Intismeran-Keytruda combo cuts melanoma recurrence risk by 42%
A Phase 3 trial shows Moderna's intismeran vaccine combined with Merck's Keytruda reduces the risk of recurrence or death in high-risk melanoma patients by 42% versus Keytruda alone, with regulatory approval possible by 2027.
The combination of Moderna's intismeran autogene vaccine and Merck's Keytruda reduced the risk of melanoma recurrence or death by 42% compared to Keytruda alone in a late-stage adjuvant trial. The Phase 3 INTerpath-001 trial achieved this result after a median follow-up of 24.6 months. This breakthrough offers a potential practice-changing treatment for the 70% of late-stage melanoma patients who face recurrence or death despite current Keytruda therapy.
The trial results showed a hazard ratio of 0.58 for recurrence-free survival. Approximately 82.2% of patients who received the vaccine alongside Keytruda were alive without their melanoma returning after two years. That compares with 70% of patients treated with Keytruda alone. The combination also reduced the risk of cancer spreading to distant organs or tissues, or death, by 38%.
Analyst Myles Minter said the findings represent a highly compelling efficacy profile. He added they substantially clear the physician-defined bar for a practice-changing dataset in adjuvant melanoma. The companies announced in August that the bespoke vaccines, when given with Keytruda, led to significant and clinically meaningful reductions in the recurrence of the deadly tumors.
Safety profile and discontinuation rates
The combination therapy showed a favorable safety profile. The most common adverse events were typical vaccine-like reactions, including fever, fatigue, and swelling at the injection site. About 7% of the people who got intismeran discontinued treatment because of an adverse event. That compares with 5% of those in the comparator group.
There were eight deaths in the treatment arm. Five occurred before the patients had received intismeran. The remaining three were not attributed to the vaccine.
Market reaction and regulatory outlook
Shares of Moderna fell significantly following a data leak, while Merck's stock declined modestly. Moderna's shares dropped 21% to $193.65 apiece. Merck's shares fell by just over 1% to $147.93. An FDA approval could arrive in 2027, as the companies are already engaging with regulatory authorities.
Merck and Moderna are testing the vaccine in other cancers. These include renal cell carcinoma, non-small cell lung cancer, bladder cancer, and other types of melanoma. The full dataset will be published at the European Society for Medical Oncology Congress on Saturday.
