Merck/Moderna cancer vaccine cuts melanoma death or recurrence risk by 42%, shares fall

Moderna's shares dropped by up to 25% following the leak of partial clinical trial data on its personalized cancer vaccine, which was co-developed with Merck. The leak occurred despite the full results indicating promising outcomes for melanoma patients. Analysts believe the stock's decline is primarily due to overinflated investor expectations rather than the vaccine's disappointing clinical performance.

According to CNBC, the vaccine, named intismeran autogene, when combined with Merck's immunotherapy Keytruda, reduced the risk of recurrence or death from melanoma by 42% compared to Keytruda alone. The same combination also reduced the likelihood of the cancer spreading to other parts of the body or causing death by 38%, compared to Keytruda alone.

The companies claim that approximately 82% of patients who received the personalized cancer vaccine in conjunction with Keytruda were alive without their melanoma returning after two years, compared to 70% of those who received Keytruda alone. Investors view the vaccine as a potential breakthrough treatment with the potential for use in other types of cancer in the future, which could also serve as a crucial commercial product for Moderna's pipeline following its Covid-19, flu, and respiratory syncytial virus vaccines.

BMO Capital Markets analyst Evan Seigerman asserts that the relative reduction in recurrence or death is clinically meaningful. UBS analysts describe the data as strong and provide more confidence in future studies of the vaccine in kidney and bladder cancers, suggesting that the stock's reaction may be more a result of exaggerated expectations than the vaccine's disappointing performance.