A patient with inflammatory bowel disease has been stable on IV infliximab, covered under the medical benefit, for three years. Their gastroenterologist wants to switch them to subcutaneous infliximab to reduce treatment failure and improve convenience. The Subcutaneous Infliximab Switch Study (SISS), presented at Digestive Disease Week 2026, showed that switching from IV to subcutaneous infliximab reduced treatment failure from 39.6% to 14.6% at 48 weeks.
But when the prescription is sent to the pharmacy, the claim is rejected. The drug is not covered under the pharmacy benefit. The patient's plan requires all self-administered drugs — including this new subcutaneous formulation — to go through the pharmacy benefit, where it faces a different prior authorization process, a different formulary tier, a specialty pharmacy mandate, and possibly a copay accumulator. The patient's years of medical-benefit stability do not transfer.
This article covers why route-of-administration changes can shift a drug between benefit channels, what coverage surprises result, and how access teams should prepare.
How benefit channel is determined by route of administration
The general rule
In most commercial and Medicare plans, the benefit channel is determined by who administers the drug:
- Medical benefit: Drugs administered by a healthcare provider in a clinical setting — infusions in a hospital outpatient department, physician office, or infusion center. These drugs bill under HCPCS J-codes on a CMS-1500 or UB-04 claim form.
- Pharmacy benefit: Drugs self-administered by the patient at home — oral medications, subcutaneous injections, inhalers, and topical therapies. These drugs bill under NDC codes through the PBM's claims adjudication system.
The California Health Benefits Review Program's 2026 analysis of pharmacy benefit coverage in state-regulated health insurance confirmed that pharmacy benefits "cover outpatient prescription drugs by covering scripts that are generally filled at a retail pharmacy, a mail-order pharmacy, or a specialty pharmacy," while biological drugs "administered under the supervision of a physician" are covered through the medical benefit.
When the boundary shifts
The boundary is not always fixed. A drug can move from medical to pharmacy benefit when:
- The manufacturer introduces a subcutaneous formulation of a drug previously available only as an IV infusion (e.g., Keytruda Qlex, a subcutaneous formulation of pembrolizumab approved September 2025)
- A provider trains the patient to self-administer a drug that was previously office-administered (e.g., subcutaneous immune globulin after IV immune globulin)
- The plan or PBM implements a site-of-care edit that reclassifies certain self-injectable drugs from medical to pharmacy benefit
- The plan changes its benefit design to move a drug from one channel to another for cost reasons
SmithRx's 2026 pharmacy benefits trend report described the trend: "More companies will utilize medical data to move high-cost, provider-administered J-Code drugs off opaque medical benefit plans and onto more transparent, manageable pharmacy benefits."
Coverage surprises when a drug shifts benefit channels
Prior authorization resets
Prior authorization criteria differ between medical and pharmacy benefit. A drug that was approved under the medical benefit may require a completely new PA when it moves to the pharmacy benefit — with different forms, different documentation requirements, and different review timelines.
The CMS proposed rule on interoperability and prior authorization standards (published April 2026) acknowledged this gap and proposed requiring impacted payers to expand their Prior Authorization API to incorporate drugs covered under a medical benefit, with an October 2027 compliance date. Until then, the two benefit channels operate on separate PA workflows.
For patients switching from IV to subcutaneous formulations, this means:
- A new PA submission is required even though the active ingredient is identical
- The PA reviewer may be a different team (pharmacy benefit PA vs. medical benefit PA)
- Approval criteria may differ (e.g., the pharmacy benefit may require documented failure of the IV formulation, while the medical benefit may not)
Formulary exclusion risk
A drug covered on the medical benefit formulary may not appear on the pharmacy benefit formulary at all, or may appear at a different tier. PSG's 2026 Trends in Specialty Drug Benefits Report found that while 93% of respondents receive rebates under the pharmacy benefit, only 51% receive rebates under the medical benefit. This structural asymmetry means that formulary decisions are made by different committees with different cost considerations.
