GLP-1 Off-Label Coverage 2026: MASH and Sleep Apnea Battles

The Off-Label GLP-1 Landscape in 2026

Demand for GLP-1 receptor agonists has expanded far beyond the original FDA-approved indications of type 2 diabetes and chronic weight management. In 2026, prescribers are routinely writing semaglutide and tirzepatide for cardiometabolic conditions, metabolic dysfunction-associated steatohepatitis (MASH, formerly known as nonalcoholic steatohepatitis or NASH), obstructive sleep apnea (OSA), and other obesity-driven comorbidities. Most of this prescribing remains off-label and faces significant payer friction.

The single FDA-approved expansion to date is tirzepatide (Zepbound), which received FDA approval in December 2024 for moderate-to-severe obstructive sleep apnea in adults with obesity. Every other indication beyond T2D and chronic weight management is still off-label, including the high-profile MASH use case. This matters because off-label prescribing in 2026 is no longer just a prior authorization fight — many commercial plans have moved to formulary exclusion of GLP-1s for any indication outside the FDA label, which is a fundamentally different appeal pathway.

Off-label MASH demand has surged despite the March 2024 FDA accelerated approval of resmetirom (Rezdiffra), the first MASH-specific therapy. Hepatologists are reaching for GLP-1s when patients have concurrent obesity, T2D, or cardiovascular disease, citing emerging trial data and compendia support. Plans, in turn, are tightening criteria and excluding GLP-1s from formularies entirely for non-FDA-labeled hepatic indications.

Zepbound for Sleep Apnea: The Only On-Label Win

Tirzepatide became the first GLP-1 (technically a dual GIP/GLP-1 receptor agonist) approved for a non-diabetes, non-obesity indication when the FDA approved Zepbound for moderate-to-severe OSA in obesity on December 20, 2024. Approval was based on the SURMOUNT-OSA program, two phase 3 trials showing significant reductions in apnea-hypopnea index (AHI) compared with placebo, both with and without concurrent positive airway pressure therapy.

Coverage criteria most plans have adopted post-approval require: a documented BMI of 30 kg/m² or greater, polysomnography confirming moderate-to-severe OSA (commonly AHI ≥15), and clinical notes establishing the patient is either intolerant of, non-adherent to, or has failed CPAP. Some plans add documentation of concurrent obesity counseling. Because this is now an FDA-labeled indication, coverage requests should be submitted as standard prior authorizations rather than formulary exceptions wherever Zepbound is on formulary.

Practical billing note: this approval did not extend to semaglutide-based products. Wegovy and Ozempic for OSA remain off-label, and most payers will reject coverage for sleep apnea indications written for any GLP-1 other than Zepbound. If a patient is already stable on semaglutide for weight management and has comorbid OSA, the cleanest coverage path is usually to keep the obesity indication primary rather than switch the request to OSA.

MASH (Formerly NASH) and the Formulary Battle

Most commercial and Medicare Part D plans do not cover GLP-1s for MASH. The reason is structural: resmetirom (Rezdiffra) received FDA accelerated approval in March 2024 as the first and only therapy specifically indicated for noncirrhotic MASH with moderate-to-advanced liver fibrosis (F2-F3), based on the MAESTRO-NASH trial. Plans have responded by designating Rezdiffra as the on-formulary MASH agent and excluding GLP-1s from coverage for hepatic indications.

Off-label semaglutide and tirzepatide for MASH face formulary exclusion rather than the more familiar PA denial. The clinical rationale for off-label use is real — the ESSENCE trial (semaglutide 2.4 mg in MASH) reported in 2025 showed significant improvement in steatohepatitis resolution and fibrosis stabilization compared with placebo at 72 weeks. Hepatology guidance from AASLD acknowledges GLP-1s as adjunctive options in MASH patients with obesity or T2D, particularly where Rezdiffra is contraindicated or has failed.

The practical consequence: a clean PA submission with strong clinical narrative is no longer enough. When a drug is excluded from the formulary entirely for a given indication, plans will not adjudicate it through the standard PA pathway. Practices that submit a PA on an excluded indication often see rapid administrative denials with no medical review at all, which then must be re-routed as a formulary exception request — losing days or weeks in the process.

PA Denial vs. Formulary Exclusion: A Critical Distinction

A prior authorization denial means the drug is on the formulary, but the plan determined the specific request did not meet medical-necessity criteria. PA denials are appealable through the standard internal appeal process based on medical necessity arguments, peer-reviewed evidence, and chart documentation. The medical director or designated physician reviewer evaluates the clinical case.

A formulary exclusion is different. The drug is not on the plan formulary at all for the requested indication, so there is no medical-necessity bar to clear — the gating question is whether the plan will grant a formulary exception to cover a non-formulary drug. This requires a formulary exception request, which is a distinct process with its own form, timeline, and standard. For Medicare Part D, the standard form is CMS-10146 (Request for Medicare Prescription Drug Coverage Determination), and the decision standard is whether the formulary alternative would be ineffective or cause adverse effects for this specific patient.

Confusing the two pathways is one of the most common reasons GLP-1 off-label appeals fail. If a practice files a medical-necessity appeal against a formulary exclusion, the plan will simply uphold the denial because the appeal addresses the wrong question. Always read the denial letter carefully: language like "drug is excluded from the formulary," "non-covered drug," or "not a benefit under this plan" signals an exclusion, while "does not meet medical necessity criteria" signals a PA denial.

