FDA rethinking block on compounding of Lilly's obesity drug

The FDA has said it has agreed to reconsider its decision to prevent compounding pharmacies from producing and selling versions of Eli Lilly's diabetes and obesity drug tirzepatide.

The US regulator has said that compounders can continue to trade in tirzepatide products while it undertakes a review to investigate whether shortages of the drug, which is sold by Lilly as Mounjaro for diabetes and Zepbound for obesity, have actually been resolved, as reported earlier this month.

Under US law, compounding pharmacies can make and sell patent-protected drugs that are on the FDA's shortages list in limited amounts, and have been doing a brisk trade in supplying versions of tirzepatide and other obesity therapies like Novo Nordisk's Wegovy (semaglutide), which remains on the shortages list.

After deciding that tirzepatide was no longer in short supply, the FDA removed it from the official list, effectively barring small compounders from making it immediately, while larger pharmacies were given a 60-day grace period to wind down production.

The FDA's change of heart follows a lawsuit (PDF) filed by the Outsourcing Facilities Association (OFAC), a trade organisation representing the compounding industry, alongside North American Custom Laboratories and FarmaKeio Custom Compounding, two compounders.

That calls the FDA's decision to restrict compounding of tirzepatide "a reckless and arbitrary decision […] to deprive patients of a vital treatment for type 2 diabetes and obesity."

Tirzepatide has been on the shortage list since 2022, but the FDA changed its status via a post on its website on 2nd October based on statements made by Lilly, "ignoring evidence that the shortage persists," according to the complaint.

"Put simply, [the] FDA knows its action will leave many patients with no effective treatment, but persisted with that action anyway on an expedited basis and without warning," claims the lawsuit. After the FDA agreed to reconsider its decision, the judge in the OFAC lawsuit put the case on hold, pending the outcome of the regulator's review.

It is the latest in a series of legal cases involving compounded weight-loss drugs, with Novo Nordisk and Lilly both filing lawsuits seeking to block the activity on the grounds that it is disrupting the market and could expose patients to unsafe medicines, alleging that testing has revealed impurities in some compounded products.

They also claim some defendants have claimed to be selling FDA-approved versions of their drugs, which is not permissible under the law.

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