Losartan(Angiotensin II Type 1 Receptor Blocker) and Toceranib Combination Therapy for Progressive Pulmonary Metastasis in Canine Osteosarcoma: A Case Report

Losartan(Angiotensin II Type 1 Receptor Blocker) and Toceranib Combination Therapy for Progressive Pulmonary Metastasis in Canine Osteosarcoma: A Case Report | 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 Short Report Losartan(Angiotensin II Type 1 Receptor Blocker) and Toceranib Combination Therapy for Progressive Pulmonary Metastasis in Canine Osteosarcoma: A Case Report Ji-Hoon Kwak, Mingyu Jung, Soo-Nyun Choi, Kyu-Shik Jeong This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7413733/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract Osteosarcoma (OSA) is the most common and aggressive primary bone tumor in dogs. OSA frequently metastasizes to the lungs and has a poor prognosis despite current standard treatment. This case report described the clinical course of a 3-year-old castrated male Jindo dog diagnosed with right tibial OSA and a pre-existing pulmonary metastasis. Initially, the patient received adjuvant chemotherapy and maintained a stable disease state for several months until radiographic and computed tomography (CT) examinations revealed progressive pulmonary metastasis. In response to this progression, combination therapy with high-dose losartan (angiotensin II type 1 receptor blocker [ARB], 10 mg/kg PO SID) and toceranib (2.75 mg/kg PO EOD) was initiated concurrently with ongoing carboplatin cycles. Two months after initiating this new regimen, a comprehensive CT re-evaluation demonstrated a significant positive response, marked by the radiographic disappearance of pulmonary nodules and complete resolution of the pleural effusion. This substantial improvement indicated a potential synergistic anticancer effect, likely mediated by losartan's capacity to remodel the tumor microenvironment (TME), suggesting a likely niche therapy, thereby enhancing toceranib efficacy. Despite this initial success, the patient’s condition ultimately deteriorated after the completion of chemotherapy, confirming extensive disease progression. A subsequent attempt with doxorubicin as a third-line agent resulted in severe adverse effects, such as bone marrow suppression and neutropenia, leading to the patient's death shortly thereafter (Table 1). This case contributed compelling clinical evidence of the promising short-term efficacy of high-dose losartan in combination with toceranib for progressive pulmonary metastatic OSA, potentially through favorable TME modulation. It also highlighted the inherent virulence of canine OSA and the challenges in achieving sustained long-term control. The development of innovative multimodal therapeutic approaches for the management of canine OSA is critically important. canine osteosarcoma chemotheraphy losartan toceranib combination therapy pulmonary metastasis tumor microenvironment TME Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Osteosarcoma (OSA) is the most prevalent primary malignant bone tumor in dogs, accounting for over 85% of all tumors [ 1 , 2 ]. It commonly occurs in the appendicular skeleton of older dogs, especially large and giant breeds [ 1 , 2 ]. OSA is characterized by rapid growth and a high propensity for metastasis to other organs, particularly the lungs, often at the time of diagnosis [ 1 , 2 , 3 ]. Patients typically present with progressive lameness, pain, and localized edema at the tumor site. The diagnosis of canine OSA is typically made based on clinical findings, imaging, including radiography and computed tomography (CT), and confirmatory cytology or histopathology. The current standard of care for appendicular OSA is surgical amputation of the affected limb, followed by adjuvant chemotherapy [ 1 , 2 , 3 , 4 ]. Despite interventions, the prognosis of OSA remains poor, owing to its inherent virulence and high metastatic potential in the lungs. While prognosis can vary based on factors such as tumor size, presence of macroscopic metastasis, and the dog's overall health at diagnosis, the average survival time is approximately 12 months with combined surgery and chemotherapy [ 1 , 2 , 3 ]. As the long-term outcomes of current standard therapies have remained stagnant for decades, innovative treatments are critically needed to improve the quality of life of affected patients [ 4 ]. In advanced or metastatic cancers, where a cure is unlikely, the primary objective shifts from complete remission to slowing disease progression and maximizing the patient's survival time and quality of life, making strategies to prevent recurrence and metastasis crucial. Recently, Regan et al. published a landmark study on the combined administration of losartan (a well-known ARB antihypertensive drug used in humans and dogs) and toceranib in dogs with pulmonary osteosarcoma metastasis. Their research revealed that high-dose losartan (10 mg/kg) combined with toceranib (2.75 mg/kg) achieved a 50% clinical benefit rate and demonstrated longer survival than toceranib monotherapy [ 5 ]. Regan et al. suggested that losartan possesses anticancer properties by inhibiting cancer metastasis. This effect is thought to occur through the inhibition of the C-C motif chemokine ligand 2 (CCL2)-C-C chemokine receptor type 2 (CCR2) monocyte recruitment within the tumor microenvironment (TME) [ 5 ]. Toceranib, a multi-targeted tyrosine kinase inhibitor (TKI), has been approved for the treatment of canine mast cell tumors owing to its antitumor effects via c-Kit inhibition. It also exhibits significant anti-angiogenic effects by inhibiting platelet-derived growth factor receptor (PDGFR) and vascular endothelial growth factor receptor (VEGFR), making it a widely used targeted anticancer drug in veterinary medicine [ 6 ]. The significance of this finding extends beyond veterinary medicine, as canine osteosarcoma is considered an excellent spontaneous model for the human disease, driving new therapeutic strategies through drug repurposing [ 7 ]. The case report provided a foundation for our proposed therapeutic approach. In this case, we evaluated the clinical impact and potential anticancer synergy of a combination therapy (losartan and toceranib), added to existing adjuvant chemotherapy in a Jindo dog with progressive pulmonary metastatic osteosarcoma. Our goal was to assess the efficacy of this new regimen in mitigating progressive pulmonary metastasis and potentially improving patient outcomes. Case Description A 3-year-old castrated male Jindo was diagnosed histopathologically with OSA of the right tibia on April 30, 2024 (Fig. 1 ). Two weeks later, following the right hind limb amputation, the patient was referred to the FM Animal Hospital on May 24, 2024, for adjuvant chemotherapy. Presurgical staging revealed pulmonary metastasis, but no spread to the regional lymph nodes or other organs was observed. Adjuvant chemotherapy was initiated approximately two weeks after post-amputation (Fig. 2 ). The initial regimen consisted of one cycle of cisplatin administered intravenously (IV) at a dose of 60 mg/m². Due to concerns regarding potential nephrotoxicity, the chemotherapy protocol was subsequently changed to carboplatin (200 mg/m² IV every 21 days). During chemotherapy, Serial complete blood count (CBCs) and serum biochemical profile were evaluated to monitor myelosuppression and other toxicities. Thoracic radiographs were obtained every three weeks to routinely assess pulmonary metastatic lesions, and a CT scan was performed after the completion of all chemotherapy cycles. During the first four months of this regimen, routine monitoring revealed stable hematological parameters and unremarkable serum biochemical results. Furthermore, canine C-reactive protein (cCRP) and D-dimer levels remained within the normal range, indicating an adequate early therapeutic response. The initial thoracic radiographs also showed no detectable pulmonary nodules (Fig. 3 A). A follow-up radiograph (Fig. 3 B) taken four months after the initial diagnosis showed progression of the pulmonary