Shionogi Reaches Endpoint for Phase 3 COVID-19 Pill

The company announced this week that its investigational oral antiviral, ensitrelvir fumaric acid (ensitrelvir), achieved its primary endpoint for its phase 3 trial that was conducted in 3 countries in Asia. The primary endpoint in the study was the time to first resolution of five key COVID-19 symptoms (stuffy or runny nose, sore throat, cough, feeling hot or feverish, and low energy or tiredness) which are characteristic of infection with the Omicron variant, in patients randomized within 72 hours from the onset of symptoms.

Ensitrelvir fumaric acid is an investigational therapy for COVID-19, is a 3CL protease inhibitor created through joint research between Hokkaido University and Shionogi.

This study was conducted using patients who were experiencing mild/moderate symptoms of COVID-19 and assessed clinical symptom resolution with ensitrelvir (2 dose groups; high dose and low dose), orally administered once daily for five days, compared to placebo.

A total of 1821 patients were enrolled, in Japan, South Korea, and Vietnam, regardless of risk factors for COVID-19 progression. The majority of patients were previously vaccinated.

The five assessed symptoms were selected in consultation with medical experts and regulatory authorities including the Ministry of Health, Labor and Welfare (MHLW), the Pharmaceuticals and Medical Devices Agency (PMDA) in Japan and the FDA based on their scientific and medical validity.

The emergency approval of ensitrelvir was deliberated in the Pharmaceutical Affairs and Food Sanitation Council meeting back in Japan, and review will continue based on the results of the phase 3 part of the study. The company said it would continue to consult closely with government agencies for review and deliberation on approval of ensitrelvir.