Generic GLP-1 literacy: the Orange Book, TE codes, patents and why compounded copies are not generics

What "generic" means in FDA law

FDA's Generic Drug Facts page describes a generic drug as a medication created to be the same as an already marketed brand-name drug in dosage form, safety, strength, route of administration, quality, performance characteristics and intended use. The legal route is the abbreviated new drug application (ANDA) under section 505(j) of the Federal Food, Drug, and Cosmetic Act (21 U.S.C. 355(j)), created by the Drug Price Competition and Patent Term Restoration Act of 1984, usually called Hatch-Waxman.

"Abbreviated" means the applicant does not repeat the brand's clinical trials. It relies on FDA's earlier finding that the brand, called the reference listed drug (RLD), is safe and effective, and instead shows sameness and bioequivalence. 21 CFR 314.3 defines the RLD as "the listed drug identified by FDA as the drug product upon which an applicant relies in seeking approval of its ANDA."

Labeling follows the brand. Under 21 CFR 314.94(a)(8), an ANDA must include the RLD's current labeling, including any Medication Guide, and a statement that the proposed labeling is the same "except for differences annotated and explained," such as a different manufacturer name or a carved-out use that is still under patent or exclusivity.

Drug or biologic? The 40-amino-acid line

Two laws and two books govern copies of approved medicines. Drugs approved under section 505 of the FD&C Act are listed in the Orange Book, and their copies are generics approved by ANDA. Biological products licensed under section 351 of the Public Health Service Act (42 U.S.C. 262) are listed in the Purple Book, and their copies are biosimilar or interchangeable products licensed under 351(k).

Peptides sit right at the boundary. FDA's regulation defines a "protein" as "any alpha amino acid polymer with a specific, defined sequence that is greater than 40 amino acids in size" (21 CFR 600.3(h)(6)). FDA's Q&A guidance on the transition states that a polymer of 40 or fewer amino acids is a "peptide," is not a biological product on that basis, and "will continue to be regulated as a drug under the FD&C Act."

That is why the GLP-1 field is split. The peptide backbones of glucagon (29 amino acids), semaglutide and liraglutide (31 each), and exenatide and tirzepatide (39 each) fall under the line, so these products are NDAs in the Orange Book and generic copies go through ANDAs. Dulaglutide (Trulicity) is a GLP-1 analog fused to an antibody Fc fragment, far larger than 40 amino acids; its Purple Book record lists it as a 351(a) biologic (BLA 125469) first approved September 18, 2014.

How to read an Orange Book entry

The Orange Book's formal title is Approved Drug Products with Therapeutic Equivalence Evaluations. FDA publishes it as a searchable website and as monthly data files. Each row is one approved product: ingredient, dosage form and route, trade name, applicant, strength, application type and number (N for NDA, A for ANDA), TE code, RLD and RS flags, approval date and marketing status (RX, OTC or DISCN for discontinued).

The TE code is the field most readers need. The preface explains that the first letter A marks products FDA considers therapeutically equivalent to other pharmaceutically equivalent products, while B marks products FDA "at this time, considers not to be therapeutically equivalent." The second letter tells you the dosage-form policy: AP is used for "injectable aqueous solutions." A digit is added only "when more than one RLD of the same strength has been designated under the same heading," and a generic receives the three-character code of the RLD it was compared against.

GLP-1 generics so far: a short record

The first GLP-1 receptor agonist, Byetta (exenatide), was approved in April 2005. For almost two decades no generic reached the U.S. market; a 2023 JAMA analysis found that no generic firm had yet successfully challenged GLP-1 patents to gain FDA approval. The record since then, from FDA and company announcements:

• June 24, 2024: Teva launched an authorized generic of Victoza, described by the company as the first generic GLP-1 in the U.S. An authorized generic is the brand's own product under the brand's NDA, not a new ANDA.
• November 19, 2024: FDA approved Amneal's exenatide injection (ANDA 206697), the first ANDA generic in the GLP-1 class, referencing Byetta. Drugs@FDA lists its TE code as AP. In the October 2026 data files both Byetta and this generic appear as discontinued.
• December 23, 2024: FDA approved Hikma's liraglutide injection, the first generic referencing Victoza. FDA's announcement noted that liraglutide was then in shortage and that FDA prioritizes generic applications for drugs in shortage.
• August 27, 2025: FDA approved Teva's liraglutide injection, the first generic referencing Saxenda, listed in FDA's 2025 first generic approvals.
• By the October 2026 Orange Book data files: 11 liraglutide ANDA listings from multiple applicants, and no ANDA listings for semaglutide or tirzepatide.

