Hemophilia APhase 3BASIS KIDSNCT05611801
A Clinical Trial of Study Medicine (Marstacimab) in Pediatric Patients With Hemophilia A or Hemophilia B
A Phase 3 study testing marstacimab in people with Hemophilia A and Hemophilia B, run by Pfizer at 63 sites in 23 countries.
Trial summary
The purpose of this clinical trial is to learn about the safety and effects of the study medicine (called marstacimab) for the potential treatment of hemophilia in pediatric patients. This study will enroll pediatric participants from ages 1 to 17 years in a sequential manner. Read more about this study
- Who is it for?
- Ages 1 year to 17 years, men only
- Conditions the study is for
- Hemophilia A, Hemophilia B
- What is being tested?
- marstacimab
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 100 participants
- Where
- 63 sitesin 23 countries
- Study dates
- 9 Dec 2022to 10 Sep 2028
- Phase
- Phase 3
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 1 year to 17 years
- Men only
- No healthy volunteers
- Child
Who may be able to join
- Male participants of appropriate age and required minimum weight
- Participants aged 12 to 17 years must be at least 25 kgs at time of consent.
- Participants aged 6 to 11 years must be at least 19 kgs at time of consent.
- Participants aged 1 to 5 years must be at least 5 kgs at time of consent.
- Participants with a diagnosis of severe hemophilia A or moderately severe to severe hemophilia B
- Participants must have at least 1 year (if aged 6 to 17 years), or at least 3 months (if aged 1 to 5 years) of diary and/or medical records available in which exogenous FVIII or FIX replacement or bypass agent infusions and hemophilic bleeding episodes were consistently documented over over the above specified timeframe to the time of consent.
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- Participants who are enrolled into the Non-Inhibitor Cohort must also meet the following criteria:
- No current detectable inhibitor and no documented history of inhibitors in the 5 years prior to consent
- Must have at least 50 exposure days to FVIII/FIX replacement products for participants aged 6 to 17 years. Participants from 1 to 5 years do not require a minimum documented number of exposure days
- Must be at least 80% compliant with a stable and effective routine prophylaxis regimen with FVIII/FIX replacement products, for at least 12 months prior to consent for participants aged 6 to 17 years, for at least 3 months prior to consent for participants from 1 to 5 years
- Participants who are enrolled into the Inhibitor Cohort must also meet the following criteria:
- Documentation of current high titer inhibitor (≥5 BU/mL); or current low titer inhibitor (<5 BU/mL) refractory to FVIII or FIX replacement and with FVIII or FIX recovery <60% of expected within previous 12 months prior to the time of consent
- Participants who have documented inhibitors while on factor-replacement therapy but who do not meet the high quantitative inhibitor criteria described in the prior bullet at the time of screening (eg, participant with a previously documented high-titer inhibitor ≥5 BU/mL) and whose condition precludes re-challenge with FVIII or FIX replacement may be considered for eligibility on a case-by-case basis with discussion and agreement from the Pfizer medical monitor.
- Participants aged 6 to 17 years: Hemophilia A participants with on-demand treatment regimen with ≥12 bleeding episodes or hemophilia B participants with on-demand treatment regimen with ≥8 bleeding episodes (spontaneous or traumatic) necessitating treatment with bypass factor in the 12 months prior to informed consent
- Participants aged 1 to 5 years of age with at least 3 months' on-demand bypass treatment regimen and at least 1 treated hemophilic bleeding in the last 3 months or at least 2 treated hemophilic bleedings in the last 6 months documented prior to the time of informed consent
- Participants aged 6 to 17 years must be on an on-demand bypass treatment regimen during the 12 months prior to informed consent
- Participants aged 1 to 5 years of age must be on an on-demand bypass treatment regimen during the 3 months prior to informed consent
Who cannot join
- Known coronary artery, thrombotic, or ischemic disease, or current evidence of congenital or acquired thrombophilic disease such as Anti-thrombin III deficiency, Factor V Leiden mutation, prothrombin 20210 mutation, protein C deficiency, protein S deficiency and antiphospholipid syndrome.
