Merck and Moderna said on Oct. 22 that, in a phase 3 trial of patients whose tumors had been surgically removed, adding their personalized mRNA vaccine to Keytruda lowered the risk of melanoma returning or death by 42% compared with Keytruda alone.
The INTerpath-001 trial enrolled 1,137 people with stage IIB to IV melanoma whose tumors had been completely removed by surgery. Detailed results were presented on Oct. 24 at the European Society for Medical Oncology meeting. The experimental vaccine, called intismeran autogene, is customized using mutations found in each patient’s tumor.
Keytruda, also called pembrolizumab, was given to patients in both study groups. After a median follow-up of 24.6 months, the estimated two-year rate of patients remaining alive without the cancer returning was 82.2% with the combination, compared with 70.0% with Keytruda alone. The vaccine combination also lowered the risk of cancer spreading to distant parts of the body or death by 38%.
The findings are a significant trial result, but they do not yet show that the vaccine helps patients live longer. Overall-survival data are not yet mature, and follow-up is continuing. The treatment is still under investigation.
The companies say they are talking with regulators about possibly submitting applications.