NCT06831058 · University of Minnesota
A Pilot Study of Efgartigimod for Immune-mediated Thrombotic Thrombocytopenic Purpura (iTTP)
What this study is about
Immune-mediated Thrombotic thrombocytopenic purpura (iTTP) is a rare, autoimmune disorder characterized by life-threatening episodes of thrombocytopenia, microangiopathic hemolytic anemia and organ damage. Patients have an unpredictable course punctuated by relapses associated with autoantibody-mediated (primarily IgG) depletion of ADAMTS13, a key regulator of coagulation.
View original scientific description
Immune-mediated Thrombotic thrombocytopenic purpura (iTTP) is a rare, autoimmune disorder characterized by life-threatening episodes of thrombocytopenia, microangiopathic hemolytic anemia and organ damage. Patients have an unpredictable course punctuated by relapses associated with autoantibody-mediated (primarily IgG) depletion of ADAMTS13, a key regulator of coagulation. ADAMTS13 deficiency during remission has been associated with increased risk of relapse, but also, and potentially more devastating, ischemic stroke. Until recently, it was presumed that rituximab (a monoclonal antibody targeting B cells) improved relapse-free survival in most patients, but this was based on findings from very small studies. Given concern about stroke and relapse risk, preventive immunosuppression with rituximab has also recently come into practice for patients with falling ADAMTS13 activity (ADAMTS13-relapse). It is expected that following efgartigimod therapy, there will be a rise in ADAMTS13 activity to the normal range that will be sustained during the treatment period. Following withdrawal of therapy, it is expected that most participants will experience a fall in ADAMTS13 activity, demonstrating the safety and efficacy in efgartigimod to reliably but temporarily reduce pathogenic antibodies. This would demonstrate the potential efficacy for efgartigimod as a maintenance therapy to safely prevent relapse of iTTP to be further explored in a larger efficacy study.
Interventions
DRUG
efgartigimod
intravenous efgartigimod weekly with monitoring of ADAMTS13 activity for 8 weeks, followed by an observational period of 8 weeks or until treatment failure.
Primary outcome measures
safety of efgartigimod by the incidence of relapse
Time frame: 8 weeks post-intervention
Relapse rate in the experimental arm compared with the historical rituximab arm
safety and tolerability of efgartigimodhistorical rituximab arm
Time frame: 8 weeks post-intervention
Incidence and severity of adverse events (AEs), AEs of special interest (AESIs) and serious AEs (SEAs)
efficacy of efgartigimod to achieve a normal ADAMTS13 activity by Day 60 of the study
Time frame: 60 days
Compare the mean ADAMTS13 activity and proportion with normal ADAMTS13 activity at Day 60 and 90 between the experimental and historical cohorts
efficacy of efgartigimod to prevent the need for other preemptive therapy to rescue severe ADAMTS13 deficiency
Time frame: 8 weeks post-intervention
Compare the rate use of rescue therapy between the experimental and historical cohort treated with preemptive rituximab, as required by the lack of ADAMTS13 activity increase by 20%
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Subject must provide a signed informed consent form
- Subject is 18 years or older at the time of screening
- Subject has a prior history of iTTP as defined by the presence of ADAMTS13 activity \< 10% with ADAMTS13 antibodies or inhibitor, thrombocytopenia (platelet count \< 100) and microangiopathic hemolytic anemia (defined by the presence of schistocytes on blood smear)
- Subject is in clinical remission from iTTP (normal platelet count) for at least 90 days
- Subject has ADAMTS13 activity \< 70% and \> 30% on 2 separate occasions separate by at least 7 days
- Subject is at least 6 months from last dose of rituximab or other intravenous immunosuppression
- If taking other oral immunosuppressants, no change in dose for at least 60 days
- Female subjects of childbearing potential must present with a negative pregnancy test and agree to employ highly effective birth control measures for duration of study. Sexually active male subjects must agree to use an effective method of contraception for the duration of the study
Exclusion criteria
- Subject has been diagnosed with cTTP
- Subject has been exposed to another investigational product within 30 days prior to enrollment or is scheduled to participate in another clinical study involving investigational product or investigational device during the course of the study
- Subject is unable to understand the nature, scope, and possible consequences of the study.
- Subject is pregnant or lactating
- Subject has a known life-threatening hypersensitivity reaction to efgartigimod
Where
- Minneapolis, Minnesota
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 11, 2026 · Source of record for eligibility and locations