Moderna Stock After ESMO 2026: Good Melanoma Data, and a Price That Still Needs a Second Cancer

On October 18 I wrote that ESMO could show how good intismeran, the personalized mRNA cancer vaccine Moderna makes with Merck, is in melanoma, but not whether Moderna has a cancer platform. The data leaked on October 22 and the stock fell 17.6%. My read now is that the melanoma result was good, the drop fairly took out some melanoma hype, and the price still pays for a second cancer that hasn't been tested.

The data leaked online through an erroneous posting on the morning of October 22, and Merck put out the full INTerpath-001 results that afternoon, two days before the ESMO presentation (BioSpace). The trial gave 1,137 melanoma patients, after surgery, either intismeran plus KEYTRUDA, Merck's standard immunotherapy, or KEYTRUDA alone. The hazard ratio for recurrence was 0.58, which means about 42% fewer recurrences or deaths than KEYTRUDA alone. At two years, 82.2% on the combination were recurrence-free, against 70.0%. Survival data aren't mature yet.

Against the bar I wrote down, the headline came in weaker. RBC called 0.58 the low end of what investors had hoped for, and that's roughly what the stock traded on.

I think the comparison that matters is a different one. When KEYTRUDA was approved after melanoma surgery in 2019, its hazard ratio was 0.57, and that was against placebo. Intismeran's 0.58 is against KEYTRUDA. They're different trials with different patients, so it's rough, but adding a drug to an approved one and getting about the same cut in recurrences that the approved drug got against nothing is a strong result. I'd still treat a melanoma filing as likely.

The part I didn't expect is the timing. Over the first six months the two arms looked the same. After the vaccine course was finished, the combination pulled well ahead. That's the shape you'd expect if the immune response the doses build is doing the work. Merck also reported a modified analysis that came in at 0.51, the same as the Phase 2b. Both are cuts the companies chose to show, so I wouldn't lean on them too hard, but neither points the wrong way.

I got the narrow point right. The data sized the melanoma product and said nothing about a second cancer, because no randomized trial outside melanoma has read out. The test I set in the original, a randomized win outside melanoma by the end of 2027, is exactly where it was.

I got the price wrong going in. I expected the data to be the test. Instead the stock ran 12.8% into it and then gave all of that back in one day. A drop that size on a melanoma number tells me a lot of the late buying was a bet on a huge melanoma result. I gave that possibility one paragraph in October and said I couldn't rule it out. It deserved more weight.

What's left is the question I care about. The stock page kept its bull, base and bear values after the data, because its base case already assumed a melanoma result like this one. At the October 23 close Moderna still sat above that base, so it's still paying for part of a second cancer before any randomized data exists. The scorecard has the live numbers, next to Regeneron and Vertex from the original's comparison.

The strongest argument against me is that the melanoma product is smaller than even 0.58 suggests. BMO called Bristol Myers' NADINA trial of Opdivo plus Yervoy a compelling standard for the disease, with an event-free survival hazard ratio of 0.32, though it said the two can't be compared directly (BioSpace). BMO expects doctors to choose case by case, since there's no head-to-head data. To be fair to the drug, BMO also noted serious treatment-related side effects of 10% here against 30% in NADINA, and sees intismeran as the pick for patients who can't take two checkpoint drugs.

Overall survival is the other gap. Merck says only that there's a favorable trend and that the companies are engaging with regulators, with no filing date. KEYTRUDA and Opdivo were both approved after surgery on recurrence-free survival, so I think a filing can go in without it, but I can't show that FDA will agree. Side effects also ran higher than on KEYTRUDA alone, with fever in about half the patients, though severe ones were close at 14.2% against 13.4%.

If a split market and a wait for survival data make melanoma slower than the stock at $245.81 assumed, the market was right to reprice it, and I think it mostly was. That doesn't touch the platform question. It just means the melanoma premium is gone and the second-cancer premium is still there.

The first randomized readout outside melanoma is the real test, and I'll come back to it then.