💊 A Landmark Trial Result for Cancer Immunotherapy

Moderna and Merck announced on May 4, 2026, that the pivotal Phase 3 KEYNOTE-942 trial of mRNA-4157 (V940), an investigational personalized mRNA cancer vaccine, in combination with Merck's anti-PD-1 therapy Keytruda (pembrolizumab), met its primary endpoint of recurrence-free survival in patients with resected high-risk stage III/IV melanoma. The trial enrolled 1,089 patients across 25 countries and demonstrated a 44% reduction in the risk of recurrence or death compared to Keytruda alone at a median follow-up of three years, confirming the 44% risk reduction previously observed in the Phase 2b cohort.

mRNA-4157 is custom-manufactured for each patient based on the unique mutational profile of their tumor. After surgical resection, the patient's tumor DNA is sequenced and compared to healthy tissue to identify up to 34 patient-specific neoantigens, mutant protein fragments that are most likely to provoke an immune response. An mRNA encoding these neoantigens is synthesized, encapsulated in lipid nanoparticles, and administered as an intramuscular injection in nine doses over the course of approximately one year.

The mRNA instructs the patient's cells to produce the neoantigen proteins, training T-cells to recognize and attack any remaining cancer cells bearing those mutations.

The companies plan to submit regulatory applications to both the FDA and European Medicines Agency in the first half of 2027, which could lead to approval as the first personalized mRNA cancer vaccine by 2028. Moderna's manufacturing facility in Norwood, Massachusetts has reduced the turnaround time from tumor biopsy to vaccine delivery from eight weeks to four weeks, a critical logistics improvement for an individualized therapy where patients with aggressive cancers cannot afford to wait.

🧬 BioNTech's Parallel Path

BioNTech, which collaborated with Pfizer on the first authorized COVID-19 vaccine, has been pursuing mRNA cancer vaccines since the company was founded in 2008. Its lead personalized cancer vaccine candidate, autogene cevumeran (BNT122), is in Phase 2 trials for pancreatic ductal adenocarcinoma, colorectal cancer, and melanoma. Results from a Phase 1 trial in pancreatic cancer, published in Nature in 2023, showed that 8 of 16 patients who received the vaccine plus chemotherapy and an anti-PD-L1 drug mounted a strong neoantigen-specific T-cell response and remained cancer-free at 18-month follow-up, compared to a median recurrence time of approximately 13 months in the non-responder group.

New Phase 2 data presented at AACR 2026 showed an 18-month recurrence-free survival rate of 68% in responders versus 38% in patients without detectable vaccine-induced immune response.

📋 Beyond Cancer: The Expanding mRNA Platform

The success of mRNA-based COVID-19 vaccines has catalyzed a platform technology applicable far beyond infectious disease and cancer. Moderna's mRNA-1345 for respiratory syncytial virus (RSV) was approved by the FDA in 2024 as mResvia, and its cytomegalovirus candidate mRNA-1647 is in Phase 3. mRNA-based enzyme replacement therapies for rare metabolic diseases, including methylmalonic acidemia and propionic acidemia, are in Phase 2 trials at Moderna, representing an entirely new therapeutic modality where mRNA replaces a missing enzyme inside the patient's own cells, circumventing the need for lifelong infusions of recombinant protein.

The global mRNA therapeutics market, negligible before 2020, is projected to reach $28 billion by 2035 according to Nature Reviews Drug Discovery.