A Phase 3 interventional study of Mezagitamab in Immune Thrombocytopenic Purpura (ITP), sponsored by Takeda. Recruiting at 118 sites in 15 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-30.
Sponsored by Takeda · Phase 3, Interventional, and Treatment
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.
503 studies on the registry are indexed under Purpura, Thrombocytopenic, Idiopathic; 158 are open to participants now.
This study's planned enrollment of 150 is above the median of 58 across 376 interventional studies indexed under Purpura, Thrombocytopenic, Idiopathic.
Browse Purpura, Thrombocytopenic, Idiopathic studies →Takeda is the lead sponsor of 1,026 studies on the registry; 89 are open to participants now.
Of its 178 completed or terminated interventional studies of FDA-regulated products, 154 (87%) have results posted.
Counted across the registry records on this site, refreshed daily.
Key Inclusion Criteria:
1. The participant has completed TAK-079-3002 (end of trial [EOT]) or TAK-079-1004 (EOT). Participants from TAK-079-1004 must have had a response to mezagitamab as demonstrated by meeting the criteria for " response" specified for that trial during either the main study or open-label extension.
For TAK-079-3002 participants:
1. The participant has a history of severe allergic or anaphylactic reactions to recombinant proteins or used in the mezagitamab formulation.
For TAK-079-1004 participants:
The participant has received anti-cluster of differentiation (CD) 20 treatment within 12 months before screening and either of the following applies:
10 The participant has received a live or 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 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.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Live vaccines
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Eligible participants who completed the TAK-079-3002 or TAK-079-1004 studies can receive on-demand treatment in this continuation study. The on-demand treatment course may be repeated as needed based on the pre-specified on-demand dosing criteria and investigator's clinical judgement.
Drug: Mezagitamab
Mezagitamab injection administered SC.
Also known as: TAK-079
Number of Participants With Treatment-Emergent Adverse Events (TEAEs) and Serious TEAEs
An adverse event (AE) is any untoward medical occurrence in a clinical trial participant, temporally associated with the use of the trial intervention, whether or not the occurrence is considered related to the trial intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of the trial intervention. TEAEs are defined as AEs with start dates at the time of or following the first exposure to mezagitamab in the parent trial for Cohort 1 and in this trial for Cohort 2. A serious TEAE is a TEAE that meets 1 or more of the criteria: results in death, is life threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect or was otherwise considered medically important.
Time frame: Up to approximately 108 weeks
Number of Participants With TEAEs Leading to Permanent Withdrawal of Mezagitamab
An AE is any untoward medical occurrence in a clinical trial participant, temporally associated with the use of the trial intervention, whether or not the occurrence is considered related to the trial intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of the trial intervention. TEAEs are defined as AEs with start dates at the time of or following the first exposure to mezagitamab in the parent trial for Cohort 1 and in this trial for Cohort 2.
Time frame: Up to approximately 108 weeks
Duration of Platelet Response
The duration of platelet response will be measured by the cumulative number of weeks on which platelet count was ≥30,000/microliters (μL) and ≥50,000/μL throughout the trial.
Time frame: Up to approximately 108 weeks
Duration Between On-Demand Treatment Courses
Time frame: Up to approximately 108 weeks
Time to Initiation of the First On-Demand Treatment Course
Time frame: Up to approximately 108 weeks
Number of Participants With Complete Response
Complete response is defined as achieving platelet counts ≥100,000/μL on at least 2 visits.
Time frame: Up to approximately 108 weeks
Number of Participants With Immune Thrombocytopenia (ITP) Remission
ITP Remission is defined as all platelet counts ≥50,000/μL for at least 24 weeks after any mezagitamab treatment cycle in the absence of further therapy for ITP.
Time frame: Up to approximately 108 weeks
Number of Participants With Reduction in Dose and/or Frequency of Concomitant ITP Medications
Concomitant ITP medications are defined as those given in addition to the trial intervention to treat your ITP. These medications include corticosteroids, thrombopoietin receptor agonists (TPO-RA), or fostamatinib.
Time frame: Up to approximately 108 weeks
Number of Participants Requiring Rescue Therapy
Time frame: Up to approximately 108 weeks
Serum Concentrations of Mezagitamab
Time frame: Pre-dose and at multiple time points post-dose up to Week 104
Number of Participants With Anti-Drug Antibodies (ADA)
Time frame: Pre-dose and at multiple time points post-dose up to Week 104
Number of Participants With Neutralizing Antibody (NAb)
Time frame: Pre-dose and at multiple time points post-dose up to Week 104
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Plan to share: Yes — 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?commitment=5). 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.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report
Access criteria: IPD from eligible studies will be shared with qualified researchers according to the criteria and process described on https://vivli.org/ourmember/takeda/. For approved requests, the researchers will be provided access to anonymized data (to respect patient privacy in line with applicable laws and regulations) and with information necessary to address the research objectives under the terms of a data sharing agreement.
Data sharing details ↗ · vivli.org
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Studies of the drug tested here: Mezagitamab
Purpura, Thrombocytopenic, Idiopathic →