Published: November 11, 2025
At a glance (today)
- FDA clears a new companion diagnostic tied to Keytruda/Lenvima for endometrial cancer, adding a fresh clinical utility angle to Merck’s immuno‑oncology franchise. 1
- New early‑phase data presented at SITC show encouraging results for STK‑012 plus Keytruda in first‑line PD‑L1‑negative NSCLC (notoriously tough to treat). 2
- MRK shares were among the Dow’s biggest contributors intraday, up ~3.9% at one point; the stock is also riding a six‑session win streak, its longest since August if it holds. 3
- Sector backdrop: a Bloomberg feature out today highlights a wave of oncology “combo” spending—frequently involving Keytruda—that may outpace proof of longer survival benefits. 4
Market move: MRK helps lead the Dow’s advance
By early afternoon Tuesday, Merck & Co. (NYSE: MRK) shares were up about 3.9%, helping lead the Dow Jones Industrial Average higher; Nike and Merck together contributed an estimated ~36 points to the index’s ~386‑point climb at that time. 3
In a separate Data Talk update, MRK was up for a sixth straight session, putting it on pace for its longest winning streak since August and tracking toward its highest close since Oct. 1—contingent on late‑day trading. 5
Regulatory update: FDA okays Promega’s OncoMate® MSI Dx as a Keytruda/Lenvima companion test
What happened: The FDA approved Promega’s OncoMate® MSI Dx Analysis System as a companion diagnostic to identify microsatellite‑stable (MSS) endometrial cancer patients who may be appropriate for Keytruda (pembrolizumab) + Lenvima (lenvatinib)—an already approved regimen with durable survival benefits in this setting. OncLive reported the clearance today, citing Promega’s official announcement. 1
Why it matters for Merck: Companion diagnostics sharpen patient selection and can reinforce adoption of approved drug combinations by clarifying who benefits most—especially important in MSS endometrial carcinoma, where single‑agent immunotherapy typically underperforms. Today’s test clearance therefore adds a fresh clinical utility touchpoint to Merck/Eisai’s regimen and could support continued use patterns in real‑world practice. 1
Clinic watch: STK‑012 + Keytruda combo posts promising early data in PD‑L1‑negative NSCLC
New data presented at SITC 2025 (Nov. 8) and covered today show STK‑012 (an IL‑2 pathway modulator) plus Keytruda + chemotherapy delivered a 57% overall response rate and 90% disease control rate in efficacy‑evaluable patients with first‑line, PD‑L1‑negative nonsquamous NSCLC—a hard‑to‑treat population that often includes STK11/KEAP1 alterations. Safety looked manageable, with no grade 5 events and one grade 4 case of neutropenia reported. 2
Takeaway: While early and small, these results sustain interest in rational immuno‑oncology combinations that might convert “immune‑cold” tumors into responders—an area central to extending Keytruda’s reach as the drug approaches loss of exclusivity later in the decade. 2
The bigger picture: Combo fever—and a caution flag
A Bloomberg feature out today describes a surge in spending on combination regimens (often pairing cornerstone agents like Keytruda with other therapies, such as anti‑VEGF drugs) despite limited proof of longer overall survival so far. The piece underscores both the commercial momentum and the evidence bar that payers and regulators will increasingly scrutinize—context highly relevant to Merck’s long‑term oncology strategy. 4
Background context for investors
- Q3 2025 scorecard: Merck beat consensus on revenue and EPS, with Keytruda sales at ~$8.1B for the quarter, though the company nudged full‑year guidance and flagged regional Gardasil dynamics. These late‑October results still frame investor expectations as 2025 winds down. 6
- Upcoming EU decision on subcutaneous Keytruda: After a September CHMP positive opinion, European Commission decisions are expected in Q4 2025 on a subcutaneous formulation that could streamline clinic operations (following the US approval in September). Any pan‑EU nod would be a practical adoption catalyst for Keytruda in busy infusion centers. 7
What to watch next
- Commercial impact of the new companion diagnostic in endometrial cancer clinics and whether labs rapidly operationalize OncoMate MSI testing for Keytruda/Lenvima selection. 1
- Follow‑up cohorts/phase 2 for STK‑012 + Keytruda in PD‑L1‑negative NSCLC to see if response durability and overall survival signals hold in larger, randomized settings. 2
- Any EC action on subcutaneous Keytruda by year‑end, which would add administration flexibility and potentially improve patient throughput across EU oncology centers. 7
Frequently asked questions
Why is MRK stock up today?
Intraday, Merck was among the Dow’s biggest contributors, with shares up roughly 3.9% at one point; it’s also on a six‑day win streak, the longest since August if it holds through the close. The day’s Keytruda‑linked diagnostic approval and fresh combo data coverage add supportive headlines against a broader market upswing. 3
What exactly did the FDA approve?
Not a new drug label—a companion diagnostic. The OncoMate® MSI Dx test can help identify appropriate MSS endometrial cancer patients for Keytruda + Lenvima, an already approved regimen. Better targeting can reinforce clinical use and optimize outcomes. 1
How meaningful is the SITC data for Keytruda?
It’s early‑phase, so treat it as signal‑finding. Still, a 57% ORR and 90% DCR in PD‑L1‑negative disease—plus tolerability without hallmark IL‑2 toxicities—justify moving to randomized phase 2 to test durability and survival impact. 2
What’s the near‑term European catalyst?
A potential EU authorization for subcutaneous Keytruda following the CHMP’s September positive opinion; decisions were telegraphed for Q4 2025. A green light could ease clinic bottlenecks versus IV infusions. 7
Editor’s note
This article focuses on news dated November 11, 2025 and includes brief, clearly labeled context from prior weeks to orient readers. Merck & Co., Inc. (known as MSD outside the US and Canada) is distinct from Merck KGaA of Darmstadt, Germany. This report is for information only and not investment advice.
Sources: MarketWatch Data News; Morningstar/Dow Jones; OncLive; Promega; Targeted Oncology; Bloomberg; Reuters. 3
