Takeda today announced positive findings from its Phase 2b, randomized, double-blind, placebo-controlled trial evaluating the safety, tolerability, and efficacy of mezagitamab (TAK-079) in patients with persistent or chronic primary immune thrombocytopenia (ITP). ITP is a rare autoimmune disorder that accelerates the destruction of platelets, leading to a significantly decreased platelet count and increased bleeding risks.
The results (Abstract #LB 01.1) were presented at the 32nd Congress of the International Society on Thrombosis and Haemostasis (ISTH) in Bangkok, Thailand, during the oral Late-Breakthrough Session. Takeda intends to commence a global Phase 3 trial for mezagitamab in ITP patients in the second half of FY2024.
The TAK-079-1004 trial (NCT04278924) assessed three dosages of subcutaneous mezagitamab (100mg, 300mg, and 600mg) versus placebo, administered weekly for eight weeks, followed by over eight weeks of safety follow-up. The primary endpoint was the proportion of patients experiencing Grade 3 or higher treatment-emergent adverse events (TEAEs), serious adverse events (SAEs), and adverse events (AEs) leading to discontinuation of mezagitamab. Secondary endpoints included various measures of platelet response.
The Phase 2b trial demonstrated that mezagitamab significantly improved platelet responses across all dosages compared to placebo. Patients receiving mezagitamab showed rapid and sustained increases in platelet counts (exceeding the therapeutic threshold of 50,000/μL) that persisted through Week 16, illustrating the drug’s efficacy both during and post-therapy.
Key findings include:
- Among patients treated with the 600mg dose, 81.8% achieved complete platelet response, 90.9% achieved clinically meaningful platelet response, and 100% achieved hemostatic platelet response.
- Fewer patients treated with mezagitamab experienced disease activity-related bleeding AEs compared to those receiving placebo (17.9% vs 46.2%).
“Despite available therapies, a significant disease burden persists for those living with ITP. These Phase 2b results are promising, showcasing mezagitamab’s favorable efficacy and safety profile,” said Dr. David Kuter, a leading expert in ITP and study presenter at ISTH. “These findings set the stage for further clinical development of this potentially best-in-class anti-CD38 monoclonal antibody.”
Mezagitamab exhibited a favorable safety profile with no new safety signals, consistent with previous studies. The rates of TEAEs leading to discontinuation, Grade >3 TEAEs, and SAEs for mezagitamab combined doses versus placebo were 14.3% vs 0%, 17.9% vs 23.1%, and 14.3% vs 7.7%, respectively.
“We are honored that our Phase 2b results were chosen for presentation as a late-breaking abstract at the ISTH Congress,” said Dr. Obi Umeh, Vice President, Franchise Global Program Leader at Takeda. “These encouraging results support our plans to initiate a Phase 3 study in FY2024, reinforcing our commitment to developing transformative treatments in areas with high unmet patient needs.”