metastasis, characterized by the appearance of multiple pulmonary nodules and an accompanying pleural effusion. This was corroborated by sequential transverse CT images (Fig. 4 , Upper Panel B; Lower Panel B), which revealed an increase in the size and number of nodules along with bilateral pleural fluid. No distant skeletal or regional lymph node metastases were observed. In response to disease progression, an alternative therapeutic strategy was initiated on September 24, 2024. A combination of high-dose losartan (10 mg/kg PO SID) and toceranib (2.75 mg/kg PO EOD) was initiated concurrently with a second set of carboplatin cycles. Normal blood pressure was confirmed before the combination therapy was commenced. Throughout the combined treatment, CBCs and vital biochemical markers (renal and hepatic parameters, CRP levels, and other relevant markers) were carefully monitored. These markers showed stable trends with no statistically or clinically significant long-term fluctuations. Two months after initiating high-dose losartan and toceranib therapy, comprehensive CT re-evaluation revealed a significant positive response. Thoracic radiographs (Fig. 3 C) showed that the pulmonary nodules were no longer visible and the pleural effusion resolved. This impressive regression was further corroborated by sequential transverse CT images (Fig. 4 , Upper Panel C; Lower Panel C), which demonstrated a partial response with decreased nodule size and attenuation and a substantial reduction in pleural fluid volume. During this period, D-dimer and cCRP levels showed a notable decrease, returning to a near-normal range, corresponding to the observed clinical improvement. Encouraged by these positive results, the patient was switched to losartan or toceranib monotherapy after the completion of chemotherapy. However, on February 7, 2025, during the 3rd post-operative CT examination, the patient's clinical condition deteriorated. Clinically, a noticeable decline in vitality and appetite was observed, accompanied by harsh breathing sounds and reduced exercise tolerance. The CT tomography confirmed disease progression, showing an increase in both the size and number of pulmonary metastatic nodules, with the largest increase being approximately 30%. Recurrent pleural effusion and multiple pulmonary nodules were also observed on subsequent radiographs (Fig. 3 D) and computed tomography (CT) scans (Fig. 4 , Upper Panel D; Lower Panel D), consistent with extensive disease. At this time, the D-dimer and cCRP levels showed a marked increase, reflecting renewed disease progression. At this time, the D-dimer and cCRP levels showed a marked increase, reflecting renewed disease progression. Doxorubicin was administered as a third-line chemotherapeutic agent on February 19, 2025. The patient's condition rapidly deteriorated following treatment. Significant adverse effects, including severe vomiting and a drastic decrease in the neutrophil count, were noted. The patient ultimately died six days later, on February 25, 2025. Discussion Canine OSA remains a formidable challenge in veterinary oncology because of its aggressive nature and the high metastatic risk, particularly in the lungs [ 1 , 2 , 3 ]. Despite established standard-of-care treatments, the prognosis for affected patients remains poor [ 1 , 2 , 3 , 4 ]. The development of innovative therapeutic strategies to improve patient outcomes is urgently needed. This case highlighted the limitations of conventional chemotherapy in the management of advanced metastatic OSA. After four months of adjuvant carboplatin therapy, the patient's pulmonary metastasis progressed, underscoring the need for an adapted therapeutic approach. This finding is consistent with the variable and often limited efficacy of traditional cytotoxic agents against metastatic diseases. It is also important to note that throughout this period, while the hematological parameters remained relatively stable, the patient experienced periods of transient myelosuppression following carboplatin cycles. However, no sustained long-term trends were observed in renal or hepatic function. In response to disease progression, we initiated a combination therapy of high-dose losartan(ARB) and toceranib, guided by Regan et al . [ 5 ]. This strategic decision proved highly impactful. A comprehensive CT re-evaluation two months into this regimen revealed a significant positive therapeutic response. The pulmonary nodules became radiographically invisible, and the previously observed pleural effusion was completely resolved (Figs. 3 C and 4 C). This substantial improvement strongly suggests a synergistic anti-cancer effect of the losartan and toceranib combination against aggressive pulmonary metastasis, a level of response that is unlikely to be achieved with either agent alone. The synergy likely stems from losartan's capacity to remodel the tumor microenvironment (TME), thereby enhancing the anticancer efficacy of toceranib [ 5 ]. This remarkable clinical response, mirrored by a notable decrease in D-dimer and cCRP levels, not only highlights the potential of this novel combination therapy in veterinary medicine but also reinforces the value of canine osteosarcoma as a model for advancing therapeutic strategies in human oncology [ 7 ]. This positive outcome further emphasizes the critical role of TME in OSA progression and therapeutic response, which is consistent with recent findings [ 8 ]. Losartan, an ARB, modulates the TME by reducing desmoplasia and immune cell infiltration [ 9 ]. Given the complex immune landscape of OSA, in which the TME significantly influences tumor behavior, the ability of losartan to alter this permissive environment likely amplifies the effectiveness of toceranib. Toceranib, a multi-targeted tyrosine kinase inhibitor [ 6 ], not only directly targets tumor cells and angiogenesis, but may also operate more efficiently within a TME rendered less immunosuppressive or fibrotic by losartan, indicating a true synergistic interaction beyond its individual mechanisms [ 5 , 8 ]. However, despite this initial success, the patient's condition ultimately deteriorated, and disease progression was confirmed during the third postoperative CT examination on February 7, 2025 (Figs. 3 D and 4 D). This underscores the inherent virulence of canine OSA and the challenges in achieving durable long-term remission, even with novel and seemingly effective combinations. Unfortunately, a subsequent attempt with doxorubicin as a third-line agent led to severe adverse effects and rapid decline, culminating in the patient's death on February 25, 2025. This final decline included severe neutropenia (0.47 × 10 3 /L) and a peak cCRP level (61.39 mg/L) following doxorubicin administration. Although our case provides compelling evidence, it is essential to acknowledge the limitations. As this is a single-case report, the findings may not be generalizable to all dogs with osteosarcoma, and the observed response may not reflect long-term efficacy. Furthermore, the concurrent administration of carboplatin during the initial phase of the combination therapy makes it difficult to ascertain the precise contribution of each drug. It remains unclear whether the positive outcome was a result of the losartan/toceranib combination alone or if a synergistic effect with ongoing chemotherapy was also at play. Therefore, future prospective studies comparing losartan/toceranib monotherapy and combination regimens are warranted to fully delineate optimal therapeutic strategies. Conclusion This case report provides compelling clinical evidence of the potential utility of high-dose losartan combined with toceranib for the management of progressive pulmonary metastasis in canine osteosarcoma. The initial profound response, likely augmented by favorable TME modulation, supports the exploration of drug repurposing for anticancer properties in combination with targeted therapies. Although this single case demonstrated a promising initial effect, the ultimate disease progression highlights the ongoing need for continuous