Holy Grail In Cancer Treatment? Moderna Erupts After Melanoma Vaccine Late-Stage Trial Success

Moderna's shares soared as much as 83% in premarket trading in New York after its personalized cancer vaccine, developed in collaboration with Merck & Co., reduced the risk of melanoma returning in a large, late-stage trial. The result marks the first positive Phase 3 trial for a personalized cancer vaccine by any company. 

The study met its primary endpoint by showing that the cancer vaccine, called intismeran autogene, combined with Merck's blockbuster immunotherapy Keytruda, improved recurrence-free survival compared with Keytruda alone. The study also met a secondary endpoint by reducing the risk of cancer spreading to other parts of the body.

Professor Georgina Long, the study's principal investigator, medical director of Melanoma Institute Australia, and chair of Melanoma Medical Oncology and Translational Research at the University of Sydney, wrote in a statement:

Today's results represent a landmark moment for adjuvant melanoma treatment. This is the first Phase 3 study to show that intismeran, a treatment designed based on the unique mutational 'fingerprint' of a patient's own tumor, given in combination with pembrolizumab, can reduce the risk of recurrence or death in patients with completely resected stage IIB-IV melanoma compared with KEYTRUDA alone.

Intismeran in combination with pembrolizumab has the potential to establish a new treatment paradigm in the adjuvant melanoma setting, helping patients remain cancer-free for longer.

Moderna and Merck did not disclose exact figures showing how much the therapy improved recurrence-free survival. The trial remains ongoing. Additional details will be presented at an upcoming medical meeting, and the vaccine could receive approval as early as 2027, depending on the regulatory review.

As of 0700 ET, Moderna shares were up 60% and trading around $100 per share. Short interest represents 13.5% of the float, equivalent to 49.8 million shares. Merck shares are up 7% in premarket as well. 

Melanoma is the most serious form of skin cancer. About 112,000 people are diagnosed annually in the US, and about 8,500 die from the disease, according to the American Cancer Society.

"Therapeutic vaccines have been something of a holy grail in cancer. People have been trying to do this for, you know, over 100 years in one way or another," Jane Healy, head of oncology early development at Merck, said in an interview with Bloomberg several weeks ago. She noted that one potential benefit of the personalized shot would be to extend survival without significantly increasing side effects.