E.1 Medical condition or disease under investigation |
E.1.1 | Medical condition(s) being investigated |
severe to moderately severe hemophilia B ≤2% |
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E.1.1.1 | Medical condition in easily understood language |
Hemophilia B, or Christmas disease, results from a deficiency of blood coagulation Factor IX (FIX). |
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E.1.1.2 | Therapeutic area | Diseases [C] - Blood and lymphatic diseases [C15] |
MedDRA Classification |
E.1.2 Medical condition or disease under investigation |
E.1.2 | Version | 20.0 |
E.1.2 | Level | LLT |
E.1.2 | Classification code | 10060614 |
E.1.2 | Term | Hemophilia B (Factor IX) |
E.1.2 | System Organ Class | 100000004850 |
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E.1.3 | Condition being studied is a rare disease | Yes |
E.2 Objective of the trial |
E.2.1 | Main objective of the trial |
• To demonstrate the efficacy of a single infusion of PF-06838435 in male participants ≥18 years of age with moderately severe to severe hemophilia B (FIX:C ≤2%). |
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E.2.2 | Secondary objectives of the trial |
- To demonstrate the efficacy of PF-06838435 in terms of the use of exogenous FIX, the treated bleeds and FIX:C. - To compare additional efficacy parameters post-PF-06838435 infusion to baseline in order to further characterize PF-06838435 treatment, including use of exogenous FIX, information on bleeding events, and patient reported outcomes. - Safety and tolerability of PF-06838435. - Efficacy assessment over the 6 years of the study. |
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E.2.3 | Trial contains a sub-study | No |
E.3 | Principal inclusion criteria |
1. Participants must have completed at least 6 months of routine FIX prophylaxis therapy during the lead-in study (C0371004) prior to providing consent at the screening visit for this study. 2. Participants who have documented moderately severe to severe hemophilia B, defined as FIX:C ≤2%. 3. Participants must agree to suspend prophylaxis therapy for hemophilia B after administration of the IP. FIX replacement therapy is allowed as needed 4. Acceptable screening laboratory values as follows: Hemoglobin ≥11 g/dL; Platelets ≥100,000 cells/mL; Creatinine ≤ 2.0 mg/dL. 5. Sex: Male. Contraceptive use by men should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies. Male participants are eligible to participate if they agree to the following for at least time required for 3 consecutive ejaculate samples to test negative for vector shedding: Refrain from donating sperm. PLUS either: Be abstinent from heterosexual or homosexual intercourse as their preferred and usual lifestyle (abstinent on a long term and persistent basis) and agree to remain abstinent. OR Must agree to use contraception/barrier as detailed below: Agree to use male condom when engaging in any activity that allows for passage of ejaculate to another person 6. Capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol. |
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E.4 | Principal exclusion criteria |
1. Anti-AAV-Spark100 neutralizing antibodies (nAb) titer≥1:1 (i.e., positive for nAb), performed by a central laboratory during screening. 2. Prior history of inhibitor to FIX or positive inhibitor testing as measured by the central laboratory ≥0.6 Bethesda Units (BU) during screening. Clinical signs or symptoms of decreased response to FIX. 3. Known hypersensitivity to FIX replacement product or intravenous immunoglobulin administration. 4. History of chronic infection or other chronic disease that investigator deems as an unacceptable risk. 5. Any concurrent clinically significant major disease or condition that the investigator deems unsuitable for participation or other acute or chronic medical or psychiatric condition including recent (within the past year) or active suicidal ideation or behavior (including alcoholism) or laboratory abnormality that may ncrease the risk associated with study participation or may interfere with the interpretation of study results and, in the judgment of the investigator, would make the participant inappropriate for entry into this study. 6. Alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase(ALP) >2 × upper limit of normal (ULN), based on central laboratory results. 7. Bilirubin >1.5 × ULN (isolated bilirubin >1.5 × ULN is acceptable if bilirubin is fractionated and direct bilirubin <35%) based on central laboratory results. 8. Current unstable liver or biliary disease per investigator assessment defined by the presence of ascites, hepatic encephalopathy, coagulopathy, hypoalbuminemia, esophageal or gastric varices, persistent jaundice, or cirrhosis. NOTE: Stable chronic liver disease (including Gilbert's syndrome, asymptomatic gallstones, is acceptable if the participant otherwise meets entry criteria). Note: Participants who have a central laboratory test value that is outside the range specified by the exclusion criteria may have the test repeated, by the central laboratory, to determine eligibility; however, the result must be available prior to Baseline Visit /Visit 2. 9. Currently on antiviral therapy for hepatitis B or C. 10. Any participant with a planned surgical procedure requiring FIX surgical prophylactic factor treatment in the next 15 months. 11. Participants using therapies that are restricted. See Section 6.5.2 for therapies not allowed during study participation. 12. Previously dosed in a gene therapy research trial at any time or in an interventional clinical study within the last 12 weeks, excluding participation in Study C0371004. 13. Active hepatitis B or C; HBsAg, HBV-DNA positivity, or HCV-RNA positivity. 14. Significant liver disease, as defined by pre-existing diagnosis of portal hypertension, splenomegaly, or hepatic encephalopathy. Additionally, during screening, a serum albumin level below normal limits and/or significant liver fibrosis by any of the following diagnostic modalities: FibroScan score >8 kPa units, Fibro Test/FibroSURE >0.48* or AST-to-Platelet Ratio Index (APRI) >1. In the investigator's opinion, if there is concern regarding the FibroTest results due to a confounding medical history (e.g., proteinuria can impact FibroTest result), the investigator can perform a different assessment of liver fibrosis (e.g., FibroScan or APRI) during the screening period.*Please note: if a participant has a known history of Gilbert's syndrome, a FibroTest cannot be used for fibrosis testing. However, the participant could be tested using FibroScan or APRI. 15. Serological evidence of HIV-1 or HIV-2 infection either with CD4+ cell count ≤200 mm3 or viral load >20 copies/mL. 16. 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 participants who are Pfizer employees, including their family members, directly involved in the conduct of the study. 17. Unable to comply with scheduled visits, treatment plan, laboratory tests and other study procedures for up to six years post-infusion of PF-06838435 in the investigator’s judgement. 18. Sensitivity to heparin or heparin induced thrombocytopenia. 19. Sensitivity to any of the study interventions, or components thereof, or drug or other allergy that, in the opinion of the investigator or the sponsor’s medical monitor, contraindicates participation in the study. |
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E.5 End points |
E.5.1 | Primary end point(s) |
•ABR for total bleeds (treated and untreated) from Week 12 to Month 15 vs SOC FIX prophylaxis replacement regimen, comparing pre- and post- IP infusion.
