Will generic Wellbutrin live up to brand?

It's not often that we get data on patients switching from a branded med to a rival generic. But complaints about Teva Pharmaceutical Industries' version of the antidepressant Wellbutrin XL drove FDA to study the matter. The generics giant promised the agency it would run a head-to-head trial, pitting its version against the brand-name product.

Well, Teva has now proposed the parameters of that clinical trial, and Biovail--which makes the brand-name version--is objecting. Biovail claims that the trial's design--138 patients and 24-day duration--would be inadequate for a true compare-and-contrast look at the two medications. The Canadian drugmaker says it learned of this trial design in a December 2 news article.

The trial's outcome could be big for Biovail, which bought out GlaxoSmithKline's U.S. rights to Wellbutrin XL last year for $510 million. If Teva's version were proven to be somehow inferior to the brand-name product, then Biovail might reap millions in additional sales. At one time Biovail reaped $2 billion a year from Wellbutrin XL, Reuters notes, but that was before generic competition ate into sales.

But the trial--provided its design was considered sufficient by objective third parties--could end up being a big deal for brand-name and generics drugmakers alike. If a true, well-crafted, head-to-head trial found statistically significant differences between a branded product and a generic copycat, that could throw the whole generic-substitution thing way off whack--and soften the blow of generic competition in a big way.

- read the Reuters piece