. Radiological assessments were performed on average every 6 weeks. Secondary \nobjectives included safety, disease control rate (DCR), progression-free survival (PFS), and \noverall survival (OS). ORR was defined as the proportion of patients with complete response (CR) \nor partial response (PR). DCR was defined as the percentage of patients with CR, PR, or stable \ndisease (SD) from enrollment. OS was calculated from the enrollment date to the date of death or \nlast known alive. PFS was calculated from the enrollment date to disease progression, death, or \ncensored at the last clinical follow-up. After the conclusion of treatment, all trial participants will \nundergo survival follow-up every 3 months until death, loss to follow-up, withdrawal of informed \n . CC-BY 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted August 15, 2025. ; https://doi.org/10.1101/2025.08.13.25333549doi: medRxiv preprint \n\nconsent, or the sponsor decides to terminate the study. The nature, frequency, and severity of \nadverse events were assessed based on the Common Terminology Criteria for Adverse Events \nversion 5.0 (CTCAE 5.0). Lymphocyte subset counts and cytokine analysis were examined as \nexploratory endpoints.\nStatistical analysis\nData analysis was conducted using SPSS 18.0 statistical software. Residuals were examined \nfor normality using the Shapiro-Wilk test, with a significance level α>0.05. For variables that met \nthe assumptions of normal distribution, a randomized block analysis of variance was employed; \nfor those that did not, a non-parametric rank-sum test based on a randomized block design was \nutilized, with a significance level α<0.05. Comparisons were made for changes in the number of \nwhite blood cells, granulocytes, lymphocytes, and their subtypes, and cytokine levels before and \nafter radiotherapy to determine if there were statistically significant differences. Survival time was \nconsidered in conjunction with these changes, using Cox regression analysis to assess the impact \nof changes in white blood cell counts, granulocyte counts, lymphocyte and its subtype counts, and \ncytokine levels on patient survival rates. Kaplan-Meier analysis was used to compare the survival \nrates between patients who experienced side effects and those who did not. The relationship \nbetween patient survival rates and associated cytokine levels was also analyzed using the Kaplan-\nMeier method. \nPatient and public involvement \nPatients and/or the public were not involved in the design, conduct, reporting, or \ndissemination plans of this research. \nEthics and dissemination \nThe study protocol has been approved by the Ethics Committee of the Second Affiliated \nHospital of Soochow University and all other participating hospitals. It will be conducted in \ncompliance with the Declaration of Helsinki. Informed consent will be obtained from each \nparticipant before the trial. The results of the PRaG3.0 study, regardless of the outcome, are \nintended to be published in a peer-reviewed international medical journal[20, 21]. The reporting of \nthe trial's findings will adhere strictly to the guidelines set forth in the Consolidated Standards of \nReporting Trials (CONSORT) statement.\nDiscussion\nThe results of this trial hold significant promise for advancing the treatment landscape of \nHER2-expressing advanced solid tumors, addressing key challenges associated with tumor \nheterogeneity and resistance to standard therapies. The PRaG3.0 regimen, integrating RC48-ADC \nwith hypofractionated radiotherapy (HFRT), immune checkpoint inhibitors, GM-CSF, and IL-2, \nexemplifies the potential of combining targeted therapy, radiotherapy, and immunotherapy to \nachieve synergistic antitumor effects. RC48 inducing immunogenic cell death (ICD) not only \nenhances its direct cytotoxic potential but also primes the immune system for further activation, \nmaking it an ideal partner in this combination approach[9, 15-19].\nThe preliminary results, which suggest a favorable objective response rate (ORR) across \ndiverse tumor types [14], highlight the versatility of this regimen in targeting HER2 expression \nregardless of tissue origin. This aligns with the broader trend of moving toward biomarker-driven, \n . CC-BY 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted August 15, 2025. ; https://doi.org/10.1101/2025.08.13.25333549doi: medRxiv preprint \n\npan-cancer therapies[22]. Moreover, the dual role of HFRT in both local tumor control and immune \nactivation underscores its importance as a central component of this strategy, particularly in \nfacilitating antigen release and enhancing the efficacy of subsequent immune therapies[11].\nHowever, the study also brings to light several challenges and areas for further investigation. \nThe safety profile of this multi-modal approach warrants close monitoring, given the potential for \noverlapping toxicities, particularly from ADC-related adverse events and immune-related \ncomplications. Additionally, the variability in HER2 expression levels (IHC 1+, 2+, 3+) across \ntumors may influence treatment efficacy, suggesting the need for further stratified analyses to \nidentify optimal patient subgroups[5, 23].