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

• ClinicalTrials.gov Identifier: NCT05070845
• Recruitment Status: Suspended
• First Posted: October 7, 2021
• Last Update Posted: March 20, 2023
• Sponsor: Pfizer
• Information provided by (Responsible Party): Pfizer

Tracking Information

• First Submitted Date: September 27, 2021
• First Posted Date: October 7, 2021
• Last Update Posted Date: March 20, 2023
• Actual Study Start Date: February 2, 2022
• Estimated Primary Completion Date: March 21, 2025 (Final data collection date for primary outcome measure)

Current Primary Outcome Measures (submitted: January 25, 2023)

Proportion of participants with change from baseline of platelet counts [ Time Frame: baseline through 12 and 16 weeks ]

To evaluate absolute value of platelet count of treated participants

Original Primary Outcome Measures (submitted: September 27, 2021)

Change from baseline of platelet counts at Week 12 [ Time Frame: baseline through 12 weeks ]

To evaluate absolute value of platelet count of treated participants

Current Secondary Outcome Measures (submitted: January 25, 2023)

• proportion of participants with modified overall response (mOR) [ Time Frame: 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) [ Time Frame: 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) [ Time Frame: 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 [ Time Frame: baseline to Week 20 and Week 24 ]
• Proportion of participants with change from baseline of circulating B cells [ Time Frame: baseline to Week 20 and Week 24 ]
• Proportion of participants with change from baseline of circulating cTfh cells [ Time Frame: baseline to Week 20 and Week 24 ]

Original Secondary Outcome Measures (submitted: September 27, 2021)

• proportion of participants with modified overall response (mOR) at Week 12 [ Time Frame: baseline through 12 weeks ]
  To evaluate the modified overall response of platelet count of treated participants
• proportion of participants with complete response (CR) at Week 12 [ Time Frame: baseline through 12 weeks ]
  To evaluate the complete response of platelet count of treated participants
• Number of Participants With Treatment Emergent Treatment-Related Adverse Events (AEs) [ Time Frame: baseline through end of study (Week 20) ]
• Change from baseline of platelet counts [ Time Frame: baseline to Week 20 ]
• Change from baseline of circulating B cells [ Time Frame: baseline to Week 20 ]
• Change from baseline of circulating cTfh cells [ Time Frame: baseline to Week 20 ]

• Current Other Pre-specified Outcome Measures: Not Provided
• Original Other Pre-specified Outcome Measures: Not Provided

Descriptive Information

• Brief Title: Safety and Efficacy Study of PF-06835375 in Primary Immune Thrombocytopenia
• Official Title: 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
• 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 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.
• Study Type: Interventional
• Study Phase: Phase 2

Study Design

Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Masking Description:

open label

Primary Purpose: Treatment

• Condition: Primary Immune Thrombocytopenia

Intervention

Biological: PF-06835375

CXCR5 inhibitor

Study Arms

• Experimental: Open Label PF-06835375 dose 1 Treatment
  subcutaneous injection once monthly for 3 months
  Intervention: Biological: PF-06835375
• Experimental: Open Label PF-06835375 dose 2 Treatment
  subcutaneous injection once monthly for 4 months
  Intervention: Biological: PF-06835375

• Publications *: Not Provided

Recruitment Information

• Recruitment Status: Suspended
• Estimated Enrollment (submitted: January 25, 2023): 61
• Original Estimated Enrollment (submitted: September 27, 2021): 40
• Estimated Study Completion Date: March 21, 2025
• Estimated Primary Completion Date: March 21, 2025 (Final data collection date for primary outcome measure)

Eligibility Criteria

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.

Sex/Gender

• Sexes Eligible for Study: All

• Ages: 18 Years to 70 Years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Contacts: Contact information is only displayed when the study is recruiting subjects
• Listed Location Countries: Australia, Canada, Czechia, Hungary, Poland, United States

Administrative Information

• NCT Number: NCT05070845
• Other Study ID Numbers: C1131003; 2021-002897-19 ( EudraCT Number )
• Has Data Monitoring Committee: No

U.S. FDA-regulated Product

• Studies a U.S. FDA-regulated Drug Product: Yes
• Studies a U.S. FDA-regulated Device Product: No

IPD Sharing Statement

• Plan to Share IPD: Yes
• Plan Description: Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.
• URL: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests

• Current Responsible Party: Pfizer
• Original Responsible Party: Same as current
• Current Study Sponsor: Pfizer
• Original Study Sponsor: Same as current
• Collaborators: Not Provided

Investigators

• Study Director: Pfizer CT.gov Call Center; Pfizer

• PRS Account: Pfizer
• Verification Date: March 2023