WASHINGTON — The Food and Drug Administration has reviewed new data that indicated that budeprion XL (bupropion hydrochloride extended-release tablets) in the 300-mg strength, manufactured by Impax Labs and Teva Pharmaceuticals USA, is not therapeutically equivalent to Wellbutrin XL in the 300-mg strength.
The agency said that when it approved five generic versions of the antidepressant in the 300-mg strength, each of these generics was approved based on bioequivalence studies comparing the 150-mg strength of the products with Wellbutrin XL in the 150-mg strength. Studies, however, were not performed directly on the 300-mg strength of the products, but rather, bioequivalence studies were performed using the 150-mg strength and the results were extrapolated to establish bioequivalence of the 300-mg product, the agency said.
"[The] FDA has determined that this approach is no longer appropriate to establish bioequivalence of 300-mg bupropion hydrochloride extended-release tablets to Wellbutrin XL 300 mg, and the agency is revising its guidance to industry for how to conduct premarket bioequivalence studies in generic bupropion products," the FDA said in a statement, adding that it has changed the therapeutic equivalence rating for this product in the agency's Approved Drug Products with Therapeutic Equivalence Evaluations (Orange Book) to reflect this conclusion.
The move has drawn praise from the industry, particularly, the Generic Pharmaceutical Association.
"We commend the FDA for its ongoing commitment to ensuring the safety and efficacy of generic medicines," GPhA president and CEO Ralph Neas said. "Our manufacturers are dedicated to complying with FDA guidelines and providing high quality and affordable medicines to consumers and will continue their work with the agency to fulfill our joint commitment to patients. Assuring the safety and efficacy of the prescription drugs we supply is priority one. The fact that the FDA can rely on its scientific expertise to make critical decisions regarding the safety and effectiveness of pharmaceuticals &dmash; whether brand name or generic — is the surest evidence that our rigorous regulatory controls are working."