Actively Recruiting
Open-Label Extension Study of Marstacimab in Hemophilia Participants With or Without Inhibitors
Led by Pfizer · Updated on 2026-04-14
245
Participants Needed
75
Research Sites
454 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
Study B7841007 is an open-label extension study to assess the long-term safety, tolerability, and efficacy of prophylaxis treatment with marstacimab in participants who did not require "Early Termination" from the Phase 3 Study B7841005 and from the Phase 3 Study B7841008. Study B7841005: approximately 145 adolescent and adult participants 12 to \<75 years of age with severe hemophilia A or moderately severe to severe hemophilia B (defined as FVIII activity \<1% or FIX activity ≤2%, respectively) with or without inhibitors are expected to be enrolled in Study B7841005 during which they will receive prophylaxis (defined as treatment by SC injection of marstacimab). Study B7841008: this is an ongoing Phase 3, open-label study in pediatric participants \<18 years of age with severe hemophilia A (FVIII Coagulation Factor Activity \<1%) or moderately severe to severe hemophilia B (FIX Coagulation Factor Activity ≤2%). A sequential approach will be used in enrolling at least 100 pediatric participants, at least 20 of which will be aged ≥12 to \<18 years and at least 80 participants will be aged ≥1 to \<12 years. At the start of study B7841008, the dosing and data available in adolescent and adult participants in Study B7841005 supported the initiation of B7841008 study in participants aged ≥12 to \<18 years. Subsequently, additional safety and efficacy data from adolescent participants in Study B7841005 became available for benefit/risk assessment in support of dosing participants aged ≥6 to \<12 years. Based on the positive benefit/risk assessment conducted by both internal Pfizer review and eDMC review, dosing of the ≥6 to \<12 years age group was initiated in June 2023 in B7841008 Study. Data from participants ≥6 years from B7841008 Study and Study B7841005 will support the dosing of participants aged ≥1 to \<6 years. All participants will be provided the prefilled pen (PFP) for administration of marstacimab in the study. Use of the prefilled syringe (PFS) will be permitted at the investigator's discretion for those participants who have difficulty with administration of the PFP. Additionally, participants will be provided the PFS for use in this study in countries where the PFS is anticipated to be the only presentation available commercially. An optional, open-label, single arm, substudy using the PFP was completed in the first 23 participants rolled over from Study B7841005 who agreed to participate in the substudy.
CONDITIONS
Official Title
Open-Label Extension Study of Marstacimab in Hemophilia Participants With or Without Inhibitors
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Participants must have a minimum body weight as defined by parent studies
- Participants must be willing and able to comply with all scheduled visits, treatments, laboratory tests, and study procedures
- Participants must have successfully completed participation in parent studies without early termination
You will not qualify if you...
- History or current treatment for coronary artery disease, venous or arterial thrombosis (CTCAE Grade >3), or ischemic disease (except catheter-associated thrombosis)
- Abnormal kidney function defined as eGFR less than 30 mL/min/1.73 m²
- Planned surgical procedure during the study period
- Unstable liver function deemed inappropriate for study participation
- For HIV-positive participants, worsening disease status making them unsuitable for the study
- Regular use of immunomodulatory drugs such as IVIG, systemic corticosteroids, or rituximab
- Ongoing or planned use of immune tolerance induction or prophylaxis with FVIII or FIX replacement during the study
- Participation in other investigational drug or vaccine studies within 30 days or 5 half-lives prior to or during this study, except parent studies
