Severe Acute Thrombocytopenia After Biosimilar Trastuzumab Administration: A Case Report

Drug-induced immune thrombocytopenia may occur secondary to several chemotherapeutic agents or new targeted monoclonal antibodies, but thrombocytopenia induced by trastuzumab is a very rare occurrence. We report a case of severe thrombocytopenia related to the first administration of a biosimilar trastuzumab, trastuzumab rechallenge was undertaken with the reference trastuzumab without other problems.