Assessment of ethnic difference in the incidence of thrombocytopenia induced by trastuzumab emtansine (T-DM1): A meta-analysis.

e15096 Background: Trastuzumab emtansine (T-DM1) has been proved its value and efficacy in advanced metastatic cancer disease as well as in the adjuvant setting. However, there is an increasing concern in T-DM1-induced thrombocytopenia (TCP), which also showed difference of incidence in races. This meta-analysis, combining available data from all single-agent T-DM1 studies to date, aimed to evaluate the incidence of treatment-related thrombocytopenia of T-DM1 and the differences between Asian and non-Asian patients. Methods: We conducted a systematic search of the relevant published clinical studies of T-DM1 that reported safety profile including thrombocytopenia, from 1980 to March of 2020 using PubMed, Embase, and the Cochrane database. Screening and data extraction were conducted by two independent reviewers. Pooled-effect estimates calculated with fixed-effects or random-effects model were expressed as incidence with 95% CIs. Results: A total of 29 studies involving 6188 patients were included. The incidence of all-grade thrombocytopenia in Asian patients was 0.39 (95%CI 0.11-0.67) and 0.29 (95%CI 0.23-0.35) in non-Asian patients. And the incidence of the grade 3 or higher thrombocytopenia in Asians was 0.20 (95%CI 0.10-0.29), in non-Asians was 0.02 (95%CI 0.01-0.03). Gastrointestinal cancer type and the dose of 2.4 mg/kg Q3W T-DM1 treatment were both associated with the higher incidence of grade 3 or higher thrombocytopenia. Conclusions: Asian patients have the higher risk of thrombocytopenia induced by T-DM1. Clinicians should have an awareness of careful observation in platelet counts when patients receive T-DM1 therapy.