A personalized vaccine developed by Moderna and Merck has demonstrated the potential to cut the risk of high-risk melanoma returning by 49 percent, according to data from a large, final-stage clinical trial. The experimental treatment, known as Intisomeran, is designed for patients who have undergone surgery for the deadliest form of skin cancer and is used in combination with Keytruda, an immunotherapy drug already in use for various cancers.
This combination therapy significantly improved outcomes compared to Keytruda alone, extending the time patients remained cancer-free and reducing the risk of the disease spreading. While a detailed breakdown of the results is anticipated later this year, Moderna's chief executive Stéphane Bancel described the findings as a "pivotal moment for the field of cancer research," highlighting the transition of personalized mRNA cancer treatments from aspiration to reality.
The trial involved over 1,000 patients with advanced melanoma. The vaccine utilizes mRNA technology, similar to that used in COVID-19 vaccines, but is uniquely tailored to each patient. It works by analyzing tumor samples to identify specific cancer cell mutations, which are then encoded into mRNA. This engineered mRNA instructs the patient's immune system to recognize and attack any remaining tumor cells.
Melanoma affects more than 20,000 people in the UK annually, with projections indicating a substantial increase in diagnoses by 2040. Stage 4 melanoma, when the cancer has spread, has a grim prognosis, with half of patients dying within a year. The new vaccine, if approved by regulators, could potentially be available to patients as early as next year.
Experts have called the findings significant. Dr. Lennard Lee, an associate professor at the University of Oxford, noted this as the first positive Phase III trial for an individualized neoantigen therapy and an mRNA-based cancer treatment, marking a substantial advancement in a field that has been under development for years.
However, questions remain regarding the full extent of the benefits, potential side effects such as fatigue, injection site pain, and chills, as well as the cost and manufacturing complexity of producing personalized doses at scale. Pharmaceutical companies are also exploring similar personalized vaccines for bladder, kidney, and non-small cell lung cancers. Earlier phase 2 trials had also indicated a 49 percent reduction in the risk of melanoma recurrence or death when using the drug combination.