Merck & Co Stock Price, News & Analysis

Zydus Lifesciences and Formycon entered an exclusive partnership on Dec 9, 2025 for the licensing and supply of FYB206, a biosimilar to Keytruda (pembrolizumab), for the USA and Canada.

Formycon will develop, register, manufacture and supply FYB206 while Zydus Lifesciences Global FZE will handle commercialization in the defined territories. A BLA application is expected to be submitted to the US FDA in the near future. The announcement notes this marks Zydus' entry into the North American biosimilar market and references a proposed acquisition of Agenus manufacturing facilities in California to support future manufacturing integration.

Merck (NYSE:MRK) announced that the FDA granted conditional approval on December 4, 2025 for EXZOLT CATTLE-CA1 (fluralaner topical solution), an isoxazoline pour-on for prevention and treatment of New World screwworm larvae and treatment/control of cattle fever tick.

The product is approved for beef cattle ≥2 months and replacement dairy heifers <20 months, has a 98-day meat withdrawal, is prescription-only, and is conditionally approved under application 141-617 pending full effectiveness data. Commercial availability in 1 L and 5 L sizes is planned for Q1 2026. Recent market authorization was also received in Mexico.

Merck (NYSE: MRK) will present first-in-human data for two Alzheimer’s candidates, MK-2214 and MK-1167, at CTAD 2025 in San Diego, Dec 1–4, 2025.

MK-2214 is a novel antibody targeting phosphorylated serine 413 (pS413) tau; Merck reported Phase 1 safety, tolerability and pharmacokinetics from three studies and said those results informed an ongoing Phase 2 trial (NCT07033494). The U.S. FDA granted Fast Track designation to MK-2214 for Alzheimer’s disease.

MK-1167 is an oral positive allosteric modulator of the α7 nicotinic receptor; Merck presented Phase 1 proof-of-biology data on glutamate metabolism that informed Phase 2 dose selection (NCT06721156).

Merck (NYSE: MRK) said Chirfi Guindo, chief marketing officer, Human Health, and Dr. Eliav Barr, senior vice president and chief medical officer, Merck Research Laboratories, will take part in a fireside chat at the Citi 2025 Global Healthcare Conference on Wednesday, Dec. 3, 2025 at 1:00 p.m. ET.

Investors, analysts, media and the public may listen to a live audio webcast of the presentation via the company's provided weblink.

Merck (NYSE: MRK) announced that Chirfi Guindo, chief marketing officer, Human Health, and Dr. Eliav Barr, senior vice president, head of global clinical development and chief medical officer, Merck Research Laboratories, will participate in a fireside chat at the 8th Annual Evercore ISI HealthCONx Conference on Tuesday, Dec. 2, 2025 at 9:10 a.m. ET.

Investors, analysts, media and the public are invited to listen via a live audio webcast accessible through the company’s investor relations webcast page.

Merck (NYSE: MRK) will present new hematology data at the American Society of Hematology (ASH) Annual Meeting, Dec. 6-9, 2025, in Orlando.

More than 20 abstracts cover multiple malignancies and investigational programs including MK-1045 (CD19xCD3 T-cell engager), bomedemstat (LSD1 inhibitor) and nemtabrutinib (non-covalent BTK inhibitor), plus updated results for zilovertamab vedotin (ROR1 ADC).

Highlights include first presentations of updated Phase 1b/2 MK-1045 results (Abstract #647), first-time Phase 2 bomedemstat Shorespan-004 data in polycythemia vera (Abstract #83), and exploratory nemtabrutinib genomic analyses from BELLWAVE-003 (Abstract #797).

Merck (NYSE: MRK) said it was notified of an unsolicited mini-tender from Tutanota dated November 10, 2025, to buy up to 1,000,000 shares at $65.00 per share.

The company noted the offer price is about 24.66% below the Nov 7, 2025 close ($86.28) and about 31.56% below the Nov 20, 2025 close ($94.97), and recommended shareholders reject and not tender their shares. Merck warned the offer is subject to conditions including Tutanota obtaining financing, is not associated with Merck, and cited SEC guidance that mini-tenders may sell shares below market prices. The offer currently expires at 5:00 p.m. EST on December 15, 2025.

Merck (NYSE: MRK) announced FDA approvals on November 21, 2025 for KEYTRUDA (pembrolizumab) and KEYTRUDA QLEX (pembrolizumab + berahyaluronidase alfa) each in combination with Padcev (enfortumab vedotin) as perioperative therapy for adults with cisplatin-ineligible muscle-invasive bladder cancer (MIBC).

Approvals follow Phase 3 KEYNOTE-905 (EV-303): EFS HR=0.40 (60% reduction), OS HR=0.50 (50% improvement), and a pCR rate 57.1% vs 8.6%. The regimens are the first PD-1 inhibitor plus ADC options for this patient group.

Merck (NYSE: MRK) reported topline Phase 3 results for the investigational once-daily oral two-drug single-tablet doravirine/islatravir (DOR/ISL 100 mg/0.25 mg) in treatment-naïve adults with HIV-1.

The trial met its primary efficacy endpoint at Week 48, showing non-inferiority on the proportion with HIV-1 RNA <50 copies/mL versus bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF), and met the primary safety objective with a comparable safety profile. Merck plans detailed data presentation at a scientific congress and regulatory submissions.

The FDA accepted an NDA for DOR/ISL for use to replace current regimens in virologically suppressed adults and set a PDUFA target action date of April 28, 2026.