Efficacy and Safety of Pimodivir Combined with Standard-of-care in Hospitalized and Non-hospitalized High-risk Adolescents and Adults with Influenza A Infection

Background An unmet need exists for effective antivirals to treat patients hospitalized with influenza. The results of 2 phase 3 studies that evaluated the efficacy and safety of pimodivir in combination with investigator-chosen standard of care (SoC) treatment are presented. Methods Hospitalized patients (hospital study; NCT03376321) and high-risk outpatients (outpatient study; NCT03381196) with laboratory-confirmed influenza A infection were randomized 1:1 to 600 mg pimodivir twice daily + SoC or placebo twice daily + SoC for 5 days. For most patients, SoC included oseltamivir. Primary end points were Hospital Recovery Scale (HRS) at day 6 (hospital study) and median time to resolution (TTR) of influenza-related symptoms (outpatient study). Results Pimodivir + SoC (oseltamivir) treatment showed no clinical benefit over placebo + SoC on HRS at day 6 (common odds ratio, 0.943; 95% confidence interval [CI], .609–1.462; P = .397; hospital study). A shorter median TTR of 7 symptoms was estimated with pimodivir + SoC versus placebo (92.6 hours; 95% CI, 77.6–104.2 vs 105.1 hours; 95% CI, 92.7–128.6; P = .0216; outpatient study). Conclusions Pimodivir + SoC showed no additional clinical benefit versus SoC treatment alone in hospitalized patients. Pimodivir + SoC demonstrated shorter TTR of influenza symptoms versus placebo + SoC in high-risk outpatients. Clinical Trial Registration NCT03376321 and NCT03381196.