Primary Immune ThrombocytopeniaPhase 2NCT05070845
Safety and Efficacy Study of PF-06835375 in Primary Immune Thrombocytopenia
A Phase 2 study testing PF-06835375 in people with Primary Immune Thrombocytopenia, run by Pfizer at 24 sites in 7 countries.
Trial 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 Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- Primary Immune Thrombocytopenia
- What is being tested?
- PF-06835375
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 61 participants
- Where
- 24 sitesin 7 countries
- Study dates
- 2 Feb 2022to 23 Sep 2026
- Phase
- Phase 2
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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
Who cannot join
- 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.
Trial locations and contacts
24 sites in 7 countries.
24 sites in 7 countries
Australia8 sites
Flinders Medical Centre
Bedford Park, South Australia, 5042
ICON Cancer Centre - Kurralta Park
Kurralta Park, South Australia, 5037
Liverpool Hospital
Liverpool, New South Wales, 2170
South West Radiology
Liverpool, New South Wales, 2170
The Alfred Hospital
Melbourne, Victoria, 3004
Slade Pharmacy
Mount Kuring-Gai, New South Wales, 2080
Royal Perth Hospital
Perth, Western Australia, 6000
Calvary Mater Newcastle
Waratah, New South Wales, 2298
Poland6 sites
InterHem
Bialystok, 15-732
Klinika Hematologii i Transplantologii Uniwersyteckie Centrum Kliniczne
Gdansk, 80-214
Pratia Onkologia Katowice
Katowice, 40-519
Uniwersytecki Szpital Kliniczny w Poznaniu
Poznan, 60-569
AIDPORT Sp. z o.o.
Skórzewo, Greater Poland Voivodeship, 60-185
Uniwersytecki Szpital Kliniczny im. Jana Mikulicza-Radeckiego we Wroclawiu
Wroclaw, 50-367
Hungary4 sites
Semmelweis University
Budapest, 1088
Somogy Megyei Kaposi Mór Oktató Kórház
Kaposvár, Somogy County, 7400
Pécsi Tudományegyetem Klinikai Központ
Pécs, Baranya, 7624
Tolna Varmegyei Balassa Janos Korhaz
Szekszárd, 7100
Canada2 sites
McGill University Health Centre
Montreal, Quebec, H4A 3J1
Unity Health Toronto, St. Michael's Hospital
Toronto, Ontario, M5B 1W8
Czechia2 sites
Fakultni nemocnice Hradec Kralove
Hradec Králové, 500 05
Fakultni nemocnice Ostrava
Ostrava - Poruba, 708 52
United States1 site
East Carolina University
Greenville, North Carolina, 27834
About this study
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
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
Read the 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.
- Conditions
- Primary Immune Thrombocytopenia
- Being tested
- PF-06835375
- Keywords
- ITP, platelets
- Medical subject headings
- Purpura, Thrombocytopenic, Idiopathic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
PF-06835375Biological
CXCR5 inhibitor
| Study group | Role | What they receive |
|---|---|---|
| Open Label PF-06835375 dose 1 Treatment | Experimental | subcutaneous injection once monthly for 3 months Receives: Biological: PF-06835375 |
| Open Label PF-06835375 dose 2 Treatment | Experimental | subcutaneous injection once monthly for 4 months Receives: Biological: PF-06835375 |
| Open Label PF-06835375 dose 3 Treatment | Experimental | subcutaneous injection once monthly for 4 months Receives: Biological: PF-06835375 |
| Open Label PF-06835375 dose 4 Treatment | Experimental | subcutaneous injections once monthly for 4 months Receives: Biological: PF-06835375 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Proportion of participants with change from baseline of platelet counts
To evaluate absolute value of platelet count of treated participants
Measured: baseline through 12 and 16 weeks
Secondary outcomes (6)
proportion of participants with modified overall response (mOR)
To evaluate the modified overall response of platelet count of treated participants
Measured: baseline through 12 and 16 weeks
proportion of participants with complete response (CR)
To evaluate the complete response of platelet count of treated participants
Measured: baseline through 12 and 16 weeks
Number of Participants With Treatment Emergent Treatment-Related Adverse Events (AEs)
Measured: 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
Measured: baseline to Week 20 and Week 24
Proportion of participants with change from baseline of circulating B cells
Measured: baseline to Week 20 and Week 24
Proportion of participants with change from baseline of circulating cTfh cells
Measured: baseline to Week 20 and Week 24
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 Oct 2021
- Study start2 Feb 2022
- Primary completion23 Sep 2026
- Study completion23 Sep 2026
Why it stopped: The study terminated due to a business decision. The decision to terminate the trial was not based on any safety concerns.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Primary Immune ThrombocytopeniaStudies of the same condition, open and under way.
- More trials run by PfizerThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 61 participants (actual)
Sponsor and investigators
- Lead sponsor
- Pfizer
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Pfizer CT.gov Call Center, Study director, Pfizer
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05070845
- Sponsor's protocol ID
- C1131003
- Other IDs
- 2023-509338-21-00, 2023
- Status last verified
- Oct 2026
- First submitted
- 27 Sep 2021
- Last updated
- 16 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: 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.