Better Buy in 2026: Pfizer or Merck?

Merck and Pfizer are positioned to face looming patent cliffs—Pfizer’s top seller Eliquis will lose exclusivity in the next few years and Merck’s Keytruda faces a patent cliff by 2028—but Merck currently presents stronger fundamentals. Merck’s Keytruda subcutaneous formulation, recent launches (Winrevair with a >$1B revenue run rate, Capvaxive) and a pipeline addition (CD388) help offset near-term headwinds such as softer Gardasil sales in China, while Pfizer is advancing MET-097i (promising GLP‑1, phase 2) and PF‑4404 (cancer, phase 3) and pursuing cost cuts plus a three‑year tariff exemption tied to lower U.S. prices. Relative valuation/dividend tradeoffs are noted (Pfizer forward yield ~6.5% vs Merck ~3.4%; healthcare sector forward P/E ~17.8), and the author concludes Merck is the better near‑term buy given margins, dividend growth and clearer mitigation plans for its patent risk.

Analysis

Market structure: Merck (MRK) is positioned to be a near-term winner because subcutaneous Keytruda and recent launches (Winrevair, Capvaxive, CD388) materially raise its ability to defend pricing and share as biosimilars appear; Pfizer (PFE) faces a nearer patent cliff on Eliquis and needs MET-097i/PF-4404 to scale, so market-share shifts over 2026–2029 will favor firms that convert launches into >$1–5B revenue streams. Supply/demand: biosimilar entrants increase therapeutic supply and compress prices for incumbents unless delivery or label innovations (MRK SC) preserve demand; for obesity and oncology, innovative dosing or multi-indication drugs can sustain higher price elasticity. Cross-asset: expect MRK credit spreads to tighten modestly and PFE spreads to widen if guidance weakens; options vol for both will spike around phase‑3 readouts and patent rulings; modest USD moves only if large cash-flow surprises hit.

Risk assessment: tail risks include phase‑3 failure for MET‑097i/PF‑4404 (PFE), accelerated biosimilar approvals pre‑2028, or US pricing policy changes that cut drug margins by >10–20%. Timing: immediate (days) — earnings/analyst revisions; short (1–6 months) — launch uptake and tariff/pricing policy developments; long (12–36 months) — patent expiries and full revenue impact. Hidden dependencies: China Gardasil recovery and payer formulary decisions will disproportionately move MRK sales by ±10–25%. Key catalysts: MRK label expansions, PFE phase‑3 readouts, and FDA biosimilar approvals.

Trade implications: directional preference is long MRK vs underweight PFE. Practical trades: buy MRK LEAPS (Jan‑2026) calls or shares sized 2–4% portfolio, hedge PFE tail risk with 6–12 month puts sized 1–2%. Pair trade: long MRK equity/LEAPS and short PFE via puts or 1–2% notional to express relative outperformance over 12–24 months. Entry window: initiate within 2–6 weeks, trim at +25–35% or on adverse catalyst; hard stop loss 10–12% per leg.

Contrarian angles: consensus underestimates Pfizer's downside protection — a 6.5% dividend and a 3‑year tariff exemption create a cash floor that can limit downside to ~15–20% in a severe sale; MET‑097i long‑acting profile could command premium pricing if safety differentiates it, meaning PFE may be underpriced for a positive readout. Historical parallels: prior large‑cap lifecycle management (e.g., route/formulation changes) preserved >50% of pre‑biosimilar revenues for incumbents. Unintended consequence: SC Keytruda could expand total addressable market via higher clinic throughput, increasing volume even as unit price faces biosimilar pressure.

Key Decisions for Investors

• Establish a 3% long position in MRK (shares or equivalent LEAPS Jan‑2026 calls ~15–25% OTM) as a 12–24 month core biotech-defensive growth trade; target +25–35% upside, trim half at +30%, stop-loss at -12%.
• Implement a pair trade: long MRK (2–3% notional) and short PFE (1–2% notional) via buying PFE 6–12 month puts 5–10% OTM to express relative strength into 2026 patent/launch cycle; reassess after major phase‑3 readouts or biosimilar approvals.
• Allocate up to 2% to PFE for income by buying shares and selling 1–3 month covered calls to boost yield, but concurrently purchase 6–9 month PFE puts 7–12% OTM as tail protection; unwind or add if MET‑097i phase‑3 surprises positive/negative.
• Buy MRK Jan‑2026 LEAPS calls (or 12–18 month call spreads to limit premium) sized to equal 1–2% portfolio risk for asymmetric upside on label expansions (Winrevair, CD388); add another tranche on any pullback >10%.