Adding Merck & Co. and Moderna’s vaccine candidate to Keytruda has continued to cut the risk of cancer recurrence or death across five years of follow-up, boosting the companies’ prospects as they close in on phase 3 data.
The five-year results come from a phase 2b study that tested intismeran autogene in combination with Merck’s Keytruda in people with high-risk melanoma after complete resection. Compared to single-agent Keytruda, the combination cut the risk of recurrence or death by 44% after two years and by 49% after three years.
Tuesday, Merck and Moderna said the risk reduction after five years was 49%. The partners have yet to share data on other endpoints, such as the risk of distant metastasis or death, that were included in the earlier analyses.
While the companies are holding back data for a medical meeting, the snapshot shared in the top-line release supports the hypothesis that the vaccine’s mechanism will provide durable responses. Moderna CEO Stéphane Bancel said at the 2026 J.P. Morgan Healthcare Conference that hopes for durability rest on longstanding evidence that the vaccine reprograms T cells.
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Intismeran, also known as mRNA-4157 and V940, consists of a synthetic mRNA coding for up to 34 neoantigens. Merck and Moderna select neoantigens based on the mutational signature of the DNA sequence of the patient’s tumor, creating individualized therapies designed to generate T-cell responses against cancer cells.
The publication of two-year phase 2b results in 2023 encouraged the partners to start a pivotal program. The most advanced part of the program, a phase 3 trial in adjuvant melanoma, is now fully enrolled and could report interim results this year. The exact timing is unknown, because the trial is event-driven, but Bancel said the readout should happen in 2026.
Moderna has named intismeran among the growth drivers that could come online in 2027. The height of the vaccine’s sales ceiling will depend on data in adjuvant melanoma and beyond. Merck and Moderna are running phase 3 trials in two lung cancer settings, plus seven phase 1 and 2 studies across a range of other tumor types.
