Moderna, Merck say mRNA treatment cuts risk of melanoma recurrence, spread

US pharma giants Moderna and Merck have scored a breakthrough in a vaccine that could allow people with a type of skin cancer to live longer. The companies say their vaccine reduced the risk of recurrence and spread of melanoma, the deadliest form of skin cancer. It is the first positive final-stage trial for any mRNA-based cancer therapy. CNA's Poh Kok Ing explains how this new treatment works.