A Pilot Study of Efgartigimod for Immune-mediated Thrombotic Thrombocytopenic Purpura (iTTP)

Conditions

• Immune-mediated Thrombotic Thrombocytopenic Purpura

Eligibility Criteria

Sex

ALL

Age

18 Years - N/A

Healthy Volunteers

Not accepted

Interventions

• efgartigimod — DRUG
  intravenous efgartigimod weekly with monitoring of ADAMTS13 activity for 8 weeks, followed by an observational period of 8 weeks or until treatment failure.

Study Details

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.

Key Dates

Start date

May 1, 2025

Status verified

Jun 2026

Primary completion

May 1, 2028

Completion

May 1, 2028

Study Design

Enrollment

15 participants (estimated)

Allocation

NA

Intervention model

SINGLE_GROUP

Primary purpose

TREATMENT

Arms

• Experimental: iTTP patients
  participants with a history of iTTP in clinical remission but with ADAMTS13 deficiency (\>30% but \< 70% activity)

Primary Outcome Measure

safety of efgartigimod by the incidence of relapse [ Time Frame: 8 weeks post-intervention ]

Central Contacts

• Diondra Howard
  651-208-7476
  [email protected]

Locations (1)

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