A Study of Recombinant AAV2/6 Human Factor 8 Gene Therapy SB-525 (PF-07055480) in Subjects With Severe Hemophilia A
Study Details
- Hemophilia A
- Biological: SB-525 (PF-07055480)
- Male ≥18 years of age
- Severe hemophilia A (past evidence of circulating FVIII activity of \< 1% normal)
- Treated or exposed to FVIII concentrates or cryoprecipitate for at least 150 exposure days
- ≥12 bleeding episodes if receiving on-demand therapy over the preceding 12 months
- Agree to use double barrier contraceptive until at least 3 consecutive semen samples are negative for AAV 2/6 after SB-525 infusion
- Presence of neutralizing antibodies
- Current inhibitor, or history of FVIII inhibitor (except for transient low titer inhibitor detected in childhood)
- History of hypersensitivity response to FVIII
- History of Hepatitis B or HIV-1/2 infection
- History of Hepatitis C, unless viral assays in two samples, collected at least 6 months apart, are negative
- Evidence of any bleeding disorder in addition to hemophilia A
- Markers of hepatic inflammation or overt or occult cirrhosis
- History of chronic renal disease or creatinine ≥ 1.5 mg/dL
- Presence of liver mass on magnetic resonance imaging (MRI), or, positive alpha fetoprotein
- Presence of \> grade 2 liver fibrosis on elastography for subjects with history of treated Hepatitis C or suspicion of chronic liver disease
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.