treatment adaptation and underscores the limitations of achieving sustained control in such aggressive cancers. Larger prospective studies are needed to fully evaluate the long-term efficacy, optimal dosing, and generalizability of this combination therapy, thereby contributing to the broader development of innovative multimodal approaches that account for the intricate interplay within the tumor microenvironment to effectively combat canine osteosarcoma. Declarations Acknowledgments The authors extend sincere gratitude to the owner for providing informed consent for the patient's treatment and for allowing the use of the patient's clinical data for this scientific report. This works supported by FM Animal Medical Center, Gimpo City 10080, Republic of Korea and Stellamed Co., LTD, Daegu City 41504, Republic of Korea Author’s Contributions JH and MG participated in the diagnosis, treatment and wrote initial manuscript; SN conceptualized, analyzed, and wrote the manuscript; and KS conceptualized the initial idea, led the project, and edited the manuscript. Conflict of Interest The authors declare no conflict of interest. Funding Source No funding was received for this study. Ethical Approval statement Written consent was obtained from the patient’s owner. Data Availability Statement Data sharing is not applicable to this article because no new datasets were generated or analyzed during the current study owing to patient privacy concerns. References Zanardi S, Sabattini S, Rossi F, et al. Adjuvant Chemotherapy Is Associated With Prolonged Survival Time in Small-Breed Dogs Undergoing Amputation for Appendicular Osteosarcoma. Vet Comp Oncol. 2025;23(2):161–7. 10.1111/vco.13041 . Morello E, Martano M, Buracco P. Biology, diagnosis and treatment of canine appendicular osteosarcoma: similarities and differences with human osteosarcoma. Vet J. 2011;189(3):268–77. 10.1016/j.tvjl.2010.08.014 . Dolnicka A, Fosse V, Raciborska A, Śmieszek A. Building a Therapeutic Bridge Between Dogs and Humans: A Review of Potential Cross-Species Osteosarcoma Biomarkers. Int J Mol Sci. 2025;26(11):5152. 10.3390/ijms26115152 . Poon AC, Matsuyama A, Mutsaers AJ. Recent and current clinical trials in canine appendicular osteosarcoma. Can Vet J. 2020;61(3):301–8. Regan DP, Chow L, Das S, et al. Losartan Blocks Osteosarcoma-Elicited Monocyte Recruitment, and Combined With the Kinase Inhibitor Toceranib, Exerts Significant Clinical Benefit in Canine Metastatic Osteosarcoma. Clin Cancer Res. 2022;28(4):662–76. 10.1158/1078-0432.CCR-21-2105 . Maeda S. Second era of molecular-targeted cancer therapies in dogs. J Vet Med Sci. 2023;85(8):790–8. 10.1292/jvms.23-0204 . Weiss MC, Eulo V, Van Tine BA. Truly Man's Best Friend: Canine Cancers Drive Drug Repurposing in Osteosarcoma. Clin Cancer Res. 2022;28(4):571–2. 10.1158/1078-0432.CCR-21-3471 . Orrapin S, Moonmuang S, Udomruk S, Yongpitakwattana P, Pruksakorn D, Chaiyawat P. Unlocking the tumor-immune microenvironment in osteosarcoma: insights into the immune landscape and mechanisms. Front Immunol. 2024;15:1394284. 10.3389/fimmu.2024.1394284 . Carlos-Escalante JA, de Jesús-Sánchez M, Rivas-Castro A, Pichardo-Rojas PS, Arce C, Wegman-Ostrosky T. The Use of Antihypertensive Drugs as Coadjuvant Therapy in Cancer. Front Oncol. 2021;11:660943. 10.3389/fonc.2021.660943 . Tables Table 1 Changes in hematological and biochemical parameters during treatment. Variables (RI) Day 0 Week 3 Week 6 Week 9 Week 12 Week 15 Week 18 Week 21 Week 24 Week 27 Week 30 Week 33 Week 36 Week 39 RBC (5.65 ~ 8.87 10 12 /L) N/A 8.09 8.21 9 9.37 8.87 N/A 8.61 8 7.05 7.64 8.23 8.51 6.88 Neutrophil (2.95 ~ 11.64 10 9 /L) N/A 3.3 3.1 3.4 3.8 4.37 N/A 3.77 5.21 0.25 1.91 3.23 2.51 0.47 Platelete (148 ~ 484 10 9 /L) N/A 189 302 338 256 242 N/A 125 258 120 236 228 246 236 BUN (9.2–29.2 mg/dL) 23 29 29 N/A 32.1 27 N/A 24.2 24.3 24.7 23.3 28.3 24.6 N/A CREA (0.4–1.4 mg/dL) 1.7 2.3 2.5 N/A 1.57 1.82 N/A 1.32 1.5 1.29 1.59 1.3 1.42 N/A ALP (47–254 U/L) N/A N/A N/A N/A N/A N/A N/A 38 35 33 23 63 128 N/A ALT (17–78 U/L) N/A N/A N/A N/A N/A N/A N/A 31 26 32 28 N/A 43 N/A AST (17–44 U/L) N/A N/A N/A N/A N/A N/A N/A 46 36 N/A N/A N/A N/A N/A cCRP (0–10.00 mg/L) N/A 5.94 N/A 4.9 N/A N/A N/A 37.13 18.07 6.58 6.43 17.62 23.67 61.39 D-dimer (0-250 ng/mL) 109.1 N/A N/A 76.01 N/A N/A N/A 334.5 239.2 81.58 82.17 492.9 433.1 343.3 N/A indicates no test result. Abbreviations: RI, reference interval; RBC, red blood cell; BUN, blood urea nitrogen; CREA, creatinine; ALP, alkaline phosphatase; ALT, alanine aminotransferase; AST, aspartate aminotransferase; cCRP, canine C-reactive protein; D-dimer, degradation fragment. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 01 Dec, 2025 Reviewers agreed at journal 15 Nov, 2025 Reviews received at journal 14 Nov, 2025 Reviewers agreed at journal 12 Nov, 2025 Reviews received at journal 06 Oct, 2025 Reviewers agreed at journal 11 Sep, 2025 Reviewers invited by journal 07 Sep, 2025 Editor assigned by journal 25 Aug, 2025 Submission checks completed at journal 20 Aug, 2025 First submitted to journal 20 Aug, 2025 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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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7413733","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Short Report","associatedPublications":[],"authors":[{"id":505117300,"identity":"47dd506c-9287-4ed0-948f-4076000a6c2b","order_by":0,"name":"Ji-Hoon Kwak","email":"","orcid":"","institution":"FM Animal Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Ji-Hoon","middleName":"","lastName":"Kwak","suffix":""},{"id":505117301,"identity":"41317b7a-281e-4882-9dbc-1290e112cb3c","order_by":1,"name":"Mingyu Jung","email":"","orcid":"","institution":"FM Animal Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Mingyu","middleName":"","lastName":"Jung","suffix":""},{"id":505117302,"identity":"d2b3f56f-8741-47b1-9da4-c31f13f35c84","order_by":2,"name":"Soo-Nyun Choi","email":"","orcid":"","institution":"Kyungpook National University","correspondingAuthor":false,"prefix":"","firstName":"Soo-Nyun","middleName":"","lastName":"Choi","suffix":""},{"id":505117303,"identity":"4c192908-8e9d-4017-a4aa-74ab17728831","order_by":3,"name":"Kyu-Shik Jeong","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0UlEQVRIiWNgGAWjYBACxgYQeYBBjuEGRMCAaC3GxGuBgAMMiQ1Ea2Fubz728MuZuvS+2z0GDD9qGIzNGwg5rOdYurHMjcO5M++cMQByGMxkDhDSMiPHTFriw4HcDTdyDBh4GxhsJAg5jHH+G5CWunQDoBbGv0RpmcFjJvnhBnMCSAsz0BYzwlp60tKkGc4cNpx5I63gsMwxCWOCWgzbDx+T/HGsTp7vRvLGh29qbAxnENTSAAxoHijnAAMDQTsYGORBjvtBWN0oGAWjYBSMZAAAbShB8XFqniQAAAAASUVORK5CYII=","orcid":"","institution":"Daegu Haany University","correspondingAuthor":true,"prefix":"","firstName":"Kyu-Shik","middleName":"","lastName":"Jeong","suffix":""}],"badges":[],"createdAt":"2025-08-20 05:53:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7413733/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7413733/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":90319532,"identity":"1152b777-8a79-4ae9-aa56-6161275435a7","added_by":"auto","created_at":"2025-09-01 10:39:22","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":257344,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eHistological hallmark of osteosarcoma (hematoxylin and eosin staining).\u003c/strong\u003e (A) Low magnification image showing the overall architecture of the osteosarcoma lesion. The tumor extensively infiltrates the bone tissue, characterized by the destruction of normal bone structures. (B) The intermediate magnification image revealing the characteristic histology of osteosarcoma, including malignant osteoclastic and osteoblastic features. Irregularly-shaped eosinophilic osteoid is seen, surrounded by highly pleomorphic neoplastic osteoblasts. Multinucleated giant cells are also observed. (C) The high magnification image highlighting the cytological atypia of the neoplastic cells. Malignant osteoblasts with atypical nuclei and coarse chromatin are actively producing osteoid. The presence of hemorrhage within the tumor stroma is also noted.