Personalizing cancer vaccines is a step closer to market, as Merck and Moderna demonstrated that their mRNA vaccine, combined with Keytruda, effectively treats melanoma in a dramatic presentation at the European Society of Medical Oncology (ESMO) Congress last month.
The Challenge of Personalized Supply Chains
However, these vaccines differ from a flu shot—because samples of the patient’s individual tumor are taken during tumor removal, companies must prove they can provide the vaccine as patients need it.
The drug is one that you want to be able to use worldwide and give this benefit every single time,” Jane Healy, head of oncology early clinical development at Merck, told BioSpace before the presentation in Spain.
The mRNA vaccine intismeran autogene combined with Merck’s mega-blockbuster Keytruda cut the risk of recurrence or death by 42%, or a hazard ratio of 0.58 in patients with resected stage 2b to 4 melanoma, in the Phase 3 INTerpath-001 trial. A total of 1,137 patients were included in the study.
Global Manufacturing Viability
The medicine was also found to be successfully produced during the trial, says Merck. 99% of patients in the vaccine treatment arm were able to receive a manufactured vaccine, with similar results from earlier phase 1 and 2 trials, Healy said.
“It’s possible to get this to patients anywhere in the world,” Healy said. The study involves locations across the U.S., in South America, Australia, Europe, U.K., Canada, the Middle East, South Africa and in Asia, ClinicalTrials.gov reports.
Making individualized neoantigen therapy (INT) is an involved process. The tissue from the patient’s tumor is removed and sequenced to understand the unique mutational signature of the cancer, and a synthetic mRNA code is then synthesized for up to 34 neoantigens. That code instructs the immune system on how to battle the cancer with its own distinctiveness. Ideally, patients receive the full 34 neoantigens, but they can still reap benefit from fewer, Healy noted.
You have to have enough tissue for you to be able to do the sequencing analysis and then the design of the INT, which can be made later.”
High Success Rates in Tissue Sample Design
When screening for the trial, Merck discovered 82% of the patients had sufficient tissue. Of these, 91% managed to obtain the complete neoantigen range from samples, while the remaining 6% obtained less, but still successfully manufactured, resulting in 99% of patients in the treatment arm. Those that didn’t receive the 34 total neoantigens were still very close to the highest level, said Healy.
In total, the manufacturing process is very efficient, and in most situations, in patients with melanoma which is amenable to surgery, they will have enough tissue that they can make the vaccine,” Healy said.
Expanding Beyond Melanoma
For intismeran, it’s only the beginning of melanoma. Merck and Moderna are also running trials in renal cell carcinoma, non-small cell lung cancer, bladder cancer, and other types of melanoma. This early milestone has led to proof of concept of the manufacturing by the partners.
“It’s a place that’s conducive to it being successful, and the experience that we had during the trial demonstrated that we can do it consistently,” Healy said.
Merck and Moderna Advance Personalized mRNA Vaccines
Merck and Moderna are moving personalized mRNA cancer vaccines closer to the market following encouraging results from their Phase 3 melanoma trial. The study explored a customized treatment designed to work alongside Merck’s Keytruda immunotherapy.
The Phase 3 INTerpath-001 trial included 1,137 patients with high-risk melanoma. According to recent reporting, the personalized mRNA vaccine program successfully delivered customized doses to 99% of trial participants, highlighting the potential for this complex treatment approach to be used at a larger scale. BioSpace
How Personalized mRNA Cancer Vaccines Work
Unlike traditional vaccines, a personalized mRNA cancer vaccine is designed using information from an individual patient’s tumor. The treatment aims to help the immune system recognize specific cancer-related targets and strengthen the body’s response against cancer cells.
Positive Results in Melanoma
The combination of the investigational mRNA vaccine and Keytruda showed promising results in the late-stage melanoma trial. Merck and Moderna previously reported that the treatment reduced the risk of melanoma recurrence and spread compared with Keytruda alone. Reuters
Bringing Customized Treatments Closer to Market
One of the biggest challenges for personalized mRNA therapies is manufacturing and delivering a unique treatment for each patient. The reported success in serving 99% of participants demonstrates progress in building the operational systems needed to support personalized cancer care.
The Future of mRNA in Cancer Treatment
The success of this program could represent an important milestone for mRNA technology beyond infectious diseases. If future regulatory and clinical developments remain positive, personalized mRNA vaccines may create new opportunities for treating melanoma and potentially other types of cancer.
The collaboration between Merck and Moderna shows how mRNA technology could help shape a more personalized future for oncology, combining genetic insights, advanced manufacturing, and immunotherapy.