\nThe exploratory nature of this trial provides a foundation for future research to refine the \nregimen, including adjustments in dosing schedules, biomarker-guided patient selection, and \ncombination strategies with other novel agents. As HER2-targeted therapies evolve, this study \nunderscores the importance of leveraging the unique mechanisms of ADCs like RC48 to enhance \nthe effectiveness of radiotherapy and immunotherapy, potentially setting a new standard for \npersonalized cancer treatment.\nFuture studies should focus on long-term outcomes such as overall survival (OS), progression-\nfree survival (PFS), and quality of life, as well as the mechanisms underlying the observed immune \nmodulation. The inclusion of correlative studies examining cytokine levels, immune cell \npopulations, and tumor microenvironment changes will be critical to fully elucidate the biological \nbasis of the observed clinical responses. With continued validation, the PRaG3.0 regimen could \nestablish a transformative framework for treating HER2-positive and HER2-low tumors across \nmultiple cancer types[20, 21].\nAuthor contributions \nStudy conception and design: MLX, YHK, JJZ, LYZ; Drafting of the trial protocol: MLX, \nLYZ; Critical review of the trial protocol for important intellectual content: RZC, PFX, XRZ, LYZ; \nObtaining funding: LYZ; Coordinating investigator: SCL, YYX; Study implementation: MLX, \nYHK, JJZ, RZC, PFX, XRZ, SCL, YYX, LYZ; All authors read and approved the final manuscript.\nFunding \nThis work was supported by Suzhou Medical Center (Szlcyxzx202103) ;the National Natural \nScience Foundation of China (82171828) ;the Subject construction support project of the Second \nAffiliated Hospital of Soochow University (XKTJHRC20210011);Wu Jieping Medical Foundation \n(320.6750.2021-01-12);The special project of “ Technological Innovation ”  project of CNNC \nMedical Industry Co. Ltd (ZHYLTD2021001);Suzhou Science and Education Health Project \n(KJXW2021018);Foundation of Chinese Society of Clinical Oncology(Y-pierrefabre202102-\n0113);Beijing Bethune Charitable Foundation(STLKY0016);Research Projects of China Baoyuan \nInvestment Co.(270004);Suzhou Gusu Health Talent Program(GSWS2022028);Open Project of \nState Key Laboratory of Radiation Medicine and Protection of Soochow \nUniversity(GZN1202302);New medical technology project of the Second Affiliated Hospital of \nSoochow University(23zl001);Multi-center Clinical Research Project for Major Diseases in \nSuzhou(DZXYJ202304);Postgraduate Research & Practice Innovation Program of Jiangsu \nProvince (SJCX24_1814);Gusu health talent research Fund (GSWS2022053);the National Natural \nScience Foundation of China (82102824);Scientific Research Program for Young Talents of China \n . CC-BY 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted August 15, 2025. ; https://doi.org/10.1101/2025.08.13.25333549doi: medRxiv preprint \n\nNational Nuclear Corporation (Junjun Zhang ).\nEthics approval and consent to participate declaration\nThe trial was approved by the Ethics Committee of the Second Affiliated Hospital of Soochow \nUniversity (JD-LK-2022-121-02). The study is registered in ClinicalTrails. gov (NCT0511550). \nReferences\n1. Khongorzul, P., et al., Antibody-Drug Conjugates: A Comprehensive Review.  Mol Cancer Res, \n2020. 18(1): p. 3-19.\n2. Yaghoubi, S., et al., Potential drugs used in the antibody-drug conjugate (ADC) architecture \nfor cancer therapy. J Cell Physiol, 2020. 235(1): p. 31-64.\n3. 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CC-BY 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted August 15, 2025. ; https://doi.org/10.1101/2025.08.13.25333549doi: medRxiv preprint \n\n18. Wu, X., et al., A HER2-targeting antibody-MMAE conjugate RC48 sensitizes immunotherapy in \nHER2-positive colon cancer by triggering the cGAS-STING pathway. Cell Death Dis, 2023. \n14(8): p. 550.\n19. Xu, Y., et al., Phase I study of the recombinant humanized anti-HER2 monoclonal antibody-\nMMAE conjugate RC48-ADC in patients with HER2-positive advanced solid tumors. Gastric \nCancer, 2021. 24(4): p. 913-925.\n20. Kong, Y.H., et al., PRaG 3.0 therapy for human epidermal growth factor receptor 2-positive \nmetastatic pancreatic ductal adenocarcinoma: A case report. World J Gastroenterol, 2024. \n30(9): p. 1237-1249.\n21. Liu, Z., et al., Combination treatment with anti-HER2 therapeutic antibody RC48, PD-1 \ninhibitor, radiotherapy, and granulocyte macrophage-colony stimulating factor (GM-CSF) in \npatient with metastatic gastric cancer: a case report. Front Immunol, 2024. 15: p. 1321946.\n22. Charoentong, P., et al., Pan-cancer Immunogenomic Analyses Reveal Genotype-\nImmunophenotype Relationships and Predictors of Response to Checkpoint Blockade. Cell \nRep, 2017. 18(1): p. 248-262.\n23. Yoon, J. and D.Y. Oh, HER2-targeted therapies beyond breast cancer - an update. Nat Rev Clin \nOncol, 2024. 21(9): p. 675-700.\n . CC-BY 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted August 15, 2025. ; https://doi.org/10.1101/2025.08.13.25333549doi: medRxiv preprint \n\n . CC-BY 4.0 International licenseIt is made available under a \nperpetuity. \n is the author/funder, who has granted medRxiv a license to display the preprint in(which was not certified by peer review)preprint \nThe copyright holder for thisthis version posted August 15, 2025. ; https://doi.org/10.1101/2025.08.13.25333549doi: medRxiv preprint","source_license":"CC-BY-4.0","license_restricted":false}