A Phase 3 interventional study of Mezagitamab and Placebo in Immune Thrombocytopenic Purpura (ITP), sponsored by Takeda. Recruiting at 124 sites in 18 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-11-04.
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 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).
503 studies on the registry are indexed under Purpura, Thrombocytopenic, Idiopathic; 158 are open to participants now.
This study's planned enrollment of 171 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:
Key Exclusion Criteria:
The participant has received anti-cluster of differentiation (CD) 20 treatment within 12 months before screening, and either of the following applies:
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.
A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.
“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
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.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
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.
Line of therapy
A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.
“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
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.
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.
Participants will receive mezagitamab injection, SC, once weekly (QW). They will receive 8 weekly doses, followed by 8 weekly doses off, and then receive 8 more weekly doses.
Drug: Mezagitamab
Participants will receive mezagitamab-matching placebo injection, SC, QW. They will receive 8 weekly doses, followed by 8 weekly doses off, and then receive 8 more weekly doses.
Drug: Placebo
Mezagitamab injection administered SC.
Also known as: TAK-079
Mezagitamab-matching placebo injection administered SC.
Percentage of Participants With Durable Platelet Response
Durable platelet response is defined as platelet count greater than or equal to (≥)50,000/microliter (μL) on at least 4 of the 6 weekly platelet measurements between Weeks 19 and 24.
Time frame: Up to Week 24
Cumulative Number of Weeks With a Platelet Count of ≥50,000/μL
The cumulative number of weeks in which the platelet count is ≥50,000/μL through Week 24.
Time frame: Up to Week 24
Time to First Platelet Count ≥50,000/μL
Time frame: Up to Week 24
Cumulative Number of Weeks With a Platelet Count of ≥30,000/μL
The cumulative number of weeks in which the platelet count is ≥30,000/μL, and at least doubled from baseline through Week 24.
Time frame: Up to Week 24
Percentage of Participants With Complete Platelet Response
Complete platelet response is defined as a platelet count ≥100,000/μL on at least 2 visits through Week 24.
Time frame: Up to Week 24
Percentage of Participants With Platelet Response at Week 16
Platelet response is defined as a platelet count ≥50,000/μL before investigational medicinal product (IMP) administration at the Week 16 visit.
Time frame: Week 16
Change from Baseline in the Symptoms Domain Score of the Immune Thrombocytopenia Patient Assessment Questionnaire (ITP-PAQ) at Weeks 16 and 24
ITP-PAQ is a 44-item participant reported outcome (PRO) measure that assesses disease-specific health-related quality of life (HRQoL) that includes 10 domains: Symptoms, Fatigue/Sleep, Physical Health - Bother, Physical Health - Activity, Emotional Health - Psychological, Emotional Health - Fear, Overall Quality of Life (QoL), Social Activity, Women's Reproductive Health (including Fertility subscale, and Menstrual Symptoms subscale), and Work. The 6-item symptoms domain is scored from 0 to 100, with a positive change from baseline representing improvement of symptoms.
Time frame: Weeks 16 and 24
Change from Baseline in Physical Fatigue (Item 10) Score of the ITP-PAQ at Weeks 16 and 24
ITP-PAQ is a 44-item participant reported outcome (PRO) measure that assesses disease-specific health-related quality of life (HRQoL) that includes 10 domains: Symptoms, Fatigue/Sleep, Physical Health - Bother, Physical Health - Activity, Emotional Health - Psychological, Emotional Health - Fear, Overall Quality of Life (QoL), Social Activity, Women's Reproductive Health (including Fertility subscale, and Menstrual Symptoms subscale), and Work. Physical fatigue is scored from 0 to 100, with a positive change from baseline representing improvement in physical fatigue.
Time frame: Weeks 16 and 24
Percentage of Participants Receiving Rescue Therapy
Time frame: Up to Week 24
Percentage of Participants With Bleeding Events
Bleeding events are defined as Grade ≥2 in the skin domain, or Grade ≥1 in the mucosal domain, or Grade ≥1 in the organ domain, in the immune thrombocytopenia-specific bleeding assessment tool (ITP-BAT) through Week 24.
Time frame: Up to Week 24
Serum Concentration of Mezagitamab During and After Intervention
Time frame: Predose on Day 1 and at multiple time points post-dose up to Day 169
Number of Participants With Anti-drug Antibodies (ADA)
Time frame: Predose on Day 1 and at multiple time points post-dose up to Day 169
Change in ADA Titers Over Time
Time frame: Up to Day 169
Number of Participants With Neutralizing ADA
Time frame: Predose on Day 1 and at multiple time points post-dose up to Day 169
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Showing the first 100 of 124 sites across 18 countries. Choose a country and city above to see the rest.
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 ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
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Studies of the drug tested here: Mezagitamab
Purpura, Thrombocytopenic, Idiopathic →