Eli Lilly intervenes in the tirzepatide shortage case to defend FDA

Eli Lilly moved to intervene in Outsourcing Facilities Association v. FDA in January 2025, joining the federal government against compounding pharmacies that had sued to keep making cheaper, unapproved copies of tirzepatide-based drugs Mounjaro and Zepbound.^[2] The case, filed in the US District Court for the Northern District of Texas, centered on whether the FDA was right to say tirzepatide was no longer in shortage.

The FDA first declared the shortage over on October 2, 2024, then reversed course three weeks later after the Outsourcing Facilities Association sued and public pressure grew.^[2] The agency reaffirmed the delisting in December 2024.^[2] The Outsourcing Facilities Association and Farmakeio Custom Compounding argued the FDA should have used formal notice-and-comment rulemaking and that its decision was arbitrary and capricious.^[2] Lilly's intervention put the drugmaker directly alongside the agency defending that call.

The compounders lost a bid for a preliminary injunction in March 2025.^[1] On May 7, 2025, the district court upheld the FDA's shortage determination, finding the agency had acted within its statutory authority and that the plaintiffs had not shown enough harm to justify judicial intervention.^[1] The 5th US Circuit Court of Appeals affirmed that outcome on August 27, ruling the compounders had actual notice and a real chance to weigh in, since the FDA's reevaluation period ran nearly 60 days, double the standard comment window under federal administrative law.^[2] On the merits, the appeals panel said the FDA reasonably relied on Lilly's own supply data, which showed an 11.6 million-dose surplus by November 2024 following about $23 billion in manufacturing investment, rather than less reliable evidence like wholesaler screenshots and patient surveys.^[2]

The ruling matters because it closes off a legal path compounders had used to keep selling tirzepatide products. Discretionary enforcement periods that had shielded compounders during the transition ended February 18, 2025, for 503A pharmacies and March 19, 2025, for 503B outsourcing facilities.^[1] Once those periods lapsed and courts sided with the FDA, compounding pharmacies and outsourcing facilities generally lost the shortage-list exception that let them make "essentially copies" of tirzepatide injections.^[1]

Why it matters for patients

Patients who had been getting compounded tirzepatide, often at a lower price than brand-name Mounjaro or Zepbound, may find that supply harder to access as enforcement tightens.^[1] Compounders can still make versions of the drug that are not substantially the same as, or given by a different route than, the commercially available products, but the broad shortage exception is gone.^[1] The McDermott law firm noted this shift signals a move toward more FDA enforcement as the agency pushes compounding practices to align with regular manufacturing rules.^[1] Lilly has also separately raised safety concerns about compounded tirzepatide combined with B12, claims the Alliance for Pharmacy Compounding has disputed.^[2]

What happens next

A parallel case over Novo Nordisk's semaglutide products, filed in February 2025, is pending before the same 5th Circuit panel.^[2] In April 2026, the FDA told pharmacies to stop compounding GLP-1 medications once brand-name versions clear the shortage list, a directive tied to the broader enforcement push against compounders.^[2] It is not yet known from these sources how quickly individual pharmacies will change their practices or how patients currently using compounded tirzepatide will be affected in the near term.