\u003c/p\u003e","description":"","filename":"image1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7413733/v1/67f2064ed9ff31669b105c2b.jpeg"},{"id":90319533,"identity":"213aff4a-7596-4900-b9fd-d517db584b87","added_by":"auto","created_at":"2025-09-01 10:39:22","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":92654,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eA timeline of the treatment protocol and monitoring schedule.\u003c/strong\u003e This figure illustrates the chronological progression of the therapeutic regimen, encompassing the initial chemotherapy (cisplatin followed by carboplatin), the introduction of losartan and toceranib, and the final administration of doxorubicin. It also details the schedule for routine monitoring, including blood work, X-rays, and CT scans.\u003c/p\u003e","description":"","filename":"image2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7413733/v1/b911f2fe756688b8c9e82256.jpeg"},{"id":90319539,"identity":"b3939c33-e692-4e0b-adf6-c389c04de5b9","added_by":"auto","created_at":"2025-09-01 10:39:22","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":182085,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTemporal changes in pulmonary nodules and pleural effusion on left lateral thoracic radiographs from a dog with osteosarcoma and pulmonary metastasis before and after high-dose losartan (ARB) and toceranib administration. \u003c/strong\u003e(A) At baseline, no radiographically detectable pulmonary nodules or pleural effusion are identified. (B) Four months later, the radiograph shows multiple pulmonary nodules (soft tissue opacity, well-defined margins, white arrowheads) throughout the lung fields. Pleural effusion (black arrows) is also present. (C) Two months after beginning high-dose losartan therapy, pulmonary nodules are no longer radiographically visible, and the previously noted pleural effusion has resolved. (D) At follow-up, after clinical deterioration, recurrent pleural effusion (black arrows) and multiple pulmonary nodules (white arrowheads) are again identified, consistent with disease progression.\u003c/p\u003e","description":"","filename":"image3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7413733/v1/6736d8a2c28bf7aab5ac368a.jpeg"},{"id":90320530,"identity":"3f4c0c80-d1bf-4c75-9915-a00ea2c0d572","added_by":"auto","created_at":"2025-09-01 10:47:22","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":371599,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSequential transverse CT images of the thorax demonstrating the progression of pulmonary metastasis and changes in pleural effusion in a canine osteosarcoma.\u003c/strong\u003eThe upper panels illustrate the temporal evolution of pulmonary metastatic nodules, while the lower panels depict changes in pleural effusion volume over time. All images were acquired using 1.0-mm slice thickness.\u003c/p\u003e","description":"","filename":"image4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7413733/v1/3da4bb4b33e75840133c6780.jpeg"},{"id":90321656,"identity":"2434509d-cbb1-4545-8ddd-b97bfc252284","added_by":"auto","created_at":"2025-09-01 10:55:22","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1634069,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7413733/v1/ac6667df-4466-465b-9365-de5e430fbba8.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Losartan(Angiotensin II Type 1 Receptor Blocker) and Toceranib Combination Therapy for Progressive Pulmonary Metastasis in Canine Osteosarcoma: A Case Report","fulltext":[{"header":"Introduction","content":"\u003cp\u003eOsteosarcoma (OSA) is the most prevalent primary malignant bone tumor in dogs, accounting for over 85% of all tumors [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. It commonly occurs in the appendicular skeleton of older dogs, especially large and giant breeds [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. OSA is characterized by rapid growth and a high propensity for metastasis to other organs, particularly the lungs, often at the time of diagnosis [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e\u003cp\u003ePatients typically present with progressive lameness, pain, and localized edema at the tumor site. The diagnosis of canine OSA is typically made based on clinical findings, imaging, including radiography and computed tomography (CT), and confirmatory cytology or histopathology. The current standard of care for appendicular OSA is surgical amputation of the affected limb, followed by adjuvant chemotherapy [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eDespite interventions, the prognosis of OSA remains poor, owing to its inherent virulence and high metastatic potential in the lungs. While prognosis can vary based on factors such as tumor size, presence of macroscopic metastasis, and the dog's overall health at diagnosis, the average survival time is approximately 12 months with combined surgery and chemotherapy [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. As the long-term outcomes of current standard therapies have remained stagnant for decades, innovative treatments are critically needed to improve the quality of life of affected patients [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. In advanced or metastatic cancers, where a cure is unlikely, the primary objective shifts from complete remission to slowing disease progression and maximizing the patient's survival time and quality of life, making strategies to prevent recurrence and metastasis crucial.\u003c/p\u003e\u003cp\u003eRecently, Regan \u003cem\u003eet al.\u003c/em\u003e published a landmark study on the combined administration of losartan (a well-known ARB antihypertensive drug used in humans and dogs) and toceranib in dogs with pulmonary osteosarcoma metastasis. Their research revealed that high-dose losartan (10 mg/kg) combined with toceranib (2.75 mg/kg) achieved a 50% clinical benefit rate and demonstrated longer survival than toceranib monotherapy [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Regan \u003cem\u003eet al.\u003c/em\u003e suggested that losartan possesses anticancer properties by inhibiting cancer metastasis. This effect is thought to occur through the inhibition of the C-C motif chemokine ligand 2 (CCL2)-C-C chemokine receptor type 2 (CCR2) monocyte recruitment within the tumor microenvironment (TME) [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Toceranib, a multi-targeted tyrosine kinase inhibitor (TKI), has been approved for the treatment of canine mast cell tumors owing to its antitumor effects via c-Kit inhibition. It also exhibits significant anti-angiogenic effects by inhibiting platelet-derived growth factor receptor (PDGFR) and vascular endothelial growth factor receptor (VEGFR), making it a widely used targeted anticancer drug in veterinary medicine [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe significance of this finding extends beyond veterinary medicine, as canine osteosarcoma is considered an excellent spontaneous model for the human disease, driving new therapeutic strategies through drug repurposing [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe case report provided a foundation for our proposed therapeutic approach. In this case, we evaluated the clinical impact and potential anticancer synergy of a combination therapy (losartan and toceranib), added to existing adjuvant chemotherapy in a Jindo dog with progressive pulmonary metastatic osteosarcoma. Our goal was to assess the efficacy of this new regimen in mitigating progressive pulmonary metastasis and potentially improving patient outcomes.\u003c/p\u003e"},{"header":"Case Description","content":"\u003cp\u003eA 3-year-old castrated male Jindo was diagnosed histopathologically with OSA of the right tibia on April 30, 2024 (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Two weeks later, following the right hind limb amputation, the patient was referred to the FM Animal Hospital on May 24, 2024, for adjuvant chemotherapy. Presurgical staging revealed pulmonary metastasis, but no spread to the regional lymph nodes or other organs was observed.