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

Phase 3Active Not RecruitingNCT03861273

Pfizer51 enrolled

Overview

This study will evaluate the efficacy and safety of PF-06838435 (a gene therapy drug) in adult male participants with moderately severe to severe hemophilia B (participants that have a Factor IX circulating activity of 2% or less). The gene therapy is designed to introduce genetic material into cells to compensate for missing or non-functioning Factor IX. Eligible study participants will have completed a minimum 6 months of routine Factor IX prophylaxis therapy during the lead in study (C0371004). Participants will be dosed once (intravenously) and will be evaluated over the course of 6 years. The main objective of the study will evaluate the annualized bleeding rate \[ABR\] for participants treated with gene therapy versus standard of care (SOC) therapy (FIX prophylaxis replacement regimen).

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

Hemophilia B

Interventions

Eligibility

Sex: MALEMin age: 18 YearsMax age: 65 Years

Medical Language ↔ Plain English

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

Locations (65)

UCSF IDS Pharmacy

San Francisco, California, United States

University of California, San Francisco - Clinical Research Center

San Francisco, California, United States

University of California, San Francisco - Outpatient Hematology Clinic

San Francisco, California, United States

The Regents of the University of California, San Francisco campus

San Francisco, California, United States

Hemophilia and Thrombosis Center at the University of Colorado Anschutz Medical Campus

Aurora, Colorado, United States

Outcomes

Primary Outcomes

Annualized Bleeding Rate (ABR) for Total Bleeds (Treated and Untreated) From Week 12 to Month 15

ABR = number of total bleeding episodes on study during the given time period) \*365.25/ (Date of last day - date of first day +1) in that time period. Surgical procedures were excluded from summary/analyses. Treated Bleed: An event necessitating administration of coagulation factor within 72 hours of signs or symptoms of bleeding (protocol definition, unless specifically referring to untreated bleed). Untreated Bleed: A bleeding event not necessitating administration of coagulation factor within 72 hours of signs or symptoms of bleeding. This outcome measure compared data collected from lead-in study C0371004 and from current study C0371002. Pre-infusion period = at least 6 months of prospectively collected data while receiving FIX prophylaxis replacement therapy in lead-in study C0371004 up to dosing in current study C0371002.

Time frame: Pre-infusion period: minimum of 6 months through first dose of current study, an average of 1.31 years (FIX Prophylaxis arm); Week 12 to Month 15 post infusion in current study (PF-06838435 arm)

Secondary Outcomes

ABR for Treated Bleeds From Week 12 to Month 15

ABR = number of total bleeding episodes on study during the given time period) \*365.25/ (Date of last day - date of first day +1) in that time period. Surgical procedures were excluded from summary/analyses. Treated Bleed: An event necessitating administration of coagulation factor within 72 hours of signs or symptoms of bleeding (protocol definition, unless specifically referring to untreated bleed). This outcome measure compared data collected from lead-in study C0371004 and from current study C0371002. Pre-infusion period = at least 6 months of prospectively collected data while receiving FIX prophylaxis replacement therapy in lead-in study C0371004 up to dosing in current study C0371002.

Annualized Infusion Rate (AIR) of Exogenous FIX From Week 12 to Month 15

AIR = number of exogenous infusions (for any reason) received during given time period \*365.25/ (Date of last day - date of first day +1) in that time period. This outcome measure compared data collected from lead-in study C0371004 and from current study C0371002. Pre-infusion period = at least 6 months of prospectively collected data while receiving FIX prophylaxis replacement therapy in lead-in study C0371004 up to dosing in current study C0371002.

Steady State Circulating Factor IX (FIX:C) From Week 12 to Month 15

The certified central clinical laboratory analyzed the sample by two one-stage assays and a chromogenic assay. The first one-stage assay was performed on BCSXP analyzer with Actin-FSL reagent. The second one-stage assay used the same analyzer but SynthAsil as reagent. Data reported in this Outcome Measure is the geometric mean of all assessments from week 12 to Month 15.

Time frame: Week 12 to Month 15

Circulating Factor IX (FIX:C) at Week 12, Week 24, Week 65

Time frame: Week 12, Week 24, Week 65

Annualized Factor IX (FIX) Consumption From Week 12 to Month 15

Annualized FIX consumption was reported by International Units per kilogram (IU/kg). This outcome measure compared data collected from lead-in study C0371004 and from current study C0371002. Pre-infusion period = at least 6 months of prospectively collected data while receiving FIX prophylaxis replacement therapy in lead-in study C0371004 up to dosing in current study C0371002. Data reported in this Outcome Measure is average of all assessments from Week 12 to Month 15.

