© Reuters. FILE PHOTO: A COVID-19 treatment pill, called molnupiravir developed by Merck & Co and Ridgeback Biotherapeutics LP is seen in this undated handout photo released by Merck & Co Inc and obtained by Reuters May 17, 2021. Merck & Co Inc/Handout via REUTERS/
Merck, which developed the drug with Ridgeback Biotherapeutics, said in an emailed statement on Wednesday that it needs an updated letter of authorization from the U.S. Food and Drug Administration to allow it to start selling the drug commercially. It has also been linked to potentially transmissable mutations in the COVID-19 virus, according to a study published in the journal Nature last month. Merck said the study was limited and that it is confident in the clinical profile of the drug.