Molecular Templates, Inc. (NASDAQ:MTEM) has announced the first patient has been dosed in the Phase 1 clinical trial for MT-8421, a novel engineered toxin body targeting CTLA-4, for the treatment of advanced solid tumors. The study will enroll adult patients with tumors where CTLA-4 inhibitors have been proven to provide benefit and in other select tumor types known to frequently have an immune rich tumor microenvironment. Approximately 24-30 patients are anticipated to enroll in Part A dose escalation with a starting dose of 32 mcg/kg.