ModeX Therapeutics, a subsidiary of OPKO Health, has announced the dosing of the first patients in a clinical trial of its investigational therapy MDX2003, targeting relapsed or refractory B-cell lymphoma. The development marks a key milestone in advancing next-generation immunotherapies for hard-to-treat cancers.

MDX2003 is a first-in-class tetraspecific T-cell engager engineered to simultaneously target CD19 and CD20 proteins on B-cell malignancies, along with CD3 and CD28 receptors on T cells. This multi-target approach is designed to improve tumour recognition while enhancing and sustaining T-cell activation to drive more effective cancer cell destruction.

The ongoing Phase I study (MDX-2003-101) is assessing the therapy’s safety, tolerability, pharmacokinetics and immune activity in adult patients with various forms of B-cell lymphoma. The trial includes both dose-escalation and dose-expansion phases to determine optimal dosing and treatment regimens. B-cell lymphoma, a subtype of non-Hodgkin lymphoma, accounts for the majority of lymphoma cases globally, with a significant proportion of patients experiencing relapse or resistance following standard treatments.

According to company leadership, the therapy has been developed to address limitations seen in earlier T-cell engager approaches by combining dual tumour targeting with co-stimulatory signals that enhance immune cell persistence and activity. Preclinical studies have demonstrated strong anti-tumour responses and balanced immune activation, supporting its transition into clinical evaluation.

Findings from preclinical research and dose-selection analyses were previously presented at major scientific forums, including the American Society of Hematology Annual Meeting and the ESMO Targeted Anticancer Therapies Congress 2026.

The company stated that the study will play a critical role in defining dosing strategies and guiding future trials aimed at evaluating the therapy’s efficacy in larger patient populations.

ModeX Therapeutics focuses on developing multispecific biologics across oncology, immunology and infectious diseases, while OPKO Health continues to expand its portfolio through innovative drug development and diagnostic solutions.