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Reference Product

The FDA-licensed biologic against which a biosimilar is compared and approved under BPCIA, equivalent to the brand-name innovator biologic.

How It Works

Reference product is a defined BPCIA term at 42 U.S.C. 262(i)(4) meaning the single biological product licensed under section 351(a) against which a biosimilar applicant seeks approval. For Humira biosimilars, the reference product is Humira (adalimumab, BLA 125057 approved December 2002); for Stelara biosimilars, the reference product is Stelara (ustekinumab, BLA 125261 approved September 2009). Reference products are entitled to 12 years of marketing exclusivity from initial FDA licensure under BPCIA Section 7002(a), with a 4-year ban on biosimilar application filing. This is longer than any small-molecule exclusivity and has been criticized as excessive; the Obama administration proposed reducing it to 7 years, which was never enacted. Reference-product exclusivity is calculated from the licensure date of the first approval of that biologic; supplemental approvals for new indications do not reset the clock. For Humira, licensed December 2002, the 12-year exclusivity expired December 2014, though composition patents and patent thickets delayed actual biosimilar entry to January 2023 in the U.S. The reference product also drives the "patent dance" process under BPCIA Section 262(l), a detailed exchange of patent lists and arguments between biosimilar applicant and reference product sponsor, replacing traditional Orange Book Paragraph IV litigation. Reference products are listed in the Purple Book with their biosimilars, exclusivity expiration, and interchangeable status. IRA negotiation uses the reference product approval date to calculate the 11-year biologic eligibility threshold.

Related Terms

  • Biosimilar, A biologic product that is "highly similar" to an already approved reference biologic, with no clinically meaningful differences in safety, purity, or potency.
  • Biologic Drug, A complex medication derived from living cells, including monoclonal antibodies, vaccines, and cell therapies, that treats serious conditions like cancer and autoimmune diseases.
  • Biosimilar Interchangeability, An FDA designation under BPCIA allowing a biosimilar to be substituted for the reference biologic at the pharmacy without prescriber consultation, requiring additional switching studies.
  • Follow-On Biologic, An informal term for a biologic similar to an already approved innovator biologic, historically used before BPCIA created the formal biosimilar pathway in 2010.
  • Exclusivity Period, A period of market protection granted by the FDA (separate from patents) during which generic competitors cannot be approved, even if no patent exists.

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About This Definition

This definition is part of the DrugPrice Drug Pricing Glossary, 49 terms explaining how prescription drug pricing works in the United States. All definitions are written in plain language for patients, caregivers, journalists, and healthcare professionals.

this entity is one of the U.S. Medicare prescription-drug pricing concepts that recurs across this site. The definition above is the technical answer; the paragraphs below add the practical context for how the concept connects to the CMS Medicare Part D Drug Spending data data behind every per-entity page on the site.

In the CMS Medicare Part D Drug Spending data data, this concept shapes one or more of the fields that drive the per-entity grades and rankings on this site. The methodology page describes which fields feed into which output; this glossary entry documents the underlying term.

Source: CMS Medicare Part D Spending, 2026.