The Complete Response Letter (CRL)

A CRL is the FDA's way of declining to approve an application in its current form. It lists the deficiencies the company must fix before resubmitting.

Severity varies

• Mild — a manufacturing/facility (CMC) issue or label wording; often fixable in months.
• Severe — the FDA wants additional clinical trials; that means years and a lot of cash (often dilution).

Price impact

CRLs usually drop the stock sharply (often -20% to -50%), scaling to how much new work is required. A later resubmission becomes its own catalyst with a fresh PDUFA date.