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Pirtobrutinib for adults with primary immune thrombocytopenia

A Phase 1/2, Dose-finding Study Investigating the Safety and Efficacy of Pirtobrutinib in Adults With Immune Thrombocytopenia

Phase1; Phase2 Interventional Eli Lilly and Company · NCT06721013

This trial tests whether oral pirtobrutinib can help adults with relapsed or treatment‑resistant primary immune thrombocytopenia (ITP) raise platelet counts and reduce bleeding risk.

Quick facts

PhasePhase1; Phase2
Study typeInterventional
Enrollment58 (estimated)
Ages18 Years and up
SexAll
SponsorEli Lilly and Company Industry-sponsored
Drugs / interventionspirtobrutinib
Locations45 sites (Los Angeles, California and 44 other locations)
Trial IDNCT06721013 on ClinicalTrials.gov

What this trial studies

The phase 1 portion uses a dose‑escalation design to define tolerability, safety, and pharmacokinetics with blood sampling to measure drug levels and elimination. The phase 2 portion randomizes participants to multiple pirtobrutinib doses or placebo to compare effects on platelet counts and overall safety over about 28 weeks. Participants are adults with primary ITP who are relapsed or treatment‑resistant and meet laboratory and organ‑function criteria. The study is sponsored by Eli Lilly and is being conducted at three U.S. academic centers.

Who should consider this trial

Good fit: Ideal candidates are adults with primary ITP who have relapsed or are treatment‑resistant, have had a prior documented response to at least one therapy, currently have platelet counts below 30,000/µL, and meet specified organ‑function and contraceptive requirements.

Not a fit: Patients with recent thrombotic events, significant cardiovascular disease, recent transfusions, secondary causes of thrombocytopenia, or those who have not received prior therapy are unlikely to be eligible or to benefit from this protocol.

Why it matters

Potential benefit: If successful, pirtobrutinib could offer an effective oral treatment option to raise platelet counts and lower bleeding risk for people with relapsed or refractory ITP.

How similar studies have performed: Other BTK‑targeting agents have shown early promising results in autoimmune cytopenias including ITP, but randomized, definitive phase‑3 evidence is limited, making this application of pirtobrutinib relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Have a diagnosis of primary ITP, defined as isolated thrombocytopenia not associated with another known disease process
* Have documented history of response, defined as 2 or more platelet counts greater than or equal to 50,000/microliter (μL), to at least 1 prior line of therapy. Splenectomy is considered a line of therapy
* Have relapsed or treatment-resistant primary ITP, with no available therapies known to provide clinical benefit
* Have a platelet count less than 30,000/μL on 2 occasions more than 5 days apart in the 15 days before randomization
* Have adequate liver, renal, and hematologic functions as defined by a table
* Are willing to follow contraception requirements

Exclusion Criteria:

* Have a history of any thrombotic or embolic event within 12 months before screening
* Had a transfusion with blood or blood products or plasmapheresis within 14 days (Phase 1) or within 28 days (Phase 2) of randomization
* Have significant cardiovascular disease
* Have a diagnosis or history of hematologic malignancy
* Have hepatitis B virus (HBV) defined as positive for antigen of hepatitis B (HBsAg) or polymerase chain reaction (PCR) positive for HBV deoxyribonucleic acid (DNA)
* Have hepatitis C virus (HCV) defined as positive for anti-HCV antibodies and PCR positive for HCV ribonucleic acid (RNA)

Where this trial is running

Los Angeles, California and 44 other locations

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 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.