A Study to Evaluate the Efficacy and Safety of Factor IX Gene Therapy With PF-06838435 in Adult Males With Moderately Severe to Severe Hemophilia B
Study Details
- Hemophilia B
- Biological: PF-06838435/ fidanacogene elaparvovec
- Inclusion Criteria
- Males who completed 6 months of Factor IX prophylaxis therapy during the lead-in study (C0371004) prior to providing consent at the screening visit for this study.
- Documented moderately severe to severe hemophilia B (Factor IX activity \< =2%)
- Previous experience with FIX therapy (=\>50 documented exposure days to a FIX protein product)
- Suspension of prophylaxis therapy for hemophilia B after administration of the study drug
- Laboratory values (hemoglobin, platelets and creatinine) within study specified limits
- Agree to contraception until components of the drug are eliminated from their body
- Capable of giving signed informed consent
- Exclusion Criteria
- Anti-AAVRh74var neutralizing antibodies (nAb) titer above the established threshold (ie, positive for nAb).
- History of inhibitor to Factor IX or inhibitor detected during screening. Clinical signs or symptoms of decreased response to Factor IX
- Hypersensitivity to Factor IX replacement product or IV immunoglobulin administration
- History of chronic infection or other chronic disease
- Any conditions associated with increased thromboembolic risk
- Concurrent clinically significant major disease or condition unsuitable for participation and/or may interfere with the interpretation of study results
- Laboratory values at screening visit that are abnormal or outside acceptable study limits
- Current unstable liver or biliary disease
- Currently on antiviral therapy for hepatitis B or C
- Planned surgical procedure requiring Factor IX surgical prophylactic factor treatment 15 months from screening visit
- Use of restricted therapies (e.g., blood products, acetylsalicylic acid \[aspirin\] or ibuprofen, other investigational therapy, and by-passing agents)
- Previously dosed in a gene therapy research trial at any time or in an interventional clinical study within 12 weeks of screening visit
- Active hepatitis B or C; hepatitis B surface antigen, hepatitis B virus deoxyribonucleic acid positivity, or hepatitis C virus ribonucleic acid positivity
- Significant liver disease
- Serological evidence of HIV1 or HIV2 infection with either CD4+ cell count \<=200 mm3 and/or a viral load \>20 copies/mL
- Study and sponsor staff involved in the conduct of the study and their families
- Unable to comply with study procedures
- Sensitivity to heparin or heparin induced thrombocytopenia
- Sensitivity to any of the study interventions, or components thereof, or drug or other allergy
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.