ABR for Spontaneous Bleeds From Week 12 to Month 15

ABR = number of total bleeding episodes on study during the given time period) \*365.25/ (Date of last day - date of first day +1) in that time period. Surgical procedures were excluded from summary/analyses. Surgical procedures were excluded from summary/analyses. Spontaneous Bleeds: Bleeding for no apparent/known reason particularly into the joints, muscles, and soft tissues. This outcome measure compared data collected from lead-in study C0371004 and from current study C0371002. Pre-infusion period = at least 6 months of prospectively collected data while receiving FIX prophylaxis replacement therapy in lead-in study C0371004 up to dosing in current study C0371002.

ABR for Traumatic Bleeds From Week 12 to Month 15

ABR = number of total bleeding episodes on study during the given time period) \*365.25/ (Date of last day - date of first day +1) in that time period. Surgical procedures were excluded from summary/analyses. Surgical procedures were excluded from summary/analyses. Traumatic Bleeds: Bleeding event occurring for an apparent/known reason. This outcome measure compared data collected from lead-in study C0371004 and from current study C0371002. Pre-infusion period = at least 6 months of prospectively collected data while receiving FIX prophylaxis replacement therapy in lead-in study C0371004 up to dosing in current study C0371002.

ABR for Untreated Bleeds From Week 12 to Month 15

ABR = number of total bleeding episodes on study during the given time period) \*365.25/ (Date of last day - date of first day +1) in that time period. Surgical procedures were excluded from summary/analyses. Surgical procedures were excluded from summary/analyses. Untreated Bleed: A bleeding event not necessitating administration of coagulation factor within 72 hours of signs or symptoms of bleeding. This outcome measure compared data collected from lead-in study C0371004 and from current study C0371002. Pre-infusion period = at least 6 months of prospectively collected data while receiving FIX prophylaxis replacement therapy in lead-in study C0371004 up to dosing in current study C0371002.

Number of Target Joint Bleeds From Week 12 to Month 15

Target Joint: Defined as a major joint (e.g., hip, elbow, wrist, shoulder, knee, and ankle) into which repeated bleeds occurred (three or more spontaneous bleeds into a single joint within a consecutive 6-month period). A target joint was considered resolved when there were =\<2 bleeds into the joint within a 12-month period. Joint Bleed: A bleeding episode characterized by rapid loss of range of motion as compared with baseline that was associated with any combination of the following: pain or an unusual sensation in the joint, palpable swelling, and warmth of the skin over the joint. This outcome measure compared data collected from lead-in study C0371004 and from current study C0371002. Pre-infusion period = at least 6 months of prospectively collected data while receiving FIX prophylaxis replacement therapy in lead-in study C0371004 up to dosing in current study C0371002.

Percentage of the Participants Without Bleeds From Week 12 to Month 15

Percentage of participants without bleeds (total bleeds and treated bleeds) were summarized by type from Week 12 to Month 15.

Time frame: Week 12 to Month 15

Change From Baseline in Joint Health as Measured by the Hemophilia Joint Health Score (HJHS) Instrument at Month 12

A qualified healthcare professional assessed six joints (left ankle, right ankle, left elbow, right elbow, left knee, right knee) scored from 0 to 20 based on: duration of swelling, muscle atrophy, crepitus, flexion loss, extension loss, instability, joint pain, and strength. Gait was scored (0 to 4) based on walking, stairs, running, hopping on one leg. Total score = sum of scores from all joints + gait score ranged from 0 to 124, with the higher the number equating to more severe joint damage.

Time frame: Baseline, Month 12

Change From Baseline in Hemophilia Quality of Life (Haem A QoL) Physical Health Domain at Month 12

The Haem-A-QoL questionnaire contained 46 items with ten domains that assessed health in the following areas: Physical Health; Feelings; View of Self; Sports and Leisure; Work and School; Dealing with Haemophilia; Treatment; Future; Family Planning; and Partnership and Sexuality. The physical health domain was considered as the primary domain in this questionnaire, had a transformed score range from 0 to 100, with lower scores representing higher quality of life. In this Outcome Measure Physical Health domain scores of Haem A QoL are reported.

Time frame: Baseline, Month 12

Change From Baseline in Hemophilia Activities List (HAL) Complex Lower Extremity Activities Component Score at Month 12

The HAL was a multiple domain measure of the impact of hemophilia on functional abilities in adults. The 7 domains of this instrument contained 42 items in total, as follows: lying/sitting/kneeling/standing; lower (leg) functioning; upper (arm) functioning; transportation; self-care; household tasks; and sports/leisure. Selected items from five of the domains were used to create three components: upper extremity; basic lower extremity; and complex lower extremity activities. The component score of "complex lower extremity activities" was the most important in this questionnaire, had a transformed score range from 0 to 100, higher values indicated less functional limitations in performing tasks.

Time frame: Baseline, Month 12

Number of Participants With Treatment-Emergent Adverse Events (TEAEs) and Serious TEAEs