Moderna, Merck confirm melanoma vaccine data after leak

Moderna ↘ 1.25% shares fell as much as 25% on Thursday, and Merck ↘ 1.34% dropped 3.9%. The slide began after results for the companies' personalized melanoma vaccine, intismeran autogene, appeared online two days before their scheduled debut at a major cancer conference, Bloomberg reported. The early figures showed the vaccine working, but the benefit looked smaller than in an earlier study. Investors had pushed Moderna's stock up sharply this year on expectations for the program.reuters.com

How the Data Surfaced

According to Investing.com, the results showed up on the medical news site Oncology Central around 12:30 p.m. ET and were removed soon after. Unverified accounts on X then shared a report credited to the site. It said the vaccine cut the risk of recurrence or death by 42%, though the link posted with it no longer worked, Bloomberg noted. An earlier mid-stage study had shown a 49% reduction. That trial enrolled a different group of patients over a different period, so the two results cannot be compared directly. A Moderna spokesperson declined to comment, MarketWatch reported.morningstar.com+2

Companies Confirm the Results

Later on Thursday, Merck and Moderna released the detailed Phase 3 INTerpath-001 results. In the trial, the vaccine plus Merck's immunotherapy Keytruda lowered the risk of recurrence or death by 42% compared with Keytruda alone. It also lowered the risk of distant metastasis or death by 38%, after a median follow-up of 24.6 months, the companies said. After two years, 82.2% of patients on the combination were alive with no recurrence, compared with 70% on Keytruda alone. The trial enrolled 1,137 patients with melanoma that had been surgically removed. Overall survival data are not yet mature, and the companies said they are talking with regulators.businesswire.com

Reuters reported that the study is the first to show that a vaccine built from mutations unique to each patient's tumor, combined with an immunotherapy, can keep the disease at bay. Several Wall Street analysts had said investors wanted to see the risk of recurrence cut by at least 40%. CNBC noted that the stock fell even though the full results looked positive measured against those expectations. Oncologists told STAT the results are an important step forward for melanoma treatment.reuters.com+2

What Comes Next

The companies said in August that the trial had met its goals but did not give any numbers. Georgina Long is scheduled to present the full data at the European Society for Medical Oncology Congress in Madrid on Saturday, October 24, at 10:30 a.m. EDT. Moderna will host an investor webcast later that day, according to the company. The results have also been accepted for publication in The New England Journal of Medicine.merck.com+2