Shionogi¡¯s COVID-19 treatment Xocova was found to reduce the risk of developing at least one of the symptoms of long COVID-19, the Osaka-based pharmaceutical company said Wednesday.

Shionogi, which has yet to publish its results in a journal, presented the data at an academic conference held in the U.S. this week.

The data was obtained through a follow-up study of patients with mild or moderate COVID-19 registered in a clinical trial for the approval of Xocova as a treatment for the virus. The drug received emergency approval in Japan in November as the third oral treatment available in the country and the first to be developed domestically.

For the clinical trial, 1,821 COVID-19 patients in Japan, South Korea and Vietnam were given the oral drug once a day for five days. Symptoms of long COVID-19 were examined only for those with stronger symptoms three and six months after the patients were given the drug. A total of 604 responses were analyzed for long COVID-19 risks.

For 14 major symptoms of COVID-19 including cough, throat pain, fatigue and taste and smelling disorders, 14.5% of those given Xocova reported at least one of the symptoms six months later, compared with 26.3% who were given a placebo, meaning that the drug reduced the relative risk by 45%, the firm said.

For four neurological symptoms ¡ª a decrease in problem-solving abilities, loss of concentration, forgetfulness and insomnia ¡ª 29.4% of those given the drug reported one or more of the symptoms six months later, compared with 44% of those given a placebo, meaning that the relative risk was reduced by 33%.

The firm said the results are interim and the follow-up study will continue until one year after the start of the treatment.

The announcement comes on the heels of a separate study by the National Center for Global Health and Medicine Hospital that found over 25% of people with mild COVID-19 had at least one symptom lingering 18 months after the onset of the disease.

covered 502 people who had recovered from COVID-19 from February 2020 to November 2021, before the highly infectious omicron variant started spreading widely.