High risks adverse events associated with trastuzumab emtansine and trastuzumab deruxtecan for the treatment of HER2-positive/mutated malignancies: a pharmacovigilance study based on the FAERS database

T-DM1 and T-DXd are two promising antibody-drug conjugates for treating advanced HER2-positive breast cancer and HER2-mutated lung cancer. Understanding the differences in the adverse events (AEs) profile of both drugs may help clinicians make an appropriate treatment decision.All data obtained from the FDA Adverse Event Reporting System (FAERS) database from Q1 2004 to Q3 2022 underwent disproportionality analysis and Bayesian analysis to detect and assess the AE signals of T-DM1 and T-DXd for comparison.A total of 2,113 and 1,269 AE reports associated with T-DM1 and T-Dxd, respectively, were retrieved from FAERS database, in which, respondents were mostly elderly women. Their statistical differences (p < 0.001), poses high incidence of thrombocytopenia, including cardiotoxicity (p < 0.05) for T-DM1, while myelosuppression, interstitial lung disease (ILD), and pneumonitis for T-DXd. Splenomegaly, nodular regenerative hyperplasia, hepatic cirrhosis, portal hypertension, neuropathy peripheral, and spider nevus, are particular to T-DM1. Similarly, febrile neutropenia, pneumocystis jirovecii pneumonia, neutrophil count decreased, and KL-6 increased, are unique to T-DXd.T-DXd is more likely to induce ILD/pneumonia and myelosuppression than T-DM1, whereas T-DM1 has higher risk of hepatotoxicity, cardiotoxicity, and thrombocytopenia than T-DXd. T-DM1-related hepatotoxicity may need redefinition. Clinicians may need to balance the benefits and risks of antibody-drug conjugates treatment for certain patients.