Open-Label Extension Study of Marstacimab in Hemophilia Participants With or Without Inhibitors

NCT05145127 | Recruiting Phase 3 DMC FDA Drug

• 3 other identifiers: B7841007PHASE 3 ANTI-TFPI OLE2022-500470-33-00
• Study Type: interventional
• Target: 245
• Locations: 24 countries
• Sites: 75

Brief Summary

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

Hemophilia A; Hemophilia B

Keywords

Factor VIII Inhibitor; Factor IX Inhibitor; PF-06741086; Marstacimab; Anti-TFPI

Outcome Measures

Primary Outcomes (10)

• Number of subject reporting Adverse Events

  Baseline up to 7 years

• Number of subjects reporting Serious Adverse Events

  Baseline up to 7 years

• Incidence and severity of thrombotic events

  Baseline up to 7 years

• Incidence and severity of thrombotic microangiopathy

  Baseline up to 7 years

• Number of subjects reporting Disseminated intravascular coagulalopathy/consumption coagulopathy

  Baseline up to 7 years

• Incidence of clinically significant persistent NAb against marstacimab

  Baseline up to 7 years

• Incidence and severity of injection site reaction

  Baseline up to 7 years

• Clinically significant changes in vital signs from baseline

  Baseline up to 7 years

• Incidence of clinically significant laboratory value abnormalities

  Baseline up to 7 years

• Incidence of severe hypersensitivity and anaphylactic reactions

  Baseline up to 7 years

Secondary Outcomes (13)

• Annualized rate of bleeding episodes

  Baseline up to 7 years

• Total coagulation factor product consumption

  Baseline up to 7 years

• Incidence of joint bleeds

  Baseline up to 7 years

• Incidence of spontaneous bleeds

  Baseline up to 7 years

• Incidence of target joint bleeds

  Baseline up to 7 years

Study Arms (1)

PF-06741086

EXPERIMENTAL

For participants aged ≥12 years 300 milligrams(mg) subcutaneous (sc) loading dose followed by 150 mg sq once weekly (qw). 300 mg sc qw is prescribed for participants who meet dose escalation criteria. For participants aged ≥6 to \<12 years is marstacimab 150 mg SC for initial loading dose followed by 75 mg SC QW. 150 mg sc qw is prescribed for participants who meet dose escalation criteria.

Drug: PF-06741086

Interventions

PF-06741086 DRUG

For participants aged ≥12 years 300 milligrams(mg) subcutaneous (sc) loading dose followed by 150 mg sq once weekly (qw). 300 mg sc qw is prescribed for participants who meet dose escalation criteria. For participants aged ≥6 to \<12 years is marstacimab 150 mg SC for initial loading dose followed by 75 mg SC QW. 150 mg sc qw is prescribed for participants who meet dose escalation criteria.

Also known as: marstacimab

PF-06741086

Eligibility Criteria

• Age: 1 Year - 74 Years
• Gender Eligibility Details: Male participants only
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

• All participants will have a minimum body weight as defined by parent studies
• Participants who are willing and able to comply with all scheduled visits, treatment plan, laboratory tests, and other study procedures.
• Participants have successfully completed participation in parent studies, defined as did not require "Early Termination"

You may not qualify if:

• Previous or current treatment for or history of coronary artery disease, venous or arterial thrombosis (CTCAE Grade \>3), or ischemic disease (except catheter-associated thrombosis)
• Abnormal renal function as defined by eGFR \<30 mL.min/1.73 m(2)
• Known planned surgical procedure during the planned study period
• Unstable hepatic function as determined by the Investigator clinical assessment and review of the participant's most recent laboratory results, which would make the participant inappropriate for the study
• For participants known to be HIV+, worsening disease status as determined by the Investigator clinical assessment and review of participant's most recent laboratory results, to include recent locally available CD4 count (if available), which would make the participant inappropriate for the study
• Regular, concomitant therapy with immunomodulatory drugs (eg, IVIG, and routine systemic corticosteroids, rituximab)
• Ongoing or planned use of immune tolerance induction or prophylaxis with FVIII or FIX replacement during the study
• Participation in other study involving investigational drug(s) or investigational vaccine(s) within 30 days or 5 half-lives prior to or during study participation, with the exception of participation in parent studies
• Investigator site staff or Pfizer employees directly involved in the conduct of the study, site staff otherwise supervised by the Investigator, and their respective family members

Sponsors & Collaborators

• Pfizer: lead

Study Sites (75)