- Known planned surgical procedure during the planned study period
- Known hemostatic defect other than hemophilia A or B
- Abnormal hematology, renal or hepatic function laboratory results at screening
- Current unstable liver or biliary disease per investigator assessment defined by the presence of ascites, encephalopathy, coagulopathy, hypoalbuminaemia, oesophageal or gastric varices, persistent jaundice, or cirrhosis. Participants aged 1 to 5 years with known hepatitis B or C will also be excluded
- Known HIV-positive for participants aged 1 to 5 years of age
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- Other acute or chronic medical or psychiatric condition that may increase the risk associated with study participation or investigational product administration or may interfere with the interpretation of study results and, in the judgment of the investigator
- Individuals with known allergic reaction or hypersensitivity to hamster protein or other components of the study intervention
- Current routine prophylaxis with bypassing agent, non-coagulation non-factor replacement therapy (eg, emicizumab), or any previous treatment with a gene therapy product for treatment of hemophilia
- Participants with inhibitors who are being treated using a prophylaxis treatment regimen with a bypass agent, and, participants who have previously received non-factor-based hemophilia therapy (eg, fitusiran, concizumab, emicizumab) will be considered on a case-by-case basis, only after discussion and agreement between the investigator and the Pfizer medical monitor
- Regular use of immunomodulatory medications (eg, IVIG, routine systemic corticosteroids, rituximab)
- Use of systemic antifibrinolytics, medications that may increase the risk of bleeding, and certain non-steroidal anti-inflammatory drugs within 120 hours of first dose of study intervention and while on study. Some of these agents may be permitted if it is authorized for use in the respective country, is part of the standard of care in the study population, its use is short term and on a PRN basis and following discussion with the Pfizer medical monitor.
- Ongoing or planned use of ITI, or prophylaxis with FVIII or FIX replacement at any time after initiation of treatment with study intervention
- Participation in other studies involving investigational drug(s) or investigational vaccine(s) within 30 days (or as determined by local requirements) or 5 half-lives prior to study entry or during study participation
- Previous exposure to marstacimab during participation in other marstacimab clinical studies
- CD4 cell count ≤200/uL if HIV-positive, for participants aged 6 to 17 years
- Abnormal ECG of clinical relevance that may affect participant safety or interpretation of study results
- Investigator site staff members directly involved in the conduct of the study and their family members, site staff members otherwise supervised by the investigator, and sponsor and sponsor delegate employees directly involved in the conduct of the study and their family members
Trial locations and contacts
63 sites in 23 countries. Contact the study team or a site near you to ask about taking part.
63 sites in 23 countries
Turkey (Türkiye)10 sites, 10 recruiting
- Recruiting
Adana Acibadem Hastanesi Pediatrik Hematoloji Bilim Dali
Adana, Adana, 01130
- Recruiting
