Long-term hepatobiliary disorder associated with trastuzumab emtansine pharmacovigilance study using the FDA Adverse Event Reporting System database.

Trastuzumab emtansine (T-DM1) is widely utilized as a second-line and subsequent treatment for metastatic HER2+ breast cancer and has shown promise in early breast cancer treatment, particularly in adjuvant settings for residual disease after neoadjuvant chemotherapy. However, concerns have arisen regarding long-term hepatic adverse drug reactions (ADRs) not identified in clinical trials. We investigated potential safety signals of T-DM1 in hepatobiliary disorders and the time-to-onset of ADRs using the FDA Adverse Event Reporting System (FAERS) database. Suspected ADRs were extracted and divided into two groups: T-DM1 (N = 3387) and other drugs (N = 11,833,701). Potential signal for T-DM1 in hepatobiliary disorder were identified (reporting odds ratio [ROR] = 5.66, 95% confidence interval [CI] = 5.11-6.27; information component [IC] = 2.35, 95% Credibility Interval [Crl] = 2.18-2.51). A breast cancer indicated subgroup analysis (2519 T-DM1; 172,329 other drugs) also identified a potential safety signal (ROR = 3.28, 95% CI = 2.92-3.68; IC = 1.53, 95%CrI = 1.35-1.71). The median time-to-onset for T-DM1-associated hepatobiliary disorders was 41 days. For prolonged and chronic hepatobiliary disorders, median times were 322.5 and 301.5 days, respectively. These findings highlight the need for further research to inform clinical decisions on optimal T-DM1 treatment duration, balancing benefits with potential adverse reactions.