Best Practices for Communicating with FDA Reviewers

Reviewer Assignment: Who to Contact and Why It Matters

When FDA accepts your 510(k) or PMA, the submission is assigned to a primary reviewer — typically a scientist or engineer within the relevant CDRH product division. That reviewer is your official point of contact for the duration of the substantive review. Their name and contact information are listed in your acknowledgment letter.

This assignment structure is not bureaucratic formality. It reflects FDA's accountability model: one reviewer is responsible for the technical record, and all formal communications with sponsors flow through that record. Attempting to route questions around the assigned reviewer — to their branch chief, the division director, or the Office Director — does not accelerate the review. It creates confusion about the communications record and signals that the sponsor may not understand how the process works.

For PMA reviews, FDA typically assigns both a primary reviewer and a secondary reviewer representing a different scientific discipline (e.g., a biostatistician alongside an engineer). Sponsor communications should still route through the primary reviewer unless FDA explicitly directs you otherwise.

The Interactive Review Program: FDA's Clock-Stop Prevention Tool

FDA's Interactive Review Program — described in FDA's guidance on the 510(k) program and operationalized across CDRH product divisions — is the mechanism by which FDA reviewers can contact sponsors informally to resolve a question before issuing a formal Additional Information (AI) letter.

Under the traditional review model, when a reviewer identifies a gap in your submission, the formal response is an AI letter. An AI letter stops the review clock — the day the AI letter issues, your 90-day (or 180-day for PMA) review period pauses and does not restart until FDA receives and acknowledges your complete response. A single AI letter can cost 30 to 90 additional days on your timeline, plus the time it takes your team to prepare the response.

The Interactive Review Program short-circuits this sequence. A reviewer may call or email you directly — informally — to ask a targeted clarifying question. If you can answer completely and promptly, the reviewer documents the exchange in the administrative record and the review continues without a clock stop.

Keep in mind that the Interactive Review Program is at FDA's discretion. Not every reviewer will use it, and not every question is suited to informal resolution. Reviewers are under their own performance metrics, and informal exchanges add documentation burden. Sponsors who respond cleanly and quickly to informal inquiries build the kind of review record that makes continued informal resolution the path of least resistance.

When It Is Appropriate for the Sponsor to Contact FDA During Review

There is a widely held belief among device companies that any sponsor-initiated contact during an active review is risky — that it could irritate the reviewer or introduce new issues. That belief is largely unfounded, but it is not entirely wrong either. The question is not whether to contact the reviewer; it is why and how.

Appropriate reasons for a sponsor to initiate contact with their assigned reviewer during an active review include:

• Status inquiries: Asking where the review stands is entirely appropriate, particularly if you have not received any communication for an extended period relative to FDA's typical review timeline. Keep the question simple: "We submitted [submission number] on [date]. Could you give us a brief status update?"
• Clarification of a reviewer question: If FDA sent you a written question — formally or informally — and the question itself is ambiguous, you may call to ask a scoped clarifying question before preparing your written response. Document that call immediately afterward.
• Notification of a material change: If your device, labeling, intended use, or manufacturing site has changed materially since submission, you are obligated to notify FDA. Do this in writing through the assigned reviewer — a change you fail to disclose, then later resolve under an AI letter, is a much worse outcome than one you surface proactively.
• Submission of a voluntary amendment: If you identify an error or omission in your original submission, you may file a voluntary amendment (also called a supplemental submission or amendment to the submission). Notify the reviewer before filing so the material is expected and routed to the correct administrative record.

What Not to Do: Communication Patterns That Undermine a Review

The following patterns reliably create problems, and some can cause formal consequences:

Formal AI Letters vs. Informal Reviewer Questions: How to Treat Each

The distinction matters procedurally. A formal AI letter is an official FDA communication that stops your review clock. It must be responded to completely — meaning every item addressed, not just the items you find straightforward. FDA will not restart the clock on a partial response.

An informal reviewer question (phone call, email outside the AI letter process) carries no clock-stop consequence, but it carries an implicit deadline: respond promptly, or the reviewer moves to a formal AI letter. There is no bright-line rule on how long you have to respond to an informal inquiry, but a reviewer waiting more than one to two business days for a response to a simple question has a reasonable basis to issue the formal letter instead.

When you receive a formal AI letter:

• Read every item carefully before preparing any individual response. Some items are interconnected, and addressing them in isolation produces inconsistent answers.
• Use the same numbering and section designations FDA used. Do not reorganize the questions.
• Do not address topics not raised in the AI letter. Scope discipline matters: extra information introduces new questions rather than resolving existing ones.
• Attach all supporting materials — updated test summaries, revised labeling, amended performance specifications — as appendices referenced from the relevant response item. Do not promise to provide materials in a future correspondence.
• Keep a copy of every AI letter response in your regulatory file, with the date and method of transmission documented.

Record Keeping During FDA Review: The Communication Log

Every substantive communication with FDA during an active review — phone calls, emails, written correspondence — should be logged in a contemporaneous communication record. This is not a regulatory requirement under 21 CFR Part 820, but it is an essential risk management practice.

A basic communication log entry should capture: the date and time; the name and title of the FDA contact; the FDA submission number and review division; a summary of what was asked and what was said; any commitments made by either party; and the next action, with a due date.

This record serves two practical purposes. First, it gives your regulatory team continuity — if the primary contact at your company changes, the new person can reconstruct the review history without relying on memory or searching email threads. Second, if a dispute arises about what FDA said or agreed to during a call, a contemporaneous log is far more persuasive than recollection.

Note that FDA maintains its own administrative record of communications with sponsors. If your log diverges materially from what FDA documented, you will need to reconcile that discrepancy before the record becomes the basis for any adverse decision.

When to Escalate Within FDA: The Dispute Resolution Path

Dispute resolution under 21 CFR Part 16 and FDA's guidance on resolving disputes regarding CDRH regulatory decisions is a formal mechanism — not a first resort. It is appropriate when:

• The assigned reviewer has reached a decision you believe is inconsistent with FDA law, regulation, or FDA's own guidance documents, and
• You have attempted to resolve the disagreement through direct communication with the reviewer and their immediate supervisor without success.

Before initiating dispute resolution, document every prior communication attempt — dates, contacts, the positions taken, and the specific regulatory basis for your disagreement. A dispute resolution request without this documentation will not advance your position.

Dispute resolution is not a tool for relitigating a close scientific question that FDA has resolved against you. FDA's scientific judgments on performance, biocompatibility, or substantial equivalence are not easily displaced through the dispute resolution process. The mechanism is most effective for procedural questions — whether FDA applied the correct statutory standard, whether FDA followed its own guidance, or whether FDA applied a requirement that does not apply to your device category.

Pre-Sub Q&A as a Complement to Review Communication

One of the most effective ways to reduce the burden of reviewer communication during an active review is to resolve the most complex scientific and strategic questions before the submission is filed. FDA's Pre-Submission (Q-Sub) program allows sponsors to obtain written FDA feedback on specific, well-formed questions related to their device and regulatory pathway — typically with a written response within 70 calendar days of acknowledgment.

A well-executed Q-Sub does not prevent AI letters entirely, but it substantially reduces the questions that remain unresolved at submission time. A reviewer who receives a submission that has already incorporated written FDA feedback on predicate selection, performance testing, or biocompatibility is working from a cleaner record — and has fewer grounds for an AI letter.

The Q-Sub also creates a written record of FDA's position before the substantive review clock starts. If a reviewer later takes a position inconsistent with FDA's prior Q-Sub feedback, that record is the foundation of a dispute resolution request and sometimes prompts informal resolution by the reviewer's supervisor without formal proceedings.

PMA Reviews: Patient Representatives and Public Sessions

PMA reviews involve communication channels that do not exist in 510(k) reviews. For significant PMAs, FDA may convene an advisory committee meeting — a public session at which FDA panelists, the sponsor, and sometimes patient representatives all present and discuss the device's safety and effectiveness data.

Sponsor communication with FDA before and during the advisory committee process is governed by specific guidance. Sponsors are generally permitted to meet with FDA prior to the panel meeting to discuss logistics and the format of their presentation. They are not permitted to engage panel members directly outside the formal session.

Patient representatives may participate in advisory committee meetings as voting or non-voting members. Sponsors who have pre-existing relationships with patient advocacy organizations should be thoughtful about how those relationships appear in the context of an active PMA review. FDA's guidance on conflicts of interest for advisory committee members includes provisions about sponsor relationships with patient organizations.

In post-approval phases, sponsors communicate with FDA through their assigned post-market reviewer — a different contact from the pre-market reviewer who handled the PMA. Establishing that relationship early, before the first required post-approval study report, reduces friction when questions arise.