Ensitrelvir in hospitalized patients with COVID-19 who were moderately to severely immunocompromised: a single-center cohort study.

BACKGROUND: Immunocompromised patients have a risk of severe COVID-19. OBJECTIVES: To describe the outcomes of ensitrelvir in hospitalized immunocompromised patients with COVID-19, with remdesivir as a reference. DESIGN: Single-center retrospective cohort study. METHODS: We analyzed patients with moderate/severe immunodeficiency who received ensitrelvir or remdesivir as initial therapy. The primary outcome was 28-day all-cause mortality; secondary outcomes were time to discharge and viral clearance. Exploratory analyses used inverse probability of treatment weighting (IPTW) based on propensity scores and Cox proportional-hazards models. RESULTS: Among 56 patients (22 ensitrelvir; 34 remdesivir), 28-day mortality was 4.5% versus 8.8%, respectively. Time to discharge and viral clearance were similar. IPTW-adjusted 28-day mortality was 4.2% with ensitrelvir and 10.7% with remdesivir (hazard ratio 0.39; 95% CI 0.04-3.64). CONCLUSION: In this small, single-center exploratory cohort, ensitrelvir was associated with low mortality, although comparison with remdesivir should be interpreted cautiously given treatment selection, treatment switching, and limited sample size.