FDA Finalizes Therapeutic Equivalence Guidance Changing Orange Book TE Codes

FDA's finalized "Evaluation of Therapeutic Equivalence" guidance, published under docket FDA-2022-D-0528, resets the interpretive baseline for TE codes assigned to multisource prescription drug products listed in the active section of the Orange Book, with direct consequences for generic manufacturers managing substitutability status and pharmacists navigating state-level dispensing decisions.

The guidance, issued by the Center for Drug Evaluation and Research (CDER), formalizes FDA's current thinking on how therapeutic equivalence evaluations are conducted and communicated. It applies to products approved under the Federal Food, Drug, and Cosmetic Act and listed in the Approved Drug Products With Therapeutic Equivalence Evaluations, the Orange Book. The document finalizes the draft guidance of the same title issued in July 2022, closing a four-year comment and review cycle.

For QA directors and regulatory affairs leads at generic manufacturers, the practical read centers on TE code assignment criteria. Orange Book TE codes function as the operative signal for state health agencies and pharmacists determining whether a generic may be substituted for a reference listed drug without prescriber intervention. Any clarification in FDA's evaluation methodology affects how manufacturers frame their ANDA submissions, bioequivalence study designs, and post-approval change strategies when substitutability is at stake.

The guidance also carries weight for pharmacists and state health agencies, which rely on TE code designations as the primary public advisory mechanism for drug product selection. FDA frames the document explicitly as public information and advice intended to promote drug product selection education and support healthcare cost containment, language that signals the agency views TE code transparency as a policy instrument, not merely a technical classification exercise.

Generic manufacturers with products currently listed under "BX" codes or under review for therapeutic equivalence determinations should assess whether the finalized guidance introduces any interpretive shifts relative to the 2022 draft, particularly around products where bioequivalence data or labeling conditions have been contested. Comments on the finalized guidance may still be submitted online or in writing to FDA's Dockets Management office, referencing docket number FDA-2022-D-0528, per 21 CFR 10.115(g)(5).

The competitive landscape for multisource prescription products will be shaped, in part, by how consistently CDER applies the finalized criteria across pending and future Orange Book listings.

Source: FDA Center for Drug Evaluation and Research via FDA Guidance Documents Search, August 21, 2026. Docket: FDA-2022-D-0528.