- Investigator site staff, Pfizer employees involved in the study, and their family members
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Trial Site Locations
Total: 75 locations
1
University of Iowa
Iowa City, Iowa, United States, 52242
Active, Not Recruiting
2
Northwell Health HTC
New Hyde Park, New York, United States, 11040
Actively Recruiting
3
The Feinstein Institutes for Medical Research
Philadelphia, Pennsylvania, United States, 19195
Actively Recruiting
4
Washington Institute for Coagulation d/b/a WACBD
Seattle, Washington, United States, 98101
Actively Recruiting
5
Arbesu Hematología
Mendoza, Argentina, M5501
Actively Recruiting
6
Royal Children's Hospital
Melbourne, Victoria, Australia, 3052
Actively Recruiting
7
HEMOES
Vitória, Espírito Santo, Brazil, 29047-105
Actively Recruiting
8
Stollery Children's Hospital
Edmonton, Alberta, Canada, T6G 2B7
Actively Recruiting
9
Hamilton Health Sciences - McMaster University Medical Centre
Hamilton, Ontario, Canada, L8N 3Z5
Actively Recruiting
10
Hamilton Health Sciences - McMaster University Medical Centre
Hamilton, Ontario, Canada, L8N3Z5
Actively Recruiting
11
Nanfang Hospital, Southern Medical University
Guangzhou, Guangdong, China, 510515
Actively Recruiting
12
The Affiliated Hospital of Guizhou Medical University
Guiyang, Guizhou, China, 550004
Actively Recruiting
13
Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology
Wuhan, Hubei, China, 430030
Actively Recruiting
14
Jiangxi Provincial People's Hospital
Nanchang, Jiangxi, China, 330006
Actively Recruiting
15
Jiangxi Provincial People's Hospital
Nanchang, Jiangxi, China, 330038
Actively Recruiting
16
Institute of hematology&blood disease hospital
Tianjin, Tianjin Municipality, China
Actively Recruiting
17
Beijing Children's Hospital, Capital Medical University
Beijing, China, 100045
Actively Recruiting
18
Klinicki bolnicki centar Zagreb
Zagreb, Croatia, 10000
Active, Not Recruiting
19
Aarhus Universitetshospital, Skejby
Aarhus, Central Jutland, Denmark, 8200
Actively Recruiting
20
Hôpital Universitaire Necker Enfants Malades
Paris, France, 75015
Actively Recruiting
21
The University of Hong Kong (HKU)-Queen Mary Hospital (QMH)
Hong Kong, Hong Kong, 999077
Actively Recruiting
22
Prince of Wales Hospital
Hong Kong, Hong Kong
Actively Recruiting
23
Queen Mary Hospital
Hong Kong, Hong Kong
Actively Recruiting
24
The Chinese University of Hong Kong
Ma Liu Shui, Hong Kong
Actively Recruiting
25
Nirmal Hospital Pvt Ltd.
Surat, Gjuarat, India, 395002
Actively Recruiting
26
K.J Somaiya Hospital & Research Centre, Somaiya Ayurvihar Complex
Mumbai, Maharashtra, India, 400022
Actively Recruiting
27
Sahyadri Super Speciality Hospital
Pune, Maharashtra, India, 411004
Actively Recruiting
28
Nil Ratan Sircar Medical College and Hospital
Kolkata, West Bengal, India, 700014
Actively Recruiting
29
Sheba Medical Center
Ramat Gan, Central District, Israel, 5262100
Actively Recruiting
30
IRCCS Istituto Giannina Gaslini
Genoa, Liguria, Italy, 16147
Actively Recruiting
31
Istituto Clinico Humanitas
Rozzano, Milano, Italy, 20089
Actively Recruiting
32
AOU Policlinico Umberto I
Roma, RM, Italy, 00161
Actively Recruiting
33
Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico
Milan, Italy, 20122
Actively Recruiting
34
Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico
Milan, Italy, 20122
Actively Recruiting
35
Nagoya University Hospital - Transfusion Medicine
Nagoya, Aichi-ken, Japan, 466-8560
Actively Recruiting
36
Nagano Children's Hospital
Azumino, Nagano, Japan, 399-8288
Actively Recruiting
37
Nara Medical University Hospital
Kashihara, Nara, Japan, 634-0813
Actively Recruiting
38
Saitama Medical University Hospital
Lruma-gun, Saitama, Japan, 350-0495
Actively Recruiting
39
Saitama Children's Medical Center
Saitama-shi, Saitama, Japan, 330-8777
Actively Recruiting
40
Hiroshima University Hospital
Hiroshima, Japan, 734-8551
Actively Recruiting
41
Saga University Hospital
Saga, Japan, 849-8501
Actively Recruiting
42
Centro Multidisciplinario para el Desarrollo Especializado de la Investigacion Clinica en Yucatán S.
