[TOKYO] Shares of Shionogi & Co plunged in Tokyo trading on Wednesday (Apr 13) amid concerns that the drugmaker's oral treatment for Covid-19, which is still awaiting approval from regulators, could pose pregnancy risks.
Shionogi does not recommend use of the pill during pregnancy based on the preclinical data showing a link to birth defects, the company said through a spokesperson.
The indications for use will be decided by regulators based on a comprehensive review of the data, he added.
A Kyodo News report had earlier cited a source saying that testing of the antiviral drug on animals found foetal abnormalities.
Its shares sank more than 15 per cent, and was set for its biggest 1-day loss since 1987, following the Kyodo report.
Shionogi last month signed a basic agreement to sell the drug, a protease inhibitor known as S-217622, to the Japanese government, with plans to supply about a million doses, pending approval by regulators.
The company filed for approval in February for the pill, which could become Japan's third antiviral approved for coronavirus patients, following those developed by Pfizer and Merck & Co.
The company has global aspirations for the treatment, with plans to launch a Phase III trial worldwide with US government support. Chief executive Isao Teshirogi has said production could reach 10 million doses a year.
Jefferies analyst Stephen Barker cut Shionogi to "underperform" from "buy". He said in a note to clients on Wednesday that the birth defect concerns reduced the chances of success of the Covid treatment from about 50 per cent to 5 per cent.
Merck's antiviral pill has similar risks, and demand has been subdued compared with the rival Pfizer drug.
Molnupiravir, developed by Merck and Ridgeback Biotherapeutics, introduces errors into the genetic code of the coronavirus, and both men and women taking it are instructed to use effective birth control due to potential safety issues. REUTERS