Moderna shares nearly tripled after successful trial of an experimental skin cancer vaccine developed with Merck. The therapy is custom‑made for each patient, and analysts expect US regulatory approval next year.

The stock surged 177%, adding $44bn to market capitalization and lifting it to $69.6bn, making Moderna the second‑best performer in the S&P 500 this year behind Sandisk. Merck shares rose 12.6% to an all‑time high, while BioNTech jumped 21.6%.

Chief executive Stéphane Bancel called the result a landmark for a new class of medicine that uses mRNA to train the immune system, and principal investigator Georgina Long echoed the significance. The regimen combines Moderna’s mRNA vaccine with Merck’s Keytruda.

After a pandemic‑driven boom, Moderna faced weaker Covid‑19 demand and was the most shorted S&P 500 stock last year. The company is betting on cancer vaccines for a turnaround and is expanding manufacturing, including a new Massachusetts facility.