Merck's cholesterol pill gets U.S. FDA approval

Merck said the FDA approved Lipfendra (enlicitide), the first oral PCSK9 inhibitor, making it a potential new blockbuster as Keytruda faces key patent expiry starting in 2028. The once-daily pill is supported by two late-stage trials showing significant LDL reductions across broad patient groups, including familial hypercholesterolemia and those already on statins. Scotiabank estimates peak sales could reach tens of billions of dollars, and the approval was accelerated via the FDA’s National Priority Voucher program.

Analysis

MRK is the clear strategic winner, but the real equity story is not the launch itself—it is the optionality it creates against the 2028 Keytruda cliff. If adoption is even modestly credible, this gives the market a second growth leg to underwrite a higher terminal multiple, especially if management can frame the asset as a platform rather than a one-drug event. The first re-rating window is days to weeks on sentiment; the fundamental re-rate needs 1-3 earnings cycles of prescription data and payer access.

AMGN and SNY face a slower-burn category risk rather than an immediate earnings hit. Oral convenience broadens the addressable population and could pull demand away from injectable PCSK9s in primary care, but the more important second-order effect is payer leverage: a new oral option gives PBMs a fresh anchor for rebate negotiations, which can compress economics across the class. That said, injectables still retain an edge in high-risk, high-adherence patients, so this is more likely a share and pricing headwind than a full displacement story.

The market is likely overpricing the phrase "first oral PCSK9" and underpricing execution risk. The thesis fails if formulary wins are slow, if real-world adherence is no better than existing therapies, or if the LDL-lowering signal does not translate into broad guideline adoption. In the 6-18 month window, the key question is whether this becomes a meaningful launch or just another incremental specialty-drug asset; until then, the move is more about option value on MRK and relative-pressure on AMGN/SNY than a clean earnings step-up.

Key Decisions for Investors

• Long MRK vs short AMGN on a 1-3 month horizon: express the view that MRK gets a diversification rerating while AMGN faces category share and rebate pressure; risk/reward improves if early launch commentary shows payer traction.
• Add MRK on pullbacks rather than chase the first-day reaction; the base case is narrative optionality now, with real FCF impact dependent on launch execution over 2-4 quarters.
• Use AMGN and/or SNY as relative-value shorts only if channel checks show formulary preference for the oral agent; otherwise keep sizing small because the near-term earnings impact may be limited.
• Watch the first payer/formulary updates and initial script trends as the key catalyst; if access is broad and early refill behavior is strong, raise MRK target exposure, but if access is restricted, fade the move.
• If MRK rallies to price in a multi-$10B peak-sales outcome before launch data, consider trimming and reloading after the first quarter of prescription evidence; that is the point where valuation can outrun fundamentals.