Merck and Moderna notched a first for cancer vaccines on Wednesday. Their personalized mRNA shot slowed how often melanoma returned after surgery in a late-stage trial. No neoantigen therapy has previously succeeded in a phase 3 study.
The vaccine, called intismeran autogene and previously known as mRNA-4157, was tested in the INTerpath-001 study as an adjuvant treatment for patients with surgically removed stage IIB to IV melanoma. Given alongside Merck’s Keytruda, it met the primary endpoint of recurrence-free survival and the key secondary endpoint of distant metastasis-free survival, both with statistically significant and clinically meaningful improvements over Keytruda alone.
The result also marks the first positive phase 3 readout for an mRNA-based cancer therapy, and the first time any regimen has shown a meaningful benefit over Keytruda alone in this adjuvant setting.
The companies plan to present full data at an upcoming medical meeting and to start regulatory submissions. The trial will continue to track overall survival, while safety profiles for the combination matched earlier studies with no new signals.
Investors cheered the readout, with Moderna shares roughly doubling in early trading. Principal investigator Georgina Long of the Melanoma Institute Australia called it a landmark moment for adjuvant melanoma care, and Moderna CEO Stéphane Bancel said the win turns an aspirational idea into reality.
The shot is built from each patient’s tumor mutations to train the immune system to recognize and attack cancer, and the companies now hope the same approach can extend beyond melanoma into other tumor types.
