According to ConsumerLab.com, which evaluates health and nutrition products, its tests showed that the generic product released the active ingredient at a different rate than GlaxoSmithKline'S brand name Wellbutrin XL. Tests also demonstrated that two generic Wellbutrin SR products released the drug at different rates.
ConsumerLab.com used water to dissolve the pills and release the active ingredient, whereas drug approvals are based on a drug'S behavior inside the human body. For brand-name drugs, clinical trials provide much of the proof regarding safety and efficacy, with lab results supporting trial conclusions. For generics, the proof consists of lab data and the demonstration of bioequivalence in healthy volunteers. The Wellbutrin generics tested met all Food and Drug Administration (FDA) requirements.
"All generic drugs are put through a rigorous, multistep review process that includes a review of scientific data on the generic drug'S ingredients and performance," says FDA spokesperson Sandy Walsh. "Generic manufacturers must scientifically demonstrate that their product is bioequivalent-that is, performs in the same manner-to the pioneer drug. The generic version must deliver the same amount of active ingredients into a patient'S bloodstream over the same amount of time as the pioneer drug."
Walsh says the FDA is aware of the ConsumerLab.com report. "We would have to have our scientists review that report before we could comment further," she says, adding that the FDA has great confidence in the quality and equivalence of generic drug products and that it has received no complaints about generic Wellbutrin.
"[The] FDA works with pharmaceutical companies to assure that all drugs marketed in the U.S.-both brand-name and generic-meet specifications for identity, strength, quality, purity, and potency. We continue to monitor, and if indicated, investigate reports of potential inequivalence," says Walsh.
According to press reports, ConsumerLab.com'S testing was initiated following patient reports of side effects, including re-emergence of the symptoms of depression, when patients switched to the generic version. Side effects cleared for some patients when they returned to the brand-name drug.
Separately, in early October, the FDA announced a plan to speed the approval of generic drugs and address a backlog of more than 1,000 applications. Officials outlined changes intended to streamline the generics approval process, including the review of multiple applications for the same product at the same time. The FDA also hopes to beef up the staff it devotes to the review of generics applications.
Generic drug submissions to the FDA have more than doubled over the past five years, according to press reports, and the agency approved nearly 700 in fiscal year 2007. Generics represent 63% of all the prescriptions dispensed in the United States but only 20% of all dollars spent on prescription drugs, according to the Generic Pharmaceutical Association (GPhA). GPhA represents the manufacturers and distributors of finished generic pharmaceuticals, the manufacturers and distributors of bulk active pharmaceutical chemicals, and the suppliers of other goods and services to the generic drug industry.
[The] FDA works with pharmaceutical companies to assure that all drugs marketed in the U.S., both brand-name and generic, meet specifications for identity, strength, quality, purity, and potency.
-SANDY WALSH, FDA spokesperson
In responding to the FDA proposal, GPhA President and Chief Executive Kathleen Jaeger says: "Another initiative in name only simply will not get the job done. What consumers need is for the FDA to address the core issues blocking timely consumer access to affordable generics. There are serious legislative and regulatory issues that must be addressed to yield a true increase in the number of affordable generics brought to market."