Moderna Shares Extend Losses Friday: What's Happening?

Moderna Inc. shares extended declines in premarket trading Friday after plunging over 17% on Thursday, as investors flagged concerns over clinical trial data for its investigational personalized melanoma vaccine.

The selloff followed an allegedly leaked ESMO 2026 abstract that raised questions about the vaccine's efficacy.

Late Thursday, Moderna and Merck & Co. released detailed results from the Phase 3 INTerpath-001 trial.

The study evaluated intismeran plus Merck's Keytruda versus Keytruda alone in patients with stage IIB-IV melanoma who had undergone surgery.

Combination Therapy Reduces Risk of Cancer Recurrence

In the trial's primary analysis, after a median follow-up of 24.6 months, intismeran plus Keytruda reduced the risk of cancer recurrence or death by 42%.

The combination also reduced the risk of distant metastasis or death by 38% compared with Keytruda alone.

Researchers reported consistent improvements in recurrence-free survival and distant metastasis-free survival across prespecified patient subgroups.

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Vaccine Shows Greater Benefit After Six Months

After patients completed the initial vaccination series, the combination therapy showed greater benefit.

During the first six months, outcomes were similar between treatment groups. However, a prespecified sensitivity analysis showed that after this period, the combination reduced the risk of recurrence or death by 58%.

It also reduced the risk of distant metastasis or death by 50%.

Another separate sensitivity analysis excluded patients who did not receive at least one planned dose.

In that group, the combination reduced the risk of recurrence or death by 49% and the risk of distant metastasis or death by 45%.

William Blair Sees 'Sell-the-News' Reaction

William Blair analyst Myles Minter said that despite encouraging trial results, Thursday's sharp selloff reflected profit-taking.

"We had believed investors were looking for a recurrence-free survival hazard ratio of 0.6 or better, and based on the leaked information, that target was achieved, but the market seems to be playing out a 'sell-the-news' scenario," the analyst wrote.

The firm noted that even after Thursday's decline, Moderna shares were still up 525% year-to-date.

Minter also said the data showed similar efficacy in patients with low- and high-risk disease, which could signal benefits across different tumor mutation burden levels.

While calling the INTerpath-001 interim results encouraging, Minter cautioned that investors will continue debating Moderna's valuation and the vaccine's potential across different tumor types.

MRNA Stock Movement

MRNA stock movement: Premarket trading data Friday showed Moderna shares down 4.04% at $194.45.