Table of contents
The news (announced this morning, Aug 19)
The stock reaction (premarket)
What's next
🧑 You
Check out the news about the Merck and Moderna melanoma cancer vaccine. The stock is going nuts right now in pre trading.
▶ Reasoning
Let me check the skill index first as instructed before running web search.
🤖 Assistant
I'll check my skill index first, then look into the Merck/Moderna melanoma vaccine news.
▶ Tool: read_file [path='~/Personal/skills/skill_index.md']
▶ Reasoning
This is a news request. Let me check the bottalk gate — I should search BotTalk about the topic. But bottalk is about re…
🤖 Assistant
This is a fresh news lookup, so I'll go straight to searching the web for what's driving Merck and Moderna today.
▶ Tool: web_search [query='Merck Moderna melanoma cancer vaccine stock news']
▶ Tool: web_search [query='Moderna MRNA stock premarket melanoma vaccine news']
▶ Reasoning
🤖 Assistant
Let me get the details from the primary reports — CNBC and Bloomberg have the most complete coverage.
▶ Tool: fetch_url [url='https://www.cnbc.com/2026/08/19/moderna-merck-cancer-v]…
▶ Tool: fetch_url [url='https://www.bloomberg.com/news/articles/2026-08-19/mod]…
▶ Reasoning
I have enough info. Let me summarize for the user. The user just wants to check out the news. Let me give a clear summar…
🤖 Assistant
Here's what's going on with the Merck + Moderna melanoma vaccine situation today:
The news (announced this morning, Aug 19)
Merck and Moderna reported positive initial results from their first-ever late-stage (Phase 3) trial of an experimental mRNA-based personalized cancer vaccine for melanoma, given in combination with Merck's immunotherapy Keytruda.
Key highlights:
- The trial enrolled more than 1,100 patients with high-risk/advanced melanoma that had been fully removed by surgery.
- The combo met its main goal: significantly extending the time patients lived without their melanoma returning, vs. Keytruda alone.
- It also met a key secondary goal — reducing the risk of the cancer spreading to distant parts of the body.
- This builds on the positive Phase 2 data from earlier this year, and validates the "personalized" approach: the vaccine is tailored to the specific mutations in each patient's tumor to train the immune system to kill those markers (paired with Keytruda to ramp up the attack).
- Moderna (MRNA) — popped ~90% in premarket (some outlets citing 87–113%; the exact figure depends on the reference point). Moderna's market cap was only ~$25B before this, so the move is massive relative to its size.
- Merck (MRK) — climbed ~8% in premarket. Its much larger ~$333B market cap means the percentage move is smaller.
- Moderna had already run up ~113% year-to-date into yesterday's close on hopes for this shot — this was widely seen as a "make-or-break" event for the stock, and it has delivered.
What's next
- The companies haven't set a submission date for regulatory approval yet, but plan to start talking to regulators about the therapy and its safety "in the next few months."
- Full data will be presented at an upcoming international medical meeting.
- The trial keeps running to assess overall survival benefit.
- Beyond melanoma, Merck and Moderna are also testing the vaccine in non-small cell lung, bladder, and kidney (renal cell) cancers — which is partly why analysts say Moderna's valuation already reflects the hope that this platform works across multiple tumor types.
So yes — you called it, the stock is nuts right now. Moderna is the one really flying because it's much smaller and this validates the entire platform for them. Want me to pull current premarket/opening price quotes for MRNA and MRK, or look into what analysts are saying about valuation at these levels?