Safety & Effectiveness of Tovinontrine in Chronic Heart Failure With Preserved Ejection Fraction (Cycle-2-PEF)

Inclusion Criteria: * Is an adult male or female patient ≥ 18 years of age * Has evidence in the medical history supporting a diagnosis of clinical HF syndrome, NYHA functional class II to III, with the duration of at least 6 months prior to the time of Screening. The HF syndrome is defined by documentation of 1 or more of the following: * At least 1 of the typical symptoms due to HF such as dyspnea and/or fatigue limiting exercise capacity; * At least 1 of the typical signs of HF such as peripheral edema, elevated jugular venous pressure, pulmonary crackles; or * Hospitalization, emergency department visit, or outpatient visit for HF requiring intravenous (IV) or subcutaneous (SQ) diuresis within the past 12 months. * Has ejection fraction (EF) \>40% and left atrial enlargement by transthoracic echocardiogram (TTE) performed and interpreted locally at the time of Screening; * Has NT-proBNP level ≥ 300 pg/mL at the time of Screening. Patients with atrial fibrillation or flutter at the time of Screening are required to have an NT proBNP level of ≥500 pg/mL at the time of Screening; * Is on stable optimized doses of guideline-directed HF therapy, per Investigator's clinical judgment, for a minimum of 4 weeks prior to the time of Screening and during the Screening Period, with no planned changes after randomization; Has had no addition of new guideline-directed HF therapy within the 3 months prior to the time of Screening or during the Screening Period; Exclusion Criter…