About this trial
The purpose of the phase 1 part of this study was 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.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
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 at least 5 days apart in the 15 days before randomization
Disqualifiers
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
Trial design
Sequential
Treatments tested in this trial
Pirtobrutinib
DrugAdministered orally
Placebo
DrugAdministered orally
Treatment groups
Trial outcomes
Primary outcomes
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
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
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
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)
Hematology, Clinical Chemistry, Urinalysis, Pregnancy, Hepatitis Serology and Cytomegalovirus (CMV)
Secondary outcomes
Phase 1-Preliminary Efficacy of Pirtobrutinib
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
Number of cumulative weeks with platelet counts greater than or equal to 50 k/μL by Week 12
Phase 1: Pharmacokinetics (PK) of Pirtobrutinib
PK: Plasma Concentrations of Pirtobrutinib
Phase 2-Assess Additional Efficacy of Pirtobrutinib Versus Placebo
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
Sponsors and contacts
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