Trial Outcomes & Findings for A Study to Evaluate the Safety and Tolerability of PF-06939926 Gene Therapy in Duchenne Muscular Dystrophy (NCT NCT03362502)

The study reached its primary completion date (PCD) on 28 Mar 2022. The data cutoff for PCD was on 30 Sep 2022. As of 30 Sep 2022, a total of 22 participants, including 19 ambulatory participants and 3 non-ambulatory participants, were enrolled and assigned to treatment.

One participant was enrolled but not dosed due to a pause in enrollment. The participant was considered as an early termination due to screening window running out. The participant was subsequently re-screened and assigned to study intervention with another participant ID. Therefore, a total of 22 unique participants were enrolled as of 30 Sep 2022.

A Study to Evaluate the Safety and Tolerability of PF-06939926 Gene Therapy in Duchenne Muscular Dystrophy

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. Any AE that started following start of treatment of PF-06939926 was counted as a treatment-emergent AE (TEAE). A serious AE (SAE) was an untoward medical occurrence that resulted in death, was life-threatening (immediate risk of death), required in-patient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect, or was considered to be an important medical event. Severe AE=an event that prevents normal everyday activities.

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. Any AE that started following start of treatment of PF-06939926 was counted as a TEAE. For this outcome measure, TEAEs were reported according to Medical Dictionary for Regulatory Activities (MedDRA) version 25.0 SOC and PT.

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. Any AE that started following start of treatment of PF-06939926 was counted as a TEAE. An SAE was an untoward medical occurrence that resulted in death, was life-threatening (immediate risk of death), required in-patient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect, or was considered to be an important medical event. Severe AE=an event that prevents normal everyday activities. Treatment-related AE was any untoward medical occurrence attributed to study treatment in a participant who received study treatment. Treatment-related AEs and SAEs were determined by the investigator.

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. Any AE that started following start of treatment of PF-06939926 was counted as a TEAE. For this outcome measure, TEAEs were reported according to MedDRA version 25.0 SOC and PT. Treatment-related AE was any untoward medical occurrence attributed to study treatment in a participant who received study treatment. Treatment-related AEs were determined by the investigator.

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. Any AE that started following start of treatment of PF-06939926 was counted as a TEAE. An SAE was an untoward medical occurrence that resulted in death, was life-threatening (immediate risk of death), required in-patient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect, or was considered to be an important medical event. For this outcome measure, TEAEs were reported according to MedDRA version 25.0 SOC and PT.

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. Any AE that started following start of treatment of PF-06939926 was counted as a TEAE. An SAE was an untoward medical occurrence that resulted in death, was life-threatening (immediate risk of death), required in-patient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, resulted in congenital anomaly/birth defect, or was considered to be an important medical event. Treatment-related AE was any untoward medical occurrence attributed to study treatment in a participant who received study treatment. Treatment-related AEs and SAEs were determined by the investigator. For this outcome measure, TEAEs were reported according to MedDRA version 25.0 SOC and PT.

Following hematologic parameters were analyzed for laboratory examination: hemoglobin, hematocrit, red blood cell (RBC) count, platelet count, white blood cell count, total neutrophils, absolute neutrophils (ANC), eosinophils, monocytes, basophils, lymphocytes, red blood cell indices, and haptoglobin. Laboratory abnormalities with occurrence in at least 1 participant are reported for this outcome measure. Baseline was defined as the last pre-dose measurement.

Following parameters for clinical chemistry were analyzed for laboratory examination: blood urea nitrogen (BUN) and creatinine, glucose, calcium, sodium, potassium, chloride, total CO2 (bicarbonate), aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (direct and indirect bilirubin), alkaline phosphatase, uric acid, albumin, total protein, serum phosphorus, cystatin C, creatine kinase, creatine kinase myocardial b fraction (CK-MB), amylase, lipase, gamma-glutamyl transferase (GGT), C-reactive protein (CRP), and cardiac troponin I. Laboratory abnormalities with occurrence in at least 1 participant are reported for this outcome measure. Baseline was defined as the last pre-dose measurement.

Following parameters for urinalysis were analyzed for laboratory examination: pH, glucose, protein, blood, ketones, nitrites, leukocyte esterase, and microscopy. Laboratory abnormalities with occurrence in at least 1 participant are reported for this outcome measure. Baseline was defined as the last pre-dose measurement.

Cardiac MRI was performed after thigh and upper limb MRI or on separate days within the required visit window. Change in LVEF is presented as percentages, and was calculated as \[(stroke volume) / (end-diastolic volume)\]\*100%. Baseline is defined as the last pre-dose measurement. Change from baseline on Day 360 (ie, 1 year post dose) was reported for this outcome measure.

Triplicate ECG was performed after the participant had rested quietly for at least 10 minutes in a supine position. The pre-defined categorical criteria include PR interval aggregate (msec): value\>=300, baseline\>200 and percent change\>=25%, baseline\<=200 and percent change\>=50%; QRS duration aggregate (msec): value\>=140, percent change\>=50%; QTcF interval aggregate (msec): 450\<=value\<480, 480\<=value\<500, value\>=500, 30\<=change\<60, change\>=60. Only the category(ies) with at least 1 participant meeting the pre-defined criterion is/are reported for this outcome measure. Baseline for ECG was defined as the measurement before the Day 1 study drug administration.

C-SSRS is a participant rated questionnaire to assess whether participant experienced the following: completed suicide(1), suicide attempt(2)("Yes" on "actual attempt"), preparatory acts toward imminent suicidal behavior(3)("Yes" on "preparatory acts or behavior"), suicidal ideation(4)("Yes" on "wish to be dead","non-specific active suicidal thoughts","active suicidal ideation with methods without intent to act or some intent to act, without specific plan or with specific plan and intent), any suicidal behavior or ideation, self-injurious behavior(7)("Yes" on "Has subject engaged in non-suicidal self-injurious behavior"). Yes/No responses are mapped to C-CASA categories. C-SSRS was conducted with the participant's care giver/legal guardian on the participant's behalf throughout the study for participants\<=12 years of age at screening. Baseline is defined as the last predose measurement. Number of participants with responses of "Yes" is reported for this outcome measure.

Vital signs consisted of blood pressure, respiratory rate, and heart rate, was obtained with these measurements at the following timepoints: within 30 minutes before and approximately 30 minutes, 1, 2, 4, 8, and 24 hours after the start of the infusion, and on Days 4, 7, 10, 14, 30, 90, 180, and 360. Baseline was defined as the last pre-dose recording. Number of participants who had at least 1 vital sign measurement at the specified timepoints meeting the pre-defined criteria from baseline up to the end of 1-year follow-up is reported for this outcome measure.