Clinical trial NCT06948318: A Continuation Study of Mezagitamab in Adults With Chronic Primary Immune Thrombocytopenia
Official title: A Phase 3, Open-label, Multicenter Continuation Trial to Evaluate the Long-term Safety and Efficacy of Mezagitamab Subcutaneous Injection in Adults With Chronic Primary Immune Thrombocytopenia
Study type: INTERVENTIONAL
Overall status: NOT_YET_RECRUITING
Phase: PHASE3
Conditions: Immune Thrombocytopenic Purpura (ITP)
Keywords: TAK-079
Immune Thrombocytopenia
Chronic Primary Immune Thrombocytopenia
Blood Platelet Disorders
Hematologic Diseases
Cytopenia
Purpura
Hemorrhagic Disorders
Autoimmune Diseases
Immune System Diseases
Hemorrhage
Skin Manifestations
Purpura, Thrombocytopenic, Idiopathic
Purpura, Thrombocytopenic
Lead sponsor: Takeda
Sponsor class: INDUSTRY
First posted: 2025-04-29
Enrollment: 150
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: TREATMENT

Brief summary: 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 lower number of platelets, making it easier to bruise or bleed. The main aim of this study is to check how safe mezagitamab is and how well it is tolerated by adults with chronic primary ITP, if given over a longer time. Other aims are to learn how effective treatment with mezagitamab is and how the body processes it (called pharmacokinetics or PK) over a longer time.

Participants of the following previous mezagitamab studies will be invited to join this continuation study: TAK-079-3002 and TAK-079-1004. In this continuation study, participants will receive mezagitamab when certain protocol criteria are met.

During the study, participants will visit their study clinic several times.


Eligibility criteria: * Key Inclusion Criteria:

  1. The participant has completed TAK-079-3002 (end of trial \[EOT\]) or TAK-079-1004 (EOT).
* Key Exclusion criteria:

For TAK-079-3002 participants:

1. The participant has a history of severe allergic or anaphylactic reactions to recombinant proteins or excipients used in the mezagitamab formulation.

For TAK-079-1004 participants:

1. The participant has had any thrombotic or embolic event within 12 months before signing the ICF.
2. The participant has had a splenectomy within 3 months before signing the ICF.
3. The participant has active infection with hepatitis B virus (HBV), hepatitis C virus (HCV), or human immunodeficiency virus (HIV).
4. 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.
5. 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.
6. 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 CD19+ count below the lower limit of normal.
7. The participant has received any monoclonal or polyclonal antibody for immunomodulation within 6 months before Visit 1.
8. The participant has been exposed to another investigational agent within 4 weeks or 5 half-lives, whichever is longer, before Visit 1.
9. The participant has used anticoagulants (for example, vitamin K antagonists, direct oral anticoagulants) within 3 weeks prior to Visit 1.

10 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.

11. The participant has used the following immunosuppressive agents as specified prior to Visit 1: alkylating agents (for example, cyclophosphamide) within 8 weeks, vinca alkaloids (for example, vincristine) within 4 weeks, sulfones (for example, dapsone) within 3 weeks, antiproliferative agents: (for example, mycophenolate mofetil and azathioprine) within 2 weeks, and calcineurin inhibitors: (for example, cyclosporine) within 2 weeks.

12. The participant has a history of severe allergic or anaphylactic reactions to recombinant proteins or excipients used in the mezagitamab formulation.

Other protocol defined inclusion/exclusion criteria may apply.

Primary outcomes:
measure: Number of Participants With Treatment-Emergent Adverse Events (TEAEs) and Serious TEAEs
timeFrame: Up to approximately 108 weeks
measure: Number of Participants With TEAEs Leading to Permanent Withdrawal of Mezagitamab
timeFrame: Up to approximately 108 weeks
Secondary outcomes:
measure: Duration of Platelet Response
timeFrame: Up to approximately 108 weeks
measure: Duration Between On-Demand Treatment Courses
timeFrame: Up to approximately 108 weeks
measure: Time to Initiation of the First On-Demand Treatment Course
timeFrame: Up to approximately 108 weeks
measure: Number of Participants With Complete Response
timeFrame: Up to approximately 108 weeks
measure: Number of Participants With Immune Thrombocytopenia (ITP) Remission
timeFrame: Up to approximately 108 weeks
measure: Number of Participants With Reduction in Dose and/or Frequency of Concomitant ITP Medications
timeFrame: Up to approximately 108 weeks
measure: Number of Participants Requiring Rescue Therapy
timeFrame: Up to approximately 108 weeks
measure: Serum Concentrations of Mezagitamab
timeFrame: Pre-dose and at multiple time points post-dose up to Week 104
measure: Number of Participants With Anti-Drug Antibodies (ADA)
timeFrame: Pre-dose and at multiple time points post-dose up to Week 104
measure: Number of Participants With Neutralizing Antibody (NAb)
timeFrame: Pre-dose and at multiple time points post-dose up to Week 104
Other outcomes:
Locations:
Study officials:
affiliation: Takeda
name: Study Director
role: STUDY_DIRECTOR
References: