What a Complete Response Letter means, and what usually follows

A Complete Response Letter, or CRL, is the letter the FDA sends when it has finished reviewing a drug or biologic application and decided it can't approve it in its current form. It isn't a permanent rejection. It's a list of what would have to change, and plenty of drugs are approved after one. But how long that takes depends almost entirely on what the letter asks for.

The rule behind it

For drugs, the CRL is defined in 21 CFR 314.110; for biologics the equivalent is in 21 CFR 601.3. The regulation says the letter will describe all of the specific deficiencies the FDA has identified and, where possible, recommend what the company could do to resolve them. A CRL replaced the older "approvable" and "not approvable" letters in 2008, so there are now only two possible outcomes at the end of a review: approval or a CRL.

The FDA can issue a CRL before finishing every part of the review. If the agency decides the core data can't support approval, it doesn't have to inspect the factory or negotiate the label first. That's why some CRLs deal with a single issue and others with many.

What a CRL usually asks for

Deficiencies tend to fall into a few broad groups, and the group matters more than anything else for what happens next.

Clinical efficacy. The FDA isn't convinced the drug works: the trial missed its endpoint, the effect was too small, the endpoint wasn't one the agency accepts, or one trial isn't enough. This is the most serious category, because the fix is often another trial, which can take years.
Safety. The risks seen so far, or the size of the safety database, don't support approval for the proposed population. The fix might be more patients, longer follow-up or a narrower use.
Manufacturing and quality (CMC). Problems with how the product is made, tested or controlled, often found during a facility inspection. These can be resolved in months if the issue is at a contract manufacturer and is fixable, but they can also be stubborn.
Other items. Labelling, data integrity questions, a bioequivalence gap, or a need for a risk-management programme.

A CRL caused purely by a third-party manufacturing site, with no clinical issues, is generally a different situation from one that questions whether the drug works. Companies know this, which is one reason the announcement often stresses which kind it is.

The company's options

Under the regulation, a company that receives a CRL can:

Resubmit the application, addressing every deficiency in the letter;
Withdraw the application; or
Ask for an opportunity for a hearing on whether there are grounds to deny approval (for NDAs). This is rare.

If the company does none of these within a year, the FDA can treat the silence as a request to withdraw, though companies can ask for more time.

Before deciding, most companies request a meeting with the FDA to go through the letter. This is usually a Type A meeting, the category reserved for stalled programmes, which the FDA aims to hold within 30 days of the request. What the company says after that meeting ("the FDA agreed that no new trial is needed", or "we plan to align with the FDA on a path forward") is usually more informative than the first announcement. A company that disagrees with the decision can also file a formal dispute and appeal above the review division.

Resubmission and the new clock

A resubmission starts a new, shorter review with its own goal date, set under the PDUFA commitments:

Class 1 resubmission: a 2-month goal. For minor items such as final labelling, a safety update or a few clarifications.
Class 2 resubmission: a 6-month goal. For everything else, including new clinical data, anything that needs a new facility inspection, or anything that would go to an advisory committee.

So the fastest realistic path from a CRL back to a decision is a few months: a meeting, a resubmission, and a 2- or 6-month review. If the letter asks for a new trial, add the time it takes to run one.

From the tracker

Corcept says it expects a decision on its relacorilant NDA in Cushing's syndrome "by December 17, 2026" (8-K exhibit, 29 July 2026), and the tracker's note records that the NDA was resubmitted in June 2026. A June resubmission and a December decision is the six-month gap a Class 2 resubmission produces. See the Corcept page.

From the tracker

Outlook Therapeutics' LYTENAVA (bevacizumab-vikg) for wet age-related macular degeneration was approved on 24 July 2026 (8-K), the company's first FDA approval after three earlier rejections. It's a reminder that a CRL closes one review, not the programme. See the Outlook page.

How you hear about a CRL

For most of the FDA's history, only the company knew what a CRL actually said. The company would announce it, usually in a press release furnished on Form 8-K, and describe the letter in its own words. An FDA analysis published in the BMJ in 2015 compared letters with the matching press releases and found that the releases often left out deficiencies the FDA had raised, particularly about safety and efficacy.

That changed in 2025. In July the FDA published more than 200 past CRLs for products that were later approved. In September it released letters for applications that were still pending or had been abandoned, and said it would publish newly issued CRLs promptly from then on. The letters are searchable through openFDA. When a CRL is announced you can now, increasingly, compare the company's summary with the letter itself.

Reading a CRL announcement

When a company announces a CRL, these are the questions that matter:

Which category? Efficacy, safety, manufacturing or labelling. Look for the words "additional clinical trial" or "additional study", which mean the timeline is measured in years.
Is it the company's facility or a supplier's? A third-party site issue may be outside the company's control, in either direction.
Did the company quote the letter or paraphrase it? Paraphrase leaves room for optimism. Check the FDA's published copy when it appears.
What's the stated next step, and when? "Type A meeting requested" with a date is concrete. "Evaluating options" is not.
Is there more than one application? A CRL in one indication doesn't affect a separate application for another indication with its own PDUFA date.

On this site, a CRL moves the row into the decided archive with the outcome and a link to the announcement. If the company resubmits and gets a new PDUFA date, that becomes a new upcoming row with its own source.

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