Real-World Efficacy and Safety of Trastuzumab Emtansine Biosimilar (UJVIRA ® ) in Early and Metastatic HER2-Positive Breast Cancer: A Multicenter Pooled Retrospective Analysis from India 

<title>Abstract</title> <p>Purpose Trastuzumab-emtansine (T-DM1), an antibody drug conjugate, is approved in the adjuvant (residual disease post-neoadjuvant chemotherapy) and metastatic settings for HER2-positive breast cancer. Real-world evidence on T-DM1 biosimilar from India remains sparse. Methods During October 2021–July 2025, 101 cases treated with T-DM1 biosimilar - UJVIRA ®, across seven oncology centers in India were retrospectively analyzed. The adjuvant cohort (n = 19), had patients with residual disease after neoadjuvant therapy and surgery, and the metastatic cohort (n = 82), comprised patients progressing on trastuzumab-chemo regimens. Primary endpoints were invasive Disease-Free Survival (iDFS) and Progression Free Survival (PFS) in the adjuvant and metastatic cohort respectively. Overall Survival (OS) and safety were secondary endpoints. Results In the adjuvant cohort (median follow-up 19 months), median iDFS was not reached (mean 14.6 months), with 2 events (10.5%). In the metastatic cohort (median follow-up 8 months), median PFS was 7.5 months (mean 8.3 months; 61 events, 74.4%). PFS was longer when T-DM1 was administered earlier: 28 months in first-line, 9 months in second-line, and 8 months in third- and fourth-line (p = 0.06). Median OS in the metastatic cohort was 15.5 months and 36 months with 1st line T-DM1. In 14.6% of metastatic patients, grade 3 thrombocytopenia occurred; there were no grade 3/4 events in the adjuvant cohort. Conclusion UJVIRA® demonstrated real-world clinical effectiveness and an acceptable safety profile in both adjuvant and metastatic HER2-positive breast cancer, with outcomes similar to landmark clinical trials supporting its role as a cost-effective biosimilar in India.</p>