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

Phase 2

Recruiting

• Conditions: Primary Immune Thrombocytopenia
• Interventions: Biological: PF-06835375

• Registration Number: NCT05070845
• Lead Sponsor: Pfizer

Brief Summary

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

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 cohorts 2 and 3 will receive 1 subcutaneous injection of dose 2 or 3 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.

Basic Information
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Recruitment & Eligibility
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Study & Design
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Trial Locations

Study Timeline

• Study First Submitted: 2021-09-27
• Study First Submitted QC: 2021-09-27
• Study First Posted: 2021-10-07
• Study Start: 2022-02-02
• Status Verified: 2024-10
• Last Update Submitted: 2024-10-23
• Last Update Posted: 2024-10-26
• Primary Completion: 2026-10-27
• Study Completion: 2026-10-27

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 61

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

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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.

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Open Label PF-06835375 dose 3 Treatment	PF-06835375	subcutaneous injection once monthly for 4 months
Open Label PF-06835375 dose 1 Treatment	PF-06835375	subcutaneous injection once monthly for 3 months
Open Label PF-06835375 dose 2 Treatment	PF-06835375	subcutaneous injection once monthly for 4 months

Primary Outcome Measures

Name	Time	Method
Proportion of participants with change from baseline of platelet counts	baseline through 12 and 16 weeks	To evaluate absolute value of platelet count of treated participants

Secondary Outcome Measures

Name	Time	Method
proportion of participants with modified overall response (mOR)	baseline through 12 and 16 weeks	To evaluate the modified overall response of platelet count of treated participants
proportion of participants with complete response (CR)	baseline through 12 and 16 weeks	To evaluate the complete response of platelet count of treated participants
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 cohorts 2 and 3)
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

Trial Locations

Locations (29)

Uniwersytecki Szpital Kliniczny im. Jana Mikulicza-Radeckiego we Wroclawiu; 🇵🇱 Wroclaw, Poland

Mayo Clinic in Florida; 🇺🇸 Jacksonville, Florida, United States

American Oncology Partners of Maryland, PA; 🇺🇸 Germantown, Maryland, United States

American Oncology Partners of MD, PA; 🇺🇸 Bethesda, Maryland, United States

Hematology Oncology Associates of Rockland; 🇺🇸 Nyack, New York, United States

East Carolina University; 🇺🇸 Greenville, North Carolina, United States

Thomas Jefferson University; 🇺🇸 Philadelphia, Pennsylvania, United States

Clinical Research Unit Haematology, Division of Cancer Services, St. George Hospital; 🇦🇺 Kogarah, New South Wales, Australia

Liverpool Hospital; 🇦🇺 Liverpool, New South Wales, Australia

South West Radiology; 🇦🇺 Liverpool, New South Wales, Australia

Slade Pharmacy; 🇦🇺 Mount Kuring-Gai, New South Wales, Australia

Calvary Mater Newcastle; 🇦🇺 Waratah, New South Wales, Australia

Flinders Medical Centre; 🇦🇺 Bedford Park, South Australia, Australia

The Alfred Hospital; 🇦🇺 Melbourne, Victoria, Australia

Royal Perth Hospital; 🇦🇺 Perth, Western Australia, Australia

Unity Health Toronto, St. Michael's Hospital; 🇨🇦 Toronto, Ontario, Canada

McGill University Health Centre; 🇨🇦 Montreal, Quebec, Canada

Fakultni nemocnice Hradec Kralove; 🇨🇿 Hradec Kralove, Czechia

Vseobecna fakultni nemocnice v Praze; 🇨🇿 Praha 2, Czechia

Pécsi Tudományegyetem Klinikai Központ; 🇭🇺 Pécs, Baranya, Hungary

Somogy Megyei Kaposi Mór Oktató Kórház; 🇭🇺 Kaposvár, Somogy, Hungary

Semmelweis University; 🇭🇺 Budapest, Hungary

Petz Aladár Egyetemi Oktató Kórház; 🇭🇺 Györ, Hungary

Centrum Medyczne Pratia Poznań; 🇵🇱 Skorzewo, Wielkopolskie, Poland

InterHem; 🇵🇱 Bialystok, Poland

Klinika Hematologii i Transplantologii Uniwersyteckie Centrum Kliniczne; 🇵🇱 Gdansk, Poland

Pratia Onkologia Katowice; 🇵🇱 Katowice, Poland

Uniwersytecki Szpital Kliniczny w Poznaniu; 🇵🇱 Poznan, Poland

Derriford Hospital; 🇬🇧 Plymouth, Devon, United Kingdom