Moderna slides after its cancer vaccine data leaked early, even though the results looked strong
Partial Phase 3 results with Merck slipped out ahead of Saturday's ESMO presentation. The full data showed a 42% cut in the risk of recurrence or death, but after a 530%-plus run this year, analysts say expectations were higher still.
By Marcus Rodriguez ·
For information only, not investment advice. Prices delayed.
Moderna ($MRNA) closed down 17.57% at $202.63 as of Oct 22, 4:00 PM ET, after partial results from its melanoma vaccine trial with Merck ($MRK) got out two days early. The stock dropped as much as 25% during the session, CNBC reported. The odd part: the full data, released later Thursday, looked good.
The results were meant to be presented Saturday at the European Society for Medical Oncology (ESMO) congress in Madrid. That plan fell apart when an oncology news website published some of the data, breaking the conference's media embargo, according to STAT, as republished by the Boston Globe. ESMO then released the abstract and lifted the embargo on the full dataset.
In their joint release, the companies said the personalized vaccine, intismeran autogene, given with Merck's Keytruda cut the risk of recurrence or death by 42% versus Keytruda alone in patients whose stage IIB to IV melanoma had been surgically removed, after a median follow-up of 24.6 months. The risk of the cancer spreading to distant parts of the body, or death, fell 38%. Two-year recurrence-free survival was 82.2% against 70.0%. Overall survival data aren't mature yet, and the companies say they're engaging with regulators. Approval is not a given.
So why the drop? Analysts cited elevated expectations, not the data. BMO's Evan Seigerman said the move "likely reflects inflated expectations into the full data release, rather than a true indictment on the efficacy of the combo therapy," per CNBC, and UBS said the reaction may be due more to massive expectations than disappointing data. William Blair's Myles Minter called it a "sell-the-news reaction".
Those expectations were large. CNBC said Moderna shares were up more than 530% this year as of Thursday afternoon, and STAT reported the stock had more than tripled since August's topline announcement, adding roughly $60 billion in market value. STAT also flagged the number some may have been watching: an earlier study showed a 59% reduction in distant-metastasis risk, so the Phase 3's 38% is smaller, which it said might raise concerns about the vaccine's overall benefit.
Merck, the much larger drugmaker, closed down 1.76% at $147.24 as of Oct 22, 4:00 PM ET. Analysts forecast intismeran could bring in $6 billion or more a year in melanoma alone if approved, split evenly between the two partners.
Sources
- Moderna shares plunge after leak of partial cancer vaccine data, CNBC
- STAT report on the Moderna and Merck melanoma vaccine trial results, The Boston Globe (republished from STAT)
- Merck and Moderna will present results from landmark Phase 3 INTerpath-001 trial at ESMO 2026, Merck (joint Merck and Moderna release)
Tags: healthcare-pharma · markets-moves · analysts