Meiji Seika Pharma has initiated a Phase I clinical trial of ME3241, a novel anti-PD-1 agonist monoclonal antibody discovered through collaborative research with the Foundation for Biomedical Research and Innovation at Kobe (FBRI) in Japan.

The early-stage study is designed as a randomised, placebo-controlled, double-blind clinical trial aimed at evaluating the safety and tolerability of ME3241 following both single and multiple dosing. Researchers will also assess the drug candidate’s pharmacokinetics and pharmacodynamics as part of the first-in-human evaluation.

ME3241 was discovered through a collaborative research programme led by Tasuku Honjo, professor emeritus at Kyoto University. The therapy targets the Programmed Cell Death Protein 1 (PD-1) pathway, a molecule expressed on activated T cells and other lymphocytes that regulates immune responses.

Unlike widely used cancer immunotherapies that block PD-1 to stimulate immune activity, ME3241 works as a PD-1 agonist, stimulating the receptor to suppress excessive immune responses. This mechanism could offer a new therapeutic approach for inflammatory and autoimmune diseases driven by immune system overactivation.

The research collaboration between Meiji Seika Pharma and FBRI identified conditions that induce immunosuppression by activating PD-1 with antibodies. The findings were published in the journal Science Immunology in January 2023.

According to Honjo, the initiation of a clinical trial for an autoimmune disease therapy based on a PD-1 agonist antibody represents a significant milestone. The concept originated from basic research conducted shortly after he assumed his role at FBRI and progressed through successful preclinical studies in animal models before entering human trials.

If the Phase I trial confirms safety and tolerability, the programme is expected to advance to Phase II clinical trials to evaluate therapeutic efficacy, followed by Phase III studies aimed at potential clinical application.

Takeshi Naruse, senior Managing Executive Officer and Head of Research and Development at Meiji Seika Pharma, noted that the company has been collaborating with Honjo and his research team to identify and develop innovative treatments for inflammatory diseases. He added that the company aims to accelerate the development of ME3241 with the goal of delivering a new treatment option for patients with autoimmune conditions.

The development of ME3241 highlights Japan’s ongoing efforts to translate advanced immunology research into innovative therapies through collaborations between academic institutions and the biopharmaceutical industry.