Gazi University Medical Faculty
Ankara, Ankara, 06500
- Recruiting
Gazi Universitesi Tip Fakultesi Hastanesi Cocuk Hematologi Bolumu
Ankara, Ankara, 06560
- Recruiting
Gazi University Health Research and Application Center Gazi Hospital
Ankara, 06560
- Recruiting
Istanbul Universitesi Istanbul Tıp Fakultesi Hastanesi
Istanbul, Istanbul, 34093
- Recruiting
Ege Universitesi Tip Fakultesi Hastanes
Izmir, İzmir, 35100
- Recruiting
Ege University
Izmir, 35010
- Recruiting
Erciyes University Faculty of Medicine Pediatric
Kayseri, Kayseri, 38039
- Recruiting
Erciyes University Health Application and Research Center Directorate
Melikgazi, Kayseri, 38039
- Recruiting
Ondokuz Mayıs Universitesi
Samsun, Samsun, 55200
China7 sites, 4 recruiting
- Recruiting
Beijing Children's hospital, Capital Medical University
Beijing, Beijing Municipality, 100045
- Active, not recruiting
Southern Medical University Nanfang Hospital
Guangzhou, Guangdong, 510515
- Active, not recruiting
The Affiliated Hospital of Guizhou Medical University
Guiyang, Guizhou, 550004
- Active, not recruiting
Jiangxi Provincial People's Hospital
Nanchang, Jiangxi, 330006
- Recruiting
Institute of hematology&blood disease hospital
Tianjin, Tianjin Municipality
- Recruiting
Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology
Wuhan, Hubei, 430030
- Recruiting
Tongji Hospital of Tongji Medical College of HUST/Pediatric Hematology Department Pharmacy
Wuhan, Hubei, 430030
Italy5 sites, 5 recruiting
- Recruiting
IRCCS Istituto Giannina Gaslini
Genoa, Liguria, 16147
- Recruiting
Azienda Ospedaliero Universitaria di Parma
Parma, PARMA, 43126
- Recruiting
Ospedale Pediatrico Bambino Gesù IRCCS
Rome, ROMA, 00165
- Recruiting
Istituto Clinico Humanitas - Humanitas Mirasole SPA
Rozzano, Milan, 20089
- Recruiting
Azienda Ospedaliero-Universitaria Città della Salute e della Scienza di Torino
Torino, TORINO, 10126
Japan5 sites, 3 recruiting
- Active, not recruiting
Nagano Children's Hospital
Azumino, Nagano, 399-8288
- Recruiting
Nara Medical University Hospital
Kashihara, Nara, 634-8522
- Recruiting
Hyogo prefectural Kobe Children's Hospital
Kobe, Hyōgo, 650-0047
- Active, not recruiting
Saga University Hospital
Saga, Saga-ken, 849-8501
- Recruiting
Saitama Prefectural Children's Medical Center
Saitama-shi, Saitama, 330-8777
United Kingdom5 sites, 4 recruiting
- Recruiting
Birmingham Children's Hospital
Birmingham, B4 6NH
- Recruiting
Evelina London Children's Hospital
London, SE1 7EH
- Terminated
Royal Manchester Children's Hospital
Manchester, M13 9WL
- Recruiting
Royal Victoria Infirmary
Newcastle upon Tyne, England, NE1 4LP
- Recruiting
Freeman Hospital
Newcastle upon Tyne, NE7 7DN
Czechia3 sites, 3 recruiting
- Recruiting
Detska nemocnice FN Brno
Brno, Brno-město, 613 00
- Recruiting
Fakultni nemocnice Brno
Brno, 625 00
- Recruiting
Fakultni Nemocnice Motol a Homolka
Prague, 150 00
Denmark3 sites, 3 recruiting
- Recruiting
Aarhus University
Aarhus N, Aarhus N, DK-8200
- Recruiting
Aarhus Universitetshospital, Skejby
Aarhus N, 8200
- Recruiting
Rigshospitalet
Copenhagen, Capital Region, 2100
India3 sites, 3 recruiting
- Recruiting
Nil Ratan Sircar Medical College and Hospital
Kolkata, West Bengal, 700014
- Recruiting
K. J. Somaiya Hospital and Research Centre, Somaiya Ayurvihar Complex
Mumbai, Maharashtra, 400022
- Recruiting
Nirmal Hospital Pvt Ltd.
