Myriad Genetics and Moderna Shares Plummet, What You Need To Know

What Happened?

A number of stocks fell in the afternoon session after shares across biotech and big pharma cooled further as traders continued to secure profits following the extraordinary run. The sector had jumped after Phase 3 results for Moderna’s individualized neoantigen mRNA therapy, intismeran, used with Merck’s Keytruda — the first positive late-stage readout for an mRNA-based cancer vaccine over Keytruda alone.

With no fresh clinical or regulatory catalyst to extend the advance, the tape has shifted into orderly, multi-session consolidation rather than a one-day fade. According to BioPharma Dive, TD Cowen’s Tyler Van Buren called the readout a “landmark moment,” while Leerink’s Daina Graybosch said the reaction looked “overly optimistic” versus nearer-term sales potential, as filings, fuller data, and a multi-year commercial ramp still stand between the trial win and widespread vaccine revenue — a setup that has left profit-taking intact into August 24, 2026.

The stock market overreacts to news, and big price drops can present good opportunities to buy high-quality stocks.

Among others, the following stocks were impacted:

Zooming In On Myriad Genetics (MYGN)

Myriad Genetics’s shares are extremely volatile and have had 42 moves greater than 5% over the last year. In that context, today’s move indicates the market considers this news meaningful but not something that would fundamentally change its perception of the business.

The previous big move we wrote about was 24 days ago when the stock dropped 46.1% on the news that the company reported disappointing second-quarter 2026 results that missed Wall Street’s expectations and included a reduced full-year forecast. Revenue for the quarter came in at $190.7 million, down 10.5% year-over-year, falling short of analysts’ projections.

The genetic testing company’s adjusted loss per share of $0.25 was also significantly wider than anticipated. Compounding the negative news, Myriad slashed its full-year revenue guidance to a midpoint of $780 million, a decrease of over 10% from its previous forecast, signaling expectations of continued business challenges.

Myriad Genetics is down 51.2% since the beginning of the year, and at $3.00 per share, it is trading 63.4% below its 52-week high of $8.18 from November 2025. Investors who bought $1,000 worth of Myriad Genetics’s shares 5 years ago would now be looking at only $85.35.

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