Meiji Seika Pharma has begun a Phase I clinical trial of ME3241, an experimental monoclonal antibody designed to treat autoimmune and inflammatory diseases by activating the immune checkpoint protein PD-1.

 

The early-stage study will test the drug’s safety, tolerability and biological effects in humans. The randomized, placebo-controlled, double-blind trial will examine both single and multiple doses of the therapy while measuring pharmacokinetics and pharmacodynamics.

 

ME3241 emerged from a collaborative research program between Meiji Seika Pharma and the Foundation for Biomedical Research and Innovation at Kobe (FBRI). The work was led by Program Director Tasuku Honjo, a professor emeritus at Kyoto University and a pioneer in PD-1 research.

 

PD-1 is a molecule found on activated T cells and other immune cells that suppresses immune responses. By stimulating PD-1 with antibodies, researchers aim to dampen excessive immune activity — a hallmark of many autoimmune diseases. The underlying research defining conditions for antibody-driven PD-1 immunosuppression was published in Science Immunology on January 13, 2023.

 

Unlike widely used cancer drugs that block PD-1 to boost immune responses, ME3241 is designed to activate the pathway, potentially calming overactive immune systems in inflammatory and autoimmune disorders.

 

Meiji Seika Pharma and FBRI say they will continue working together to accelerate development of the therapy and deliver new treatment options for patients.

 

Tasuku Honjo, Program Director, Honorary President, Foundation for Biomedical Research and Innovation at Kobe (FBRI), said, “The initiation of the Phase I clinical trial of an autoimmune disease therapy by a PD-1 agonist antibody is highly significant, as our finding marks a major milestone in taking a step toward potential therapeutic application for human disease.

 

“This therapeutic approach, which is completely opposite of the widely used cancer therapy employing a PD-1 antagonist antibody, originated from basic research initiated shortly after my appointment as director. After achieving robust results in animal models, we have now reached this clinical stage.

 

“Should safety be confirmed in Phase I, there is strong expectation that the program will progress to Phase II to evaluate efficacy, and subsequently to Phase III with the aim of practical implementation. I am truly delighted by this advancement toward the practical realization of the vision of Kobe Biomedical Innovation Cluster.”