AUSTIN, TX, USA I July 09, 2021 I Molecular Templates, Inc. (Nasdaq: MTEM, “Molecular Templates” or “MTEM”), a clinical-stage biopharmaceutical company focused on the discovery and development of proprietary targeted biologic therapeutics, engineered toxin bodies (ETBs), today announced the dosing of the first subject in a Phase 1 study investigating MT-6402 in patients with PD-L1-positive solid tumors.

“We are excited to have dosed the first subject in the Phase 1 study for MT-6402, a third generation ETB, which is being developed as a potential treatment for patients with PD-L1-positive cancers. MT-6402 utilizes both our proprietary de-immunized toxin scaffold and antigen seeding technology,” said Eric Poma, Ph.D., CEO and CSO of Molecular Templates. “The PD-1/PD-L1 axis is central to many tumors and targeting that axis with a new mechanism of action has an opportunity to provide meaningful benefit to patients. We look forward to providing an update on this study by year-end 2021.”

The Phase 1 study for MT-6402 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. The starting dose is 16 mcg/kg. Following determination of the maximum tolerated dose (MTD) or recommended Phase 2 dose, expansion cohorts are planned to evaluate MT-6402 as a monotherapy in tumor-specific and tumor-agnostic cohorts. For more information on the Phase 1 study for MT-6402, refer to ClinicalTrials.gov identifier: NCT04795713.

About MT-6402

MT-6402 is an ETB consisting of a single chain variable fragment (scFv) with affinity for PD-L1, fused to the enzymatically active de-immunized Shiga-like toxin-A subunit (SLTA) and a class I antigen derived from the human cytomegalovirus (HCMV) pp65 protein. MT-6402 was designed to induce potent anti-tumor effects via PD-L1 targeting through multiple mechanisms that may overcome the limitations of the existing PD-L1 antibody therapies. In MTEM’s preclinical studies, MT-6402 was found to specifically bind and kill both tumor and immune PD-L1 expressing cells in a manner consistent with SLTA mediated cellular cytotoxicity through ribosomal inactivation, independent of checkpoint inhibition. Additionally, MT-6402 alters the immunophenotype of targeted cells by delivering foreign class I antigen from CMV for presentation in complex with MHC class I, which may provoke a CMV-specific immune response against the targeted cells. MT-6402 may rehabilitate the tumor microenvironment (TME) and allow for immune recognition of tumors by destroying PD-L1-expressing immune cells in the TME.

About Molecular Templates

Molecular Templates is a clinical-stage biopharmaceutical company focused on the discovery and development of targeted biologic therapeutics. Our proprietary drug platform technology, known as engineered toxin bodies, or ETBs, leverages the resident biology of a genetically engineered form of Shiga-like Toxin A subunit to create novel therapies with potent and differentiated mechanisms of action for cancer and other serious diseases.

SOURCE: Molecular Templates