A subcutaneous formulation moving to the pharmacy benefit may encounter:
- Formulary exclusion: The drug may not be on the PBM's formulary at all, requiring a non-formulary exception request
- Higher tier placement: The drug may be placed on a higher copay tier under the pharmacy benefit than it occupied under the medical benefit
- Step therapy requirements: The pharmacy benefit may require the patient to try a preferred alternative before the new formulation is covered, even if the patient has been stable on the IV version
Copay accumulator and maximizer exposure
Medical benefit drugs are generally not subject to copay accumulator programs, which operate through the pharmacy claim transaction. When a drug moves from medical to pharmacy benefit, the patient's copay assistance card suddenly becomes visible to accumulator and maximizer programs.
The AIDS Institute's 2026 report, "Shortchanged," documented the financial impact: in one scenario, a copay accumulator nearly doubled the amount collected by the insurer/PBM — from $8,550 to $15,160 — by preventing copay assistance from counting toward the patient's out-of-pocket maximum.
For a patient switching from an IV biologic (no accumulator exposure) to a subcutaneous formulation (pharmacy benefit, accumulator active), the financial impact can be severe: manufacturer copay assistance that previously functioned as a bridge to out-of-pocket maximum protection now serves only as a short-term cost offset.
Specialty pharmacy mandate
Many PBMs require that pharmacy-benefit specialty drugs be dispensed through the PBM's preferred specialty pharmacy network. A patient who was receiving IV infusions at their physician's office or local infusion center may suddenly be required to switch to a mail-order specialty pharmacy for the subcutaneous formulation.
UnitedHealthcare's April 2026 medical benefit specialty drug update bulletin listed numerous drugs with prior authorization and notification requirements that differ between the medical and pharmacy benefit channels. A drug that was seamlessly approved under the medical benefit may face a 5-15 business day PA turnaround when routed through the pharmacy benefit specialty pharmacy.
Deductible and out-of-pocket tracking disruption
Medical benefit claims and pharmacy benefit claims track toward the patient's deductible and out-of-pocket maximum on different timelines. A patient who has nearly met their annual out-of-pocket maximum through IV infusions under the medical benefit may find that their pharmacy benefit deductible is untouched when the drug switches to the pharmacy benefit.
As LUX Infusion's analysis explained: "Under the pharmacy benefit, associated out-of-pocket costs are immediately applied toward the deductible and max out-of-pocket. Under the medical benefit, the claim submitted by the provider's office undergoes review before it is approved. This can take time, and associated out-of-pocket expenses take longer to be applied."
Specific drugs at risk for benefit channel shifts
IV-to-subcutaneous switches
Several high-profile drug transitions illustrate the benefit channel shift problem:
- Infliximab: The SISS trial at DDW 2026 demonstrated significant benefits of switching from IV to subcutaneous infliximab, but the subcutaneous formulation routes through the pharmacy benefit while the IV version bills under the medical benefit.
- Pembrolizumab (Keytruda Qlex): The subcutaneous formulation, approved September 2025, is a fixed-dose injection administered over approximately 3 minutes compared to 30-minute IV infusion. UHC's April 2026 bulletin added Keytruda Qlex as a non-preferred product for certain oncology indications, with different PA requirements than IV Keytruda.
- Nivolumab (Opdivo Qvantiq): Similarly, the subcutaneous formulation was added as a non-preferred product with different PA criteria than the IV version.
- Immune globulin: CMS drug fee schedules for 2025 include separate JB (subcutaneous) modifier codes for immune globulin products, indicating that the same drug can bill differently depending on route of administration.
Drugs with dual-route availability
Some drugs are available in both IV and subcutaneous formulations, creating a permanent benefit channel ambiguity:
- Ustekinumab (Stelara) and biosimilars: CMS's self-administered drug exclusion list notes that ustekinumab biosimilars (Imuldosa, Steqeyma, Yesintek) should use modifier JA for IV administration and JB for subcutaneous administration, with subcutaneous injection "considered self-administered." This designation routes the subcutaneous version to the pharmacy benefit.
- Vedolizumab (Entyvio): Available as both IV infusion and subcutaneous injection. The subcutaneous formulation routes through the pharmacy benefit with different PA criteria.
How access teams should prepare
Proactive benefit verification before route switches
Before switching a patient from an IV to a subcutaneous formulation, the prescriber's office or hub team should:
- Verify benefit channel: Confirm which benefit (medical or pharmacy) will cover the new formulation. Do not assume it will follow the same channel as the IV version.
- Check formulary status: Determine whether the subcutaneous formulation is on the pharmacy benefit formulary, at what tier, and with what PA requirements.
