Moderna (NASDAQ: MRNA) shares fell more than 17% to $202.63 on Thursday after detailed results from its Phase 3 melanoma vaccine trial surfaced ahead of schedule, even though the study, conducted alongside Merck's immunotherapy Keytruda, met its main treatment goals.

Early Data Release Triggers Sharp Selloff

The trial figures briefly appeared on an oncology website ahead of the findings' scheduled Saturday presentation, prompting Moderna and Merck to publish the results on Thursday. Moderna shares fell more than 25% at the intraday lows, temporarily erasing roughly $24 billion in market value, before recovering some losses by the close. The stock weakened again in Friday's premarket session. Merck shares also declined following the melanoma findings.

Even after Thursday's drop, Moderna remained up approximately 587% for the year — a run-up that had left expectations for the data unusually high heading into the release.

Trial Demonstrates Lower Recurrence Risk

The INTerpath-001 trial enrolled 1,137 patients whose high-risk stage IIB-IV melanoma had been removed through surgery. Participants received either the personalized vaccine, intismeran autogene, designed from genetic changes found in each patient's tumor, together with Merck's anti-PD-1 therapy Keytruda (pembrolizumab), or a placebo combined with Keytruda. That structure makes Keytruda alone the benchmark, testing whether a vaccine tailored to each patient's tumor can add benefit beyond what the immunotherapy delivers on its own.

After a median follow-up of 24.6 months, the combination reduced the risk of melanoma recurrence or death by 42%. Two-year recurrence-free survival reached 82.2% with the combined treatment, compared with 70% for Keytruda alone. The regimen also cut the risk of the cancer spreading to distant areas of the body, or of death, by 38%.

Analysts Weigh Results and Safety

Severe treatment-related side effects affected 14.2% of patients in the combination group and 13.4% in the comparison group, and the companies reported no new safety concerns. In separate oncology news, Roche shares rose this week after the U.S. Food and Drug Administration approved one of its colon cancer treatments.

UBS analyst Michael Yee described the recurrence findings as solid overall but attributed the selloff to the stock's earlier gains. William Blair's Myles Minter questioned whether similar benefits would appear in other cancer types. Analysts also noted that the reduction in distant spread trailed expectations set by earlier research, although the studies differed in design.

Regulatory Talks Continue as Tokenized Shares Slide

Moderna and Merck plan to present the full findings on Saturday, October 24, at a medical conference in Madrid, and are discussing the results with regulators. Overall survival figures remain incomplete, meaning the trial has not yet shown a definitive survival benefit — leaving that maturing data, together with the ongoing regulatory discussions, as the program's main open items to track.

Separately, tokenized Moderna shares (MRNAB) were quoted at $191.91, down 20.67% over 24 hours; the token trades separately from the Nasdaq-listed stock, and its steeper one-day decline echoed the equity selloff. In related market activity, BNB Chain recorded $25.6 billion in tokenized-stock trades during the third quarter.

Source: Blockonomi