Stock Market Today, Oct. 22: Moderna Stock Plummets 18% on Melanoma Vaccine Data Leak Reports
Moderna (NASDAQ:MRNA), an mRNA medicines and preventive vaccine developer, closed at $202.63, down 17.57%. Reports of a possible leak of late-stage personalized melanoma vaccine data sent shares lower today. Investors are waiting for the planned full Phase 3 presentation and Oct.
On October 22, Moderna's stock plummeted 18% following reports of a potential leak regarding its personalized melanoma vaccine data. The company's shares fell to $202.63 from $202.63. The leak reportedly indicated that Moderna's intismeran autogene, when combined with Merck's Keytruda, reduced the risk of recurrence or death in certain melanoma patients by 42% compared to Keytruda alone.
This figure was lower than the 49% decline observed in Phase II trials. Trading volume surged to 49.3 million shares, about 148% above the three-month average of 19.9 million shares. While Moderna's stock has risen over sixfold in 2026, the leak has raised doubts among investors about the company's prospects.
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