A Phase 3, Randomized, Double-blind, Placebo-controlled Study to Evaluate Efficacy and Safety of Mezagitamab Subcutaneous Injection in Participants with Chronic Primary Immune Thrombocytopenia

Condition studied

Chronic Primary Immune Thrombocytopenia

Investigational medicinal product(s)

Eligibility

Primary endpoint

Durable platelet response through Week 24, defined as platelet count ≥50,000/μL on at least 4 of the 6 weekly platelet measurements between Week 19 and Week 24.

Endpoint detail

1. The cumulative number of weeks that a platelet count was ≥50,000/μL through Week 24., 2. Time to first platelet count ≥50,000/µL., 3. The cumulative number of weeks that a platelet count was ≥30,000/μL through Week 24 and at least doubled from baseline., 4. Complete platelet response, defined as a platelet count ≥100,000/µL on at least 2 visits through Week 24., 5. Platelet response at Week 16, defined as a platelet count ≥50,000/µL before IMP administration at the Week 16 visit., 6. Change from baseline in the Symptoms scale score of the ITP-PAQ at Week 16., 7. Change from baseline in the Symptoms scale score of the ITP-PAQ at Week 24., 8. Change from baseline in physical fatigue (Item 10) score of the ITP-PAQ at Week 16., 9. Change from baseline in physical fatigue (Item 10) score of the ITP-PAQ at Week 24., 10. Occurrence of receiving rescue therapy., 11. Presence of bleeding events, defined as Grade ≥2 in the Skin domain, or Grade ≥1 in the Mucosal domain, or Grade ≥1 in the Organ domain, in the ITP-BAT through Week 24., 12. The serum concentration of mezagitamab during and after intervention., 13. Incidence of ADA and change in ADA titers., 14. Incidence of neutralizing ADA.