Step 1: Understanding the STEP-HFpEF trial.
The STEP-HFpEF trial focuses on heart failure with preserved ejection fraction (HFpEF), a specific subgroup of heart failure. This trial examines treatment options for patients with this condition, which is characterized by a normal ejection fraction but with heart failure symptoms.
Step 2: Analysis of the options.
(2) STEP-HFpEF trial: Correct, as this trial specifically addresses heart failure with preserved ejection fraction (HFpEF).
Step 3: Conclusion.
The STEP-HFpEF trial is focused on HFpEF and is a major trial in treating this specific type of heart failure. Therefore, the correct answer for this part is the STEP-HFpEF trial.