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
Primary immune thrombocytopenia (ITP) is a condition where the immune system mistakenly destroys platelets, which are cells that help stop bleeding. This leads to a low number of platelets, making it easier to bruise or bleed. The main aim of this study is to learn whether mezagitamab, when given just under the skin (subcutaneously \[SC\]), is effective in keeping the platelet count of adults with ITP stable when compared to a placebo. A placebo looks like medicine but doesn't have any active ingredients in it. The participants will be treated with mezagitamab for up to 6 months. During the study, participants will visit their study clinic several times. Participants who complete the TAK-079-3002 study or do not have any response to study treatment by week 16 (according to study criteria) will be given the opportunity to participate in a continuation study to receive open label mezagitamab (if they are eligible and the site is able to open the continuation study).
• The participant has been diagnosed with ITP that has persisted for at least 12 months.
• The participant's diagnosis of ITP is supported by a prior response to an ITP therapy (not including a thrombopoietin receptor agonist \[TPO-RA\]), defined as having achieved a platelet count ≥50,000/μL.
• The participant has evidence of insufficient response or intolerance to at least 1 currently available first-line therapy for treatment of ITP (for example, corticosteroids), and at least 1 currently available second-line therapy for treatment of ITP (for example, TPO-RA, rituximab, fostamatinib, mycophenolate). Insufficient response to previous treatment is defined as failure to achieve a sustained platelet count of at least 50,000/μL or doubling of baseline platelet count after an appropriate course of prior ITP treatment. Intolerance is defined as a documented side effect causing discontinuation of the therapy.
• The participant has a mean platelet count of \<30,000/μL.
• If the participant is receiving allowed standard-of-care treatment for ITP at screening, and continued use is intended, treatment may continue during the trial if the dose, and frequency have been stable for at least 4 weeks before receiving the first dose of IMP (i.e., Day 1), and are expected to remain stable throughout the trial.
• If the participant is an individual with potential for pregnancy, the participant is not pregnant as confirmed by negative human chorionic gonadotropin during screening, and before the first dose of trial intervention.