Shares of Merck and Moderna jumped early Tuesday after the drugmakers said a potential skin cancer vaccine they are developing using the same technology behind COVID-19 preventive shots did well in a mid-stage study.

The drugmakers said a combination of the vaccine and Merck�s immunotherapy Keytruda led to a statistically significant improvement in recurrence-free survival time in patients with phase three or four melanoma who had the tumors removed in surgery.

That combination was compared with Keytruda alone in a mid-stage clinical trial of 157 patients.

The patient group that took the potential vaccine and Keytruda saw a 44% reduction in the risk of death or the cancer returning, the companies said.

Merck and Moderna expect to start a phase 3 study of the combination next year. That�s generally the last and largest clinical study before a drug is submitted to regulators for approval.

The potential vaccine aims to train a patient�s immune system to recognize and respond specifically to mutations in their tumor. Keytruda, Merck�s top seller, primes the body�s immune system to detect and fight tumor cells.

Shares of Moderna jumped more than 8% in premarket trading, while Merck rose more than 2% and futures indexes increased slightly.

(AP)