Earlier this week, Merck and Moderna, two pharmaceutical companies specializing in vaccines, released statements about their collaborative efforts to develop a personalized cancer vaccine for advanced melanoma.
Both companies released statements detailing interim results of the Phase 2b KEYNOTE-942/mRNA-4157-P201 study (NCT03897881). This phase of the clinical trial has reached a five-year milestone, a predetermined point for stakeholders to evaluate the trial's progress.
The trial enrolled adults with resectable melanoma that had metastasized to the lymph nodes (Stage III disease), a diagnosis associated with a high rate of recurrence. All patients on the trial had curative surgical procedures, rendering them disease-free at the time of enrollment. All patients received pembrolizumab (KEYTRUDA®), a PD-1 targeting immune checkpoint inhibitor (ICI) every three weeks. In addition to PD-1 blockade, a cohort of patients also received an adjuvant experimental vaccine called intismeran autogene.
The vaccine in the study, called intismeran autogene (also known as mRNA-4157 or V940), is a personalized mRNA cancer vaccine, developed collaboratively by Merck and Moderna. The goal of the vaccine centers around training a patient’s immune cells to selectively kill cancer cells by recognizing unique genetic mutations in tumor cells, abnormalities called neoantigens.
The data show that adjuvant treatment with intismeran autogene, in combination with pembrolizumab, substantially improved recurrence-free survival. Compared to those receiving pembrolizumab only, patients receiving the combination of vaccine and ICI had nearly 50% less risk of experiencing a recurrence or dying.
The companies previously released other interim reports approximately two and three years into the study, which showed reductions in the risk of recurrence or death of 44% and 49%, respectively. The three-year report also indicated a 62% reduction in the risk of distant metastasis, a condition that could significantly impact treatment options as well as quality of life for cancer survivors.
According to this week’s press releases, Moderna and Merck plan to present findings on additional endpoints at an upcoming medical meeting.
Sources: Merck (2026), Moderna (2026), Merck (April 2023), Merck (December 2024), ESMO Annal Oncol