Moderna-Merck Cancer Vaccine Maintains 49% Risk Reduction in High-Risk Melanoma at Five-Year Mark
Key Insights
Intismeran autogene combined with Keytruda reduced the risk of melanoma (search) recurrence or death by 49% at five years, maintaining the same benefit observed at three years.
The Phase 2b KEYNOTE-942 study enrolled 157 patients with high-risk stage III/IV melanoma (search) following complete surgical resection.
Eight Phase 2 and Phase 3 clinical trials are currently underway across multiple tumor types including lung cancer, bladder cancer (search) and renal cell carcinoma (search).
Moderna and Merck (search) announced sustained five-year efficacy data for their investigational mRNA-based cancer vaccine intismeran autogene when combined with Keytruda (pembrolizumab) in patients with high-risk melanoma (search). The combination therapy maintained a 49% reduction in the risk of recurrence or death compared to Keytruda alone, matching the benefit observed at the three-year analysis.
The data come from a pre-planned analysis of the Phase 2b KEYNOTE-942/mRNA-4157-P201 study, which enrolled 157 patients with high-risk stage III/IV melanoma (search) following complete surgical resection. Patients were randomized 2:1 to receive either intismeran autogene (1 mg every three weeks for nine doses) plus Keytruda (200 mg every three weeks for up to 18 cycles) or Keytruda alone for approximately one year.
Sustained Clinical Benefit
At the median five-year follow-up, the combination demonstrated a hazard ratio of 0.510 (95% CI, 0.294-0.887; one-sided nominal p=0.0075) for the primary endpoint of recurrence-free survival. This represents the same 49% risk reduction that was observed at the three-year mark, indicating sustained therapeutic benefit over an extended period.
"Now with five years of follow-up data, today's results highlight the potential of a prolonged benefit of the intismeran autogene and KEYTRUDA combination in patients with resected high-risk melanoma (search)," said Kyle Holen, M.D., Moderna's Senior Vice President and Head of Development, Oncology and Therapeutics.
The safety profile remained consistent with previous analyses, with no new safety signals identified in the extended follow-up period. The study originally reached its primary endpoint in December 2022, achieving a 44% risk reduction, which improved to 49% at both the three-year and five-year analyses.
Mechanism and Development Program
Intismeran autogene is a novel investigational messenger RNA-based individualized neoantigen therapy consisting of synthetic mRNA coding for up to 34 neoantigens. The therapy is designed and produced based on the unique mutational signature of each patient's tumor DNA sequence. Upon administration, the algorithmically derived and RNA-encoded neoantigen sequences are translated and undergo natural cellular antigen processing and presentation, training the immune system to generate specific T-cell responses against the patient's tumor.
Dr. Marjorie Green, senior vice president and head of oncology at Merck (search) Research Laboratories, emphasized the clinical significance: "For many patients with stage III/IV melanoma (search), there is a significant risk of recurrence following surgery. As such, demonstrating the longer-term potential of intismeran autogene and KEYTRUDA to reduce the risk of recurrence for certain patients with melanoma is a meaningful milestone."
Expanding Clinical Development
The companies are advancing a comprehensive development program with eight Phase 2 and Phase 3 clinical trials underway across multiple tumor types. The Phase 3 clinical trial for adjuvant melanoma (search) (INTerpath-001) is fully enrolled, while two non-small cell lung cancer (search) Phase 3 studies are currently enrolling patients.
Additional ongoing studies include a fully enrolled randomized Phase 2 study for adjuvant renal cell carcinoma (search) and enrolling Phase 2 studies for patients with resected muscle invasive and non-muscle invasive bladder cancer (search). The program also encompasses Phase 2 studies for first-line treatment of patients with metastatic melanoma (search) and metastatic squamous NSCLC.
Market Context and Implications
Melanoma (search) represents the most serious form of skin cancer, with more than 330,000 new cases diagnosed worldwide in 2022. In the United States, it is estimated there will be over 100,000 new cases of melanoma diagnosed and over 8,000 deaths resulting from the disease in 2025.
William Blair analysts noted that while the data update was incremental, they viewed the five-year results as "positive maintenance of an impressive effect over Keytruda monotherapy, the first therapy, to our knowledge, to show added benefit in this post-surgical setting."
Jefferies analysts highlighted the potential commercial implications, noting that while intismeran autogene could reach the market as early as 2027, "the 50:50 collaboration agreement with MRK could result in more meaningful sales in 2028, around MRNA's breakeven guidance by 2028."
The companies plan to present additional data from follow-up analyses of primary and secondary endpoints at an upcoming medical meeting, providing further insights into the long-term therapeutic potential of this personalized cancer vaccine approach.