Mérida, Yucatán, Mexico, 97130
Actively Recruiting
43
Sultan Qaboos University Hospital
Muscat, Oman, 123
Actively Recruiting
44
Institute for Mother and Child healthcare "Dr Vukan Cupic"
Belgrade, Serbia, 11000
Actively Recruiting
45
Clinical Center Nis
Niš, Serbia, 18000
Actively Recruiting
46
Detska fakultna nemocnica Kosice
Košice, Slovakia, 040 11
Actively Recruiting
47
Univerzitna nemocnica Martin
Martin, Slovakia, 036 59
Actively Recruiting
48
Worthwhile Clinical Trials
Benoni, Gauteng, South Africa, 1500
Active, Not Recruiting
49
Charlotte Maxeke Johannesburg Academic Hospital
Johannesburg, Gauteng, South Africa, 2193
Active, Not Recruiting
50
WITS Health Consortium
Johannesburg, Gauteng, South Africa, 2193
Active, Not Recruiting
51
Kyung Hee University Hospital at Gangdong
Seoul, Seoul-teukbyeolsi [seoul], South Korea, 05278
Actively Recruiting
52
Severance Hospital, Yonsei University Health System
Seoul, Seoul-teukbyeolsi[seoul], South Korea, 03722
Actively Recruiting
53
Kyungpook National University Hospital
Daegu, Taegu-kwangyǒkshi, South Korea, 41944
Actively Recruiting
54
Hospital Universitario A Coruna
A Coruña, Spain, 15006
Actively Recruiting
55
Hospital Universitario Vall d´Hebron
Barcelona, Spain, 08035
Actively Recruiting
56
Hospital Universitario La Paz
Madrid, Spain, 28046
Actively Recruiting
57
Hospital Universitario Miguel Servet
Zaragoza, Spain, 50009
Actively Recruiting
58
ChangHua Christian Hospital
Changhua, Changhua County, Taiwan, 500
Actively Recruiting
59
Taichung Veterans General Hospital
Taichung, Taiwan, 407219
Actively Recruiting
60
Acibadem Adana Hospital
Adana, Turkey (Türkiye), 01130
Actively Recruiting
61
Hacettepe University Faculty of Medicine
Ankara, Turkey (Türkiye), 06100
Actively Recruiting
62
Hacettepe University Medical Faculty Hospital
Ankara, Turkey (Türkiye), 06230
Actively Recruiting
63
Gazi University Medical Faculty
Ankara, Turkey (Türkiye), 06500
Actively Recruiting
64
Gazi University Health Research and Application Center Gazi Hospital
Ankara, Turkey (Türkiye), 06560
Actively Recruiting
65
Gaziantep University Şahinbey Research and Practice Hospital
Gaziantep, Turkey (Türkiye), 27310
Actively Recruiting
66
Istanbul University Oncology Institute
Istanbul, Turkey (Türkiye), 34093
Actively Recruiting
67
Istanbul Universitesi Klinik Arastirmalar Mukemmeliyet Uygulama ve Arastirma Merkezi
Istanbul, Turkey (Türkiye), 34452
Actively Recruiting
68
Ege University Faculty of Medicine
Izmir, Turkey (Türkiye), 35040
Actively Recruiting
69
Ege University Faculty of Medicine
Izmir, Turkey (Türkiye), 35100
Actively Recruiting
70
Erciyes University Faculty of Medicine
Kayseri, Turkey (Türkiye), 38039
Actively Recruiting
71
Ondokuz Mayıs University Healthcare Practice and Research Center
Samsun, Turkey (Türkiye), 55200
Actively Recruiting
72
Ondokuz Mayıs University Medical Faculty Local Laboratory
Samsun, Turkey (Türkiye), 55280
Actively Recruiting
73
Royal Victoria Infirmary
Newcastle upon Tyne, England, United Kingdom, NE1 4LP
Actively Recruiting
74
Guy's & St Thomas' NHS Foundation Trust
London, London, CITY of, United Kingdom, SE1 9RT
Actively Recruiting
75
Guy's & St Thomas' NHS Foundation Trust, St Thomas' Hospital
London, United Kingdom, SE1 7EH
Actively Recruiting
Research Team
P
Pfizer CT.gov Call Center
CONTACT
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NA
Model
SINGLE_GROUP
Primary Purpose
TREATMENT
Number of Arms
1
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