Story perspectives

Merck and Moderna’s Keytruda mRNA Vaccine Cuts Melanoma Recurrence

8/23/2026

Summary

Story summary

Moderna and Merck announced an mRNA vaccine with Keytruda that cut melanoma recurrence risk in a Phase 3 trial.
The trial enrolled 1,137 stage IIB-IV melanoma patients and showed statistically significant recurrence-free and distant metastasis-free survival improvements.
Shares of Merck and Moderna rose on Aug 19, with Moderna up roughly 150% and Merck about 11%.
Regulators will review the experimental treatment’s safety and durability, which currently lacks FDA approval.

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Story summary

Moderna and Merck announced an mRNA vaccine with Keytruda that cut melanoma recurrence risk in a Phase 3 trial.
The trial enrolled 1,137 stage IIB-IV melanoma patients and showed statistically significant recurrence-free and distant metastasis-free survival improvements.
Shares of Merck and Moderna rose on Aug 19, with Moderna up roughly 150% and Merck about 11%.
Regulators will review the experimental treatment’s safety and durability, which currently lacks FDA approval.