Moderna and Merck Report First Successful Phase 3 Trial of a Personalized mRNA Cancer Therapy

Merck and Moderna announced that the Phase 3 INTerpath-001 trial of intismeran autogene combined with the immunotherapy pembrolizumab met its primary endpoint of recurrence-free survival and a key secondary endpoint of distant metastasis-free survival. The trial enrolled 1,137 patients with completely resected stage IIB to IV melanoma and compared the combination against pembrolizumab alone.

The therapy is individualized. Clinicians sequence a patient's tumor, compare it against healthy tissue to identify mutations unique to the cancer, and a computational pipeline selects which of those mutations are most likely to provoke an immune response. The resulting messenger ribonucleic acid (mRNA) construct encodes up to 34 of these neoantigens. That selection step is where machine learning does the work, and it had not previously been confirmed by a positive late-stage trial. BioPharma Dive reported this as the first such result for an individualized neoantigen therapy.

The market reaction was large. The Motley Fool's market summary recorded Moderna closing up 177% on August 19, and BioSpace reported the company's market value moving from roughly $25 billion to roughly $69 billion. Merck rose by a far smaller margin.

What is verified so far is a company statement that a pre-specified interim analysis crossed its thresholds. The effect sizes, the hazard ratios and the safety profile have not been published, and interim analyses of recurrence endpoints do not by themselves establish an overall survival benefit. The AI Post summary circulating on Telegram describes the result as a milestone, which the companies also claim, but the detailed data are still pending presentation.