Japanese regulators on Tuesday signed off on Shionogi’s homegrown antiviral for Covid-19, known as Xocova (ensitrelvir), making it the first approval under Japan’s emergency regulatory approval system.
The emergency approval, following a back-and-forth with regulators since last February, is based on a safety profile with more than 2,000 patients who have accessed the pill, and clinical symptomatic efficacy for five typical Omicron-related symptoms (primary endpoint) and antiviral efficacy (key secondary endpoint) in patients with mild to moderate SARS-CoV-2 infection, regardless of risk factors or vaccination status, and during the Omicron-dominant phase of the pandemic.
New data in September showed that when the pill was administered daily for five days, it led to a significant reduction in symptoms such as stuffy or runny nose, sore throat, cough, feeling hot or feverish, and low energy or tiredness within 72 hours of its onset, the company announced. A total of 1,821 mostly vaccinated patients from Japan, South Korea and Vietnam were enrolled in this study.
The median time for patients to experience relief in five Covid-19 symptoms was significantly reduced in the cohort that was treated with the low dose of ensitrelvir (the dose level submitted for approval) compared to placebo: 167.9 hours versus 192.2. No significant adverse effects were noted, the company said.
Meanwhile, the study also hit its secondary endpoint — reduction in viral RNA on day 4 — following the third dose.
Shionogi says it will work toward obtaining a standard approval, as well as approvals in other countries too, in addition to work with the Medicines Patent Pool to provide access to low- and middle-income countries.
The antiviral, developed via a joint research collaboration between Hokkaido University and Shionogi, targets an enzyme in the SARS-CoV-2 virus called 3CL protease, which is essential for the replication of the virus.
The Japanese government in March agreed to purchase one million courses of the drug.