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAdjuvant chemotherapy was initiated approximately two weeks after post-amputation (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The initial regimen consisted of one cycle of cisplatin administered intravenously (IV) at a dose of 60 mg/m\u0026sup2;. Due to concerns regarding potential nephrotoxicity, the chemotherapy protocol was subsequently changed to carboplatin (200 mg/m\u0026sup2; IV every 21 days). During chemotherapy, Serial complete blood count (CBCs) and serum biochemical profile were evaluated to monitor myelosuppression and other toxicities. Thoracic radiographs were obtained every three weeks to routinely assess pulmonary metastatic lesions, and a CT scan was performed after the completion of all chemotherapy cycles.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eDuring the first four months of this regimen, routine monitoring revealed stable hematological parameters and unremarkable serum biochemical results. Furthermore, canine C-reactive protein (cCRP) and D-dimer levels remained within the normal range, indicating an adequate early therapeutic response. The initial thoracic radiographs also showed no detectable pulmonary nodules (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eA follow-up radiograph (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB) taken four months after the initial diagnosis showed progression of the pulmonary metastasis, characterized by the appearance of multiple pulmonary nodules and an accompanying pleural effusion. This was corroborated by sequential transverse CT images (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, Upper Panel B; Lower Panel B), which revealed an increase in the size and number of nodules along with bilateral pleural fluid. No distant skeletal or regional lymph node metastases were observed.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eIn response to disease progression, an alternative therapeutic strategy was initiated on September 24, 2024. A combination of high-dose losartan (10 mg/kg PO SID) and toceranib (2.75 mg/kg PO EOD) was initiated concurrently with a second set of carboplatin cycles. Normal blood pressure was confirmed before the combination therapy was commenced. Throughout the combined treatment, CBCs and vital biochemical markers (renal and hepatic parameters, CRP levels, and other relevant markers) were carefully monitored. These markers showed stable trends with no statistically or clinically significant long-term fluctuations.\u003c/p\u003e\u003cp\u003eTwo months after initiating high-dose losartan and toceranib therapy, comprehensive CT re-evaluation revealed a significant positive response. Thoracic radiographs (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eC) showed that the pulmonary nodules were no longer visible and the pleural effusion resolved. This impressive regression was further corroborated by sequential transverse CT images (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, Upper Panel C; Lower Panel C), which demonstrated a partial response with decreased nodule size and attenuation and a substantial reduction in pleural fluid volume. During this period, D-dimer and cCRP levels showed a notable decrease, returning to a near-normal range, corresponding to the observed clinical improvement.\u003c/p\u003e\u003cp\u003eEncouraged by these positive results, the patient was switched to losartan or toceranib monotherapy after the completion of chemotherapy. However, on February 7, 2025, during the 3rd post-operative CT examination, the patient's clinical condition deteriorated. Clinically, a noticeable decline in vitality and appetite was observed, accompanied by harsh breathing sounds and reduced exercise tolerance. The CT tomography confirmed disease progression, showing an increase in both the size and number of pulmonary metastatic nodules, with the largest increase being approximately 30%. Recurrent pleural effusion and multiple pulmonary nodules were also observed on subsequent radiographs (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eD) and computed tomography (CT) scans (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, Upper Panel D; Lower Panel D), consistent with extensive disease. At this time, the D-dimer and cCRP levels showed a marked increase, reflecting renewed disease progression. At this time, the D-dimer and cCRP levels showed a marked increase, reflecting renewed disease progression.\u003c/p\u003e\u003cp\u003eDoxorubicin was administered as a third-line chemotherapeutic agent on February 19, 2025. The patient's condition rapidly deteriorated following treatment. Significant adverse effects, including severe vomiting and a drastic decrease in the neutrophil count, were noted. The patient ultimately died six days later, on February 25, 2025.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eCanine OSA remains a formidable challenge in veterinary oncology because of its aggressive nature and the high metastatic risk, particularly in the lungs [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Despite established standard-of-care treatments, the prognosis for affected patients remains poor [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. The development of innovative therapeutic strategies to improve patient outcomes is urgently needed.\u003c/p\u003e\u003cp\u003eThis case highlighted the limitations of conventional chemotherapy in the management of advanced metastatic OSA. After four months of adjuvant carboplatin therapy, the patient's pulmonary metastasis progressed, underscoring the need for an adapted therapeutic approach. This finding is consistent with the variable and often limited efficacy of traditional cytotoxic agents against metastatic diseases. It is also important to note that throughout this period, while the hematological parameters remained relatively stable, the patient experienced periods of transient myelosuppression following carboplatin cycles. However, no sustained long-term trends were observed in renal or hepatic function.\u003c/p\u003e\u003cp\u003eIn response to disease progression, we initiated a combination therapy of high-dose losartan(ARB) and toceranib, guided by Regan \u003cem\u003eet al\u003c/em\u003e. [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. This strategic decision proved highly impactful. A comprehensive CT re-evaluation two months into this regimen revealed a significant positive therapeutic response. The pulmonary nodules became radiographically invisible, and the previously observed pleural effusion was completely resolved (Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eC and \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eC). This substantial improvement strongly suggests a synergistic anti-cancer effect of the losartan and toceranib combination against aggressive pulmonary metastasis, a level of response that is unlikely to be achieved with either agent alone. The synergy likely stems from losartan's capacity to remodel the tumor microenvironment (TME), thereby enhancing the anticancer efficacy of toceranib [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. This remarkable clinical response, mirrored by a notable decrease in D-dimer and cCRP levels, not only highlights the potential of this novel combination therapy in veterinary medicine but also reinforces the value of canine osteosarcoma as a model for advancing therapeutic strategies in human oncology [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThis positive outcome further emphasizes the critical role of TME in OSA progression and therapeutic response, which is consistent with recent findings [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Losartan, an ARB, modulates the TME by reducing desmoplasia and immune cell infiltration [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Given the complex immune landscape of OSA, in which the TME significantly influences tumor behavior, the ability of losartan to alter this permissive environment likely amplifies the effectiveness of