Filing a Formulary Exception for Off-Label GLP-1 Use

A successful formulary exception request for off-label GLP-1 use follows a different structure than a standard medical-necessity appeal. The reviewer is not asking whether the drug works for this patient; they are asking whether the formulary alternatives are inadequate and whether off-label use is supported by recognized clinical evidence.

• ✓ Document why all on-label or on-formulary alternatives are inadequate — for MASH, this means addressing why Rezdiffra is contraindicated, has failed, or is inappropriate (e.g., decompensated cirrhosis, intolerance, lack of fibrosis improvement after adequate trial)
• ✓ Cite the strongest peer-reviewed evidence available — ESSENCE for semaglutide in MASH, SURMOUNT-OSA for tirzepatide in OSA, MAESTRO-NASH for the comparator landscape
• ✓ Reference compendium support for the off-label indication — DRUGDEX (Micromedex) and AHFS DI are the compendia that drive Medicare Part D off-label coverage under 42 USC § 1396r-8(g)(1)(B)(i) for Medicaid and analogous Part D rules
• ✓ File on the plan's formulary exception form, not the standard PA form — for Part D, that is CMS Form 10146; commercial plans typically have a "Formulary Exception" or "Non-Formulary Request" form distinct from the standard PA form
• ✓ Include a prescriber statement that the formulary alternative would not be as effective or would have adverse effects for this patient — this is the regulatory standard for an exception in Part D
• ✓ Mark the request as expedited if delay would seriously jeopardize health or function (24-hour decision standard for Part D expedited)

Payer-Specific Off-Label Coverage Patterns

Off-label GLP-1 coverage varies dramatically by payer category and individual plan, and patterns have shifted noticeably in 2025-2026 as plans react to MASH and OSA demand.

• ✓ UnitedHealthcare commercial — generally restricts GLP-1 coverage to FDA-labeled indications; off-label MASH and other hepatic uses typically excluded; Zepbound for OSA covered with documentation of AHI and BMI
• ✓ Cigna commercial — Coverage Policies allow compendium-supported off-label use in some categories, but recent CP updates have specifically excluded GLP-1 hepatic indications absent compendia support; OSA covered for Zepbound
• ✓ Aetna commercial — Clinical Policy Bulletins increasingly exclude GLP-1s for off-label hepatic and metabolic indications outside T2D, obesity, and the new OSA indication
• ✓ Medicare Part D — follows the statutory compendia (DRUGDEX, AHFS DI, Clinical Pharmacology) for off-label oncology and a more restrictive standard for non-oncology; Part D plans are required to consider formulary exceptions but routinely deny off-label MASH absent strong compendia citations
• ✓ Medicaid — varies dramatically by state; some state Medicaid programs cover off-label GLP-1s for documented metabolic indications, others mirror commercial restrictions; preferred drug lists (PDLs) often exclude GLP-1s for non-T2D indications entirely
• ✓ Blue Cross Blue Shield — varies by individual plan/state because each BCBS licensee maintains its own medical policy; the Federal Employee Program (FEP) Blue tends to follow FDA-labeled indications strictly

Practical Appeal Strategy for Off-Label GLP-1 Coverage

Effective off-label GLP-1 appeals lead with whatever level of regulatory and evidence support exists for the specific indication, then layer patient-specific medical necessity on top.

For OSA, the strategy is straightforward: lead with the FDA approval of Zepbound for moderate-to-severe OSA in obesity, document BMI ≥30 and the polysomnography AHI, attach the sleep study report, and address CPAP history. Because this is on-label, the appeal should follow the standard medical-necessity pathway and frame the case to the plan's published OSA criteria.

For MASH, the appeal is harder because there is no FDA approval to lead with. The strongest structure is: (1) cite ESSENCE trial outcomes and the AASLD guidance acknowledging GLP-1s as an option in MASH with obesity or T2D, (2) document why resmetirom is inappropriate for this specific patient (failed prior course, contraindication, lack of fibrosis benefit), (3) attach fibrosis staging evidence (FibroScan, MRE, or biopsy showing F2-F3), and (4) connect the GLP-1 to a covered comorbidity such as T2D, obesity, or established cardiovascular disease so the request also stands on a labeled indication. Always exhaust internal appeals before external review — most plans require this and will reject external review requests filed prematurely.

When to Give Up vs. Escalate to External Review

Independent external review through a state-administered Independent Review Organization (IRO) overturns roughly 40% of denials nationally, and rates are higher for specialty drugs with strong clinical evidence. For off-label GLP-1 appeals, external review is most worth pursuing when there is a coherent, well-documented clinical case that an outside physician reviewer can evaluate against published evidence.

For MASH specifically, the cases worth escalating to external review typically share three features: documented F2-F3 fibrosis (by biopsy, MRE, or FibroScan), documented inadequate response to or contraindication for resmetirom, and a covered comorbidity (obesity with BMI ≥30, T2D, or cardiovascular disease) that the GLP-1 also addresses. Cases without these features rarely succeed at IRO because the reviewer has limited grounds to override a formulary exclusion when the on-label MASH alternative has not been adequately tried.

For OSA, external review is rarely necessary because the indication is FDA-approved and most denials are correctable at the internal appeal level by supplying complete polysomnography and BMI documentation. If a Zepbound OSA denial is upheld through internal appeal despite complete documentation, that is usually a signal to file external review with the full sleep study and a clear policy citation. RxCheckUp's appeal workflow flags formulary-exclusion denials separately from medical-necessity denials, routes them to the correct exception form, and pulls the matching compendium and trial citations automatically — avoiding the most common procedural errors that derail off-label GLP-1 appeals.