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Assessing the effects of efgartigimod IV in adults with primary immune thrombocytopenia

A Phase 3, Multicenter, Randomized, Double-Blinded, Placebo-Controlled, Parallel-Arm Study Followed by an Open-Label Arm to Evaluate the Efficacy and Safety of Efgartigimod IV in Adult Participants With Primary Immune Thrombocytopenia

Phase 3 Interventional argenx · NCT06544499

This study is testing whether a new treatment called efgartigimod IV can help adults with primary immune thrombocytopenia feel better and improve their platelet counts.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment69 (estimated)
Ages18 Years and up
SexAll
Sponsorargenx Industry-sponsored
Drugs / interventionsrituximab, prednisone
Locations94 sites (Phoenix, Arizona and 93 other locations)
Trial IDNCT06544499 on ClinicalTrials.gov

What this trial studies

This study evaluates the efficacy and safety of efgartigimod IV in adults diagnosed with primary immune thrombocytopenia (ITP). Participants will undergo a screening period followed by randomization to receive either efgartigimod IV or a placebo in a double-blinded manner. After a treatment period of up to 24 weeks, all participants will receive efgartigimod IV in an open-label phase lasting up to 52 weeks, with the possibility of an additional open-label treatment phase. The total duration of participation in the study may extend up to 138 weeks.

Who should consider this trial

Good fit: Ideal candidates include adults aged 18 and older with a documented history of primary immune thrombocytopenia and insufficient response to prior treatments.

Not a fit: Patients who have not previously received treatment for ITP or those with a platelet count above the specified threshold may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly improve platelet counts and overall management of primary immune thrombocytopenia in affected patients.

How similar studies have performed: Previous studies have shown promise with similar treatments for ITP, indicating potential for success with this approach.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Is at least 18 years of age and the local legal age of consent for clinical studies when signing the informed consent form (ICF).
* Has documented baseline mean platelet count of \<30 x 10\^9/L before randomization
* Has a documented duration of primary immune thrombocytopenia (ITP) of more than 12 months on the date of informed consent form (ICF) signature.
* Has documented prior ITP treatment with at least 1 of the following treatments: corticosteroids, intravenous immunoglobulin (IVIg), anti-D immunoglobulin, thrombopoietin receptor agonist (TPO-RAs), or rituximab.
* Has documented insufficient response to a prior ITP treatment (the specific criteria can be found in the protocol).
* Has documented prior response defined as 1 platelet count of ≥50 × 109/L to at least 1 of the following ITP treatments in the 3 years before the date of ICF signature: prednisone, dexamethasone, other or nonspecified corticosteroids, IVIg, or anti-D immunoglobulin

Exclusion Criteria:

* Other than the indication under study, known autoimmune disease or any medical condition that would interfere with an accurate assessment of clinical symptoms of ITP, confound the results of the study or put the participant at undue risk.
* Secondary ITP
* Nonimmune thrombocytopenia
* Autoimmune hemolytic anemia
* ITP-associated critical or severe bleeding The complete list of criteria can be found in the protocol.

Where this trial is running

Phoenix, Arizona and 93 other locations

+44 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Primary Immune Thrombocytopenia
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.