toceranib. Toceranib, a multi-targeted tyrosine kinase inhibitor [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], not only directly targets tumor cells and angiogenesis, but may also operate more efficiently within a TME rendered less immunosuppressive or fibrotic by losartan, indicating a true synergistic interaction beyond its individual mechanisms [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eHowever, despite this initial success, the patient's condition ultimately deteriorated, and disease progression was confirmed during the third postoperative CT examination on February 7, 2025 (Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eD and \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eD). This underscores the inherent virulence of canine OSA and the challenges in achieving durable long-term remission, even with novel and seemingly effective combinations. Unfortunately, a subsequent attempt with doxorubicin as a third-line agent led to severe adverse effects and rapid decline, culminating in the patient's death on February 25, 2025. This final decline included severe neutropenia (0.47 \u0026times; 10\u003csup\u003e3\u003c/sup\u003e/L) and a peak cCRP level (61.39 mg/L) following doxorubicin administration.\u003c/p\u003e\u003cp\u003eAlthough our case provides compelling evidence, it is essential to acknowledge the limitations. As this is a single-case report, the findings may not be generalizable to all dogs with osteosarcoma, and the observed response may not reflect long-term efficacy. Furthermore, the concurrent administration of carboplatin during the initial phase of the combination therapy makes it difficult to ascertain the precise contribution of each drug. It remains unclear whether the positive outcome was a result of the losartan/toceranib combination alone or if a synergistic effect with ongoing chemotherapy was also at play. Therefore, future prospective studies comparing losartan/toceranib monotherapy and combination regimens are warranted to fully delineate optimal therapeutic strategies.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis case report provides compelling clinical evidence of the potential utility of high-dose losartan combined with toceranib for the management of progressive pulmonary metastasis in canine osteosarcoma. The initial profound response, likely augmented by favorable TME modulation, supports the exploration of drug repurposing for anticancer properties in combination with targeted therapies. Although this single case demonstrated a promising initial effect, the ultimate disease progression highlights the ongoing need for continuous treatment adaptation and underscores the limitations of achieving sustained control in such aggressive cancers. Larger prospective studies are needed to fully evaluate the long-term efficacy, optimal dosing, and generalizability of this combination therapy, thereby contributing to the broader development of innovative multimodal approaches that account for the intricate interplay within the tumor microenvironment to effectively combat canine osteosarcoma.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors extend sincere gratitude to the owner for providing informed consent for the patient's treatment and for allowing the use of the patient's clinical data for this scientific report. This works supported by FM Animal Medical Center, Gimpo City 10080, Republic of Korea and Stellamed Co., LTD, Daegu City 41504, Republic of Korea\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor’s Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eJH and MG\u0026nbsp;participated in the diagnosis,\u0026nbsp;treatment\u0026nbsp;and wrote initial manuscript; SN conceptualized, analyzed, and wrote\u0026nbsp;the manuscript; and\u0026nbsp;KS conceptualized the initial idea, led the project, and edited the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding Source\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo funding was received for this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical Approval statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWritten consent was obtained from the patient’s owner.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData sharing is not applicable to this article because no new datasets were generated or analyzed during the current study owing to patient privacy concerns.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eZanardi S, Sabattini S, Rossi F, et al. Adjuvant Chemotherapy Is Associated With Prolonged Survival Time in Small-Breed Dogs Undergoing Amputation for Appendicular Osteosarcoma. Vet Comp Oncol. 2025;23(2):161\u0026ndash;7. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/vco.13041\u003c/span\u003e\u003cspan address=\"10.1111/vco.13041\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMorello E, Martano M, Buracco P. Biology, diagnosis and treatment of canine appendicular osteosarcoma: similarities and differences with human osteosarcoma. Vet J. 2011;189(3):268\u0026ndash;77. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.tvjl.2010.08.014\u003c/span\u003e\u003cspan address=\"10.1016/j.tvjl.2010.08.014\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDolnicka A, Fosse V, Raciborska A, Śmieszek A. Building a Therapeutic Bridge Between Dogs and Humans: A Review of Potential Cross-Species Osteosarcoma Biomarkers. Int J Mol Sci. 2025;26(11):5152. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3390/ijms26115152\u003c/span\u003e\u003cspan address=\"10.3390/ijms26115152\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePoon AC, Matsuyama A, Mutsaers AJ. Recent and current clinical trials in canine appendicular osteosarcoma. Can Vet J. 2020;61(3):301\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRegan DP, Chow L, Das S, et al. Losartan Blocks Osteosarcoma-Elicited Monocyte Recruitment, and Combined With the Kinase Inhibitor Toceranib, Exerts Significant Clinical Benefit in Canine Metastatic Osteosarcoma. Clin Cancer Res. 2022;28(4):662\u0026ndash;76. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1158/1078-0432.CCR-21-2105\u003c/span\u003e\u003cspan address=\"10.1158/1078-0432.CCR-21-2105\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMaeda S. Second era of molecular-targeted cancer therapies in dogs. J Vet Med Sci. 2023;85(8):790\u0026ndash;8. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1292/jvms.23-0204\u003c/span\u003e\u003cspan address=\"10.1292/jvms.23-0204\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWeiss MC, Eulo V, Van Tine BA. Truly Man's Best Friend: Canine Cancers Drive Drug Repurposing in Osteosarcoma. Clin Cancer Res. 2022;28(4):571\u0026ndash;2. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1158/1078-0432.CCR-21-3471\u003c/span\u003e\u003cspan address=\"10.1158/1078-0432.CCR-21-3471\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eOrrapin S, Moonmuang S, Udomruk S, Yongpitakwattana P, Pruksakorn D, Chaiyawat P. Unlocking the tumor-immune microenvironment in osteosarcoma: insights into the immune landscape and mechanisms. Front Immunol. 2024;15:1394284. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fimmu.2024.1394284\u003c/span\u003e\u003cspan address=\"10.3389/fimmu.2024.1394284\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCarlos-Escalante JA, de Jes\u0026uacute;s-S\u0026aacute;nchez M, Rivas-Castro A, Pichardo-Rojas PS, Arce C, Wegman-Ostrosky T. The Use of Antihypertensive Drugs as Coadjuvant Therapy in Cancer. Front Oncol. 2021;11:660943. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fonc.2021.660943\u003c/span\u003e\u003cspan address=\"10.3389/fonc.2021.660943\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\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\u003cdiv class=\"SimplePara\"\u003eChanges in hematological and biochemical parameters during treatment.