Generic Antidepressant Formulation Withdrawn Over Efficacy.

Dow Jones Newswire (10/4, Dooren) reports that the Food and Drug Administration issued a statement Wednesday, saying it has been receiving reports from consumers who experienced a reduction in efficacy after substituting GlaxoSmithKline’s Wellbutrin XL (bupropion hydrochloride) with the generic Budeprion XL 300 that is manufactured by Impax Laboratories Inc. and marketed by Teva Pharmaceuticals USA Inc. The agency said, however, that it has asked four other pharmaceutical companies that make generic versions of Wellbutrin XL to conduct additional Phase III trials, comparing the 300-milligram dosage generic with the brand-name formulation.

The AP (10/4) reports that the FDA said it has “called on Teva to withdraw Budeprion XL 300 after chemical testing showed the drug releases its key ingredient faster” than GSK’s original version.

Bloomberg News (10/4, Edney) notes that the FDA approved Teva’s Budeprion XL 300 in 2006. The agency’s Office of Generic Drugs Director Greg Geba said that “from January 2007 to June 2007,” the FDA received reports about efficacy from 86 people. He said, however, that “at the time, the agency determined recurring symptoms are common during major depressive disorder and the differences in the drugs weren’t outside established rules for equivalence.” Division of Bioequivalence II Director Barbara Davit explained that FDA “initially required companies to study generic versions of Wellbutrin XL only in the 150-mg dose and allowed them to extrapolate the results to the 300-mg dose because of concerns with stroke risk.” She said the agency will “now require testing on the highest available strength.” Geba added that the FDA is also “issuing new guidelines for bupropion.”