Moderna and Merck cancer vaccine trial data suspected of early leak; stock price falls

Moderna (MRNA.US) dropped by nearly 25% at one point during Thursday’s trading session, while Merck (MRK.US) fell by 3.7%. Trial data for their jointly developed experimental cancer vaccine was apparently published ahead of schedule on the medical website Oncology Central and was subsequently taken down. The data was originally scheduled to be presented on Saturday at the European Society for Medical Oncology (ESMO) Congress. According to the briefly disclosed results, the vaccine combined with Merck’s cancer drug Keytruda can reduce the risk of melanoma recurrence or death. The two companies had previously announced that the Phase III trial had met its primary endpoint but have not yet released the detailed results.