Takeda's mezagitamab promising for immune thrombocytopenia

Takeda has recently revealed encouraging mid-stage findings for mezagitamab (TAK-079) in patients with persistent or chronic primary immune thrombocytopenia (ITP). These results were showcased at the 32nd Congress of the International Society on Thrombosis and Haemostasis. Takeda is planning to commence a global phase 3 clinical trial in the latter half of 2024.

Immune thrombocytopenia (ITP) is a rare autoimmune disorder, affecting roughly four out of every 100,000 people annually. Characterized by a low platelet count, ITP leads to a deficiency in the small blood cells that play a crucial role in preventing or stopping bleeding. The TAK-079-1004 trial has been exploring the efficacy of a once-weekly subcutaneous dose of mezagitamab in 100mg, 300mg, and 600mg quantities compared to a placebo over an eight-week period, followed by an additional eight weeks of safety monitoring.

Mezagitamab is a fully human IgG1 monoclonal antibody designed to target CD38-expressing cells with high affinity. Its primary goal is to provide a rapid and sustained improvement in platelet response, ultimately restoring platelet counts to functional levels. The trial results indicated that mezagitamab significantly enhanced platelet response across all three tested dose levels in comparison to the placebo. Furthermore, it showed a rapid and sustained increase in platelet counts, which persisted for eight weeks post the final dose.

Notably, over 81% of patients administered with the 600mg dose achieved a complete platelet response. Nearly 91% of these patients had a meaningful platelet response, while 100% demonstrated a haemostatic platelet response. Additionally, mezagitamab exhibited a favorable safety and tolerability profile in ITP patients. No new safety issues emerged, and the safety profile remained consistent with previous studies.

The US Food and Drug Administration (FDA) has previously granted mezagitamab Orphan Drug Designation and Fast Track Designation for the treatment of chronic/persistent ITP, although it has not yet been approved for use. Obi Umeh, vice president and franchise global programme leader at Takeda, expressed optimism about the future of mezagitamab. He stated, “Based on these results, we plan to initiate a phase 3 study of mezagitamab in ITP in the second half of 2024, further underscoring our goal to develop transformative treatments in therapeutic areas with high unmet patient needs.”

These developments follow Takeda's announcement last year of positive phase 3 results for its enzyme replacement therapy, TAK-755, in treating congenital thrombotic thrombocytopenic purpura, an extremely rare and chronic blood clotting disorder. This underscores Takeda's ongoing commitment to addressing significant unmet medical needs through innovative treatments.