What is a Complete Response Letter (CRL)?

A Complete Response Letter (CRL) is the FDA's formal notice that it will not approve a drug application in its current form. It's not a permanent rejection; it lists the deficiencies the company must address before the FDA can approve.

A Complete Response Letter is the FDA's formal notice that it will not approve an application in its current form. It is not a permanent rejection: the company fixes the listed deficiencies and resubmits. A Class 1 resubmission carries a two-month FDA review clock; a Class 2 resubmission carries six months.

Common CRL reasons

Manufacturing/CMC and inspection CRLs are often the most fixable; a strong efficacy package can survive a facility finding. An efficacy CRL is usually the hardest.

What happens after a CRL?

The company resubmits after addressing the issues; the FDA then sets a new review clock (Class 1 resubmission ≈ 2 months, Class 2 ≈ 6 months). Stocks often crash on a CRL, then trade the run-up into the resubmission: the 'fallen-angel' pattern. Browse real examples in our CRL archive.

Our own archive shows how varied the road back can be. Replimune's RP1 took a CRL in July 2025 and a second in April 2026 before approval in August 2026, a recovery that ran through an advisory committee meeting. Capricor's Deramiocel took a CRL in July 2025 and a year later its advisory panel voted 3-9 against. A CRL starts a story; it does not end one, and the same letter can lead to approval or to a longer fight depending on what the FDA asked for.

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