A Study to Evaluate the Efficacy and Safety of Mezagitamab Subcutaneous Injection Compared With Placebo in Adults With Chronic Immune Thrombocytopenia

Overview

Sponsor-declared trial summary

Key facts

Sponsor

Takeda Development Center Americas Inc.

Participant type

Patients

Age range

18-64 years, 65+ years

Gender

Male and Female

Therapeutic area

Diseases [C] - Hemic and Lymphatic Diseases [C15]

Trial duration

13 Nov 2025 → ongoing

Decision date (initial)

2025-10-23

Transition trial

No

Low-intervention

No

Rare-disease indication

Yes

Vulnerable population

Yes

Funding sources

Takeda Development Center Americas, Inc.

External identifiers

EU CT number

2024-514401-54-00

ClinicalTrials.gov

NCT06722235

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Efficacy, Safety, Pharmacokinetic, Pharmacodynamic, Therapy

To assess the efficacy of mezagitamab compared with placebo in achieving durable platelet response in participants aged ≥18 years with chronic ITP.

Secondary objectives 6

1. 1. To assess the efficacy of mezagitamab compared with placebo in achieving platelet response in participants aged ≥18 years with chronic ITP.
2. 2. To assess the effects of mezagitamab compared with placebo on patient-reported symptoms of ITP in participants aged ≥18 years with chronic ITP.
3. 3. To assess the use of rescue therapy in participants aged ≥18 years receiving mezagitamab compared with those receiving placebo.
4. 4. To assess the effects of mezagitamab compared with placebo on occurrence of bleeding in participants aged ≥18 years with chronic ITP.
5. 5. To determine the PK profile of mezagitamab in trial participants who are receiving mezagitamab.
6. 6. To evaluate the immunogenicity of mezagitamab.

Conditions and MedDRA coding

Chronic Primary Immune Thrombocytopenia

Study design 1 period

Regulatory references

Scientific advice from competent authorities

European Medicines Agency, Central Committee On Research Involving Human Subjects, Food And Drug Administration

Plan to share IPD

Yes

IPD plan description

Takeda provides access to the de-identified individual participant data (IPD) for eligible studies to aid qualified researchers in addressing legitimate scientific objectives (Takeda's data sharing commitment is available on https://clinicaltrials.takeda.com/takedas-commitment#8). These IPDs will be provided in a secure research environment following approval of a data sharing request, and under the terms of a data sharing agreement.

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 5

1. The participant has been diagnosed with primary ITP that has persisted for at least 12 months. Diagnosis is in accordance with The American Society of Hematology 2019 Guidelines for ITP (Neunert et al. 2019) or the Updated International Consensus Report on The Investigation and Management of Primary ITP (Provan et al. 2019), as locally applicable.
2. The participant’s diagnosis of ITP is supported by a prior response to an ITP therapy (not including a 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 (with individual values ≤35,000/µL) from at least 2 consecutive measurements taken at least 5 days apart during screening (and may be inclusive of Day 1), including at least 1 of those measurements within 14 days before the first dose of investigational medicinal product (IMP) (Day 1).
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 (ie, Day 1) and are expected to remain stable throughout the trial. Permitted concomitant treatments may include 1 medication from each of the following 3 categories: a) One thrombopoietin receptor agonist (eg, romiplostim, eltrombopag, avatrombopag, hetrombopag), and/or b) One oral corticosteroid given daily or every other day (not to exceed prednisone 20 mg daily or equivalent dose), and/or c) Fostamatinib. If participants do not plan to continue these agents during the trial, they must be washed out.

Exclusion criteria 6

1. The participant has secondary ITP.
2. The participant has had any thrombotic or embolic event within 12 months before signing the ICF.
3. The participant has had a splenectomy.
4. The participant has received anti-CD20 treatment within 12 months before screening and either of the following applies: a) The last dose was received within 6 months before screening. b) 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.
5. The participant has received any monoclonal or polyclonal antibody for immunomodulation within 6 months before Day 1.
6. 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 (eg, rescue therapy, administration of blood products) may be used between screening and Day 1.

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 1

1. 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.

Secondary endpoints 13

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

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 1

Placebo 1

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Takeda Development Center Americas Inc.

Sponsor organisation

Takeda Development Center Americas Inc.

Address

500 Kendall Street

City

Cambridge

Postcode

02142-1108

Country

United States

Scientific contact point

Organisation

Takeda Development Center Americas Inc.

Contact name

Takeda

Public contact point

Organisation

Takeda Development Center Americas Inc.

Contact name

Takeda

Third parties 21

Locations

12 EU/EEA countries · 40 investigational sites

By country

Investigational sites

Country notifications

Trial-start, recruitment-start, end and early-termination notifications submitted per Member State

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 137 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

Application history

11 submissions — initial application plus substantial / non-substantial modifications