Surat, Gujarat, 395002
South Korea3 sites, 3 recruiting
- Recruiting
Kyungpook National University Hospital
Daegu, Taegu-kwangyǒkshi, 41944
- Recruiting
Severance Hospital, Yonsei University Health System
Seoul, Seoul-teukbyeolsi [seoul], 03722
- Recruiting
Kyung Hee University Hospital at Gangdong
Seoul, Seoul-teukbyeolsi [seoul], 05278
Canada2 sites
- Active, not recruiting
Stollery Children's Hospital
Edmonton, Alberta, T6G 2B7
- Active, not recruiting
Hamilton Health Sciences - McMaster University/McMaster Children's Hospital
Hamilton, Ontario, L8N 3Z5
Slovakia2 sites, 2 recruiting
- Recruiting
Detska fakultna nemocnica Kosice
Košice, 040 11
- Recruiting
Univerzitna nemocnica Martin
Martin, 036 59
South Africa2 sites
- Active, not recruiting
Worthwhile Clinical Trials
Benoni, Gauteng, 1500
- Active, not recruiting
Charlotte Maxeke Johannesburg Academic Hospital
Johannesburg, Gauteng, 2193
Spain2 sites, 2 recruiting
- Recruiting
Hospital Universitario La Paz
Madrid, Madrid, Comunidad de, 28046
- Recruiting
Hospital Universitario Miguel Servet
Zaragoza, ZARAGOZA, 50009
Taiwan2 sites, 2 recruiting
- Recruiting
Taichung Veterans General Hospital
Taichung, 407219
- Recruiting
National Taiwan University Hospital
Taipei, 100
United States1 site, 1 recruiting
- Recruiting
Intermountain - Primary Children's Hospital
Salt Lake City, Utah, 84113
Argentina1 site, 1 recruiting
- Recruiting
Arbesu Hematología
Mendoza, Mendoza Province, M5501
Australia1 site, 1 recruiting
- Recruiting
Murdoch Children's Research Institute
Parkville, 3052
Austria1 site, 1 recruiting
- Recruiting
Medizinische Universität Wien
Vienna, State of Vienna, 1090
Brazil1 site
- Active, not recruiting
Centro Estadual de Hemoterapia e Hematologia Marcos Daniel Santos - HEMOES
Maruípe, VITÓRIA, 29047-105
Germany1 site, 1 recruiting
- Recruiting
Charité Campus Virchow-Klinikum
Berlin, State of Berlin, 13353
Israel1 site, 1 recruiting
- Recruiting
Sheba Medical Center
Ramat Gan, Central District, 5262100
Mexico1 site, 1 recruiting
- Recruiting
Arké SMO S.A de C.V
Veracruz, Veracruz, 91900
Saudi Arabia1 site
- Active, not recruiting
King Fahad Specialist Hospital
Dammam, Dammam, 32253
About this study
Official title: AN OPEN-LABEL STUDY IN PEDIATRIC (<18 YEARS OF AGE), SEVERE HEMOPHILIA A PARTICIPANTS (COAGULATION FACTOR ACTIVITY <1%) WITH OR WITHOUT INHIBITORS OR MODERATELY SEVERE TO SEVERE HEMOPHILIA B PARTICIPANTS (COAGULATION FACTOR ACTIVITY ≤2%) WITH OR WITHOUT INHIBITORS COMPARING 12 MONTHS OF HISTORICAL STANDARD TREATMENT TO MARSTACIMAB PROPHYLAXIS
The purpose of this clinical trial is to learn about the safety and effects of the study medicine (called marstacimab) for the potential treatment of hemophilia in pediatric patients.
This study will enroll pediatric participants from ages 1 to 17 years in a sequential manner. The study opened the enrollment to adolescent participants aged 12 to 17 years first. Then children aged 6 to 11 years erere permitted to enroll. Lastly, children aged 1 to 5 years are permitted to enroll.
Read more
This study will enroll male participants who:
- have severe Hemophilia A or moderately severe to severe Hemophilia B (with or without inhibitors)
- have accurate historical records documenting all factor VIII, factor IX, or bypass agent infusions and hemophilia bleed events for at least 1 year prior to entering the study for participants from 6 to 17 years of age, and at least 3 months prior to entering the study for participants from 1 to 5 years of age
- if a non-inhibitor patient, must be on a stable routine prophylaxis regimen with factor VIII or factor IX replacement products for at least 12 months prior to study entry for participants from 6 to 17 years of age, and least 3 months for participants aged from 1 to 5 years of age
- if an inhibitor patient, must be on an on-demand bypass treatment regimen during the 12 months prior to study entry for participants from 6 to 17 years of age, and during the 3 months prior to study entry for participants aged from 1 to 5 years of age
All participants in this study will receive marstacimab to use prophylactically. Marstacimab will be given once a week as a subcutaneous (under the skin) shot. The first dose of marstacimab will be given at the study site by the study site staff. During the 12-month treatment period, weekly doses of marstacimab can be given at home, or if preferred, the doses may be given by the study site staff.
To help us determine if the study medicine is safe and effective, we will compare participant experiences when they are taking the study medicine to a historical period when they were not. Researchers want to see if the study medicine works to prevent the bleeding episodes commonly experienced by patients with Hemophilia.
