Who Cashes In
CVS Health CVS runs CVS Caremark, one of the three PBMs managing nearly 80% of U.S. prescription drug claims. Under the IRA's Part D redesign, plans must cover MFP-negotiated drugs on every formulary. Caremark benefits as formulary positioning shifts toward the negotiated drugs, predictably routing volume and plan-sponsor relationships through its managed channel. Separately, lower out-of-pocket caps under the IRA's redesign reduce the sticker shock that drives seniors to mail-order alternatives.
UnitedHealth Group UNH runs OptumRx, the largest PBM by claims volume, alongside UnitedHealthcare, a dominant Medicare Advantage insurer. As negotiated prices firm up the cost structure for Part D plans, large, integrated insurers with actuarial scale have a structural advantage over smaller plan sponsors pricing blind. CMS's Part D redesign shifts more catastrophic-phase liability to plans — a headwind for undercapitalized competitors, an advantage for scale players like UNH.
Vertex Pharmaceuticals VRTX holds the most insulated portfolio in large-cap pharma. Its core CFTR modulators — Trikafta and the newer Alyftrek — treat cystic fibrosis, a rare disease affecting roughly 40,000 Americans. Under the original IRA framework, drugs approved solely for a single rare disease are carved out of negotiation. The One Big Beautiful Bill Act, signed July 4, 2025, expanded that carve-out further: orphan-designated drugs treating one or more rare diseases are now fully exempt so long as they carry no non-orphan indication. Vertex has no such exposure. Its pipeline (pain, kidney disease) is early-stage; its CF franchise earns at will.
Who Is Exposed
Pfizer PFE co-markets Eliquis (apixaban) with Bristol-Myers Squibb — and Eliquis was selected in the first negotiation cohort, with MFPs taking effect January 1, 2026. Eliquis is Pfizer's largest single non-COVID revenue line. The negotiated discount off list price structurally caps the Medicare portion of what remains a primarily government-funded patient base, and each cohort adds more drugs. Pfizer's near-term pipeline does not obviously replace this gap at scale.
Novo Nordisk NVO had NovoLog and Fiasp (insulin aspart formulations) included in the first negotiation round. More ominously, the program's expansion pipeline will sweep in the GLP-1 class once those drugs clear the seven-year small-molecule clock — Ozempic received FDA approval in 2017, which means it becomes eligible for the 2025 selection cycle. Medicare Part D is a significant payer channel for semaglutide's diabetes indication. Any MFP on Ozempic represents a structural ceiling on NVO's most valuable franchise within the world's largest drug market.
What to Watch
Track CMS's annual drug selection announcements each August — they function as forward guidance on which company gets repriced next. The OBBBA's expanded orphan-drug carve-out is a material read-through for rare-disease biotechs broadly. For PFE and NVO, the negotiation clock is now a permanent feature of their revenue model, not a one-time event.
