Personalized Melanoma Vaccine Clears Major Phase 3 Test

Merck and Moderna’s personalized melanoma vaccine has met key goals in a large Phase 3 trial. The mRNA-based treatment was tested with Merck’s Keytruda in high-risk melanoma patients.

The companies said the combination significantly improved recurrence-free survival. It also improved distant metastasis-free survival compared with Keytruda alone.

The results mark the first successful Phase 3 test for an mRNA cancer vaccine of this kind.

How did the personalized melanoma vaccine perform?

The Phase 3 trial enrolled 1,137 patients with surgically removed stage IIB to IV melanoma. These patients faced a high risk of their cancer returning or spreading.  Patients received either Intismeran with Keytruda or Keytruda alone. Intismeran is the treatment’s generic name and was earlier known as V940 or mRNA-4157.

The trial’s main goal was recurrence-free survival. This measures how long patients remain alive without their cancer returning. A key secondary goal was distant metastasis-free survival. This measures the time patients remain free from cancer spreading to distant parts of the body.

The companies said the treatment met both goals with statistically significant and clinically meaningful results. However, detailed figures from the trial have not been released yet.

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Key highlights:

• The Phase 3 trial included 1,137 melanoma patients.
• Patients had stage IIB to IV melanoma after surgery.
• Intismeran was given with Merck’s Keytruda.
• The combination improved recurrence-free survival.
• It also improved distant metastasis-free survival.
• No new safety concerns were reported.
• Overall survival data are still being studied.
• Full trial results will be presented at a future medical meeting.

How is this cancer vaccine made for each patient?

Intismeran is designed around the genetic features of an individual patient’s tumor. Doctors first analyze a tumor sample to identify neoantigens. These are proteins linked to mutations found in cancer cells. The vaccine uses mRNA to target up to 34 selected neoantigens.

The mRNA is packaged inside lipid nanoparticles. After injection, it helps the body produce these tumor-related proteins. This process trains the immune system to recognize and attack cancer cells carrying those targets.

The treatment is being developed as an adjuvant therapy. That means it is given after surgery to reduce the risk of cancer returning.

What does the Phase 3 result mean for cancer treatment?

The results could strengthen the role of mRNA technology in cancer treatment. They also give Moderna a potential path beyond its infectious disease vaccine business. Earlier Phase 2b results had already shown encouraging results. Five-year follow-up found a 49% lower risk of recurrence or death with Intismeran plus Keytruda.

Merck and Moderna now plan discussions with health authorities. The companies will use the detailed Phase 3 results to support potential regulatory submissions.  The companies are also testing Intismeran in other cancers. These include non-small cell lung cancer, bladder cancer and kidney cancer.

The latest result is encouraging, but the full dataset