$MRNA up 112% premarket after breakthrough Phase 3 results for personalized cancer vaccine. $MRK up 9%.

How it works: Doctors sequence your tumor's DNA, then build a custom mRNA shot that trains your immune system to target those exact mutations.

Trial covered 1,137 melanoma patients. Those who got the vaccine + Keytruda saw lower recurrence vs Keytruda alone. No new safety issues.

Keytruda is the gold standard treatment, pulling in $8B/quarter for Merck. This is the first therapy to improve on it.

The vaccine doesn't replace Keytruda—it's added on top.

Nine more trials running across lung, bladder, and kidney cancers.

This is a real moment. Personalized medicine moving from concept to clinical proof.