Foundayo's Postmarketing Requirements, Decoded
The approval letter commits Eli Lilly to a thyroid cancer registry running until 2035 and a study on gastric emptying and aspiration risk. These are the questions the FDA did not resolve before approval.
Findings
- The approval letter requires a medullary thyroid carcinoma registry-based case series of at least 15 years duration.
- That study's interim reports are scheduled for September 2030 and September 2032, with study completion estimated September 2034 and a final report due September 2035.
- A separate required study addresses the effect of temporarily withholding orforglipron and of fasting duration on retained gastric contents, to inform recommendations on pulmonary aspiration risk.
- Postmarketing requirements are the public record of what an approval did not settle.
Approval letters are the most under-read documents in pharmaceutical regulation. They contain the specific commitments a sponsor makes in exchange for market access, and those commitments map precisely onto the questions the agency could not close before approving.
The Foundayo letter, NDA 220934, contains two that matter.
Requirement one: the thyroid cancer registry
MTC registry case series
The reason for this requirement is on the label. Orforglipron carries a boxed warning for potential thyroid C-cell tumors, including medullary thyroid carcinoma, and is contraindicated in patients with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2.
The class-wide thyroid C-cell signal originates in rodent studies. Whether it translates to humans has been debated for the entire history of the GLP-1 class, and it cannot be settled by a 72-week trial. Medullary thyroid carcinoma is rare, and detecting a change in its incidence requires population-scale surveillance over many years.
The final report is due in September 2035, nine and a half years after approval. First interim data arrives in September 2030. Until then, the human thyroid question for this molecule is genuinely open — not reassuring, not alarming. Open.
Requirement two: gastric emptying and aspiration
The second required study evaluates the effect of both temporary withholding of orforglipron and of fasting duration on retained gastric contents, to evaluate the delayed gastric emptying associated with GLP-1 receptor agonist use and inform recommendations to mitigate the serious risk of pulmonary aspiration. Its timetable includes a draft protocol submission in March 2027 and a final protocol submission in September 2027.
This is the most clinically actionable open question on the file. GLP-1 receptor agonists slow gastric emptying — that is part of how they work. Under general anaesthesia, a stomach that still contains food when it was assumed to be empty creates aspiration risk.
The practical question every anaesthesiologist needs answered is: how long before a procedure should this drug be held, and how long should the patient fast? The FDA required a study because there was not an evidence-based answer specific to this molecule at approval.
- The correct pre-procedure withholding interval for orforglipron specifically.
- Whether fasting duration guidance developed for injectable GLP-1s transfers to a once-daily oral small molecule.
- Human medullary thyroid carcinoma incidence attributable to the class, or to this molecule.
- Whether the postmarketing package for this accelerated approval is broader than a standard-timeline approval in the same class would have carried.
What postmarketing requirements are, and are not
They are enforceable commitments, not voluntary studies, and failure to meet them carries consequences. They are also not a finding that a problem exists. The FDA requires this surveillance because the class signal warrants monitoring and because trials of practical size and duration cannot answer these questions.
The correct reading is neither dismissive nor alarmist. The agency approved the drug, which means it concluded the benefit-risk balance supported market access on the available evidence. It simultaneously documented, in writing, exactly which questions remain open and on what schedule they will be answered. That transparency is the useful part.
If you are having surgery
Tell your surgical and anaesthesia team you are taking a GLP-1 receptor agonist, name the specific drug, and do it well before the day of the procedure. The required study exists precisely because standardised guidance for this molecule is still being developed. Your care team needs to make an individual judgement, and they can only do that if they know.
Primary sources & citations
- FDA approval letter for NDA 220934, Foundayo (orforglipron) tablets, including postmarketing requirement 4977-6 and associated timetables submitted March 25, 2026.
- US Food and Drug Administration guidance for industry, Postmarketing Studies and Clinical Trials — Implementation of Section 505(o)(3) of the Federal Food, Drug, and Cosmetic Act, October 2019.
- AJMC, reporting on the Foundayo boxed warning and contraindications.
- Pharmacy Times, coverage of the orforglipron approval and adverse event profile.
Editorial note
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