A Study of Pirtobrutinib in Participants With Immune Thrombocytopenia

Phase 1

Not yet recruiting

• Conditions: Immune Thrombocytopenia (ITP)
• Interventions: Drug: Pirtobrutinib; Drug: Placebo

• Registration Number: NCT06721013
• Lead Sponsor: Eli Lilly and Company

Brief Summary

The purpose of the phase 1 part of this study is to evaluate how well pirtobrutinib is tolerated and what side effects may occur. The phase 2 part of the study will further investigate efficacy and safety of multiple pirtobrutinib dosages versus placebo.

The study drug will be administered orally in participants with Primary Immune Thrombocytopenia (ITP). Blood tests will be performed to check how much pirtobrutinib gets into the bloodstream and how long it takes the body to eliminate it.

The study will last up to approximately 16 weeks for phase 1 dose-escalation and 28 weeks for phase 2 dose-optimization, excluding screening.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2024-12-03
• Study First Submitted QC: 2024-12-05
• Study First Posted: 2024-12-06
• Status Verified: 2025-04
• Last Update Submitted: 2025-04-17
• Last Update Posted: 2025-04-22
• Study Start: 2025-05
• Primary Completion: 2027-02
• Study Completion: 2027-02

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 58

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)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SEQUENTIAL

Arm && Interventions

Group	Intervention	Description
Pirtobrutinib Phase 1	Pirtobrutinib	Pirtobrutinib administered orally
Pirtobrutinib Phase 2	Pirtobrutinib	Pirtobrutinib administered orally
Placebo Phase 2	Placebo	Placebo administered orally

Primary Outcome Measures

Name	Time	Method
Phase 1-Number of Participants with One or More Treatment Emergent Adverse Events (TEAEs) and Serious Adverse Event(s) (SAEs) Considered by the Investigator to be Related to Study Drug Administration	Baseline Up to Week 4	A summary of TEAEs and SAEs regardless of causality, will be reported in the Reported Adverse Events module
Phase 1-Dose Limiting Toxicity (DLT) of Pirtobrutinib	Baseline Up to Week 4	DLTs of Pirtobrutinib
Phase 1-Number of Participants with Treatment-Related Adverse Events as Assessed by Vital Signs: Blood Pressure, Pulse Rate, and Body Temperature	Baseline Up to Week 16	Blood Pressure, Pulse Rate, and Body Temperature
Phase 1-Number of Participants with Treatment-Related Adverse Events as Assessed by Clinical Lab Tests: Hematology, Clinical Chemistry, Urinalysis, Pregnancy, Hepatitis Serology and Cytomegalovirus (CMV)	Baseline Up to Week 16	Hematology, Clinical Chemistry, Urinalysis, Pregnancy, Hepatitis Serology and Cytomegalovirus (CMV)
Phase 1-Number of Participants with Treatment-Related Adverse Events as Assessed by Electrocardiograms (ECGs): ECG QT Interval	Baseline Up to Week 16	ECG QT Interval
Phase 2-Efficacy of Pirtobrutinib Versus Placebo	Baseline Up to Week 24	Stable platelet response rate is defined as the proportion of participants achieving platelet count of greater than or equal to 50 thousand per microliter (k/μL) and on at least 4 of the 6 consecutive biweekly visits between weeks 14 and 24 in the absence of rescue therapy and prohibited concomitant medication that may impact efficacy

Secondary Outcome Measures

Name	Time	Method
Phase 1-Preliminary Efficacy of Pirtobrutinib	Day 1 Up to Week 12	Platelet response rate defined as proportion of participants who achieve at least 2 consecutive platelet counts of greater than or equal to 50 k/μL and an increase from baseline of greater than or equal to 20 k/μL to any time during treatment without the use of rescue medication within 4 weeks prior to the latest elevated platelet count.
Phase 1-Evaluate the Extent of Disease Control	Day 1 Up to Week 12	Number of cumulative weeks with platelet counts greater than or equal to 50 k/μL by Week 12
Phase 1: Pharmacokinetics (PK) of Pirtobrutinib	Baseline Up to Week 16	PK: Plasma Concentrations of Pirtobrutinib
Phase 2-Assess Additional Efficacy of Pirtobrutinib Versus Placebo	Week 14 Up to Week 24	Platelet response rate is defined as the proportion of participants with greater than or equal to 2 consecutive platelet counts greater than or equal to 50 k/μL and an increase of platelet count of greater than or equal to 20 k/μL from baseline to any time during treatment or follow-up without the use of rescue medication or prohibited concomitant medication that may impact efficacy within 4 weeks prior to the latest elevated platelet count
Phase 2-Evaluate the Extent of Disease Control of Pirtobrutinib Versus Placebo	Baseline Up to Week 24	Number of cumulative weeks with platelet counts greater than or equal to 50 k/μL and greater than or equal to 100 k/μL
Phase 2-Describe the Use of Rescue Medications of Pirtobrutinib Versus Placebo	Baseline Up to Week 24	Proportion of participants requiring rescue therapy
Phase 2-Describe the PK of Pirtobrutinib	Week 16 Up to Week 40	PK: Plasma Concentrations of Pirtobrutinib

Trial Locations

Locations (4)

Bleeding and Clotting Disorders Institute; 🇺🇸 Peoria, Illinois, United States

University of Texas MD Anderson Cancer Center; 🇺🇸 Houston, Texas, United States

MedStar Georgetown University Hospital; 🇺🇸 Washington, District of Columbia, United States

Clinical Research Alliance; 🇺🇸 Westbury, New York, United States