\u003c/div\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"15\"\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\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c14\" colnum=\"14\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c15\" colnum=\"15\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eVariables (RI)\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003eDay\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e0\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003eWeek\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e3\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003eWeek\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e6\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003eWeek\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e9\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003eWeek\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e12\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cdiv class=\"SimplePara\"\u003eWeek\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e15\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cdiv class=\"SimplePara\"\u003eWeek\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e18\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cdiv class=\"SimplePara\"\u003eWeek\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e21\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c10\"\u003e\u003cdiv class=\"SimplePara\"\u003eWeek\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e24\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c11\"\u003e\u003cdiv class=\"SimplePara\"\u003eWeek\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e27\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c12\"\u003e\u003cdiv class=\"SimplePara\"\u003eWeek\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e30\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c13\"\u003e\u003cdiv class=\"SimplePara\"\u003eWeek\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e33\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c14\"\u003e\u003cdiv class=\"SimplePara\"\u003eWeek\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e36\u003c/div\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c15\"\u003e\u003cdiv class=\"SimplePara\"\u003eWeek\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e39\u003c/div\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eRBC\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e(5.65\u0026thinsp;~\u0026thinsp;8.87 10\u003csup\u003e12\u003c/sup\u003e/L)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e8.09\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e8.21\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e9\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003e9.37\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cdiv class=\"SimplePara\"\u003e8.87\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cdiv class=\"SimplePara\"\u003e8.61\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cdiv class=\"SimplePara\"\u003e8\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cdiv class=\"SimplePara\"\u003e7.05\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cdiv class=\"SimplePara\"\u003e7.64\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u003cdiv class=\"SimplePara\"\u003e8.23\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c14\"\u003e\u003cdiv class=\"SimplePara\"\u003e8.51\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u003cdiv class=\"SimplePara\"\u003e6.88\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eNeutrophil\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e(2.95\u0026thinsp;~\u0026thinsp;11.64 10\u003csup\u003e9\u003c/sup\u003e/L)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e3.3\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e3.1\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e3.4\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003e3.8\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cdiv class=\"SimplePara\"\u003e4.37\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cdiv class=\"SimplePara\"\u003e3.77\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cdiv class=\"SimplePara\"\u003e5.21\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.25\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.91\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u003cdiv class=\"SimplePara\"\u003e3.23\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c14\"\u003e\u003cdiv class=\"SimplePara\"\u003e2.51\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u003cdiv class=\"SimplePara\"\u003e0.47\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003ePlatelete\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e(148\u0026thinsp;~\u0026thinsp;484 10\u003csup\u003e9\u003c/sup\u003e/L)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e189\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e302\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e338\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003e256\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cdiv class=\"SimplePara\"\u003e242\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cdiv class=\"SimplePara\"\u003e125\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cdiv class=\"SimplePara\"\u003e258\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cdiv class=\"SimplePara\"\u003e120\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cdiv class=\"SimplePara\"\u003e236\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u003cdiv class=\"SimplePara\"\u003e228\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c14\"\u003e\u003cdiv class=\"SimplePara\"\u003e246\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u003cdiv class=\"SimplePara\"\u003e236\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eBUN\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e(9.2\u0026ndash;29.2 mg/dL)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e23\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e29\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e29\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003e32.1\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cdiv class=\"SimplePara\"\u003e27\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cdiv class=\"SimplePara\"\u003e24.2\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cdiv class=\"SimplePara\"\u003e24.3\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cdiv class=\"SimplePara\"\u003e24.7\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cdiv class=\"SimplePara\"\u003e23.3\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u003cdiv class=\"SimplePara\"\u003e28.3\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c14\"\u003e\u003cdiv class=\"SimplePara\"\u003e24.6\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eCREA\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e(0.4\u0026ndash;1.4 mg/dL)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.7\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e2.3\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003e2.5\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.57\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.82\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.32\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.5\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.29\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.59\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.3\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c14\"\u003e\u003cdiv class=\"SimplePara\"\u003e1.42\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eALP\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e(47\u0026ndash;254 U/L)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cdiv class=\"SimplePara\"\u003e38\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cdiv class=\"SimplePara\"\u003e35\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cdiv class=\"SimplePara\"\u003e33\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cdiv class=\"SimplePara\"\u003e23\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u003cdiv class=\"SimplePara\"\u003e63\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c14\"\u003e\u003cdiv class=\"SimplePara\"\u003e128\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eALT\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e(17\u0026ndash;78 