does demand such an analysis." In re Wellbutrin XL
The chart below (21) shows the results of bioequivalence tests of the two drugs by measuring concentration of medicine over time for the 150 mg doses of Budeprion and Wellbutrin XL
. These are the data that were used to approve the bioequivalence of the 300 mg dose.
Previously, the company has submitted to the FDA a sANDA with the requested study, demonstrating bioequivalence of its Bupropion HCl ER Tablets USP (XL), 300 mg, to WELLBUTRIN XL
Tablets, 300 mg.
The planned withdrawal of Budeprion XL 300 mg is the result of studies conducted by the company and FDA aimed at addressing reports of reduced efficacy from patients who were switched to generic forms of Wellbutrin XL
300 mg made more than 5 years ago.
The bioequivalence problem was confirmed in an FDA-sponsored study conducted in 2010, comparing the bioequivalence of the Impax/Teva product to Wellbutrin XL
300 mg in 24 healthy adults, which determined that the generic tablets "fail to release bupropion into the blood at the same rate and to the same extent as Wellbutrin XL
300 mg," according to the statement.
GlaxoSmithKline's unique dual-acting treatment option for major depressive episodes, Wellbutrin, is currently available as a once daily extended-release tablet, Wellbutrin XL
The generic formulation of Wellbutrin XL
(300 mg) is bioequivalent to the brand, the Food and Drug Administration has determined.
In addition, GSK continued to face notable exposure to generic competition in the key US market with the Wellbutrin XL
, Zofran and Coreg IR brands all cited as generic sales casualties.
Some early studies suggest that buproprion (Wellbutrin and Wellbutrin XL
) can be helpful to the mood shifts in SAD, but the research on this is in the early stages.
A lot will depend on the timing of generic competition to Wellbutrin XL
, but we see no reason to change our positive view of the shares.
The main focus on Thursday will be on the management's guidance for this year, as there are likely to be several generic challenges to core products, including Zofran - used to prevent nausea and vomiting associated with chemotherapy - and Wellbutrin XL
, which treats depression.
However, pharmaceuticals firm GlaxoSmithKline found itself going in the other direction following a US court ruling which could open the door to a generic version of its antidepressant pill Wellbutrin XL
. The stock dropped almost 2% - or 26p to 1434p.