Long-term Safety and Efficacy Study and Dose-Escalation Substudy of PF 06838435 in Individuals With Hemophilia B
Study Details
- Hemophilia B
- Biological: PF-06838435 (formerly SPK-9001)
- This study is currently only enrolling into the dose-escalation substudy with subsequent long-term follow-up. The Eligibility Criteria for entry into the dose-escalation substudy is presented below:
- Inclusion Criteria:
- Able to provide informed consent and comply with requirements of the study
- Males age 18 to 65 years with confirmed diagnosis of hemophilia B (≤2 IU/dL or ≤2% endogenous factor IX)
- Received ≥50 exposure days to factor IX products
- No measurable factor IX inhibitor as assessed by the central laboratory and have no prior history of inhibitors to factor IX protein
- Agree to refrain from donating sperm and either abstain from intercourse or use reliable barrier contraception until 3 consecutive semen samples are negative for vector sequences
- Exclusion Criteria:
- Evidence of active hepatitis B or C
- Currently on antiviral therapy for hepatitis B or C
- Have significant underlying liver disease
- Serological evidence\* of HIV-1 or HIV-2 with CD4 counts ≤200/mm3 (\* participants who are HIV+ and stable with CD4 count \>200/mm3 and undetectable viral load are eligible to enroll)
- Neutralizing antibody titers to the capsid portion of PF-06838435 above the established threshold
- Sensitivity to heparin or heparin induced thrombocytopenia; sensitivity to any of the study interventions, or components thereof, or drug or other allergy
- Previously dosed in a gene therapy research trial at any time or in an interventional clinical study within 3 months of screening visit
- Any concurrent clinically significant major disease or condition
- Unable or unwilling to comply with the study procedures
Protocol Summary
This study is looking at how safe it is to switch from emicizumab to Mim8, in people with haemophilia A. Mim8 is a new medicine that is used to prevent bleeding episodes in people with haemophilia A. Mim8 works by replacing the function of the missing clotting factor VIII (FVIII). Mim8 will be injected under the skin using a pen-injector either once every week, once every two weeks or once every month. The participants will be trained in using the pen injector. The participants can choose themselves, in collaboration with the study doctor how often they get Mim8 in this study. When the participant will get their first Mim8 injection depends on their current treatment with emicizumab. The participants will get their first Mim8 injection at Visit 2. Participants will have between 6 and 27 Mim8 injections. The total number of injections participants will have depends on their dosing frequency. The study will last for about 6-12 months. While taking part in this study, there are some restrictions about what medicine participant can use. The study doctor will tell the participants more about this. In case the participants experience bleeds, these can be treated with additional haemostatic medicine as agreed with the study doctor. Female participants cannot take part if they are pregnant, breast-feeding or plan to get pregnant during the study period.