U/L)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cdiv class=\"SimplePara\"\u003e31\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cdiv class=\"SimplePara\"\u003e26\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cdiv class=\"SimplePara\"\u003e32\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cdiv class=\"SimplePara\"\u003e28\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c14\"\u003e\u003cdiv class=\"SimplePara\"\u003e43\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eAST\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e(17\u0026ndash;44 U/L)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cdiv class=\"SimplePara\"\u003e46\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cdiv class=\"SimplePara\"\u003e36\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c14\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003ecCRP\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e(0\u0026ndash;10.00 mg/L)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003e5.94\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e4.9\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cdiv class=\"SimplePara\"\u003e37.13\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cdiv class=\"SimplePara\"\u003e18.07\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cdiv class=\"SimplePara\"\u003e6.58\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cdiv class=\"SimplePara\"\u003e6.43\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u003cdiv class=\"SimplePara\"\u003e17.62\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c14\"\u003e\u003cdiv class=\"SimplePara\"\u003e23.67\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u003cdiv class=\"SimplePara\"\u003e61.39\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cdiv class=\"SimplePara\"\u003eD-dimer\u003c/div\u003e\u003cdiv class=\"SimplePara\"\u003e(0-250 ng/mL)\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cdiv class=\"SimplePara\"\u003e109.1\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cdiv class=\"SimplePara\"\u003e76.01\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cdiv class=\"SimplePara\"\u003eN/A\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cdiv class=\"SimplePara\"\u003e334.5\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cdiv class=\"SimplePara\"\u003e239.2\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cdiv class=\"SimplePara\"\u003e81.58\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cdiv class=\"SimplePara\"\u003e82.17\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u003cdiv class=\"SimplePara\"\u003e492.9\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c14\"\u003e\u003cdiv class=\"SimplePara\"\u003e433.1\u003c/div\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u003cdiv class=\"SimplePara\"\u003e343.3\u003c/div\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"15\"\u003eN/A indicates no test result. Abbreviations: RI, reference interval; RBC, red blood cell; BUN, blood urea nitrogen; CREA, creatinine; ALP, alkaline phosphatase; ALT, alanine aminotransferase; AST, aspartate aminotransferase; cCRP, canine C-reactive protein; D-dimer, degradation fragment.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003cbr/\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"irish-veterinary-journal","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Irish Veterinary Journal](https://irishvetjournal.biomedcentral.com/)","snPcode":"13620","submissionUrl":"https://submission.springernature.com/new-submission/13620/3?","title":"Irish Veterinary Journal","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"canine osteosarcoma, chemotheraphy, losartan, toceranib, combination therapy, pulmonary metastasis, tumor microenvironment, TME","lastPublishedDoi":"10.21203/rs.3.rs-7413733/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7413733/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eOsteosarcoma (OSA) is the most common and aggressive primary bone tumor in dogs. OSA frequently metastasizes to the lungs and has a poor prognosis despite current standard treatment. This case report described the clinical course of a 3-year-old castrated male Jindo dog diagnosed with right tibial OSA and a pre-existing pulmonary metastasis. Initially, the patient received adjuvant chemotherapy and maintained a stable disease state for several months until radiographic and computed tomography (CT) examinations revealed progressive pulmonary metastasis.\u003c/p\u003e\n\u003cp\u003eIn response to this progression, combination therapy with high-dose losartan (angiotensin II type 1 receptor blocker [ARB], 10 mg/kg PO SID) and toceranib (2.75 mg/kg PO EOD) was initiated concurrently with ongoing carboplatin cycles. Two months after initiating this new regimen, a comprehensive CT re-evaluation demonstrated a significant positive response, marked by the radiographic disappearance of pulmonary nodules and complete resolution of the pleural effusion. This substantial improvement indicated a potential synergistic anticancer effect, likely mediated by losartan's capacity to remodel the tumor microenvironment (TME), suggesting a likely niche therapy, thereby enhancing toceranib efficacy. Despite this initial success, the patient’s condition ultimately deteriorated after the completion of chemotherapy, confirming extensive disease progression. A subsequent attempt with doxorubicin as a third-line agent resulted in severe adverse effects, such as bone marrow suppression and neutropenia, leading to the patient's death shortly thereafter (Table 1).\u003c/p\u003e\n\u003cp\u003eThis case contributed compelling clinical evidence of the promising short-term efficacy of high-dose losartan in combination with toceranib for progressive pulmonary metastatic OSA, potentially through favorable TME modulation. It also highlighted the inherent virulence of canine OSA and the challenges in achieving sustained long-term control. The development of innovative multimodal therapeutic approaches for the management of canine OSA is critically important.\u003c/p\u003e","manuscriptTitle":"Losartan(Angiotensin II Type 1 Receptor Blocker) and Toceranib Combination Therapy for Progressive Pulmonary Metastasis in Canine Osteosarcoma: A Case Report","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-01 10:39:17","doi":"10.21203/rs.3.rs-7413733/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-01T11:21:22+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"42324094729148414974652476075349739181","date":"2025-11-15T19:26:22+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-14T19:28:54+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"167351415500534668655271659112130104957","date":"2025-11-12T15:46:57+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-06T11:59:41+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"268439679957329527482728483385862720777","date":"2025-09-11T09:09:19+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-09-08T02:37:02+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-25T08:04:49+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-20T07:47:55+00:00","index":"","fulltext":""},{"type":"submitted","content":"Irish Veterinary Journal","date":"2025-08-20T05:47:17+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"irish-veterinary-journal","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Irish Veterinary Journal](https://irishvetjournal.biomedcentral.com/)","snPcode":"13620","submissionUrl":"https://submission.springernature.com/new-submission/13620/3?","title":"Irish Veterinary Journal","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"3e0b5a18-659a-42ca-901f-65b0b9d7e7fd","owner":[],"postedDate":"September 1st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-02-23T15:24:44+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-01 10:39:17","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7413733","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7413733","identity":"rs-7413733","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}