A novel mRNA cancer vaccine helps reduce the chances of melanoma patients' tumors returning

Moderna shares dropped 25% after leaked cancer vaccine data, despite positive results. The vaccine, developed with Merck, reduced recurrence or death risk by 42% in melanoma patients. Analysts noted the data was positive but investors had high expectations. Merck shares fell 1%.

Moderna and Merck released early phase 3 trial data for their mRNA-based skin cancer vaccine, showing a 42% reduction in recurrence or death risk compared to a single treatment. The trial involved 1,137 high-risk melanoma patients. Both companies plan to seek regulatory approval. Moderna's stock dropped following the announcement.

Moderna's shares dropped 17.57% on Oct. 22, closing at $202.63. Despite the decline, the stock is up 587.11% year-to-date. ETMarkets ranked Moderna first among U.S.-listed stocks for gains, with a 733.54% increase through Oct. 21. The company and Merck reported positive Phase 3 trial results for a melanoma treatment.

Moderna and Merck shares fell after leaked data on their personalized melanoma vaccine underwhelmed investors. The companies had previously reported promising results in August, leading to a surge in their stock prices. According to the report, the new data did not confirm the initial optimism.

Moderna and Merck reported that their mRNA cancer vaccine, intismeran, reduced death or recurrence risk by 42% in a late-stage melanoma trial. The vaccine, combined with Merck's Keytruda, showed improved recurrence-free and metastasis-free survival rates compared to Keytruda alone. The companies plan to seek regulatory approval and presented the data at a medical conference.

Moderna (MRNA) fell 17.57% to $202.63 after reports of a data leak on its melanoma vaccine. The S&P 500 and Nasdaq also declined. Investors await full Phase 3 data on Oct. 24. Trading volume was 148% above average. BioNTech (BNTX) and Novavax (NVAX) also dropped.