The US FDA has issued guidance for the pharma industry on reference listed drug standards for ANDA (abbreviated new drug application) submissions. The guidance is intended to provide information to potential applicants on how to identify a reference listed drug (RLD), reference standard, and the basis of submission for an ANDA submission.

The process for obtaining approval to market an innovator drug approved under a new drug application (NDA) differs from that for obtaining approval to market a generic drug under an ANDA. An NDA for an innovator drug must contain, among other things, a demonstration of the safety and effectiveness of the drug for the conditions of use for which approval is sought, stated the guidance.

For the approval of a generic drug, an ANDA applicant is not required to provide independent evidence of the safety and effectiveness of the proposed generic drug. Instead, it could rely on a previously approved drug product or RLD which is safe and effective. It must demonstrate, among other things, that the proposed generic drug is the same as the RLD in certain ways.
 
An ANDA applicant also must demonstrate that its proposed generic drug is bioequivalent to the RLD. If no in vivo bioequivalence studies are required for approval of the ANDA, the applicant must use the reference standard selected by FDA in such testing.
 
An ANDA applicant must first choose an RLD. If FDA has not designated an RLD for a drug product the applicant intends to duplicate, the potential applicant may submit controlled correspondence to FDA asking it to designate an RLD for that drug product.
 
If FDA has designated a listed drug as an RLD, but the potential applicant intends to refer to a different listed drug that is a pharmaceutical equivalent to the drug. If an RLD appears in the discontinued section and FDA has not yet made a determination whether the drug was withdrawn from sale for reasons of safety or effectiveness, the applicant must submit a petition under 21 CFR 10.25(a).
 
The guidance has also mandated that the generic drug must have the same labeling as the RLD, except for differences permitted under the FD&C Act and Agency regulations. Accordingly, an ANDA applicant must compare its proposed product’s labeling to that of the RLD, even if FDA has selected a new reference standard for use in in-vivo bioequivalence studies, Similarly, in evaluating drug product formulation and inactive ingredients, an ANDA applicant must compare its proposed generic drug to the RLD’s formulation, not the formulation of the reference standard.