MODERNA SHARES LOSE QUARTER OF VALUE AFTER VACCINE DATA LEAK

Moderna shares closed 25.2% lower at $183.88 on 22 October after partial results from a melanoma vaccine trial appeared online ahead of a planned presentation. The results briefly appeared on Oncology Central before the site removed them. Trading in Moderna shares briefly halted as the findings circulated. Merck, which developed the vaccine with Moderna, also saw its shares fall by nearly 1%. The companies released the full trial results later that Thursday.

Merck said its Phase 3 INTerpath-001 trial found that intismeran autogene, given with Keytruda after surgery, reduced the risk of melanoma returning or death by 42% compared with Keytruda alone. Merck reported a 38% reduction in the risk of cancer spreading to distant parts of the body or death. According to Merck, 82.2% of patients who received both treatments remained free of recurrence after two years, compared with 70.0% of those given Keytruda alone. An earlier Phase 2b result, disclosed in Moderna’s 2024 annual report, put the reduction in recurrence or death risk at 49%. The two figures come from different trial phases.

The companies had planned to present the detailed Phase 3 results at the European Society for Medical Oncology congress in Madrid on 24 October. Dr Hussein Tawbi, a trial investigator at the University of Texas MD Anderson Cancer Centre, said: “This is a huge development for our patients.” Tawbi said the vaccine’s added benefit came with milder side effects, including pain at the injection site, than other cancer treatments. Analysts at William Blair and TD Cowen characterised the share price fall as a reaction to the release of the results rather than a judgement that the trial had failed.