University of Iowa

Iowa City, Iowa, 52242, United States

ACTIVE NOT RECRUITING

Northwell Health HTC

New Hyde Park, New York, 11040, United States

RECRUITING

The Feinstein Institutes for Medical Research

Philadelphia, Pennsylvania, 19195, United States

RECRUITING

Washington Institute for Coagulation d/b/a WACBD

Seattle, Washington, 98101, United States

RECRUITING

Arbesu Hematología

Mendoza, M5501, Argentina

RECRUITING

Royal Children's Hospital

Melbourne, Victoria, 3052, Australia

RECRUITING

HEMOES

Vitória, Espírito Santo, 29047-105, Brazil

RECRUITING

Stollery Children's Hospital

Edmonton, Alberta, T6G 2B7, Canada

RECRUITING

Hamilton Health Sciences - McMaster University Medical Centre

Hamilton, Ontario, L8N 3Z5, Canada

RECRUITING

Hamilton Health Sciences - McMaster University Medical Centre

Hamilton, Ontario, L8N3Z5, Canada

RECRUITING

Nanfang Hospital, Southern Medical University

Guangzhou, Guangdong, 510515, China

RECRUITING

The Affiliated Hospital of Guizhou Medical University

Guiyang, Guizhou, 550004, China

RECRUITING

Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology

Wuhan, Hubei, 430030, China

RECRUITING

Jiangxi Provincial People's Hospital

Nanchang, Jiangxi, 330006, China

RECRUITING

Jiangxi Provincial People's Hospital

Nanchang, Jiangxi, 330038, China

RECRUITING

Institute of hematology&blood disease hospital

Tianjin, Tianjin Municipality, China

RECRUITING

Beijing Children's Hospital, Capital Medical University

Beijing, 100045, China

RECRUITING

Klinicki bolnicki centar Zagreb

Zagreb, 10000, Croatia

ACTIVE NOT RECRUITING

Aarhus Universitetshospital, Skejby

Aarhus, Central Jutland, 8200, Denmark

RECRUITING

Hôpital Universitaire Necker Enfants Malades

Paris, 75015, France

RECRUITING

The University of Hong Kong (HKU)-Queen Mary Hospital (QMH)

Hong Kong, 999077, Hong Kong

RECRUITING

Prince of Wales Hospital

Hong Kong, Hong Kong

RECRUITING

Queen Mary Hospital

Hong Kong, Hong Kong

RECRUITING

The Chinese University of Hong Kong

Ma Liu Shui, Hong Kong

RECRUITING

Nirmal Hospital Pvt Ltd.

Surat, Gjuarat, 395002, India

RECRUITING

K.J Somaiya Hospital & Research Centre, Somaiya Ayurvihar Complex

Mumbai, Maharashtra, 400022, India

RECRUITING

Sahyadri Super Speciality Hospital

Pune, Maharashtra, 411004, India

RECRUITING

Nil Ratan Sircar Medical College and Hospital

Kolkata, West Bengal, 700014, India

RECRUITING

Sheba Medical Center

Ramat Gan, Central District, 5262100, Israel

RECRUITING

IRCCS Istituto Giannina Gaslini

Genoa, Liguria, 16147, Italy

RECRUITING

Istituto Clinico Humanitas

Rozzano, Milano, 20089, Italy

RECRUITING

AOU Policlinico Umberto I

Roma, RM, 00161, Italy

RECRUITING

Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico

Milan, 20122, Italy

RECRUITING

Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico

Milan, 20122, Italy

RECRUITING

Nagoya University Hospital - Transfusion Medicine

Nagoya, Aichi-ken, 466-8560, Japan

RECRUITING

Nagano Children's Hospital

Azumino, Nagano, 399-8288, Japan

RECRUITING

Nara Medical University Hospital

Kashihara, Nara, 634-0813, Japan

RECRUITING

Saitama Medical University Hospital

Lruma-gun, Saitama, 350-0495, Japan

RECRUITING

Saitama Children's Medical Center

Saitama-shi, Saitama, 330-8777, Japan

RECRUITING

Hiroshima University Hospital

Hiroshima, 734-8551, Japan

RECRUITING

Saga University Hospital

Saga, 849-8501, Japan

RECRUITING

Centro Multidisciplinario para el Desarrollo Especializado de la Investigacion Clinica en Yucatán S.

