The personalised cancer vaccine being developed by Moderna and Merck has boosted hopes that mRNA technology could open up a new avenue of treatment, but the available evidence is still limited. Interim data from a large trial showed the experimental vaccine, when combined with Merck’s blockbuster immunotherapy Keytruda, helped reduce the risk of melanoma recurrence and spread in patients whose tumours have been surgically removed.
Known as intismeran autogene, the vaccine is designed to target mutations unique to an individual patient’s tumour. Once surgeons remove a tumour or cancerous lesion, the companies sequence it, looking for unique cancer mutations. The companies use those to create a customised vaccine that targets up to 34 mutations unique to that specific patient’s cancer.
With up to nine doses of Keytruda, infused every six weeks, plus up to nine doses of the customized mRNA vaccine, the treatment trains the immune system to recognize and attack cancer cells. Experts believe the treatment may work best in highly mutated cancers such as melanoma, where abundant tumour-specific mutations provide more targets for the vaccine to attack.
Cancers with high mutation rates, such as lung and colon cancer, could be promising targets because they may be more readily recognised by the immune system, Dr Michael Atkins, deputy director of the Georgetown Lombardi Comprehensive Cancer Center, said.
It is not clear that the vaccine technology will work against other cancers, he added. Merck and Moderna have several large trials underway in patients with non-small cell lung cancer whose tumors have been surgically removed.
Moderna is also studying the intismeran/Keytruda combination in mid-stage trials of patients with bladder and kidney cancers as well as in early-stage trials in pancreatic and stomach cancers. Data readouts from numerous trials are expected in the next year or two, according to the company.