The purpose of this study was to evaluate the effect of sacubitril/valsartan 200 mg BID compared with enalapril 10 mg BID, in addition to conventional heart failure (HF) treatment, in improving a hierarchical composite of cardiovascular (CV) events (i.e. CV death or the occurrence of first HF hospitalization) and causing a greater reduction in n terminal prohormone of brain natriuretic peptide (NT-proBNP, at Week 12 from Baseline) in participants with HF with reduced ejection fraction (HFrEF) caused by chronic Chagas' cardiomyopathy (CCC).

This was a multinational, multicenter, parallel-group, prospective, randomized, open-label, with blinded-endpoint adjudication, active-controlled study. The target projected sample size was approximately 900 participants (450 in each arm). It was estimated that approximately 1800 participants would be screened at sites in Latin America, including Argentina, Brazil, Colombia, and Mexico.

Participants who met the eligibility requirements were randomly assigned in a 1:1 ratio to receive sacubitril/valsartan (target dose of 200 mg twice daily) or enalapril (target dose of 10 mg twice daily), in addition to their usual therapy, stratified by country, using a central, concealed, web-based, automated randomization system. Both groups entered a titration period of 3 to 6 weeks, aiming to achieve the target dose of sacubitril/valsartan 200 mg twice daily or enalapril 10 mg twice daily. The study follow-up succeeded the titration period and was to last until a total number of 302 events was reached and all randomized participants had a minimum follow-up of 12 weeks.

Key Inclusion Criteria:

• Male or female ≥ 18 years of age

• Diagnosis of NYHA Class II-IV HFrEF established by:

  1. LVEF ≤ 40% within 12 months prior to Visit 1 made by any local measurement using echocardiography, multiple gated acquisition scan (MUGA), computerized tomography (CT) scanning, magnetic resonance imaging (MRI), or ventricular angiography, provided no subsequent measurement above 40% AND
  2. NT-proBNP ≥ 600 pg/mL (or BNP ≥ 150 pg/mL) at Visit 1 OR
  3. NT-proBNP ≥ 400 pg/mL (or BNP ≥ 100 pg/mL) at Visit 1 and a hospitalization for HF within the last 12 months

• Chagas' disease diagnosis confirmed by at least two different serological tests for anti-Trypanosoma cruzi based on different principles or with different antigenic preparations, such as: enzyme-linked immunosorbent assay [ELISA], indirect immunofluorescence [IFI], indirect hemagglutination [IHA], western blot (WB), chemiluminescent immunoassay (CLIA). If documented history is not available, the tests may be performed during the screening

Key Exclusion Criteria:

• Patients with history of suspected or proven angioedema or unable to tolerate ACEIs, ARBs or ARNI (e.g., due to cough, hypotension, renal dysfunction, hyperkalemia)

• Use of sacubitril/valsartan in the past 3 months

• Patients requiring continuous intravenous inotropic therapy or with indication of advanced support intervention for HF:

  1. already on list for a heart transplantation
  2. with current indication of left ventricular assist device, or cardiac resynchronization therapy (CRT)

• Systemic systolic blood pressure lower than 95 mmHg or symptomatic hypotension

• Serum potassium > 5.2 mmol/L

• Estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 m2 of body surface area

• Severe gastrointestinal form of chronic Chagas' disease (demonstrated megaesophagus and/or important megacolon, e.g.: with compromised oral intake or surgical indication).

• Clinical conditions or systemic diseases limiting proper patient participation

• Pregnant or nursing women or women of child-bearing potential unless they are using highly effective methods of contraception

• Presence of other cardiac conditions:

  1. Previous cardiac surgery
  2. Heart failure where, in the Investigator's judgement, there is a possible alternative primary etiology e.g., due to coronary artery disease, valve disease, congenital heart disease or other causes.
  3. Untreated arrhythmia or serious conduction disease e.g., bradyarrhythmias, atrial fibrillation with rapid ventricular response, second or third degree atrioventricular block, etc.
  4. Primary uncorrected valvar pathology like moderate to severe aortic stenosis, mitral stenosis and primary mitral regurgitation
  5. Planned organ transplantation (or in listing for transplantation), planned cardiac or other major surgery (including ventricular assist device implantation)

• History of malignancy of any organ system within the past 5 years.

• Current confirmed COVID19 infection

• Past COVID19 infection with persistent symptom burden suspected due to COVID19 (persistent symptoms may include, but are not limited to, continued cough, breathing difficulty, muscle/joint aches, and gastrointestinal symptoms from the time of COVID19 infection onward)

Novartis is committed to sharing with qualified external researchers, access to patient-level data and supporting clinical documents from eligible studies. These requests are reviewed and approved by an independent review panel on the basis of scientific merit. All data provided is anonymized to respect the privacy of patients who have participated in the trial in line with applicable laws and regulations.

This trial data availability is according to the criteria and process described on www.clinicalstudydatarequest.com.

Endpoint Adjudication Committee will be blinded to treatment allocation.