Success of mRNA Cancer Vaccine

• Personalized mRNA-based cancer vaccine, in combination with pembrolizumab for patients with completely resected high-risk melanoma. Moderna and MSD have reported positive Phase 3 results for intismeran autogene.
• The global clinical trials met its primary endpoint of recurrence-free survival and key secondary endpoint of distant metastasis-free survival, providing the first positive study readout.

New Era in Cancer Therapies

Intismeran autogene translates this concept into an individualized mRNA treatment. After a patient’s melanoma is surgically removed, tumor tissue is sequenced and compared with normal genetic information to identify cancer-specific mutations. Computational analysis is then used to select neoantigens considered most suitable for stimulating an immune response.

A personalized mRNA construct encoding up to 34 neoantigens is manufactured specifically for that patient and formulated in a lipid nanoparticle. The resulting medicine is the composition of the therapy itself is determined by the molecular characteristics of each patient’s cancer. Following administration, the mRNA enters cells and provides temporary instructions for production of the selected neoantigen sequences. These antigens can then be processed and presented to the immune system, enabling tumor-specific T cells to recognize molecular signatures associated with the patient’s cancer. In principle, those activated T cells can circulate throughout the body and identify malignant cells carrying the corresponding neoantigens. This is particularly relevant after surgery, when the visible tumor has been removed but microscopic residual disease may remain and ultimately cause recurrence or distant metastases. Instead of directly destroying the tumor itself, the personalized cancer vaccine is designed to provide the immune system with a molecular description of what it should search for.

The second component of the treatment, pembrolizumab (Keytruda), addresses another fundamental challenge in cancer immunology. Tumors can exploit immune-checkpoint pathways such as PD-1 and its ligands to suppress T-cell activity and escape immune attack. Pembrolizumab is an anti-PD-1 antibody that blocks this inhibitory signaling, helping restore antitumor immune responses.

Moderna and MSD’s Effective Cancer Vaccine

The first Phase 3 evidence suggests that this strategy can translate into a clinically meaningful benefit. Moderna and MSD announced that the INTerpath-001 clinical trial met both its primary endpoint of recurrence-free survival (RFS) and its key secondary endpoint of distant metastasis-free survival (DMFS) at a prespecified interim analysis.

The randomized, double-blind global study enrolled 1,137 patients with completely resected Stage IIB-IV cutaneous melanoma, assigning them 2:1 to receive intismeran plus pembrolizumab or pembrolizumab alone for approximately one year. That combination produced statistically significant and clinically meaningful improvements in both endpoints, with no new safety signal identified. Detailed Phase 3 hazard ratios, absolute event rates and survival curves have not yet been disclosed, and overall survival data remain immature.

The findings are reinforced by longer-term results from the earlier Phase 2b KEYNOTE-942 study. At five years of follow-up, the combination of intismeran and pembrolizumab was associated with a 49% reduction in the risk of recurrence or death compared with pembrolizumab alone, corresponding to a hazard ratio of 0.51. It also reduced the risk of distant metastasis or death by 59%, with a hazard ratio of 0.411. Those results were generated in a much smaller population of 157 patients, meaning that confirmation in the considerably larger Phase 3 study represents an important step in establishing whether the benefit can be reproduced in a broader melanoma population.

The significance of INTerpath-001 consequently extends beyond melanoma. It is the first positive Phase 3 readout reported for an individualized neoantigen therapy and for an mRNA-based cancer treatment, providing late-stage evidence that the mRNA platform can be used not only to prevent infectious diseases but also to manufacture patient-specific therapeutic medicines.
Moderna and MSD now plan to present the complete results at an international medical meeting and discuss regulatory submissions with health authorities.

It is ​a big deal for the field in general. With this positive study, there is ​hope (and likely investment to follow) that these approaches may change the way we treat cancer more broadly.

This success demonstrates that a concept pursued for decades has moved decisively closer to clinical practice. Personalized cancer therapies leverage information from a single tumor to identify the biological characteristics that distinguish cancer cells in a given patient.

Prepared by:

Jakub Knurek

Marketing Specialist

j.knurek@mabion.eu

Jakub Knurek

Marketing Specialist

Jakub Knurek is a marketing and business development expert specializing in CDMO operations with scientific and biopharmaceutical background. During the COVID-19 pandemic, he contributed to the development of the Novavax protein vaccine. As a side project, he runs his own pharma company.

As the author of numerous articles, he is recognized as an important voice of the younger generation of scientists. He is a member of Mabion’s representation at industry trade shows, including Central European BioForum 2026, Eurobiotech Congress 2026, BIO International Convention 2025 in Boston, 2nd Global Biologics India 2025 in Hydrabad, CPHI 2024 in Milan, CPHI 2023 in Barcelona, Life Sciences Baltics 2023 in Vilnius.

He actively participates in academic, business and industry discussions, such as the “Building the Future Pharma Workforce” panel at CPHI Milan 2024 or “Biotech in Translation: How to Tell the Story of Innovation” at Central European BioForum 2026.

For further reading

1. Steinzor P. Moderna, Merck mRNA Cancer Vaccine Succeeds in Late-Stage Trial. Am. J. Manag. Care. 2026.
2. Kauffman S. A New Milestone in Melanoma: Personalized mRNA-Based Cancer Therapy Shows Positive Phase 3 Results. Melanoma Research Alliance. 2026.
3. Weber JS, Carlino MS, Khattak A, Meniawy T, Ansstas G, Taylor MH, Kim KB, McKean M, Long GV, Sullivan RJ, Faries M, Tran TT, Cowey CL, Pecora A, Shaheen M, Segar J, Medina T, Atkinson V, Gibney GT, Luke JJ, Thomas S, Buchbinder EI, Healy JA, Huang M, Morrissey M, Feldman I, Sehgal V, Robert-Tissot C, Hou P, Zhu L, Brown M, Aanur P, Meehan RS, Zaks T. Individualised neoantigen therapy mRNA-4157 (V940) plus pembrolizumab versus pembrolizumab monotherapy in resected melanoma (KEYNOTE-942): a randomised, phase 2b study. Lancet. 2024; 403(10427): 632-644.
4. Khattak A, Carlino MS, Meniawy T, Ansstas G, Taylor MH, Kim KB, McKean M, Long GV, Sullivan RJ, Faries M, Tran TT, Cowey CL, Pecora A, Medina T, Atkinson V, Krepler C, Jemielita T, Mao H, Chow J, Ojalvo LS, Mehnert JM; KEYNOTE-942 Investigators. Intismeran Autogene Plus Pembrolizumab Versus Pembrolizumab Alone in High-Risk Resected Melanoma: 5-Year Update of the Randomized Phase IIb KEYNOTE-942 Study. J Clin Oncol. 2026: JCO2600835.