Key Summary
- Testing revealed a "significant" impurity caused by a reaction between tirzepatide and added vitamin B12 in compounded products.
- Eli Lilly has notified the FDA and called for a nationwide recall of these specific compounded combinations.
- The FDA maintains that compounded products are not reviewed for safety or quality, potentially introducing "unknown risks" to patients.
Eli Lilly has issued a formal warning regarding potential health risks associated with compounded versions of its weight-loss drugs, according to Reuters.
The U.S. drugmaker revealed on Thursday (12) that testing conducted on 10 samples of compounded products - which often combine tirzepatide (the active ingredient in Zepbound and Mounjaro) with vitamin B12 - uncovered a previously unidentified chemical impurity.
According to a letter released by the company, they found “significant levels of an impurity that results from a chemical reaction between tirzepatide and B12.” These samples were sourced from various providers, including medspas and telehealth networks. This impurity is a direct result of the interaction between the medication and the added vitamin.
Lilly has sued compounders, wellness centres and other companies for selling products claiming to contain tirzepatide.
Compounders have argued their products are legal under a narrow provision of federal law that allows compounding when patients require personalisation due to medical concerns, like the addition of vitamins or doses not available in the branded versions.
"FDA warns that compounded products can be risky for patients because they are not reviewed for safety, effectiveness, or quality," Eli Lilly chief medical officer David Hyman said in a statement. "Adding a reactive substance like vitamin B12 without clinical testing or FDA review introduces additional unknown risks."
Lilly said it notified the US Food and Drug Administration of its findings and called for a nationwide recall of products containing both ingredients.
Scott Brunner, CEO of the lobby group Alliance for Pharmacy Compounding, said Lilly's findings were concerning but that the company would need to provide details of its sampling process, how the tested samples were obtained and other specifics to fully assess any health risks to consumers.
"Based on what I’ve read so far, Lilly isn't telling us enough to make that determination," he said.
The FDA in September issued warning letters to 30 telehealth companies for making false or misleading claims about compounded versions of weight-loss drugs.
