Moderna and Merck recently announced groundbreaking positive results from a Phase 3 trial of their personalized mRNA cancer vaccine, intismeran, combined with Merck's Keytruda, for patients with high-risk melanoma. This marks the first mRNA cancer vaccine to succeed in a late-stage trial, leading to a substantial market reaction. Moderna's shares surged by 177% on August 19, 2026, adding approximately $45 billion to its market capitalization in a single day, despite the absence of specific detailed efficacy data. Merck's shares also rose by over 12% to an all-time high.
Analysts have largely reacted positively to the news. Myles R. Minter, PhD, a biotechnology analyst with William Blair, upgraded Moderna shares from "Market Perform" to "Outperform," calling the update a "clear positive." Alec Stranahan, PhD, of BofA Securities, upgraded his firm's rating to "Neutral" with a $170 price target, labeling it a "watershed moment." Joseph Stringer, PhD, of Needham & Co., called the results a "landmark win." These assessments are driven by the expectation that the cancer vaccine will significantly diversify Moderna's sales beyond its COVID-19 vaccines and potentially generate multibillion-dollar peak sales in melanoma and other solid tumor indications.
While some analysts expressed caution, such as Daina M. Graybosch, PhD, of Leerink Partners, who believes market reception was "overly optimistic" due to concerns about read-across to other cancers and lower gross margins for personalized therapies, overall sales projections remain high. Leerink Partners raised its 2032 sales forecast for intismeran by 17% to $1.4 billion, while Morningstar's Karen Andersen projected $16.8 billion in sales by 2035, more than double their previous estimate. Morningstar also doubled its fair value estimate for Moderna shares to $163 and increased Merck's by 29% to $143. J.P. Morgan analysts, including Jessica Fye, nearly doubled their price target on Moderna shares to $77 per share for December 2027 and increased success probabilities for other cancer indications like lung, kidney, and bladder cancer.
This success has also boosted rival companies in the cancer vaccine space. BioNTech, which is partnering with Roche on an mRNA-based individualized cancer vaccine, saw its shares jump 26%. Roche's shares also rose. The development is particularly crucial for Merck, as it seeks new blockbuster drugs to offset potential sales losses when Keytruda's key U.S. patents expire in 2028. Keytruda generated $15.81 billion in Q1-Q2 2026 sales and $31.641 billion in the previous year, highlighting the significant need for new revenue streams. Dean Y. Li, MD, PhD, President of Merck Research Laboratories, stated that individualized neoantigen therapies have the potential to redefine melanoma treatment.
