How Express Scripts’ 2026 National Preferred Formulary handles Mounjaro and Zepbound after FDA’s expanded sleep-apnea indication approval
Q: Why are Mounjaro and Zepbound being reconsidered for 2026 formulary placement?
The U.S. Food and Drug Administration’s 2025 approval of new obesity-related indications started this shift. The agency broadened the label for tirzepatide, marketed as Mounjaro (for type 2 diabetes) and Zepbound (for chronic weight management), to include moderate to severe obstructive sleep apnea (OSA) in adults with obesity. It marked the first time any GLP‑1/GIP agonist carried a direct OSA indication. Because Express Scripts recalibrates its National Preferred Formulary (NPF) each plan year based on updated clinical and economic factors, that new label meaningfully changed the coverage calculus heading into 2026.
Q: How did Express Scripts classify these drugs before the new indication?
During 2025, both tirzepatide products held preferred specialty brand placement in most commercial NPF segments but had to step through generic semaglutide for diabetes claims. Prior authorization required either a type 2 diabetes diagnosis (Mounjaro) or a BMI of at least 30, or 27 with a comorbidity, for Zepbound. Sleep apnea didn’t count. Average coinsurance was roughly 30% after deductible, though a growing share of large employers capped monthly out‑of‑pocket costs between $90 and $150 depending on tier structure.
Q: What specific changes have been made for the 2026 Express Scripts NPF?
When Express Scripts posted its 2026 NPF update in February, three moves stood out. Zepbound (tirzepatide, Eli Lilly) stays a preferred brand for weight management and is now recognized for OSA coverage when certain BMI thresholds are met. Mounjaro (the same molecule) remains preferred for diabetes but explicitly excluded for OSA or weight‑loss use. And the PA rules got tighter: documentation must include an apnea‑hypopnea index (AHI) of at least 15 events per hour, evidence of attempted positive‑airway‑pressure therapy, plus weight‑reduction goals reviewed at six‑ and twelve‑month intervals. Express Scripts pointed to its “evidence‑first access” framework as the reasoning.
| Product | Generic Name | Indicated Use on Formulary (2026) | Formulary Tier | PA/Step Requirements |
|---|---|---|---|---|
| Mounjaro | tirzepatide | Type 2 diabetes mellitus | Preferred Brand (Tier 3) | PA for diagnosis; step through metformin |
| Zepbound | tirzepatide | Weight management and OSA in adults with obesity | Preferred Brand (Tier 3) | PA for BMI, AHI score, and prior lifestyle/CPAP attempt |
Q: How do these changes differ from other major PBMs?
CVS Caremark and OptumRx treat tirzepatide about the same on price tiering but diverge on usage. CVS’s 2026 reference formulary accepts OSA diagnoses (G47.33 or G47.30) tied to obesity for Zepbound reimbursement. OptumRx still excludes coverage for OSA pending more cost‑effectiveness data. Express Scripts moved first, something it’s often done when it can rebate structures to secure early placement across employer and plan clients.
Q: What factors drove Express Scripts’ 2026 decision?
Three forces stood out. Clinical data from Eli Lilly’s SURMOUNT‑OSA trials (2025) showed roughly a 60% cut in AHI compared with placebo, which CMS later cited in its own evidence brief. Employer appetite for alternatives to CPAP intolerance and bariatric surgery claims accelerated demand. Plus, even though the Inflation Reduction Act’s drug‑price negotiations don’t touch commercial markets yet, PBMs sensed more and pressed for bigger manufacturer rebates this year. Hard to miss the timing.
Q: How does coverage work under Medicare Part D or Medicare Advantage plans in 2026?
No change under Part D, Medicare still bars weight‑loss drugs from statutory coverage, and CMS hasn’t extended negotiation power to that category. Some Medicare Advantage carriers, however, have added supplemental lifestyle benefits. By March 2026, KFF found 17% of major regionals offering partial Zepbound reimbursement when OSA is documented. Mounjaro remains covered solely for glycemic control under diabetic claims. So far, pretty narrow access if you’re using federal benefits.
Q: How are commercial employers expected to respond?
Benefit managers are doing the math. Short‑term drug spend will rise, but fewer OSA‑related absences and hospitalizations might offset that later. Express Scripts projects an average 0.3% plan‑cost bump in 2026 if just 2% of members start Zepbound for OSA. Its own internal model shows hospitalization costs tapering after about a year. Employers with outcomes‑based rebates could recoup expenses if member AHI scores actually fall. Some have already linked copay support to documented improvement, it’s a carrot‑and‑stick approach, depending on your angle.
Q: What are PBM clients concerned about?
Paperwork. The new PA forms ask for input from sleep doctors, PCPs, and DME vendors. Pharmacists worry about the tech side, Express Scripts is testing a more connected verification process through its Accredo specialty interface, but most systems still use manual uploads. Expect some first‑fill delays, especially midyear when plans refresh rosters. That’s the trade‑off when payers chase precision utilization.
Q: Will these formulary moves affect pricing or patient affordability?
List prices haven’t budged since late 2025: about $1,069 for Zepbound and $1,023 for Mounjaro per four‑week carton. Employers on the NPF usually end up paying 35% to 55% less after rebates. Patient costs still hinge on their plan design. For commercial members, Zepbound’s copay card can drop costs to $25 a month, but not if you’re on government insurance. As of April 2026, Express Scripts hasn’t rolled out OSA‑specific patient‑assistance tweaks. Maybe they’re waiting to see real‑world uptake first.
Q: What should patients and clinicians do next?
Patients with obesity‑related OSA should check whether their employer’s plan mirrors Express Scripts’ national template or uses its own carve‑out. Clinicians need to have the OSA diagnosis and CPAP trial notes ready before submitting prescriptions. Pharmacists can confirm tier status in the PBM portal. And since coverage rules keep shifting as fresh OSA outcome data come in, it’s worth rechecking formulary listings every few months. Don’t assume this year’s form will still be valid next one.
Disclaimer: This article is for informational purposes only and does not provide medical advice, insurance underwriting guidance, or legal interpretation. Coverage terms depend on your specific plan documents and insurer decisions. Always confirm with both your prescriber and benefits administrator before making therapy or coverage choices.