FDA Guide on ANDA Refusals Related to Impurity Limits

FDA has posted a guidance on “ANDA Submissions — Refuse to Receive for Lack of Justification of Impurity Limits” — that is intended to help applicants preparing to submit ANDAs and prior approval supplements for approval of a new strength of a drug product. The guidance highlights deficiencies about impurities that may cause the agency to refuse to receive the submission. According to the agency, typical deficiencies leading to an refuse-to-receive decision include: (1) failing to provide justification for proposed limits in drug substances and drug products for specified identified impurities that are above qualification thresholds; (2) failing to provide justification for proposed limits for specified unidentified impurities that are above identification thresholds; and (3) proposing limits for unspecified impurities(e.g., any unknown impurity) that are above identification thresholds.