The US Food and Drug Administration (FDA) has released 26 new bioequivalence (BE) standards intended to facilitate the development of abbreviated new drug applications (ANDAs) that best meet FDA's expectations for evidence.

Background

Bioequivalence refers to the "absence of a significant difference" between the bioavailability-specifically the extent and rate of absorption-of two (supposed) pharmaceutical drug equivalents over the course of a period of time, at the same dose and under the same conditions. "The generic version must deliver the same amount of active ingredients into a patient's bloodstream in the same amount of time as the pioneer drug," FDA explains on its website.

Drugs that are deemed to be bioequivalent are, for regulatory purposes, essentially the same.

But in practical terms, generic drug companies are often most concerned with two things:

• How to prove that two drugs are bioequivalent
• How to show bioequivalency in a way that will be acceptable to FDA

In order to facilitate that process, FDA regularly publishes what it calls "bioequivalence recommendations for specific products," which as of April 2014 contains more than 1,150 recommendations.

These recommendations most often contain the recommended number of bioequivalence studies that must be conducted in order to obtain approval, as well as the general designs of the study, acceptable parameters of bioequivalency, and any other considerations sponsors must keep in mind.

New Standards

On 2 April 2014, FDA released 26 new BE standards, including ones for generic versions of Merck's Lipruzet (atorvastatin, ezetimibe), Pfizer's Inlyta (axitinib), Reckitt Benckiser's Suboxone (buprenorphine HCl; naloxone HCl), Purdue's Butrans (Buprenorphine), Lundbeck's Onfi (Clobazam), transdermal estradiol, and intrauterine levonorgestrel.

Those guidances are still in draft form. FDA also said it had finalized 16 other BE guidances.

Federal Register Notice