Eli Lilly’s newly approved weight-loss pill has cleared an important regulatory hurdle, but the U.S. Food and Drug Administration is requiring the company to carry out additional safety studies after launch, showing that regulators still want closer scrutiny of the medicine’s risks. Apparently, FDA asked Lilly for more data on possible liver injury linked to the pill, branded Foundayo, according to a letter posted on the agency’s website.
Foundayo is a once-daily oral obesity treatment that targets the GLP-1 hormone, placing it in one of the fastest-growing and most competitive areas of the drug market. The drug won approval earlier this month through the FDA’s Commissioner’s National Priority voucher program, which is designed to speed decisions on products considered important to public health or national security. That faster pathway helped get the drug to market quickly, but it did not remove the need for further monitoring after approval.
The FDA’s request centers first on liver safety. The agency specifically asked Lilly for more information on liver injury potentially associated with the drug. Lilly pushed back on the concern, saying there had been no signs of liver damage in late-stage clinical testing. The company also said the post-approval requirements are consistent with the FDA’s standard approach to ongoing safety review for newly approved medicines. In other words, Lilly is presenting the extra studies less as evidence of a proven problem and more as a routine part of monitoring a major new therapy after it reaches patients.
Still, the FDA’s requests go beyond liver concerns alone. Lilly must also conduct post-marketing trials to assess risks related to cardiovascular events and delayed gastric emptying. The agency further required a milk-only lactation study in breastfeeding women who have taken the pill, so researchers can measure how much of the drug enters breast milk. In addition, Lilly must run a study using ultrasound to examine how temporary treatment interruption and fasting affect retained stomach contents, which will help regulators better understand the risk of delayed gastric emptying associated with the drug.
These requirements matter because Foundayo enters a competitive and closely watched obesity market. Lilly began selling the pill last week, intensifying competition with Novo Nordisk’s oral Wegovy, which has been available since January. In clinical trials, Foundayo produced about an 11% reduction in body weight over 72 weeks, while oral Wegovy led to roughly a 14% reduction over 64 weeks. Those figures suggest Foundayo may be commercially important even if it does not clearly surpass its main rival on weight loss in the available trial comparisons.
Analysts do not appear to think the FDA’s extra requirements will seriously damage Lilly’s position. BMO Capital Markets analyst Evan Seigerman said the post-marketing studies are notable but are not expected to have a meaningful effect on the drug’s competitive standing. He said the move looked more like FDA conservatism than a sign of a major regulatory setback. That interpretation suggests the market may view the extra studies as manageable, especially given the huge demand for effective obesity treatments.
Overall, Foundayo has won approval and reached the market, giving the company a major new entry in the obesity-drug race. But the FDA is making clear that approval does not end the safety review process. By requiring more evidence on liver injury, cardiovascular risk, delayed gastric emptying, and exposure through breast milk, regulators are signaling that they want broader real-world and follow-up data before fully settling questions about the pill’s long-term safety profile.
