Takeda Presents Late-Breaking Data from Phase 2b Study of Mezagitamab

Takeda (TSE:4502/NYSE:TAK) today presented positive results from its Phase 2b, randomized, double-blind, placebo-controlled study evaluating the safety, tolerability and efficacy of mezagitamab (TAK-079) in patients with persistent or chronic primary immune thrombocytopenia (ITP), a rare immune-mediated bleeding disorder. ITP is characterized by the accelerated destruction of platelets in blood, resulting in a decreased platelet count and an increase of bleeding that can be debilitating. These data (Abstract #LB 01.1) were presented at the oral Late-Breakthrough Session at the 32^nd Congress of the International Society on Thrombosis and Haemostasis (ISTH) in Bangkok, Thailand. Takeda plans to initiate a global Phase 3 trial of mezagitamab in patients with ITP in the second half of FY2024.

The TAK-079-1004 trial (NCT04278924) evaluated three different doses of subcutaneous mezagitamab (100mg, 300mg and 600mg) versus placebo, given once weekly for eight weeks in patients with chronic or persistent primary ITP, followed by >8 weeks of safety follow-up. The primary endpoint is the percentage of patients with at least one Grade 3 or higher treatment emergent adverse events (TEAEs), serious adverse events (SAEs), and adverse events (AEs) leading to mezagitamab discontinuation.² Secondary endpoints included platelet response, complete platelet response, clinically meaningful platelet response, and hemostatic platelet response.^1,2

The Phase 2b trial results demonstrated that mezagitamab treatment improved platelet response compared to placebo, across all three dose levels of mezagitamab tested. Patients treated with mezagitamab showed rapid and sustained increases in platelet counts (above the 50,000/μL therapeutic threshold)⁴, that persisted eight weeks after the last dose through to Week 16, illustrating the rapid and post-therapy effects of mezagitamab on platelet response.¹

• All the different measures of platelet response evaluated were highest among patients treated with the mezagitamab 600mg dose, specifically 81.8% achieved complete platelet response, 90.9% clinically meaningful platelet response, and 100% hemostatic platelet response.¹
• Fewer mezagitamab-treated patients compared to placebo had ≥1 disease activity-related bleeding AE (17.9% vs 46.2%, respectively).¹

“Despite treatment with currently available therapies, there is still a significant disease burden and need for a disease modifying treatment that people living with ITP can tolerate,” said David Kuter, M.D., D.Phil., a leading expert in ITP and study presenter at the ISTH oral Late-Breakthrough Session. “These Phase 2b trial results are especially encouraging because they show mezagitamab’s favorable efficacy and safety profile – setting the stage for the generation of additional clinical evidence for this anti-CD38 monoclonal antibody with best-in-class potential for efficacy in ITP.”

In this study, mezagitamab had a favorable safety profile in patients with ITP, with no new safety signals and consistent with prior studies of mezagitamab.¹ The rates of TEAEs leading to discontinuation, Grade >3 TEAEs, and SAEs, between the mezagitamab dose groups combined versus placebo were 14.3% versus 0%, 17.9% versus 23.1%, and 14.3% versus 7.7% respectively.¹

“It is a privilege to have these Phase 2b mezagitamab results selected for presentation as a late-breaking abstract at the ISTH Congress,” said Obi Umeh, M.D., M.Sc., Vice President, Franchise Global Program Leader at Takeda. “Based on these results, we plan to initiate a Phase 3 study of mezagitamab in ITP in the second half of FY2024, further underscoring our goal to develop transformative treatments in therapeutic areas with high unmet patient needs.”