How CVS Caremark and Express Scripts are positioning Stelara biosimilars ahead of FDA's ustekinumab interchangeability decision

How CVS Caremark and Express Scripts are positioning Stelara biosimilars ahead of FDA’s expected ustekinumab interchangeability decision in late 2024

Data first: Ustekinumab, marketed as Stelara® by Janssen Biotech, pulled in over $8.1 billion in U.S. sales in 2023, according to Johnson & Johnson’s annual report. Several biosimilars, Wezlana™ (ustekinumab‑aekn, Amgen) and Selarsdi™ (ustekinumab‑ajvy, Alvotech/Teva), received FDA approval in late 2023 and early 2024. The Food and Drug Administration expects to finalize interchangeability designations for at least one of them by late 2024, a change that could quickly reshape how PBMs handle high‑cost autoimmune drugs.

The commercial significance of ustekinumab

Stelara is an injectable monoclonal antibody targeting interleukins 12 and 23. It’s prescribed for plaque psoriasis, psoriatic arthritis, Crohn’s disease, and ulcerative colitis. The average wholesale price (AWP) for a single 90‑mg syringe exceeds $15,000. Specialty drugs dominated pharmacy benefit costs in 2023, an estimated 55%, per CVS Health’s Drug Trend Report, and Stelara’s price tag makes it an obvious target for biosimilar competition.

Patent protection for ustekinumab expired in the European Union in 2024 and ends in the United States in January 2025. That countdown drives PBM strategies. CVS Caremark and Express Scripts have already started negotiating with biosimilar manufacturers months ahead of the FDA’s final call on interchangeability.

Expected FDA action on interchangeability

The FDA declares a biosimilar interchangeable once the data show that switching between it and the reference product doesn’t alter safety or efficacy. As of mid‑2024, the biosimilar database lists thirteen interchangeable products, none for ustekinumab yet. The agency expects to complete reviews for Wezlana and Selarsdi by the fourth quarter of 2024.

Interchangeability matters for one simple reason: it allows pharmacists to make automatic substitutions, depending on state law. Without it, every switch needs prescriber or patient involvement, and that slows everything, refills, copay tracking, even PBM rebate systems. Anyone who’s worked with quantity limits in specialty drugs knows that delay adds friction fast.

CVS Caremark’s early positioning

In early 2024, CVS Caremark began outlining its biosimilar transition plan. Borrowing its 2023 playbook for adalimumab products, Caremark plans to rely on its “standard control formulary,” which prefers the lowest‑net‑cost options. Internal signals show that both Wezlana and Selarsdi are being considered for preferred status in early 2025, pending rebate terms and FDA certification.

Caremark places Stelara on a specialty tier, usually Tier 4 or Tier 5, with coinsurance in the 25% to 33% range. Biosimilars designated as preferred tend to land on Tier 3 under Caremark’s commercial plans, lowering patient out‑of‑pocket costs by roughly a fifth. For self‑funded employers, that kind of shift adds up. A single member moving from Stelara to a preferred biosimilar could save a plan around $30,000 a year at current price differentials.

Caremark’s specialty pharmacy role

Most ustekinumab prescriptions flow through CVS Specialty, the company’s mail‑order pharmacy. That setup gives Caremark the ability to coordinate substitutions once the FDA gives the green light. But execution still hinges on state consent and notification rules. Each jurisdiction has its own version of what "notice" actually means. Caremark’s real strength is its integrated setup, PBM plus specialty pharmacy, making it easier to realign its formulary and outreach in tandem.

How Express Scripts is approaching contracts and formularies

Express Scripts, part of Cigna’s Evernorth, said in May 2024 that it had inked rebate contracts with at least one ustekinumab biosimilar manufacturer. The company didn’t name names, but Evercore ISI analysts think Selarsdi is the most likely based on Teva’s past rebate patterns. The product is expected to appear on Express Scripts’ National Preferred Formulary when the 2025 plan year starts, covering about 28 million commercial members.

Express Scripts’ setup isn’t identical to Caremark’s. It depends more on Accredo, its specialty pharmacy arm, for dispensing. Automatic substitution will still rely on both FDA’s ruling and state law. The company has said it will give payers two choices, an “originator preferred” and a “biosimilar preferred” formulary, so employers can time transitions based on their tolerance for clinical change or appetite for rebate gains.

Pricing and reimbursement implications

CMS reports that biologics made up over 43% of all Part D spending in 2022. Stelara will lose exclusivity before the Inflation Reduction Act’s negotiation rules take effect, so biosimilar pressure, not government pricing, will drive costs down. CMS projects that biosimilar use could cut combined Part D and commercial spending by more than $9 billion per year by 2030 if interchangeability moves adoption forward quickly.

For high‑deductible plan members, immediate cost relief will depend on list prices. Amgen and Teva both plan dual pricing models, echoing their adalimumab approach. One version priced low and rebate‑free, another with higher list price but heavier rebates. PBMs will pick their preferred flavor. Caremark often gravitates toward the rebate‑rich model, while Express Scripts sometimes blends approaches to satisfy employers focused on transparent pricing. Personally, I’ve seen payers argue both sides, neither is wrong, it just depends on how the plan accounts for rebates.

What clinicians and patients face during the switch

Provider comfort still drives adoption rates. Surveys from the 2024 American Academy of Dermatology meeting showed that 62% of dermatologists would move stable Stelara patients to a biosimilar if the FDA grants interchangeability. For gastroenterologists treating Crohn’s, that drops to 41%. Education and prior auth updates will steer the early months post‑launch.

From the patient side, the adalimumab rollout offered a preview. Some early refill hiccups, confusion over product names, and delayed shipments. Both Caremark and Express Scripts now promise clearer labeling and pre‑shipment notifications to minimize that noise. That’s fine on paper, execution is what counts. And all of it has to comply with state rules that require notifying prescribers within five business days after a substitution.

Market trajectory through 2025

Once interchangeability calls are final, pricing battles will start almost instantly. IQVIA analysts expect ustekinumab biosimilars to capture about 25% of the U.S. market within six months of launch, reaching roughly 60% by the end of 2025 if supply holds steady. PBM formulary shifts will act as the throttle. Both Caremark and Express Scripts steer a massive share of commercial and Medicare Part D business, so their timelines will decide how quickly the market settles.

Other PBMs, Optum Rx, Prime Therapeutics, the smaller regionals, will likely follow after the two majors establish contract terms. Competitive rebate offers might trigger list price reductions around 15% to 25% versus Stelara, though what patients actually see at the counter will still depend on coinsurance rules and benefit design quirks.

Preparing for the transition

Patients on Stelara should expect formulary change notices from their PBM by late 2024. Those letters will explain whether substitutions happen automatically or only with prescriber approval. Plan sponsors should audit specialty copay programs and accumulator policies, copay assistance tied to Stelara rarely extends to biosimilars. Pharmacists can expect updated NDCs and system prompts as soon as FDA posts the interchangeable approvals.

Real‑time comparison between reference and biosimilar coverage will get easier once PBM portals update their prior authorization tools. For benefits managers, watch for overlap between medical and pharmacy benefits. Some members still get Stelara as an office infusion under the medical side, and the biosimilar switch could bring those claims over to the pharmacy benefit, altering both rebate flow and member cost share. The operational details will matter more than the headlines.

Disclaimer

This content is for informational purposes only. It doesn’t replace medical advice, legal guidance, or any specific insurance determination. Patients should talk with their prescribing clinician before changing therapy, and plan sponsors or pharmacists should confirm coverage, reimbursement, and substitution rules with the appropriate PBM or payer before making any moves.