Participants will be in this study for about 14 months (approximately 1 month in a Screening period, 12 months receiving treatment, and 1 month in a follow-up period) during which they will visit the study site at least 10 times. If preferred, and if local regulations allow it, 2 of the study visits can be completed at the participant's home instead of at the study site. There will also be 6 scheduled telephone calls approximately every 2 months.
- Conditions
- Hemophilia A, Hemophilia B
- Being tested
- marstacimab
- Keywords
- Factor VIII Inhibitor, Factor IX Inhibitor, PF-06741086, Marstacimab, Anti-TFPI, Factor VIII, Factor IX, Inhibitors, Anti-Tissue Factor Pathway Inhibitor (TFPI), Subcutaneous (sc), Prophylaxis, On-Demand, BASIS KIDS, Inhibitor, SC, Subcutaneous, Injection, On demand, aTFPI, Severe hemophilia
- Medical subject headings
- Hemophilia A, Hemophilia B, Hemorrhage
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
marstacimabDrug
Also called PF-06741086
marstacimab
| Study group | Role | What they receive |
|---|---|---|
| marstacimab (PF-06741086) | Experimental | Weekly subcutaneous injections. Receives: Drug: marstacimab |
What is being measured
The primary outcome is the main question the study is designed to answer.
Annualized bleeding rate (ABR) of treated bleeding events
Derived for each subject for each period (historical and study treatment) by using the following formula: ABR = number of bleeds requiring treatments/ (days on treatment period / 365.25)
Measured: Baseline (up to 12 months prior to informed consent) to the end of the 12-month treatment period
Incidence of adverse events and serious adverse events
Measured: Screening through end of follow-up period (approximately 14 months)
Incidence and severity of thrombotic events
Measured: Baseline to end of 12-month treatment period
Incidence and severity of thrombotic microangiopathy
Measured: Baseline to end of 12-month treatment period
Incidence and severity of disseminated intravascular coagulation/consumption coagulopathy events
Measured: Baseline to end of 12-month treatment period
Immunogenicity (incidence of ADA and clinically significant persistent NAb against marstacimab)
Measured: Baseline to end of 12-month treatment period
Incidence and severity of injection site reaction
Measured: Baseline to end of 12-month treatment period
Incidence of severe hypersensitivity and anaphylactic reactions
Measured: Baseline to end of 12-month treatment period
Secondary outcomes (10)
Incidence of joint bleeds (treated)
Measured: Baseline to end of 12-month treatment period
Incidence of spontaneous bleeds (treated)
Measured: Baseline to end of 12-month treatment period
Incidence of target joint bleeds (treated)
Measured: Baseline to end of 12-month treatment period
Incidence of total bleeds (treated and untreated)
Measured: Baseline to end of 12-month treatment period
Number of target joints
Measured: Baseline to end of 12-month treatment period
Change from baseline in joint health as measured by the HJHS for participants ≥4 years of age
Measured: Baseline to end of 12-month treatment period
Changes in quality of life measured by Haem-A-QoL/Haemo-QoL (using age-dependent versions for participants ≥8 years of age)
Measured: Baseline to end of 12-month treatment period
Changes in quality of life measured by pedHAL (using age-dependent versions for participants ≥4 years of age)
Measured: Baseline to end of 12-month treatment period
Changes in quality of life measured by Patient Global Impression of Change - Hemophilia for participants ≥4 years of age
Measured: Baseline to end of 12-month treatment period
Changes in quality of life measured by Health Utilities Measure (EQ-5D-Y) for participants ≥4 years of age
Measured: Baseline to end of 12-month treatment period
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Nov 2022
- Study start9 Dec 2022
- Primary completion10 Sep 2028 (estimated)
- Study completion10 Sep 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Hemophilia AStudies 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 3
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 100 participants (estimated)
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
- NCT05611801
- Sponsor's protocol ID
- B7841008
- Other IDs
- ANTI-TFPI PEDIATRIC STUDY, 2022-500495-65-00
- Acronym
- BASIS KIDS
- Status last verified
- Oct 2026
- First submitted
- 27 Oct 2022
- Last updated
- 14 Oct 2026
- Results posted
- No
- Data monitoring committee
- Yes
- 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.