Trial Outcomes & Findings for A Study of ARRY-371797 (PF-07265803) in Patients With Symptomatic Dilated Cardiomyopathy Due to a Lamin A/C Gene Mutation (NCT NCT03439514)

A total of 77 participants with Lamin A/C protein (LMNA)-related dilated cardiomyopathy (DCM) in New York heart association (NYHA) functional Class II and III were enrolled in the study. All participants enrolled received at least 1 dose of study intervention.

A Study of ARRY-371797 (PF-07265803) in Patients With Symptomatic Dilated Cardiomyopathy Due to a Lamin A/C Gene Mutation

The 6 MWT was an assessment where the distance that a participant could walk on a flat and hard surface in 6 minutes was measured. Participants were asked to perform the test at a pace that was comfortable to them, with as many breaks as they needed, and under supervision of a qualified professional. Study discontinuation \& death were incorporated into endpoint definition through ranking in hypothesis testing of treatment difference. Missing data resulting from study discontinuation were imputed using control-based multiple imputation method to estimate treatment effect.

The 6 MWT was an assessment where the distance that a participant could walk on a flat and hard surface in 6 minutes was measured. Participants were asked to perform the test at a pace that was comfortable to them, with as many breaks as they needed, and under supervision of a qualified professional.

The KCCQ measured the effects of symptoms, functional (physical) limitations, and psychological distress on an individual's health-related quality of life. It contains 23 items, which assessed the ability to perform activities of daily living, frequency and severity of symptoms, the impact of these symptoms, and health-related quality of life. PL was a single questionnaire with score range of 0 to 100, where higher scores reflected better physical functioning status. TSS included frequency and severity of symptoms, and the impact of these symptoms. TSS scores were transformed to a range of 0 to 100, where higher scores reflected better health status.

PGI-S is a global index that rate the severity of the disease using a 5-point scale. In this outcome the number of participants with improvements in PGI-S the severity of their heart failure symptoms and in the severity of their PL were reported. Measured by the scale of: none, mild, moderate, severe or very severe (listed from better to worse).

PGI-C is a global index that rate the severity of the disease using a 7-point scale. In this outcome the number participants with improvements in their heart failure symptoms and "in their physical activity limitations?", were reported. Measured by the scale of: very much better, moderately better, a little better, no change, a little worse, moderately worse, very much worse (listed from better to worse).

NT pro-BNP is a cardiac biomarker that is released in the blood in response to changes in the pressure inside of the heart. Levels go up when heart failure develops or gets worse, and levels go down when heart failure is stable or improves. This biomarker helps to measure the changes in the severity of heart failure over time in response to therapy.

Defined as the time from randomization to the first occurrence of any event of death due to any cause, or worsening heart failure (HF-related hospitalization or HF-related urgent care visit). Kaplan-Meier method and cox regression model were used for analysis.

OS was defined as time from randomization to death due to any cause. Participants who did not have a death date were censored for OS at their last contact date. Kaplan-Meier method and cox regression model were used for analysis.

An AE was any untoward medical occurrence in a participant who received investigational product without regard to possibility of causal relationship. Treatment-emergent AEs were events that occurred between first dose of study drug and up to 30 days after last dose. Serious adverse event (SAE) was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. AEs included both SAEs and all Non-SAEs. Grade \>=3 AEs meant severe AEs.

Following parameters were analyzed for laboratory examination: hematology (eosinophils, erythrocytes, hemoglobin, hematocrit, granulocytes, leukocytes, lymphocytes, monocytes, platelets, neutrophils, nucleated erythrocytes); blood chemistry (alanine aminotransferase, albumin, alkaline phosphatase, aspartate aminotransferase, bicarbonate, bilirubin, blood urea nitrogen, C-reactive protein, calcium, chloride, creatinine, creatine kinase, epidermal growth factor receptor, follicle stimulating hormone, gamma glutamyl transferase, glucose, magnesium, N-Terminal ProB-type natriuretic peptide, phosphate, potassium, protein, sodium, potassium, thyrotropin, troponin I, troponin T, urate).

Following vital sign parameters were assessed: diastolic blood pressure, systolic blood pressure, heart rate, and body weight. Vital sign abnormalities criteria included: a) systolic blood pressure (mmHg): decrease (change \<= -20, or value \<90) and increase (change \>=20, or value \>140); b) diastolic blood pressure (mmHg): decrease (change \<= -15, or value \<60) and increase (change \>=15, or value \>90); c) heart Rate (bpm) decrease: (change \<= -15, or value \<50) and increase (change \>=15, or value \>100); d) weight: (kg) decrease (Change \<= -7%) and increase (Change \> =7%).

Following parameters were analyzed: heart rate, QT interval, corrected QT (QTc) interval, Bazett's correction QT (QTcB) interval, and Fridericia's correction (QTcF) interval. Criteria for notable ECG values were as follows: QT interval (in millisecond \[msec\]) new (newly occurring post-baseline value) greater than (\>) 450, 480, 500, increase from baseline \>30, increase from baseline \>60; corrected QT interval by Fredericia formula (QTcF) in msec new (newly occurring post-baseline value) \> 450, 480, 500, increase from baseline \>30, increase from baseline \>60; corrected QT interval by Bazett's formula (QTcB) in msec new (newly occurring post-baseline value) \> 450, 480, 500, increase from baseline \>30, increase from baseline \>60; heart rate in bpm new (newly occurring post-baseline value) \<60 and \>100.

Arrhythmia assessment: incidence of new and clinically significant ventricular or atrial arrhythmias was assessed by an implantable cardioverter defibrillator (ICD) or CRT defibrillator (CRT-D) applicable device interrogations.