Moderna and Merck announced Wednesday that a late-stage clinical trial of a personalized messenger RNA (mRNA) cancer vaccine met its primary goals. The interim analysis found that the treatment, named Intismeran, reduced the risk of melanoma recurrence and prevented the cancer from spreading to other parts of the body when compared to using the immunotherapy drug Keytruda alone. Following the announcement, Moderna's stock price rose by as much as 160% and Merck's shares increased by 11%.
The companies tested the vaccine in combination with Keytruda, a standard treatment for melanoma. The phase 3 trial enrolled 1,137 high-risk patients with stage IIB-IV melanoma whose tumors had been surgically removed. Participants were randomized to receive either Keytruda alone for approximately one year or a combination of Keytruda and up to nine doses of the personalized vaccine. The vaccine is manufactured for each individual based on a specific analysis of the mutations found in the patient's own tumor.
This result represents the first positive late-stage trial for an mRNA cancer vaccine, a technology that directs the immune system to target specific mutations in cancer cells. While the companies did not release the full data set, they stated that no new safety signals were identified during the study. Detailed results are expected to be presented at an upcoming medical meeting. Similar mRNA approaches are currently being evaluated for breast, lung, and pancreatic cancers.
For the patients involved, the treatment would involve receiving a made-to-order vaccine alongside standard immunotherapy. According to J.P. Morgan analysts, the commercial success of Intismeran is a critical factor for Moderna's return to profitability as the company seeks to diversify its product line beyond COVID-19 vaccines. For Merck, the vaccine could provide a new revenue stream as its top-selling drug, Keytruda, faces the expiration of its patent protection later this decade.
The next steps for the treatment involve formal regulatory review. Merck confirmed that the companies are already in discussion with regulators regarding the trial data. While the vaccine has received a breakthrough therapy designation—a status intended to expedite the development and review of drugs for serious conditions—Moderna CEO Stephane Bancel noted that pricing for the treatment has not yet been determined. The companies are currently scaling up production capabilities to meet potential demand over the coming years.