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FIX-LONG Study: A Factor IX (FIX) Gene Transfer, Multi-center Evaluation of the LONG-term Safety and Efficacy Study of SPK-9001 (rAAV-Spark100-hFIX-Padua) in Individuals with Hemophilia B

Clinical Trial Details

Hemophilia B is an inherited (genetic) disease in which a protein (factor IX) that promotes blood clotting is missing or does not work properly. Hemophilia B is caused by a defect in the gene that produces the factor IX protein. Factor IX protein is important in blood clotting. Patients with severe hemophilia B have very low levels of the normal factor IX protein. Such low levels can result in spontaneous bleeding events that cause destruction of bone and tissue. 

Bleeding events can include hemorrhage in the brain and can cause severe symptoms (like stroke) and death. Bleeding events can be effectively controlled and prevented with infusion by vein of plasma-derived factor IX protein concentrate (made from the plasma of blood donors) or recombinant factor IX protein product (made in the laboratory in cultured cells). The cost of these factor IX protein products and the difficulty associated with frequent intravenous (IV) infusions often make it not feasible to prevent bleeding events. The gene transfer you were given in the C0371005 formerly SPK-9001-101 study may offer a way for levels of factor IX protein in the blood to be raised and kept raised to stop or reduce spontaneous bleeding episodes. 

You are being asked to take part in this research study because you previously received an intravenous (IV) infusion of the investigational gene therapy product, SPK-9001 (fidanacogene elaparvovec/ PF-06838435), during a gene transfer study (Sponsor Protocol Number: C0371005) for hemophilia B. The gene transfer you were given in the C0371005 study may offer a way for levels of factor IX protein in the blood to be raised and kept raised to stop or reduce spontaneous bleeding episodes. The purpose of this research study (C0371003) is to find out the long term effects to your health after having participated in the gene transfer study (C0371005) where you received a single administration of SPK-9001 (fidanacogene elaparvovec/ PF-06838435). 

Key Eligibility: 

Inclusion Criteria

  • Evidence of a personally signed and dated informed consent document indicating that the subject has been informed of all pertinent aspects of the study
  • Willing and able to comply with scheduled visits, treatment plan, laboratory tests, and other study procedures 
  • Subjects who met the C0371005 eligibility criteria, have received a single administration of SPK-9001, and completed the required assessments in the C0371005 clinical study

Exclusion Criteria

  • Investigator site staff members directly involved in the conduct of the study and their family members, site staff members otherwise supervised by the investigator, or subjects who are Pfizer employees, including their family members, directly involved in the conduct of the study
  • Participation in other studies involving investigational drug(s) within the last 12 weeks prior to study entry, excluding participation in C0371005, and/or during study participation
  • Other acute or chronic medical or psychiatric condition including recent (within the past year) or active suicidal ideation or behavior or laboratory abnormality 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, would make the subject inappropriate for entry into this study
  • Fertile male subjects who are unwilling or unable to use a condom as outlined in this protocol until 3 consecutive semen samples are negative in the vector shedding analysis after the last dose of investigational product
  • Subjects who will not consent for up to 5 years of safety follow-up
  • Subjects who are unable or unwilling to comply with the study visits and requirements
  • Subjects with any clinically significant medical condition that the Investigator believes would pose as a safety risk or are not capable of performing the endpoints of this study 

Study contact by location

Upper East Side - Manhattan


Ilene Goldberg
(212) 746-3403

Primary Investigator(s)

Protocol ID(s)

Weill Cornell Medicine IRB #:






Open to Enrollment

Age Group