Phase 2
N=86
A Study of Rilzabrutinib in Adult Patients With Immune Thrombocytopenia (ITP)
Immune Thrombocytopenia
Bottom Line
View on ClinicalTrials.gov: NCT03395210 ↗Enrolled (actual)
86
Serious AEs
17.4%
Results posted
Nov 2025
Primary outcome: Primary: Part A: Percentage of Participants Who Achieved 2 or More Consecutive Platelet Counts by Starting Dose Level and Overall — 44.4; 0.0; 40.0; 40.0 percentage of participants
Study Design & Population
- Study type
- Interventional
- Phase
- Phase 2
- Interventions
- Rilzabrutinib (Drug)
- Age
- Adult, Older Adult · 18+ yrs
- Sex
- All
- Sponsor
- Principia Biopharma, a Sanofi Company
- Primary completion
- Jan 2023
Outcome Measures
| Outcome | Result | p-value |
|---|---|---|
| PRIMARY Part A: Percentage of Participants Who Achieved 2 or More Consecutive Platelet Counts by Starting Dose Level and Overall |
44.4; 0.0; 40.0; 40.0; 40.0 | — |
| PRIMARY Part B: Percentage of Participants Who Achieved Platelet Counts >=50,000/μL |
34.6 | — |
| PRIMARY Part A: Number of Participants With Treatment-Emergent Adverse Events (TEAEs) and Treatment Related Treatment-Emergent Adverse Events |
3; 3; 5; 44; 48; 2 | — |
| PRIMARY Part B: Number of Participants With Treatment-Emergent Adverse Events and Treatment Related Treatment-Emergent Adverse Events |
22; 16 | — |
| SECONDARY Part A: Percentage of Weeks With Platelet Counts >=50,000/μL by Starting Dose Level and Overall |
27.92; 0.00; 39.58; 28.14; 28.60 | — |
| SECONDARY Part A: Percentage of Participants With 4 Out of the Final 8 Platelet Counts >=50,000/μL by Starting Dose Level and Overall |
11.1; 0.0; 40.0; 31.1; 28.3 | — |
| SECONDARY Part A: Change From Baseline to the Average of Post Day 1 Platelet Counts by Dose Level and Overall |
6.92; 68.10; 37.05; 29.92; 28.61 | — |
| SECONDARY Part A: Number of Weeks With Platelet Counts >=50,000/μL by Starting Dose Level and Overall |
5.9; 0.0; 10.2; 5.7; 6.0 | — |
| SECONDARY Part A: Number of Weeks With Platelet Counts >=30,000/μL by Starting Dose Level and Overall |
8.4; 0.0; 14.0; 8.8; 9.0 | — |
| SECONDARY Part A: Time to First Platelet Count >=50,000/μL Across All Dose Levels |
27.4 | — |
| SECONDARY Part B: Number of Weeks With Platelet Counts >= 50,000/μL or >= 30,000/μL and Doubling the Baseline |
9.3 | — |
| SECONDARY Part B: Percentage of Participants Who Achieved 2 or More Consecutive Platelet Counts |
42.3 | — |
| SECONDARY Part B: Number of Weeks With Platelet Counts >=30,000/μL and Doubling the Baseline |
9.3 | — |
| SECONDARY Part B: Percentage of Participants Who Received Rescue Medication |
11.5 | — |
| SECONDARY Part B: Change From Baseline in Idiopathic Thrombocytopenic Purpura Bleeding Scale (IBLS) |
-0.07 | — |
| SECONDARY Part A: Percentage of Participants Who Received Rescue Medication by Dose Levels and Overall |
11.1; 0.0; 8.3; 9.6; 11.7 | — |
| SECONDARY Part A: Percentage of Participants With Grade 2 or Higher Bleeding Event by Dose Level and Overall |
0.0; 0.0; 8.3; 17.3; 16.7 | — |
| SECONDARY Part A: Number of Participants With Idiopathic Thrombocytopenic Purpura/Immune Thrombocytopenia (ITP) Bleeding Assessment Tool (ITP-BAT) Scale by Dose Level |
7; 8; 6; 32; 0; 0 | — |
| SECONDARY Part A: Maximum Observed Plasma Concentration (Cmax) of Rilzabrutinib |
154; 287; 273; 451; 396; 319 | — |
| SECONDARY Part A: Time of Observed Maximum Plasma Concentration (Tmax) of Rilzabrutinib |
1.43; 1.50; 1.50; 2.00; 1.05; 1.50 | — |
| SECONDARY Part A: Area Under the Plasma Concentration-Time Curve From Time Zero to Last Quantifiable Concentration (AUClast) of Rilzabrutinib |
320; 616; 642; 986; 1150; 788 | — |
| SECONDARY Part A: Area Under the Plasma Concentration-Time Curve From Time Zero to Infinity (AUCinf) of Rilzabrutinib |
331; 653; 703; 787; 827; 818 | — |
| SECONDARY Part A: Elimination Half-Life (t1/2) of Rilzabrutinib |
1.36; 1.30; 1.32; 1.52; 1.34; 1.60 | — |
| SECONDARY Part A: Apparent Volume of Distribution of the Drug After Oral Administration (Vz/F) of Rilzabrutinib |
1780; 1180; 1720; 2090; 934; 1650 | — |
| SECONDARY Part A: Apparent Total Clearance of the Drug From Plasma After Oral Administration (CL/F) of Rilzabrutinib |
911; 592; 854; 743; 484; 713 | — |
| SECONDARY Part B: Plasma Concentration of Rilzabrutinib |
NA; 154.09; 5.07; 228.67; 26.42; 331.81 | — |
Summary
This was a 2 part (Part A and B) adaptive, open-label, dose-finding study of PRN1008 in patients with ITP who are refractory or relapsed with no available and approved therapeutic options, with a platelet count <30,000/μL on two counts no sooner than 7 days apart in the 15 days before treatment begins. The dose-finding portion of the study was completed. Part B treatment dose was 400 mg twice daily.
Eligibility Criteria
Inclusion Criteria
- Male or female patients, aged 18 to 80 years old
- Immune-related ITP (both primary and secondary)
Exclusion Criteria
- Pregnant or lactating women
- Current drug or alcohol abuse
- History of solid organ transplant
- Positive screening for HIV, hepatitis B, or hepatitis C
Data sourced from ClinicalTrials.gov (NCT03395210). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.