Merck and partner Moderna presented detailed Phase 3 results for intismeran, a personalized cancer vaccine, combined with Keytruda for melanoma. The data were shared at the ESMO 2026 congress. The combination significantly reduced the risk of cancer recurrence or death by 42% compared with Keytruda alone.
Separately, the European Commission approved Keytruda in combination with Padcev for a type of bladder cancer.
Merck shares fell in a sell-the-news reaction. Wall Street had largely anticipated the positive trial results after a top-line data release in August, limiting the immediate upside. Investors remain focused on Merck’s long-term growth strategy, particularly the eventual patent expiration of Keytruda, its blockbuster drug.