Mérida, Yucatán, 97130, Mexico

RECRUITING

Sultan Qaboos University Hospital

Muscat, 123, Oman

RECRUITING

Institute for Mother and Child healthcare "Dr Vukan Cupic"

Belgrade, 11000, Serbia

RECRUITING

Clinical Center Nis

Niš, 18000, Serbia

RECRUITING

Detska fakultna nemocnica Kosice

Košice, 040 11, Slovakia

RECRUITING

Univerzitna nemocnica Martin

Martin, 036 59, Slovakia

RECRUITING

Worthwhile Clinical Trials

Benoni, Gauteng, 1500, South Africa

ACTIVE NOT RECRUITING

Charlotte Maxeke Johannesburg Academic Hospital

Johannesburg, Gauteng, 2193, South Africa

ACTIVE NOT RECRUITING

WITS Health Consortium

Johannesburg, Gauteng, 2193, South Africa

ACTIVE NOT RECRUITING

Kyung Hee University Hospital at Gangdong

Seoul, Seoul-teukbyeolsi [seoul], 05278, South Korea

RECRUITING

Severance Hospital, Yonsei University Health System

Seoul, Seoul-teukbyeolsi[seoul], 03722, South Korea

RECRUITING

Kyungpook National University Hospital

Daegu, Taegu-kwangyǒkshi, 41944, South Korea

RECRUITING

Hospital Universitario A Coruna

A Coruña, 15006, Spain

RECRUITING

Hospital Universitario Vall d´Hebron

Barcelona, 08035, Spain

RECRUITING

Hospital Universitario La Paz

Madrid, 28046, Spain

RECRUITING

Hospital Universitario Miguel Servet

Zaragoza, 50009, Spain

RECRUITING

ChangHua Christian Hospital

Changhua, Changhua County, 500, Taiwan

RECRUITING

Taichung Veterans General Hospital

Taichung, 407219, Taiwan

RECRUITING

Acibadem Adana Hospital

Adana, 01130, Turkey (Türkiye)

RECRUITING

Hacettepe University Faculty of Medicine

Ankara, 06100, Turkey (Türkiye)

RECRUITING

Hacettepe University Medical Faculty Hospital

Ankara, 06230, Turkey (Türkiye)

RECRUITING

Gazi University Medical Faculty

Ankara, 06500, Turkey (Türkiye)

RECRUITING

Gazi University Health Research and Application Center Gazi Hospital

Ankara, 06560, Turkey (Türkiye)

RECRUITING

Gaziantep University Şahinbey Research and Practice Hospital

Gaziantep, 27310, Turkey (Türkiye)

RECRUITING

Istanbul University Oncology Institute

Istanbul, 34093, Turkey (Türkiye)

RECRUITING

Istanbul Universitesi Klinik Arastirmalar Mukemmeliyet Uygulama ve Arastirma Merkezi

Istanbul, 34452, Turkey (Türkiye)

RECRUITING

Ege University Faculty of Medicine

Izmir, 35040, Turkey (Türkiye)

RECRUITING

Ege University Faculty of Medicine

Izmir, 35100, Turkey (Türkiye)

RECRUITING

Erciyes University Faculty of Medicine

Kayseri, 38039, Turkey (Türkiye)

RECRUITING

Ondokuz Mayıs University Healthcare Practice and Research Center

Samsun, 55200, Turkey (Türkiye)

RECRUITING

Ondokuz Mayıs University Medical Faculty Local Laboratory

Samsun, 55280, Turkey (Türkiye)

RECRUITING

Royal Victoria Infirmary

Newcastle upon Tyne, England, NE1 4LP, United Kingdom

RECRUITING

Guy's & St Thomas' NHS Foundation Trust

London, London, CITY of, SE1 9RT, United Kingdom

RECRUITING

Guy's & St Thomas' NHS Foundation Trust, St Thomas' Hospital

London, SE1 7EH, United Kingdom

RECRUITING

Related Links

• To obtain contact information for a study center near you, click here.

MeSH Terms

Conditions

Hemophilia A; Hemophilia B

Interventions

marstacimab

Condition Hierarchy (Ancestors)

Blood Coagulation Disorders, Inherited; Blood Coagulation Disorders; Hematologic Diseases; Hemic and Lymphatic Diseases; Coagulation Protein Disorders; Hemorrhagic Disorders; Genetic Diseases, Inborn; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Genetic Diseases, X-Linked

Study Officials

• Pfizer CT.gov Call Center

  Pfizer

  STUDY DIRECTOR

Central Study Contacts

Pfizer CT.gov Call Center

CONTACT

1-800-718-1021; ClinicalTrials.gov_Inquiries@pfizer.com

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: November 11, 2021
• First Posted: December 6, 2021
• Study Start: November 17, 2021
• Primary Completion (Estimated): July 31, 2030
• Study Completion (Estimated): July 31, 2030
• Last Updated: April 14, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will share

Locations

ME (1); CN (7); IN (4); HK (4); JP (7); AU (1); GB (3); SL (2); BR (1); AR (1); DK (1); ES (4); CA (3); OM (1); IL (1); US (4); ZA (3); CR (1); FR (1); IT (5); TW (2); KR (3); TU (13); SE (2)