Molecular Templates, Inc. announced that the U.S. Food and Drug Administration (FDA) has accepted its Investigational New Drug (IND) application for MT-6402, a next-generation ETB targeting PD-L1 that is enabled with MTEM’s antigen seeding technology (AST). ETBs enabled with AST have dual mechanisms of action that include the enzymatic destruction of ribosomes and the delivery of viral class I antigens into the targeted tumor to be processed and presented on its cell surface to induce an antigen specific immune response. MTEM expects to start dosing enrolled subjects in a first-in-human Phase 1 study in relapsed/refractory patients with PD-L1-positive solid tumors in 2Q21. The Phase 1 study is planned as a multi-center, open-label, dose escalation and dose expansion trial in the United States and outside of the United States. Patients with confirmed PD-L1 expressing tumors or confirmed PD-L1 expression in the tumor microenvironment will be eligible to screen for enrollment in the clinical trial. Following determination of the maximum tolerated dose (MTD) or recommended Phase 2 dose, expansion cohorts are planned to study MT-6402 as a monotherapy in tumor-specific and tumor-agnostic cohorts.