Complex generics and biosimilars are the next frontier of affordable medicine, and the FDA began rewriting the rules for both in 2025 and 2026. Generics already fill about 90% of U.S. prescriptions by volume. The next wave, though, involves products far harder to copy than a standard tablet: long-acting injectables, inhalers, peptides and biologics.
Here is what manufacturers, wholesalers, distributors and pharmacies need to know about how these products reach the market and what is changing.
What is a Complex Generic?
A complex generic is a generic drug with a complex active ingredient, formulation, dosage form, route of delivery, or drug-device combination. Examples include liposomal injections, long-acting microsphere injectables, metered-dose inhalers, ophthalmic emulsions and locally acting topicals.
Complex generics still use the abbreviated new drug application (ANDA) pathway. The hard part is proving sameness and bioequivalence when performance depends on particle size, release mechanism or device design. That is why the FDA offers pre-ANDA meetings and product-specific guidances. Its FY2027 research priorities also target better characterization tools for complex injectables, implants and polymer-based formulations.
How is a Biosimilar Different from a Generic?
A generic is an equivalent copy of a small-molecule drug, while a biosimilar is a highly similar version of a biologic made from living cells. Biologics are too large and complex to duplicate exactly, so biosimilars follow a separate pathway created by the Biologics Price Competition and Innovation Act (BPCI Act).
Generics, including those in our prescription catalog, are approved through the ANDA pathway. They must contain the same active ingredient as the brand-name drug and be bioequivalent to it, and pharmacists can substitute them as state law allows.
Biosimilars are approved through the 351(k) biologics license pathway. They must be highly similar to the reference biologic, with no clinically meaningful differences in safety or effectiveness.
Pharmacy substitution splits biosimilars into two groups. A pharmacist can substitute a standard biosimilar for its reference product only with the prescriber's authorization. An interchangeable biosimilar clears one more bar: switching back and forth between it and the reference product must add no extra risk. The interchangeable designation lets a pharmacist substitute it without contacting the prescriber, much like a generic.
What’s Changing for Biosimilars and Complex Generics?
The FDA is moving the biosimilar pathway closer to the generic model by relying more on analytical data and less on large clinical trials. The key developments:
Fewer comparative efficacy studies. October 2025 draft guidance says these studies, which average about $24 million and one to three years, often aren't needed when analytical and pharmacokinetic (PK) data are strong.
Streamlined PK studies. March 2026 draft guidance lets sponsors that test against a non-U.S. version of the reference product skip the extra three-way PK bridging study when analytical data justify it.
Interchangeability without switching studies. The FDA’s June 2024 draft guidance moved away from dedicated switching studies, and the agency now says it generally doesn’t recommend them. The interchangeable designation itself is written into law, so only Congress can remove it.
Biosimilar bills awaiting floor votes. Two bills cleared the House and Senate committees in July 2026 and await floor votes. The Expedited Access to Biosimilars Act would make comparative efficacy studies the exception rather than the rule. The Biosimilar Red Tape Elimination Act would deem all approved biosimilars interchangeable.
Complex generics in GDUFA IV. The generic drug user fee program is up for reauthorization for FY2028–2032, and the proposed commitment letter adds an early-advice meeting for complex generics.
All three FDA guidances are still drafts, so expect refinements before they become final.
What Does This Mean Across the Supply Chain?
Lower development barriers should bring more complex generics and biosimilars to market, and every link in the supply chain will feel it.
Manufacturers
More competitors can enter biologic markets as clinical trial requirements shrink. Success will depend on strong analytical characterization, tight manufacturing control and early engagement with the FDA.
Wholesalers and Distributors
More biologics and complex injectables mean more products that need cold-chain handling, specialty storage and careful allocation. Accurate product data, including which biosimilars reference which biologics and their interchangeability status, keeps ordering and DSCSA compliance on track.
Pharmacies
Biosimilar substitution depends on two things: the FDA's interchangeability designation and state law. Most states have biosimilar substitution laws, but notification and recordkeeping rules vary. The FDA's Purple Book is the reference for checking a product's status.
How Can You Stay Ahead of the Next Wave of Generics?
The best preparation is to act on what is already clear and stay updated on new changes. Practical steps for trading partners:
Watch for final FDA biosimilar guidance and GDUFA IV reauthorization in 2027
Review your state's biosimilar substitution and notification rules
Assess cold-chain and specialty storage capacity
Keep product master data current as new products launch
Plan for formulary and contracting shifts as competition grows
WPRX follows regulatory and market developments closely so our partners can plan with confidence. Contact our team to talk through what these changes mean for your business.
FAQs
Are biosimilars the same as generics?
No, generics are equivalent copies of small-molecule drugs. Biosimilars are highly similar to a biologic agent but not identical.
Can a pharmacist substitute a biosimilar?
Only if the FDA has designated it interchangeable and state law permits the substitution.
What is an interchangeable biosimilar?
A biosimilar that the FDA has determined can be substituted for its reference product without prescriber intervention.
