Moderna's Melanoma Trial Outcome: A Catalyst for the Stock's Surge

Moderna's (MRNA) stock skyrocketed over the past year, and one key event stands out as a catalyst for its surge: the announcement on August 19 that Merck and Moderna's Phase III melanoma trial of intismeran autogene with KEYTRUDA had met its endpoints.

The signs were there before the readout. By Q4 2024, Moderna reported that the melanoma trial was fully enrolled, which meant it was no longer a recruiting issue but rather a waiting game to see when and how the trial would end.

Moderna's financials also looked weak at the time, with trailing-twelve-month revenue down 38.8% year over year in its fiscal Q2 2025 results. The company even cut around 10% of its headcount and said Merck was paying 50% of intismeran's cost.

Options traders had stopped pricing an unusually large move, with implied volatility on Moderna at the 12th percentile of its trailing one-year range by August 8, 2025. This suggests that investors were not bracing for a significant move in the stock.