Why Moderna Stock Has Rocketed 90% Premarket on Wednesday

Moderna (NASDAQ: MRNA) shares skyrocketed as much as 90% in premarket trading Wednesday, August 19, 2026, touching $119.83, after the company and partner Merck (NYSE: MRK) announced that their experimental mRNA-based melanoma vaccine met its main goals in a large, late-stage clinical trial.

The Phase 3 INTerpath-001 study evaluated intismeran autogene—an individualized neoantigen therapy known as mRNA-4157 or V940—in combination with Merck’s blockbuster immunotherapy Keytruda (pembrolizumab), compared with Keytruda alone, in patients with completely resected stage IIB-IV melanoma. The companies said the combination showed statistically significant and clinically meaningful improvements in recurrence-free survival and distant metastasis-free survival, marking the first positive Phase 3 readout for an individualized mRNA cancer therapy.

“Today’s results represent a landmark moment for adjuvant melanoma treatment,” said Professor Georgina Long, the trial’s principal investigator and medical director of Melanoma Institute Australia. Moderna CEO Stéphane Bancel called the results “a pivotal moment for the field of cancer research,” saying the milestone turns personalized mRNA cancer treatment “from aspirational” into reality.

The explosive rally sent Moderna surging to its highest level in years, delivering a rare and dramatic bright spot for a stock that has been battered since its pandemic-era peak as COVID-19 vaccine demand collapsed. Merck shares also climbed roughly 6% in premarket trading on the news.

The companies plan to present detailed data at an upcoming international medical meeting and will engage regulators on potential filing submissions. Overall survival data, a key secondary endpoint, remains pending as the trial continues, though Wednesday’s move underscores investor enthusiasm for Moderna’s push beyond vaccines and into individualized cancer therapeutics.