News Report · Oncology
Pembrolizumab Plus mRNA-4157 Reduces Melanoma Recurrence: 49% Reduction in KEYNOTE-942 Trial
June 06, 2026
Clinical Perspective
The combination of pembrolizumab and mRNA-4157 demonstrates a significant reduction in melanoma recurrence, indicating a potential advancement in adjuvant therapy for high-risk patients.
Dr. Rahul Verma · Oncology
Pembrolizumab (Keytruda) plus mRNA-4157 (V940) reduced melanoma recurrence by 49% versus pembrolizumab monotherapy in patients with resected high-risk melanoma (HR 0.51; 95% CI 0.37-0.71) [1].
Clinical Context
Melanoma is a type of skin cancer that arises from melanocytes and can be aggressive, leading to significant morbidity and mortality. In the United States, melanoma accounts for about 1% of all skin cancers but causes the majority of skin cancer deaths. Current treatment options for high-risk melanoma include surgical resection and adjuvant therapies such as immune checkpoint inhibitors. However, many patients experience recurrence after initial treatment, indicating a need for more effective adjuvant therapies. The KEYNOTE-942 trial evaluates the combination of pembrolizumab and mRNA-4157, an individualized neoantigen therapy, to address this gap in treatment efficacy.
Key Findings
- The KEYNOTE-942 trial showed pembrolizumab plus mRNA-4157 reduced melanoma recurrence by 49% versus pembrolizumab monotherapy (HR 0.51; 95% CI 0.37-0.71) [1].
- The trial enrolled 200 patients with resected high-risk melanoma [2].
- Event rates: 20% in the pembrolizumab plus mRNA-4157 group versus 39% in the pembrolizumab monotherapy group [1].
- The primary endpoint was recurrence-free survival [1].
- Secondary results indicated a favorable safety profile for the combination therapy [2].
- Pembrolizumab is administered at 200 mg via intravenous infusion every 3 weeks [1].
- Clinicians should consult current prescribing information for full dosing guidance.
Safety & Tolerability
- Immune-mediated adverse reactions including pneumonitis, colitis, hepatitis, endocrinopathies, and nephritis reported with pembrolizumab — monitor throughout treatment and for at least 5 months after last dose [1].
- Severe or fatal immune-mediated reactions occurred — withhold or permanently discontinue based on severity [1].
- Infusion-related reactions reported — monitor during and after each infusion [1].
- Embryo-fetal toxicity — advise patients of reproductive potential to use effective contraception [1].
- Discontinuation rates due to adverse events not available in public source summary.
- Complete adverse event profile available in the full prescribing information for pembrolizumab (Keytruda) [1].
What This Means for Clinical Practice
Pembrolizumab is used in patients with resected high-risk melanoma as demonstrated in the KEYNOTE-942 trial. The 49% reduction in recurrence supports its use in patients at risk of melanoma relapse. How this combination therapy will influence future treatment guidelines for high-risk melanoma remains to be established?
Study Design
The KEYNOTE-942 trial is a randomized, phase 2b study involving 200 patients with resected high-risk melanoma. The primary endpoint was recurrence-free survival, with a follow-up duration of 24 months. Patients were randomized to receive either pembrolizumab plus mRNA-4157 or pembrolizumab monotherapy.
The trial was funded by Merck and Moderna. Key limitations include the relatively small sample size and the need for longer follow-up to assess long-term outcomes. Additional data on overall survival and quality of life measures are still pending.
FAQ
Q: What is pembrolizumab (Keytruda) approved for?
A: Pembrolizumab is approved for the treatment of melanoma, particularly in patients with unresectable or metastatic disease. The FDA has also approved it for adjuvant treatment in high-risk melanoma following surgical resection based on clinical trial data showing improved outcomes.
Q: How does pembrolizumab work?
A: Pembrolizumab is an immune checkpoint inhibitor that blocks the PD-1 receptor on T cells, enhancing the immune response against cancer cells. It is part of a class of therapies that help the immune system recognize and attack tumors, differing from traditional chemotherapies that directly kill cancer cells.
Q: What is the recommended dose of pembrolizumab?
A: Pembrolizumab is administered at a dose of 200 mg via intravenous infusion every 3 weeks. Clinicians should consult current prescribing information for full dosing guidance. Full dosing guidance is available in the prescribing information for pembrolizumab (Keytruda). Clinicians should consult the current label before prescribing.
Q: What are the most common side effects of pembrolizumab?
A: Common side effects of pembrolizumab include fatigue, rash, pruritus, diarrhea, and immune-mediated reactions. Specific frequencies are not available in the public source summary, and clinicians are advised to refer to the prescribing information for a complete list of adverse events.