Gene Therapy for Hemophilia B Patients Aged 12-18 Years Old
Study Details
- Hemophilia B
- Drug: BBM-H901
- Inclusion Criteria:
- Subjects and statutory guardian must be able to understand the purpose and risks of the study and provide signed and dated informed consent;
- Be male and 12≤ age \<18 years of age, body wight ≥ 50kg;
- Have hemophilia B with ≤2 IU/dL (≤2 %) endogenous FIX activity levels as documented by a certified clinical laboratory at the time of screening. If the screening result is \>2% due to insufficient washout from FIX protein product, then the severity of hemophilia B may be confirmed by documented historical evidence from a certified clinical laboratory demonstrating ≤2% FIX coagulant activity (FIX:C) ;
- Had had ≥75 prior exposure days (EDs) to any recombinant and/or plasma-derived FIX protein products based on historical data from the subject's record/history;
- With ≤ 1:4 neutralizing antibodies and ≤1:200 binding antibodies against BBM-H901 capsid;
- Subjects with bleeding episode and/ or FIX agents infusion events within 12 weeks prior to screening;
- Have no prior history of hypersensitivity or anaphylaxis associated with any FIX or IV immunoglobulin administration;
- Have no measurable FIX inhibitor as assessed by laboratory; or documented no prior history of FIX inhibitor (family history of inhibitors will not exclude the subject) and no clinical signs or symptoms of decreased response to FIX administration;
- Have acceptable laboratory values:
- Hemoglobin ≥11 g/dL ;
- Platelets ≥100,000 cells/μL;
- AST, ALT ≤1.5x upper limit of normal at the testing laboratory;
- Bilirubin ≤1.5x ULN ;
- glomerular filtration rate eGFR ≥ 60ml/min.
- For those subjects with sexual maturity, subject and statutory guardian must know that subjects must agree to use reliable barrier contraception until 52 weeks;
- with good compliance to the schedule of visit and fill in the subject diary.
- Exclusion Criteria:
- Hepatitis B surface antigen antibody (HBSAg-Ab) or HBV-DNA positive; hepatitis C antibody or HCV-RNA positive;
- Currently on antiviral therapy for hepatitis B or C;
- With coagulation disorders other than hemophilia B;
- Had immunosuppressive therapy other than steroid and other suggested IST agents within 30 days prior to screening;
- Had vaccine 30 days prior to screening or have scheduled vaccination plan during the study (up to 52 weeks);
- Have significant underlying liver disease, as defined by a preexisting diagnosis of portal hypertension, splenomegaly, encephalopathy, etc; other liver conditions unsuitable to gene therapy judged by investigator;
- Have surgery plan within 52 weeks after gene therapy;
- Have history of chronic infection or high rish of infection that the Investigator considers to constitute an unacceptable risk;
- Had participated in a previous gene therapy research trial within the last 52 weeks or in a clinical study with an investigational drug within the last 12 weeks;
- Had any herb that may affect the liver function within 4 weeks prior to screening;
- Have history of fatal bleeding episode, eg intracranial hemorrhage, etc;
- Any concurrent clinically significant major disease or any other condition that, in the opinion of the Investigator, makes the subject unsuitable for participation in the study;
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.