for people ages 10 years and up (full criteria)
at San Francisco, California and other locations
study started
completion around
Principal Investigator
by Kristin Shimano



This is a randomized, double-blind study of rilzabrutinib in participants with persistent or chronic ITP, with an average platelet count of <30,000/μL (and no single platelet count >35,000/μL) on two counts at least 5 days apart in the 14 days before treatment begins. Participants will receive rilzabrutinib or placebo 400mg twice daily.

For each participant, the study will last up to 60 weeks from the start of the Screening Period to the End of Study (EOS) visit. This includes Screening (up to 4 weeks) through a 12 to 24-week Blinded Treatment Period followed by a 28-week Open-Label Period. Followed by a 4-week post dose follow-up.

For adult participants, the maximum duration of the long-term extension (LTE) period will be 12 months from the date of the last adult participant to enter the LTE.

For pediatric participants, the maximum duration of the LTE period will be 12 months from the date of the last pediatric participant to enter the LTE.

Official Title

A Phase 3, Multicenter, Randomized, Double-Blind, Placebo Controlled, Parallel-Group Study With an Open-Label Extension to Evaluate the Efficacy and Safety of Oral Rilzabrutinib (PRN1008) in Adults and Adolescents With Persistent or Chronic Immune Thrombocytopenia (ITP)


Immune Thrombocytopenia, Thrombocytopenia, Purpura, Thrombocytopenic, Idiopathic, Rilzabrutinib


You can join if…

Open to people ages 10 years and up

  1. Participants will be male and female with primary ITP with duration of >6 months in pediatric participants aged 12 to <18 years (pediatric participants aged 10 to <12 years will be enrolled in the EU [EEA countries] only) and duration of >3 months in ages 18 years and above
  2. Participants who had a response (achievement of platelet count ≥50,000/µL) to IVIg/anti-D or CSs that was not sustained and who have documented intolerance, insufficient response or any contraindication to any appropriate courses of standard of care ITP therapy
  3. An average of 2 platelet counts at least 5 days apart of <30,000/µL during the Screening period and no single platelet count >35,000/µL, within 14 days prior to the first dose of study drug.
    • Pediatric participants must additionally be determined to need treatment for ITP as per clinical assessment by the Investigator.
  4. Adequate hematologic, hepatic, and renal function (absolute neutrophil count ≥1.5 × 109/L, AST/ALT ≤1.5 × upper limit of normal [ULN], albumin ≥3 g/dL, total bilirubin ≤1.5 × ULN [unless the partcipant has documented Gilbert syndrome], glomerular filtration rate >50 [Cockcroft and Gault method])
  5. Hemoglobin >9 g/dL within 1 week prior to Study Day 1
  6. All contraceptive use by men and women should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies
  7. Participants must be able to provide written informed consent or informed assent with corresponding informed consent obtained from the participants' guardian and agree to the schedule of assessments.

You CAN'T join if...

  1. Participants with secondary ITP
  2. Pregnant or lactating women
  3. History (within 5 years of Study Day 1) or current, active malignancy requiring or likely to require chemotherapeutic or surgical treatment during the study, with the exception of non melanoma skin cancer
  4. Transfusion with blood, blood products, plasmapheresis, or use of any other rescue medications with intent to increase platelet count within 14 days before Study Day 1
  5. Change in CS and/or TPO-RA dose within 14 days prior to Study Day 1 (more than 10% variation from current doses)
  6. Immunosuppressant drugs other than CSs within 5 times the elimination half-life of the drug or 14 days of Study Day 1, whichever is longer
  7. Treatment with rituximab or splenectomy within the 3 months prior to Study Day 1
    • Participants treated with rituximab will have normal B-cell counts prior to enrollment
  8. Has received any investigational drug within the 30 days before receiving the first dose of study medication, or at least 5 times elimination half-life of the drug (whichever is longer); participant should not be using an investigational device at the time of dosing
    • Participants who previously received treatment with Bruton's Tyrosine Kinase (BTK) inhibitors (except rilzabrutinib) within 30 days before the first dose of study drug are not eligible
    • Participants who previously received rilzabrutinib at any time are not eligible
  9. History of solid organ transplant

    10. Myelodysplastic syndrome 11. Live vaccine within 28 days prior to Study Day 1 or plan to receive one during the


    12. Planned surgery in the time frame of the dosing period


  • UCSF Benioff Children's Hospital San Francisco_Investigational Site Number 84020 accepting new patients
    San Francisco California 94158 United States
  • University of Southern California_Investigational Site Number 84024 in progress, not accepting new patients
    Los Angeles California 90033 United States
  • IMMUNOe International Research Centers_Investigational Site Number 84028 accepting new patients
    Centennial Colorado 80112 United States

Lead Scientist at UCSF

  • Kristin Shimano
    Professor, Pediatrics, School of Medicine. Authored (or co-authored) 53 research publications


accepting new patients
Start Date
Completion Date
Principia Biopharma, a Sanofi Company
Phase 3 Immune Thrombocytopenia Research Study
Study Type
Expecting 194 study participants
Last Updated