A Study to Learn About the Study Medicine Called PF-07328948 in Adults With Heart Failure (BRANCH-HF)

Number of Participants with Clinical Events

Timeframe: over 36 weeks

Adjudicated cardiovascular death and worsening heart failure events through 36 weeks.

Change From Baseline in 6-Minute Walk Test (6MWD)

Timeframe: Baseline, week 36 post-dose

A submaximal exercise test that measures the distance the participant can walk within prescribed time of 6 minutes. Participants are asked to perform the test at a pace comfortable to them with as many breaks as needed. The total distance walked is recorded.

Change From Baseline in Kansas City Cardiomyopathy Questionnaire Overall Total Symptom Score (KCCQ-23 TSS)

Timeframe: Baseline, week 36

KCCQ is a 23-item heart-failure specific questionnaire quantified into the following scores: symptom frequency, symptom burden, symptom stability, physical limitations, social limitations, quality of life, and self-efficacy, total symptom score, overall summary score, and clinical summary score. To facilitate interpretation, all scores are presented on a scale of 0 to 100 points, with lower scores indicating more severe symptoms and/or limitations, and a score of 100 indicating no symptoms, no limitations, and excellent quality of life.

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

Timeframe: Baseline, up to week 40

An AE is any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. An SAE is an AE that, at any dose, results in 1 or more 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. Treatment-emergent are events between first dose of study drug and up to Week 40 that were absent before treatment or that worsened relative to pre-treatment state. AEs include both serious and non-serious adverse events.

Change From Baseline in Kansas City Cardiomyopathy Questionnaire Overall Symptom Score (KCCQ-23 TSS) and physical limitation in participants taking PF-07328948 vs. placebo on HF disease-specific health status related to HFmrEF/HFpEF.

Timeframe: Baseline, week 36

KCCQ is a 23-item participant-completed questionnaire that assesses health status and health-related quality of life in participants with heart failure. Eight domain scores were calculated for the KCCQ: Physical limitation, Social limitation, Quality of life, Self-efficacy, Symptom stability, Symptom frequency, Symptom burden, and Total symptoms (calculated as the mean of Symptom frequency and Symptom burden scores). Two summary scores are also calculated: Clinical Summary (calculated as mean of Physical limitation and Total symptom scores) and Overall Summary (calculated as mean of Physical limitation, Social limitation, Total symptoms, and Quality of life scores). Domain and summary scores were scaled to range from 0 (minimum) to 100 (maximum); higher scores represent better health status.

Change From Baseline in 6-minute walk test distance (6MWD) in participants taking PF-07328948 vs. placebo on HF disease-specific health status related to HFmrEF/HFpEF.

Timeframe: Baseline, week 36

A submaximal exercise test that measures the distance the participant can walk within prescribed time of 6 minutes. Participants are asked to perform the test at a pace comfortable to them with as many breaks as needed. The total distance walked is recorded.

CPET Substudy) : Change From Baseline in Peak Oxygen Consumption (pVO2) at Week 36

Timeframe: Baseline, Week 36

Cardiopulmonary exercise testing

Change From Baseline in N-Terminal Prohormone Brain Natriuretic Peptide (NT-proBNP) Concentration at Week 36

Timeframe: Baseline, Week 36

NT-proBNP is a biomarker of cardiac stress (myocardial necrosis and increased filling pressures/ LV wall stress).

Change From Baseline in Kansas City Cardiomyopathy Questionnaire Overall clinical symptom Score (KCCQ-23 CSS) and physical limitation) in participants taking PF-07328948 vs. placebo on HF disease-specific health status related to HFmrEF/HFpEF.

Timeframe: Baseline, week 36

KCCQ is a 23-item participant-completed questionnaire that assesses health status and health-related quality of life in participants with heart failure. Eight domain scores were calculated for the KCCQ: Physical limitation, Social limitation, Quality of life, Self-efficacy, Symptom stability, Symptom frequency, Symptom burden, and Total symptoms (calculated as the mean of Symptom frequency and Symptom burden scores). Two summary scores are also calculated: Clinical Summary (calculated as mean of Physical limitation and Total symptom scores) and Overall Summary (calculated as mean of Physical limitation, social limitation, Total symptoms, and Quality of life scores). Domain and summary scores were scaled to range from 0 (minimum) to 100 (maximum); higher scores represent better health status.