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

May 11, 2026 updated by: Pfizer

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

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

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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 received 1 subcutaneous injection of dose 1 every month for 3 months during the 12-week treatment period. Each participant in cohorts 2, 3, or 4 (will) receive(d) subcutaneous injection(s) of dose 2, 3, or 4 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

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
91

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Australia
    • New South Wales
      • Liverpool, New South Wales, Australia, 2170
        • Recruiting
        • Liverpool Hospital
      • Liverpool, New South Wales, Australia, 2170
        • Recruiting
        • South West Radiology
      • Mount Kuring-Gai, New South Wales, Australia, 2080
        • Recruiting
        • Slade Pharmacy
      • Waratah, New South Wales, Australia, 2298
        • Recruiting
        • Calvary Mater Newcastle
    • South Australia
      • Bedford Park, South Australia, Australia, 5042
        • Recruiting
        • Flinders Medical Centre
      • Kurralta Park, South Australia, Australia, 5037
        • Recruiting
        • ICON Cancer Centre - Kurralta Park
    • Victoria
      • Melbourne, Victoria, Australia, 3004
        • Recruiting
        • The Alfred Hospital
    • Western Australia
      • Perth, Western Australia, Australia, 6000
        • Recruiting
        • Royal Perth Hospital
  • Canada
    • Ontario
      • Toronto, Ontario, Canada, M5B 1W8
        • Recruiting
        • Unity Health Toronto, St. Michael's Hospital
    • Quebec
      • Montreal, Quebec, Canada, H4A 3J1
        • Recruiting
        • McGill University Health Centre
  • Czechia
      • Hradec Králové, Czechia, 500 05
        • Recruiting
        • Fakultni nemocnice Hradec Kralove
      • Ostrava - Poruba, Czechia, 708 52
        • Recruiting
        • Fakultni nemocnice Ostrava
      • Prague, Czechia, 100 34
        • Recruiting
        • Fakultní Nemocnice Královské Vinohrady
      • Prague, Czechia, 12808
        • Recruiting
        • Vseobecna fakultni nemocnice v Praze
  • Hungary
      • Budapest, Hungary, 1088
        • Recruiting
        • Semmelweis University
      • Győr, Hungary, 9024
        • Recruiting
        • Petz Aladar Egyetemi Oktato Korhaz
      • Szekszárd, Hungary, 7100
        • Not yet recruiting
        • Tolna Varmegyei Balassa Janos Korhaz
      • Tatabánya, Hungary, H-2800
        • Not yet recruiting
        • Komarom-Esztergom Varmegyei Szent Borbala Korhaz
    • Baranya
      • Pécs, Baranya, Hungary, 7624
        • Active, not recruiting
        • Pecsi Tudomanyegyetem Klinikai Kozpont
    • Somogy County
      • Kaposvár, Somogy County, Hungary, 7400
        • Recruiting
        • Somogy Megyei Kaposi Mor Oktato Korhaz
  • Poland
      • Bialystok, Poland, 15-732
        • Active, not recruiting
        • Interhem
      • Gdansk, Poland, 80-214
        • Active, not recruiting
        • Klinika Hematologii i Transplantologii Uniwersyteckie Centrum Kliniczne
      • Katowice, Poland, 40-519
        • Recruiting
        • Pratia Onkologia Katowice
      • Poznan, Poland, 60-569
        • Active, not recruiting
        • Uniwersytecki Szpital Kliniczny w Poznaniu
      • Wroclaw, Poland, 50-367
        • Recruiting
        • Uniwersytecki Szpital Kliniczny im. Jana Mikulicza-Radeckiego we Wroclawiu
    • Greater Poland Voivodeship
      • Skórzewo, Greater Poland Voivodeship, Poland, 60-185
        • Recruiting
        • AIDPORT Sp. z o.o.
  • United Kingdom
      • London, United Kingdom, W12 0HS
        • Recruiting
        • Hammersmith Hospital
    • Cambridgeshire
      • Cambridge, Cambridgeshire, United Kingdom, CB2 2QQ
        • Recruiting
        • Addenbrooke's Hospital
    • Devon
      • Plymouth, Devon, United Kingdom, Pl6 8DH
        • Recruiting
        • Derriford Hospital
    • England
      • Truro, England, United Kingdom, TR1 3LJ
        • Recruiting
        • The Royal Cornwall Hospital
  • United States
    • North Carolina
      • Greenville, North Carolina, United States, 27834
        • Recruiting
        • East Carolina University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 70 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Open Label PF-06835375 dose 1 Treatment
subcutaneous injection once monthly for 3 months
Biological: PF-06835375
CXCR5 inhibitor
Experimental: Open Label PF-06835375 dose 2 Treatment
subcutaneous injection once monthly for 4 months
Biological: PF-06835375
CXCR5 inhibitor
Experimental: Open Label PF-06835375 dose 3 Treatment
subcutaneous injection once monthly for 4 months
Biological: PF-06835375
CXCR5 inhibitor
Experimental: Open Label PF-06835375 dose 4 Treatment
subcutaneous injections once monthly for 4 months
Biological: PF-06835375
CXCR5 inhibitor

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
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
baseline through 12 and 16 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
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
baseline through 12 and 16 weeks
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
baseline through 12 and 16 weeks
Proportion of participants with change from baseline of platelet counts
Time Frame: baseline to Week 20 and Week 24
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
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
baseline to Week 20 and Week 24
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 cohorts 2 and 3)
baseline through end of study (Week 20 for cohort 1 and Week 24 for cohorts 2 and 3)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Pfizer

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Pfizer CT.gov Call Center, Pfizer

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
February 2, 2022

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
August 2, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
August 2, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 27, 2021

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 27, 2021

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 7, 2021

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 12, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 11, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • C1131003
  • 2023-509338-21-00 (Registry Identifier: CTIS (EU))

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD 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.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Primary Immune Thrombocytopenia

Clinical Trials on PF-06835375

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings