An Additional Information request isn’t FDA telling you no — it’s FDA telling you exactly what it needs to say yes. Treat it as a checklist to close, not a verdict to argue with, and the response job gets a lot more tractable.
Read the request like a checklist, not an argument
An AI request lists specific, numbered deficiencies — a test result that doesn’t support the claim as written, a device description that doesn’t match what was tested, a labeling element that’s missing an element 21 CFR 807.87 requires. Each item traces back to something the submission was supposed to establish clearly and didn’t. Build the response document to mirror the request’s own numbering, one to one, and quote the reviewer’s actual question directly above your answer. The reviewer is going to check the response against the request line by line whether you make that easy or not; making it easy is the entire craft.
Resist the urge to reorganize or improve on the request’s structure. A response that’s easier for you to write but harder for the reviewer to map back to their own list costs you time you don’t have, because it invites a second round of clarifying questions about a first round that was already answered.
Answer only what was asked
The hardest discipline in this document is not adding to it. While you’re back in the file responding to one item, you’ll notice other things — a claim you’d word differently now, a section that could be tighter, a test you could strengthen even though nobody asked. Leave all of it alone. Each addition is new material the reviewer now has to evaluate, on top of the list they already had, and it does nothing to move the items actually in front of them.
If you do need to make an unrelated correction — a genuine error, not a polish pass — flag it explicitly as a separate, clearly labeled item rather than folding it silently into the response to a different question. An unrequested change buried inside an otherwise on-scope document reads as either sloppy or evasive, and either read costs you more than the correction was worth.
Where this goes wrong
Treating it like a rejection
Reworking sections nobody flagged, or restarting parts of the submission from scratch, spends the limited runway you have on work the reviewer didn’t ask for and won’t re-read.
Padding the response
More data, more claims, more sections than the request called for reopens more of the file to scrutiny than the reviewer had planned to look at again.
Missing the clock
Not confirming the response deadline — and what happens if you miss it — before you start drafting turns a manageable rewrite into an avoidable one.
An AI request is FDA doing you a favor, even when it doesn’t feel like one: it tells you exactly what stands between the current file and clearance. Answer precisely, and the file moves. Answer broadly, and the review can quietly start over.
Sources & further reading
- 21 CFR 807.87 — Information required in a premarket notification submission ecfr.gov
- Regulatory Academy — The 510(k) Review, From Submission to the SE Letter regulatoryacademy.com
- Regulatory Academy — Building the 510(k) — eSTAR, Screening, and the Testing Burden regulatoryacademy.com
- Regulatory Academy — How to Write an FDA 483 Response regulatoryacademy.com
This essay is provided for general educational purposes and reflects the regulatory landscape as of its publication date. It is not legal, regulatory, or career advice.