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E.5.1.1 | Timepoint(s) of evaluation of this end point |
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E.5.2 | Secondary end point(s) |
•ABR for treated bleeds from Week 12 to Month 15 vs SOC FIX prophylaxis replacement regimen, comparing pre- and post-infusion. •AIR for FIX from Week 12 to Month 15 vs AIR during SOC FIX replacement regimen. •Steady state FIX:C (Week 12 to Month 15) will be compared to a threshold of 5%. FIX:C to be summarized by study visit.
The following parameters will be compared with SOC FIX replacement regimen, comparing pre- and post-IP infusion from Week 12 to Month 15: •FIX consumption. •Number of bleeding events of specific type, spontaneous and traumatic, and untreated. •Frequency of target joint bleeds. •Percentage of the participants without bleeds.
The following parameters will be compared with SOC FIX replacement regimen, comparing pre- and post-IP infusion at 12 months: •HJHS. •PROs endpoints (Haem-A-Qol, Physical Health domain, HAL, Complex Lower Extremity Activities Component Score). |
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E.5.2.1 | Timepoint(s) of evaluation of this end point |
first 15 months/first 12 months as above |
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E.6 and E.7 Scope of the trial |
E.6 | Scope of the trial |
E.6.1 | Diagnosis | No |
E.6.2 | Prophylaxis | No |
E.6.3 | Therapy | Yes |
E.6.4 | Safety | Yes |
E.6.5 | Efficacy | Yes |
E.6.6 | Pharmacokinetic | Yes |
E.6.7 | Pharmacodynamic | Yes |
E.6.8 | Bioequivalence | No |
E.6.9 | Dose response | No |
E.6.10 | Pharmacogenetic | Yes |
E.6.11 | Pharmacogenomic | Yes |
E.6.12 | Pharmacoeconomic | No |
E.6.13 | Others | No |
E.7 | Trial type and phase |
E.7.1 | Human pharmacology (Phase I) | No |
E.7.1.1 | First administration to humans | No |
E.7.1.2 | Bioequivalence study | No |
E.7.1.3 | Other | No |
E.7.1.3.1 | Other trial type description | |
E.7.2 | Therapeutic exploratory (Phase II) | No |
E.7.3 | Therapeutic confirmatory (Phase III) | Yes |
E.7.4 | Therapeutic use (Phase IV) | No |
E.8 Design of the trial |
E.8.1 | Controlled | Yes |
E.8.1.1 | Randomised | No |
E.8.1.2 | Open | Yes |
E.8.1.3 | Single blind | No |
E.8.1.4 | Double blind | No |
E.8.1.5 | Parallel group | No |
E.8.1.6 | Cross over | No |
E.8.1.7 | Other | No |
E.8.2 | Comparator of controlled trial |
E.8.2.1 | Other medicinal product(s) | No |
E.8.2.2 | Placebo | No |
E.8.2.3 | Other | Yes |
E.8.2.3.1 | Comparator description |
C0371004 lead-in observational study |
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E.8.2.4 | Number of treatment arms in the trial | 1 |
E.8.3 |
The trial involves single site in the Member State concerned
| No |
E.8.4 | The trial involves multiple sites in the Member State concerned | Yes |
E.8.4.1 | Number of sites anticipated in Member State concerned | 1 |
E.8.5 | The trial involves multiple Member States | Yes |
E.8.5.1 | Number of sites anticipated in the EEA | 10 |
E.8.6 Trial involving sites outside the EEA |
E.8.6.1 | Trial being conducted both within and outside the EEA | Yes |
E.8.6.2 | Trial being conducted completely outside of the EEA | No |
E.8.6.3 | If E.8.6.1 or E.8.6.2 are Yes, specify the regions in which trial sites are planned |
Australia |
Brazil |
Canada |
Israel |
Japan |
Saudi Arabia |
Taiwan |
United States |
France |
Sweden |
Germany |
Greece |
Turkey |
United Kingdom |
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E.8.7 | Trial has a data monitoring committee | Yes |
E.8.8 |
Definition of the end of the trial and justification where it is not the last
visit of the last subject undergoing the trial
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E.8.9 Initial estimate of the duration of the trial |
E.8.9.1 | In the Member State concerned years | 6 |
E.8.9.1 | In the Member State concerned months | 0 |
E.8.9.1 | In the Member State concerned days | 0 |
E.8.9.2 | In all countries concerned by the trial years | 6 |
E.8.9.2 | In all countries concerned by the trial months | 0 |
E.8.9.2 | In all countries concerned by the trial days | 0 |