Risk-based evaluation of efficacy of rolofylline in patients hospitalized with acute heart failure - Post-hoc analysis of the PROTECT trial.

Background: The selective adenosine A1 receptor antagonist rolofylline showed a neutral overall result on clinical outcomes in the PROTECT trial. However, we hypothesized that response to rolofylline treatment could be influenced by underlying clinical risk.

Methods: We performed a post-hoc analysis of the PROTECT trial - a large, double-blind, randomized, placebo-controlled trial that enrolled 2033 patients. Baseline risk of 180-day all-cause mortality was estimated using a previously published 8-item model. Evaluation of efficacy of rolofylline across subpopulations defined based on estimated risk of mortality was performed using subpopulation treatment effect pattern plot (STEPP) analysis. Findings were validated in an independent cohort of acute heart failure patients.

Results: Median estimated risk of mortality was 13.0%, IQR [8.0%-23.0%] and was comparable between the rolofylline and placebo arms. In low to intermediate risk subgroups of patients, rolofylline was associated with a higher rate of 180-day all-cause mortality (11.9% in the rolofylline versus 8.4% in the placebo arms, p=0.050). In the high risk subgroup of patients, particularly those with estimated risk of mortality between 20% and 30%, 180-day all-cause mortality rate was markedly lower in the rolofylline arm (18.4% in the rolofylline versus 34.0% in the placebo arms, p=0.003). The trend towards potential harm with rolofylline treatment in the low to intermediate risk subpopulations and significant benefit in high risk patients was also observed in the validation cohort.

Conclusion: Our findings suggest that selective adenosine A1 receptor antagonism could be harmful in low risk acute heart failure patients, while it might significantly benefit higher risk patients.