mRNA cancer vaccine shows protection at 5-year follow-up, Moderna and Merck say

mRNA’s potential

Previous data from the trial reported that 107 participants received the mRNA vaccine and Keytruda treatment, while the remaining 50 only received Keytruda. At the two-year follow-up, 24 of the 107 (22 percent) who got the experimental vaccine and Keytruda had recurrence or death, while 20 of 50 (40 percent) treated with just Keytruda had recurrence or death, indicating a 44 percent risk reduction. The companies did not report the breakdown of the two groups in the press release this week for the five-year follow-up, but said the risk reduction was 49 percent, which is also what the companies reported for the three-year follow-up.

As for side effects, the companies reported that little had changed from previous analyses; adverse events were similar between the two groups. The top side effects linked to the vaccine were fatigue, injection site pain, and chills.

The results “highlight the potential of a prolonged benefit” of the vaccine combined with Keytruda in patients with high-risk melanoma,” Kyle Holen, a senior vice president at Moderna, said.

They also “illustrate mRNA’s potential in cancer care,” he said, noting that the company has eight more Phase 2 and Phase 3 trials going for mRNA vaccines against a variety of other cancers, including lung, bladder, and kidney cancers.

Marjorie Green, a senior vice president at Merck, called the five-year follow-up data a “meaningful milestone” and “encouraging.”

“[W]e look forward to late-stage data from the INTerpath clinical development program with Moderna, across a range of tumor types where significant unmet needs remain,” she said.

While the top-line results appear positive, conclusions can’t be drawn until the full data from the trial are published. The vaccines are also being developed amid a political environment hostile to mRNA vaccines. Anti-vaccine Health Secretary Robert F. Kennedy Jr. has railed against mRNA COVID-19 vaccines, making false claims about their safety and efficacy. In August, Kennedy unilaterally canceled $500 million in grant funding for the development of mRNA-based vaccines against diseases that pose pandemic threats.