Moderna stock soared 177% on melanoma trial data in the stock market today, August 6, 2025. See how S&P 500, Nasdaq and rivals reacted.
Moderna, the mRNA medicine and vaccine developer, delivered one of the wildest single day moves of the year on the stock market today, August 6, 2025, with shares closing at $174.38, up 176.97 percent, after Moderna and Merck announced positive Phase 3 melanoma trial results. Investors are now watching for FDA plans and what comes next for the treatment.
At a Glance
- Moderna closed at $174.38, up 176.97 percent for the session
- Trading volume hit 185.1 million shares, roughly 1,819 percent above its three month average of 9.6 million
- Market cap jumped from $25 billion to $69 billion in a single day
- S&P 500 rose 0.21 percent to 7,708 and the Nasdaq Composite gained 0.16 percent to 26,331
- BioNTech closed up 21.96 percent to $113.12 and Pfizer rose 3.69 percent to $28.25
What Sparked the Melanoma Data Surge
The rally traces back to a Phase 3 trial pairing Moderna's intismeran autogene with Merck's Keytruda for melanoma patients. This marks Moderna's first individualized neoantigen therapy, or INT, and the combination showed meaningful improvement over Keytruda alone. Since Moderna's 2018 IPO, the stock has now climbed 838 percent, a figure that would have looked improbable just a day earlier given how far shares had fallen from their pandemic highs.
How the Broader Market Moved
Away from Moderna, trading was fairly calm. The S&P 500 added 0.21 percent to close at 7,708, and the Nasdaq Composite ticked up 0.16 percent to 26,331. Within the mRNA and vaccine space, BioNTech jumped 21.96 percent to $113.12 on the same melanoma optimism, while Pfizer, a Moderna rival in vaccine development, gained 3.69 percent to close at $28.25.
Moderna Valuation, Momentum and Yield
Valuing Moderna after a move like this is tricky. The company does not pay a dividend, so income investors get nothing here, and traditional price to earnings comparisons are complicated because Moderna has been posting losses tied to its shrinking COVID vaccine business, meaning EPS has remained negative in recent periods. Momentum, measured by relative strength, has clearly spiked into extreme territory given the volume surge, a sign the stock may be overbought in the near term even as the fundamental story shifts. The bull case rests on intismeran's potential across the multiple Phase 2 and Phase 3 cancer trials Moderna already has underway, meaning today's data could be the first of several similar catalysts. The bear case is straightforward: one trial readout does not guarantee FDA approval, competition in cancer immunotherapy is intense, and Moderna's core vaccine revenue continues to shrink from its pandemic peak.
Quick Facts
- Moderna's 52 week range has been reshaped dramatically by this single session move
- Intismeran is Moderna's first individualized neoantigen therapy to reach this stage
- The company has intismeran in multiple ongoing Phase 2 and Phase 3 cancer studies
- Moderna IPO'd in 2018 and is up 838 percent since then
Why Investors Are Watching the Cancer Pipeline
The size of today's jump suggests the market is not just reacting to melanoma results in isolation. It is pricing in the chance that intismeran, paired with Merck's Keytruda, could extend into other tumor types where Moderna already has trials running. That would open a much larger addressable market than a single indication, which explains why a company with negative earnings and no dividend just added $44 billion in market value in one trading day.
What Comes Next for Moderna's Cancer Ambitions
Attention now shifts to FDA engagement and whether regulators move toward a formal review pathway for intismeran. Given the scale of today's reaction, any additional trial updates, whether from ongoing Phase 2 or Phase 3 studies, are likely to move the stock sharply in either direction as investors try to figure out how much of this cancer optionality is now baked into the price.
Frequently Asked Questions
Why did the stock markets go down today?
They did not broadly decline today; the S&P 500 and Nasdaq Composite both closed higher, though gains were modest outside of the biotech sector, where Moderna and BioNTech posted outsized moves on melanoma trial news.
Will the stock market go down this year?
No one can say with certainty. Index direction over a full year depends on factors like interest rates, earnings growth and economic data that were not addressed in today's trading session.
Why did the stock market go down so far today?
It did not; both major indexes finished in positive territory, with the S&P 500 up 0.21 percent and the Nasdaq Composite up 0.16 percent, while Moderna and BioNTech drove outsized gains within biotech.