Clinical Trials Logo

Clinical Trial 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.


Clinical Trial Description

n/a


Study Design


Related Conditions & MeSH terms


NCT number NCT05145127
Study type Interventional
Source Pfizer
Contact Pfizer CT.gov Call Center
Phone 1-800-718-1021
Email ClinicalTrials.gov_Inquiries@pfizer.com
Status Recruiting
Phase Phase 3
Start date November 17, 2021
Completion date July 31, 2030

See also
  Status Clinical Trial Phase
Completed NCT03834727 - Characterizing the Impact and Treatment of Reproductive Tract Bleeding on Women and Post-menarchal Girls With Bleeding Disorders
Completed NCT03191799 - A Study to Evaluate the Safety and Tolerability of Prophylactic Emicizumab in Hemophilia A Patients With Inhibitors Phase 3
Completed NCT01599819 - BAX 855 Dose-Escalation Safety Study Phase 1
Terminated NCT04541628 - Safety & Efficacy of Encapsulated Allogeneic FVIII Cell Therapy in Haemophilia A Phase 1/Phase 2
Completed NCT02847637 - A Clinical Trial to Evaluate Prophylactic Emicizumab Versus no Prophylaxis in Hemophilia A Participants Without Inhibitors Phase 3
Completed NCT04072237 - Study of Coagulation Faction VIIa Variant Marzeptacog Alfa (Activated) in Adult Subjects With Hemophilia Phase 1
Completed NCT04085458 - Study to Gain More Information on How Safe and Effective Jivi Works in Patients With Severe Hemophilia A (Post-marketing Investigation) Phase 4
Completed NCT04565236 - A Post Approval Commitment Study to Gain More Information on How Safe and Effective KOVALTRY is in Chinese Children, Adolescents /Adults With Severe Hemophilia A Phase 4
Recruiting NCT05987449 - A Study to Evaluate the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Efficacy of NXT007 in Persons With Severe or Moderate Hemophilia A Phase 1/Phase 2
Active, not recruiting NCT04621916 - Preventing Inhibitor Recurrence Indefinitely Phase 4
Not yet recruiting NCT02888223 - Pharmacokinetic Study of SCT800 in Previously Treated Patients With Hemophilia A Phase 1
Completed NCT02528968 - National Study of a Pharmacokinetic-Focused Educational Package for Patients With Severe Haemophilia A N/A
Completed NCT02225483 - Phenotypic Heterogeneity in Hemophilia A: An Investigation of the Role of Platelet Function N/A
Completed NCT02199717 - An Institutional Pilot Study to Investigate Physical Activity Patterns in Boys With Hemophilia N/A
Completed NCT01217255 - Comparing the Burden of Illness of Hemophilia in the Developing and the Developed World
Completed NCT00969319 - Effekt-2 - Efficacy and Safety of Long-term Treatment With KOGENATE® FS in Latin America N/A
Terminated NCT00995046 - Individually Tailored Prophylaxis in Patients With Severe Hemophilia A N/A
Completed NCT00868530 - Study Evaluating On-Demand Treatment Of Xyntha In Chinese Subjects Phase 3
Completed NCT00839202 - Activity and Content of Factor VIII (FVIII) in Human Plasma: The Assessment of a Novel Immunoassay N/A
Completed NCT00629837 - Pharmacokinetics and Safety of a Single Intravenous Infusion of BAY 79-4980 Phase 1