Proving a generic peptide is the same: FDA's 2026 draft guidances

For a small-molecule tablet, sameness is mostly chemistry plus a bioequivalence study. Peptides add questions about impurities, aggregation and immune responses. In May 2021 FDA finalized guidance on ANDAs for highly purified synthetic peptides referring to listed drugs of rDNA origin, covering glucagon, liraglutide, nesiritide, teriparatide and teduglutide. FDA presentations summarized its core test: shared impurities no higher than in the RLD, and any new peptide-related impurity above 0.5% not acceptable.

On July 28, 2026 FDA withdrew that guidance "as it no longer reflects FDA's current scientific thinking" and published 17 revised draft product-specific guidances (PSGs) for peptide products, including Victoza, Saxenda, Ozempic, Wegovy, Mounjaro and Zepbound. FDA said they update recommendations in five areas: submission of recombinantly, synthetically or semi-synthetically produced peptides as ANDAs, innate immune response testing, impurity thresholds, higher order structure assessment, and biological activity assessment. They are drafts, open for comment, and not binding.

Patents and exclusivities: why a listed date is not a launch date

An NDA holder must list patents that claim the drug substance, the drug product, or a method of use (21 CFR 314.53), and FDA publishes them in the Orange Book addendum with expiry dates, drug substance and drug product flags, and use codes. Separately, FDA grants statutory exclusivities with their own codes and end dates. Under 21 CFR 314.108, a new chemical entity (NCE) receives 5 years during which no ANDA may be submitted, "except that the 505(b)(2) application or ANDA may be submitted after 4 years if it contains a certification of patent invalidity or noninfringement." Other exclusivities, often 3 years, attach to new clinical investigations such as new indications.

That certification is the Paragraph IV certification described in 21 CFR 314.94. Under 21 U.S.C. 355(j)(5)(B), if the patent owner sues within 45 days of notice, FDA approval is generally stayed for 30 months unless the case resolves sooner, and the first applicant to file a substantially complete Paragraph IV ANDA may earn 180 days of generic exclusivity. FDA publishes a Paragraph IV Certifications List showing when such ANDAs were first submitted, but not who filed them.

Compounded GLP-1 preparations are not generics

FDA's page on unapproved GLP-1 drugs says compounded drugs "are not FDA-approved," that FDA "does not review compounded drugs for safety, effectiveness, or quality before they are marketed," and that compounded versions are not generic drugs. A compounded preparation has no reference listed drug, no bioequivalence or sameness review, no TE code and no Orange Book entry, and may use a different salt form than the approved product. FDA has also warned telehealth companies about claims that compounded products are the same as approved drugs.

So when an advertisement says "generic semaglutide," the Orange Book is the quickest check: in the October 2026 data files, no FDA-approved generic semaglutide or tirzepatide was listed. Products sold "for research use only" are further outside the system, with no FDA-approved labeling for human use. Our compounding guides explain 503A and 503B in detail.

A six-point reading checklist

When a product, pharmacy notice or article calls something a generic GLP-1, these checks keep the records straight:

• Search the Orange Book by active ingredient. A real generic appears with application type A and an approval date.
• Read the TE code. A codes mean FDA considers the product therapeutically equivalent; for liraglutide, note AP1 (Victoza) or AP2 (Saxenda).
• Check the marketing status. DISCN means discontinued, as with Byetta and the first exenatide generic.
• For dulaglutide or insulin products, use the Purple Book instead: copies are biosimilar or interchangeable products, not generics.
• Treat patent and exclusivity dates as context, not forecasts.
• If there is no ANDA listing, the product is not an FDA-approved generic, whatever the marketing says. Ask the pharmacist what the product is and how it was approved.

Scope, disclaimer and review date

This page explains how FDA generic drug approvals, the Orange Book and Purple Book, therapeutic equivalence codes, and patent and exclusivity listings work for GLP-1 medicines, and how to read the public records. It does not provide doses, strengths, schedules, injection or device instructions, product, pharmacy or switching recommendations, or individual medical advice, and nothing here suggests starting, stopping, substituting or changing any medicine. Questions about a specific medicine belong with your pharmacist or prescriber; for a medical emergency, call 911 or your local emergency number.

Last reviewed: November 3, 2026. Orange Book listings, Paragraph IV records and draft guidances change often; verify any statement here against the current Orange Book, Purple Book, Drugs@FDA and FDA guidance pages.