- Assess accumulator/maximizer exposure: Determine whether the plan uses copay accumulator or maximizer programs for the pharmacy benefit, and whether the state's accumulator ban (if any) applies to the patient's plan type.
- Calculate out-of-pocket impact: Model the patient's cost-sharing under both benefit channels, including deductible status and progress toward the annual out-of-pocket maximum.
- Confirm specialty pharmacy routing: If the pharmacy benefit requires a specialty pharmacy, confirm that the drug is in stock and that PA can be completed before the next scheduled dose.
Plan document language review
For patients enrolled in ERISA-governed self-funded plans, the summary plan description (SPD) governs benefit channel assignment. Access teams should request the SPD to determine:
- Whether the plan defines benefit channel by route of administration, by FDA-approved labeling, or by plan discretion
- Whether the plan has a specific provision for drugs available in multiple formulations
- Whether the plan's appeals process allows challenges to benefit channel assignment
Appeal strategies for benefit channel disputes
When a drug is moved from medical to pharmacy benefit and coverage is denied or restricted:
- Medical necessity appeal: Argue that the route-of-administration change is medically appropriate and that the active ingredient is identical to the previously approved drug.
- Continuity-of-care argument: Many plans have continuity-of-care provisions that allow continued coverage during a transition period, even if the new formulation would not otherwise meet PA criteria.
- State law protections: Some states have laws restricting nonmedical switching. California's SB 1094, analyzed by the California Health Benefits Review Program in April 2026, addresses pharmacist-initiated and plan-initiated prescription switches.
- External review: Under ACA requirements, patients in non-grandfathered plans can request external review by an independent review organization when a denial involves medical judgment.
Sources
- GI and Hepatology News, "Switching to Subcutaneous Infliximab May Cut Treatment Failure in IBD." https://news.gastro.org/issues/2026/may-2026/switching-to-subcutaneous-infliximab-cuts-treatment-failure-in-ibd
- CMS, "Self-Administered Drug Exclusion List." https://www.cms.gov/medicare-coverage-database/view/article.aspx?articleid=52527
- UnitedHealthcare, "Medical Benefit Specialty Drug Update Bulletin: April 2026." https://www.uhcprovider.com/content/dam/provider/docs/public/resources/news/2026/sdub/med-benefit-specialty-drug-update-bulletin-april-2026.pdf
- Federal Register, "Medicare and Medicaid Programs; Interoperability Standards and Prior Authorization (Proposed Rule, April 2026)." https://www.federalregister.gov/documents/2026/04/14/2026-07205/medicare-and-medicaid-programs-patient-protection-and-affordable-care-act-interoperability-standards
- Pharmaceutical Strategies Group, "2026 Trends in Specialty Drug Benefits Report." https://www.psgconsults.com/press-release/psg-report-finds-cost-management-remains-payers-top-goal-as-coverage-strategy-for-new-drugs-and-indications-emerges-as-biggest-specialty-drug-management-challenge
- The AIDS Institute, "Shortchanged: The Patient Impact of Copay Accumulator Policies in 2026." https://theaidsinstitute.org/media/documents/02-27-2026-09-23-55-TAI_2026_Report_final.pdf
- LUX Infusion, "Understanding Specialty Drug Coverage: Medical vs Pharmacy Benefit." https://luxinfusion.com/understanding-specialty-drug-coverage-medical-and-pharmacy-benefit
- SmithRx, "Pharmacy Benefits Shakeup: 2026 Trends and Predictions." https://smithrx.com/blog/2026-pharmacy-benefits-trends-and-predictions
- California Health Benefits Review Program, "Pharmacy Benefit in State-Regulated Health Insurance (Projecting 2027)." https://www.chbrp.org/sites/default/files/2026-04/Pharmacy%20Benefit%20in%20State-Regulated%20Health%20Insurance%20%28projecting%202027%29%207April2026%20-%20FINAL_0.pdf
- Mintz, "PBM Policy and Legislative Update — Spring 2026." https://www.mintz.com/insights-center/viewpoints/2026-04-22-pbm-policy-and-legislative-update-spring-2026
- MedPath Trial, "High-Dose Subcutaneous Biologics Set to Transform Drug Delivery." https://trial.medpath.com/news/high-dose-subcutaneous-biologics-set-to-transform-drug-delivery-as-industry-shifts-from-iv-administration
