FDA seeks more liver safety data on Eli Lilly's obesity pill Foundayo

The FDA’s request for more liver-injury data did not stop Foundayo from reaching patients, but it added a fresh layer of scrutiny to Eli Lilly’s newest obesity drug at a moment when demand for weight-loss treatments remains intense. The agency’s letter sought more safety information on potential drug-induced liver injury, part of a broader post-approval review that also includes cardiovascular risk and other monitoring requirements.

Foundayo, the brand name for orforglipron, won FDA approval on April 1 for adults with obesity or overweight who also have at least one weight-related comorbid condition. The agency said Lilly’s application had been received on January 20 and that the drug was the first new molecular entity approved under the Commissioner’s National Priority Voucher program, a pilot the FDA launched in 2025. The agency also said the review moved at its fastest pace for a new molecular entity since 2002, and that the application was not sent to an advisory committee because there were no controversial issues that required outside discussion.

The liver request does not amount to a withdrawal or suspension. Foundayo remains approved, and Lilly said prescriptions were being accepted immediately through LillyDirect, with shipping to begin April 6. The company also said the pill could be taken any time of day without food or water restrictions, a practical advantage over some other medicines in the class.

Still, the FDA’s postmarketing demands matter because oral obesity drugs are expected to reach a broad population, including patients with metabolic disease and those taking multiple medications. The approval letter requires Lilly to complete the ongoing randomized, open-label, active-controlled ACHIEVE-4 study and provide additional safety data on major adverse cardiovascular events and potential liver injury. The post-approval file also references a milk-only lactation study and a concern related to gastric emptying.

The commercial stakes are large. Lilly said adults taking the highest dose in the ATTAIN-1 trial lost an average of 27.3 pounds, or 12.4%, compared with 2.2 pounds, or 0.9%, on placebo. The company priced the drug at $25 a month for commercially covered patients and $149 for self-pay. In a crowded obesity market dominated by close comparisons among efficacy, tolerability and access, any new liver-safety review can influence prescribing and investor expectations even before it changes a single prescription.