Effect of Montelukast vs Placebo on Time to Sustained Recovery in Outpatients with COVID-19: The ACTIV-6 Randomized Clinical Trial.

Importance: The effect of montelukast in reducing symptom duration among outpatients with mild to moderate coronavirus disease 2019 (COVID-19) is uncertain. Objective: To assess the effectiveness of montelukast compared with placebo in treating outpatients with mild to moderate COVID-19. Design Setting and Participants: The ACTIV-6 platform randomized clinical trial aims to evaluate the effectiveness of repurposed medications in treating mild to moderate COVID-19. Between January 27, 2023, and June 23, 2023, 1250 participants ≥30 years of age with confirmed SARS-CoV-2 infection and ≥2 acute COVID-19 symptoms for ≤7 days, were included across 104 US sites to evaluate the use of montelukast. Interventions: Participants were randomized to receive montelukast 10 mg once daily or matched placebo for 14 days. Main Outcomes and Measures: The primary outcome was time to sustained recovery (defined as at least 3 consecutive days without symptoms). Secondary outcomes included time to death; time to hospitalization or death; a composite of hospitalization, urgent care visit, emergency department visit, or death; COVID clinical progression scale; and difference in mean time unwell. Results: Among participants who were randomized and received study drug, the median age was 53 years (IQR 42-62), 60.2% were female, 64.6% identified as Hispanic/Latino, and 56.3% reported ≥2 doses of a SARS-CoV-2 vaccine. Among 628 participants who received montelukast and 622 who received placebo, differences in time to sustained recovery were not observed (adjusted hazard ratio [HR] 1.02; 95% credible interval [CrI] 0.92-1.12; P(efficacy) = 0.63]). Unadjusted median time to sustained recovery was 10 days (95% confidence interval 10-11) in both groups. No deaths were reported and 2 hospitalizations were reported in each group; 36 participants reported healthcare utilization events (a priori defined as death, hospitalization, emergency department/urgent care visit); 18 in the montelukast group compared with 18 in the placebo group (HR 1.01; 95% CrI 0.45-1.84; P(efficacy)=0.48). Five participants experienced serious adverse events (3 with montelukast and 2 with placebo). Conclusions and Relevance: Among outpatients with mild to moderate COVID-19, treatment with montelukast does not reduce duration of COVID-19 symptoms. Trial Registration: ClinicalTrials.gov ( NCT04885530 ).