Molecular Templates Announces First Patient Dosed in Phase 1 Trial Evaluating MT-8421, a Novel Engineered Toxin Body Targeting CTLA-4, in Advanced Solid Tumors

AUSTIN, Texas, Nov. 02, 2023 (GLOBE NEWSWIRE) -- Molecular Templates, Inc. (Nasdaq: MTEM, “Molecular Templates,” or “MTEM”), a clinical-stage biopharmaceutical company developing novel therapeutics for oncology with potent differentiated mechanisms of action, today announced that the first patient has been dosed in the Phase 1 clinical trial evaluating MT-8421, a novel engineered toxin body targeting CTLA-4, for the treatment of advanced solid tumors.

The Phase 1 study is a multi-center open-label, dose-escalation, dose-expansion, and a first-in-human study designed to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and the preliminary efficacy of MT-8421. 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 (“TME”). This will include melanoma, hepatocellular carcinoma (HCC), non-small cell lung cancer (NSCLC), renal cell carcinoma (RCC), Microsatellite Instability-High (MSI-H) / Mismatch Repair Deficient (dMMR) cancer, mesothelioma, esophageal squamous cell carcinoma (ESCC), squamous cell carcinoma of the head and neck (SCCHN), urothelial carcinoma, and cervical carcinoma. Approximately 24-30 patients are anticipated to enroll in Part A dose escalation with a starting dose of 32 mcg/kg. 

“MT-8421 represents a unique approach to immuno-oncology in general and CTLA-4 targeting in particular based on its ability to destroy Tregs in the TME but not in the periphery,” said Eric Poma, PhD., Chief Executive and Chief Scientific Officer of Molecular Templates. “We look forward to this approach providing patient benefit in this first-in-human study.”

About MT-8421 (CTLA-4 Targeting ETB) 

MT-8421, along with MT-6402 (PD-L1 Targeting ETB with Antigen Seeding Technology), represents our unique approach to immuno-oncology based on dismantling the TME through direct cell-kill of tumor and immune cells and not only the blocking of ligand-ligand interactions seen with current antibody therapeutics. The ETB approach includes potent destruction of CTLA4+ regulatory T cells (“Tregs”) via enzymatic ribosome destruction, and the mechanism of cell kill is independent of TME. MT-8421 preferentially destroys high CTLA4 expressing Tregs in the TME relative to peripheral Tregs which are lower CTLA4 expressing.

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.

Forward-Looking Statements

This press release contains forward-looking statements for purposes of the Private Securities Litigation Reform Act of 1995 (the “Act”). Molecular Templates disclaims any intent or obligation to update these forward-looking statements and claims the protection of the Act’s Safe Harbor for forward-looking statements. All statements, other than statements of historical facts, included in this press release, including, but not limited to those regarding strategy, inflection points, future operations, the Company’s ability to execute on its objectives, prospects, plans, future execution of corporate goals, and the skills and experiences of the newly appointed officer of Molecular Templates and expectations with respect to his future contributions to the Company and statements, evaluations and judgements regarding the Company’s pipeline, future clinical development of the Company’s product candidates, including any implication that results or observations in earlier clinical trials will be representative of results or observations in later clinical trials and the expected timing of such results and any potential benefits or promise of product candidates. In addition, when or if used in this press release, the words “may,” “could,” “should,” “anticipate,” “believe,” “estimate,” “expect,” “intend,” “plan,” “predict” and similar expressions and their variants, as they relate to Molecular Templates may identify forward-looking statements. Forward-looking statements are not guarantees of future performance and involve risks and uncertainties. Actual events or results may differ materially from those discussed in the forward-looking statements due to various factors including, but not limited to the following factors: the continued availability of financing on commercially reasonable terms, whether the Company’s cash resources will be sufficient to fund its continuing operations; the results of the Company’s ongoing clinical studies, its ability to effectively operate Molecular Templates and retain key employees, the ability of the Company to maintain the continued listing of its common stock on Nasdaq, and those risks identified under the heading “Risk Factors” in Molecular Templates’ filings with the Securities and Exchange Commission, including its Quarterly Report on Form 10-Q for the quarter ended June 30, 2023 and any subsequent reports filed with the Securities and Exchange Commission. Any forward-looking statements contained in this press release speak only as of the date hereof, and Molecular Templates specifically disclaims any obligation to update any forward-looking statement, whether because of new information, future events or otherwise.

Contacts:

Grace Kim