Shares of Moderna are breaking out of their post-pandemic hibernation after the company notched a big win from the mRNA vaccine it developed with Merck for melanoma patients.

The stock climbed as much as 160% on Wednesday morning to a high of $163.47. Shares are now up roughly fivefold from where they started the year. Merck shares got a lift too, rising 11% to $150.

Merck and Moderna said before the opening bell that their experimental mRNA-based vaccine prevented cancer from coming back or spreading in a study of high-risk melanoma patients.

"Patients have a better chance of being disease-free, and for longer," Merck Research Laboratories president Dr. Dean Li said in an interview with CNBC.

The study looked at people who had surgery to remove melanoma, treating them with a combination of the personalized cancer vaccine intismeran and Merck's blockbuster cancer immunotherapy Keytruda. It met the primary goal of extending the time before cancer returns in high-risk patients, as well as its secondary goal of preventing the disease from spreading to different organs.

Moderna has been looking for a second act since the pandemic receded and, along with it, demand for Moderna's Covid-19 vaccines.

After going public at $23 in late 2018, Moderna shares hit a record high of nearly $450 in September 2021. The stock has tumbled in the years since, sinking close to its IPO price as recently as last fall.

Analysts at Evercore ISI said the study's outcome was as expected, though they still anticipated that the news could surge shares given the stock's heavy retail interest and ownership.

"We'd expect the move to run well ahead of what a topline-only readout with no disclosed magnitude of benefit would otherwise justify," the analysts said in a research note.