Why Is Moderna (MRNA) Stock Up Today: Merck Partnered Vaccine Cuts Recurrence Risk

Moderna, Inc. (NASDAQ: MRNA) shares surged 7.19% to $46.09 as of 10:41:50 AM EST on January 21, 2026, following a major announcement with partner Merck regarding their experimental personalized cancer vaccine. The biotech company and Merck reported five-year follow-up data showing their investigational mRNA-based therapy, intismeran autogene, combined with Keytruda continued to demonstrate sustained benefit in preventing melanoma recurrence.

The positive long-term data represents a significant milestone for Moderna as it works to diversify its revenue beyond COVID-19 vaccines and establish its mRNA platform as a viable cancer treatment technology.

Moderna/Merck Vaccine Maintains Long-Term Melanoma Protection

Moderna and Merck announced median five-year follow-up results from their Phase 2b KEYNOTE-942/mRNA-4157-P201 study evaluating intismeran autogene in combination with Keytruda for high-risk stage III/IV melanoma patients following complete surgical resection. The treatment reduced the risk of recurrence or death by 49% compared to Keytruda alone, maintaining the same level of benefit observed at the three-year follow-up in 2023. This consistency demonstrates the durability of the therapeutic effect over an extended period.

The investigational vaccine is a personalized mRNA-based therapy that uses a patient’s unique tumor genetic signature to train the immune system to recognize and attack cancer cells. It encodes up to 34 neoantigens derived from the individual patient’s tumor DNA sequence. Morningstar analyst Karen Andersen noted that if Moderna can replicate this 49% risk reduction in their ongoing Phase 3 trial, it would bode well not only for melanoma commercialization but also for expansion into other cancer types including kidney, bladder, and lung cancers.

The safety profile remained consistent with previous reports, and the companies plan to present comprehensive follow-up data from primary and secondary endpoints at an upcoming medical conference. With approximately 112,000 new melanoma cases expected in the U.S. in 2026 according to the American Cancer Society, the potential market opportunity is substantial. Jefferies analysts estimate the vaccine could be priced around $200,000, similar to Keytruda, and achieve multi-billion-dollar peak sales in melanoma alone.

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MRNA Stock Performance and Market Metrics

As of mid-morning trading on January 21, 2026, Moderna shares were trading at $46.09, up $3.09 or 7.19% from the previous close of $43.00. The stock opened at $43.50 and reached an intraday high of $46.29, with trading volume of 4.3 million shares compared to an average volume of 11.4 million. The company’s market capitalization stood at approximately $18.07 billion, with a 52-week range of $22.28 to $46.29, indicating the stock was trading near its yearly high following the positive news.

Despite the single-day surge, Moderna’s longer-term performance has been mixed. Year-to-date returns showed an impressive gain of 56.83% compared to the S&P 500’s 0.23%, and one-year returns of 28.87% versus the index’s 13.42%. However, the company faces significant challenges with three-year returns down 76.16% and five-year returns negative 65.22%, reflecting the dramatic decline from its COVID-19 vaccine peak. The company reported negative earnings per share of -$8.06 on a trailing twelve-month basis with revenue of $2.23 billion.

Analyst sentiment remains cautiously optimistic with an average price target of $37.40, below the current trading price. Morgan Stanley recently maintained its Equal-Weight rating while lowering its price target from $30 to $28 on December 12, 2025. Goldman Sachs holds a Neutral rating as the top analyst covering the stock. The cancer vaccine data represents a critical step in Moderna’s strategy to transform from a COVID-focused company to a diversified mRNA therapeutics platform, with eight Phase 2 and Phase 3 trials currently underway across multiple tumor types.

Disclaimer: The author does not hold or have a position in any securities discussed in the article. All stock prices were quoted at the time of writing.