https://www.live-feeds.com/feed/moderna-stock-plummets-18-after-cancer-vaccine-data-leakContinuously updated, source-cited coverage. https://www.live-feeds.com/feed/moderna-stock-plummets-18-after-cancer-vaccine-data-leakhttps://www.live-feeds.com/feed/moderna-stock-plummets-18-after-cancer-vaccine-data-leak#u155997Mon, 26 Oct 2026 11:17:09 +0000Moderna shares dropped sharply following an unauthorized data leak concerning its experimental melanoma vaccine developed alongside Merck. The decline follows a massive stock rally driven by optimism over the personalized treatment. Investors awaited the full late-stage trial results for the combination of intismeran autogene and Merck's Keytruda ahead of the European Society for Medical Oncology Congress. While reports indicated the fuller trial data released later appeared positive relative to Wall Street expectations, the initial leak left the stock down between 18% and 25% due to vary