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Mezagitamab treatment for adults with chronic immune thrombocytopenia

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

Phase 3 Interventional Takeda · NCT06722235

This study is testing if a new treatment called mezagitamab can help adults with chronic immune thrombocytopenia keep their platelet counts stable compared to a placebo.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment171 (estimated)
Ages18 Years and up
SexAll
SponsorTakeda Industry-sponsored
Drugs / interventionsrituximab, mezagitamab, fostamatinib, cyclophosphamide
Locations112 sites (Los Angeles, California and 111 other locations)
Trial IDNCT06722235 on ClinicalTrials.gov

What this trial studies

This clinical trial evaluates the effectiveness of mezagitamab, administered subcutaneously, in stabilizing platelet counts in adults diagnosed with chronic primary immune thrombocytopenia (ITP). Participants will receive either mezagitamab or a placebo for up to 6 months, with regular clinic visits to monitor their condition. The study aims to determine if mezagitamab can provide a better response compared to the placebo in maintaining platelet levels. Those who do not respond to treatment by week 16 may have the opportunity to continue with open-label mezagitamab in a follow-up study.

Who should consider this trial

Good fit: Ideal candidates are adults diagnosed with chronic ITP for at least 12 months who have not responded adequately to previous therapies.

Not a fit: Patients who have not been diagnosed with ITP or those who have not tried any prior therapies for ITP may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly improve the management of chronic immune thrombocytopenia, leading to better platelet stability and reduced bleeding risks for patients.

How similar studies have performed: Other studies have shown promise with similar therapeutic approaches in managing ITP, suggesting potential for success with mezagitamab.

Eligibility criteria

Show full inclusion / exclusion criteria 
Key Inclusion Criteria:

1. The participant has been diagnosed with ITP that has persisted for at least 12 months.
2. 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.
3. 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.
4. The participant has a mean platelet count of \<30,000/μL.
5. 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.
6. 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.

Key Exclusion Criteria:

1. The participant has secondary ITP.
2. The participant has had any thrombotic or embolic event within 12 months before signing the informed consent form (ICF).
3. The participant has had a splenectomy.
4. The participant has active infection with hepatitis B virus, hepatitis C virus, or human immunodeficiency virus (HIV).
5. History of malignancy (including myelodysplastic syndrome) within 5 years of signing the ICF, except for treated non-melanoma skin cancer or cervical carcinoma in situ.
6. In the opinion of the investigator, the participant has a serious medical or psychiatric illness that could potentially interfere with the completion of treatment according to this protocol.
7. The participant has received anti-cluster of differentiation (CD)20 treatment within 12 months before screening, and either of the following applies:

   1. The last dose was received within 6 months before screening.
   2. The last dose was received between 6, and 12 months before screening, and the participant has a cluster of differentiation 19 positive (CD19+) count below the lower limit of normal.
8. The participant has received any monoclonal or polyclonal antibody for immunomodulation within 6 months before Day 1.
9. The participant has any prior exposure to mezagitamab or has been exposed to another investigational agent within 4 weeks or 5 half-lives, whichever is longer, before Day 1.
10. The participant has used anticoagulants (e.g., vitamin K antagonists, direct oral anticoagulants) within 3 weeks prior to the first dose of trial treatment.
11. The participant has received a live or live-attenuated vaccine within 4 weeks prior to the first dose of trial treatment or has any live or live-attenuated vaccine planned during the trial.
12. The participant has used the following immunosuppressive agents as specified prior to the first dose of trial treatment: alkylating agents (e.g., cyclophosphamide) within 8 weeks, vinca alkaloids (e.g., vincristine) within 4 weeks, sulfones (e.g., dapsone) within 3 weeks, antiproliferative agents: (e.g., mycophenolate mofetil, and azathioprine) within 2 weeks, and calcineurin inhibitors: (e.g., cyclosporine) within 2 weeks.
13. The participant has used intravenous immunoglobulin (IVIg), SC immunoglobulin, recombinant human thrombopoietin, anti-D immunoglobulin treatment, or efgartigimod within 4 weeks before signing the ICF or it is expected that any treatment for thrombocytopenia other than the participant's standard-of-care ITP therapy (e.g., rescue therapy, administration of blood products) may be used between screening, and Day 1.
14. The participant has a history of severe allergic or anaphylactic reactions to recombinant proteins or excipients used in the mezagitamab/placebo formulation.

Other protocol defined inclusion/exclusion criteria may apply.

Where this trial is running

Los Angeles, California and 111 other locations

+62 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Immune Thrombocytopenic PurpuraThrombocytopeniaTAK-079Blood Platelet DisordersHematologic DiseasesCytopeniaPurpuraHemorrhagic Disorders
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.