Safety and Efficacy Study of PF-06835375 in Primary Immune Thrombocytopenia

Study Overview
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Brief Summary
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This is a Phase 2, open-label, multicenter, multiple subcutaneous injection, safety and efficacy study of PF-06835375 in adult participants with primary immune thrombocytopenia (ITP). This study will focus on participants with persistent (>3 months and ≤12 months), or chronic (>12 months) ITP

Detailed Description
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This study is designed to elucidate the effects of PF-06835375 on platelet counts in participants with moderate to severe primary ITP. Based on the experience with other B-cells depleting agents, it is expected that the platelet counts will increase following a standard treatment. Each participant in cohort 1 will receive 1 subcutaneous injection of dose 1 every month for 3 months during the 12-week treatment period. And each participant in cohort 2 will receive 1 subcutaneous injection of dose 2 every month for 4 months during the 16-week treatment period. This should provide sufficient levels of exposure and depletion of CXCR5 positive cells to sustain the effects of PF-06835375 during the treatment period. Additional depletion of Tfh cells may provide sustained increase in platelet count following the last treatment.

Official Title
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AN INTERVENTIONAL PHASE 2, OPEN-LABEL, MULTI-CENTER STUDY TO EVALUATE SAFETY AND EFFICACY OF PF-06835375 IN ADULT PARTICIPANTS WITH MODERATE TO SEVERE PRIMARY IMMUNE THROMBOCYTOPENIA

Conditions
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Primary Immune Thrombocytopenia

Intervention / Treatment
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* Biological: PF-06835375


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnosis of Primary ITP. Ongoing ITP (platelet counts <50 x 109/L) [No severe bleeding within 1 month or during screening] AND Persistent ITP (3 to 12 months) or Chronic ITP >12 months Exclusion Criteria: Bleeding event according to the WHO grading scale ≥2 occurring ≤4 weeks prior to screen OR a current bleeding event that, in the opinion of the investigator, requires treatment with standard of care therapy OR require blood or blood products during screening Splenectomy within 3 months of randomization or planned during the study duration.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Open Label PF-06835375 dose 1 Treatment<br>subcutaneous injection once monthly for 3 months | Biological: PF-06835375<br>* CXCR5 inhibitor<br>|
| Experimental: Open Label PF-06835375 dose 2 Treatment<br>subcutaneous injection once monthly for 4 months | Biological: PF-06835375<br>* CXCR5 inhibitor<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of participants with change from baseline of platelet counts | To evaluate absolute value of platelet count of treated participants | baseline through 12 and 16 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| proportion of participants with modified overall response (mOR) | To evaluate the modified overall response of platelet count of treated participants | baseline through 12 and 16 weeks | 
| proportion of participants with complete response (CR) | To evaluate the complete response of platelet count of treated participants | baseline through 12 and 16 weeks | 
| Number of Participants With Treatment Emergent Treatment-Related Adverse Events (AEs) |  | baseline through end of study (Week 20 for cohort 1 and Week 24 for cohort 2) | 
| Proportion of participants with change from baseline of platelet counts |  | baseline to Week 20 and Week 24 | 
| Proportion of participants with change from baseline of circulating B cells |  | baseline to Week 20 and Week 24 | 
| Proportion of participants with change from baseline of circulating cTfh cells |  | baseline to Week 20 and Week 24 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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ITP, platelets