Federal Circuit Vacates Preliminary Injunction Against Teva Relating to Generic Version of Abbott's Biaxin XL (Clarithromycin Extended Release)

In a 31-page opinion by Judge Prost, joined by Judge Gajarsa, a Federal Circuit panel held yesterday that Teva had raised a substantial question as to the validity of Abbott's patents covering its extended release clarithromycin product, Biaxin XL, and therefore vacated a preliminary injunction that had been entered against Teva by the U.S. District Court for the Northern District of Illinois.

Clarithromycin is used to treat bacterial respiratory infections.  Annual sales of Biaxin XL are approximately $255 million.

The majority opinion found that Teva had raised a substantial question that the patent in suit was obvious.  For example, with respect to two claims covering extended release formulations of clarithromycin, the court held that Abbott's own prior art patent on azithromycin compositions rendered the clarithromycin claims of the patent in suit obvious.  In reaching this holding, the majority inferred an "admission" from Abbott's prior art patent (the '190 patent):

We presume that Abbott filed and prosecuted the '190 patent respresenting that claim 14 of the '190 patent [directed to azithromycin compositions] satisfies the written description and enablement requirements of 35 U.S.C. 112.  See Amgen Inc. v. Hoechst Marion Roussel, Inc., 314 F.3d 1313 (Fed. Cir. 2003) ("We hold a presumption arises that both the claimed and unclaimed disclosures in a prior art patent are enabled.").  Because the '190 patent explicitly discloses only clarithromycin controlled release compositions, yet claims azithromycin compositions, we conclude that Abbott has represented to the [patent office] that the differences between clarithromycin and azithromycin were such that azithromycin could be substituted into a controlled release clarithromycin composition by a person of ordinary skill in the art without undue experimentation.

Judge Newman wrote a 9-page dissent in which she characterized the majority opinion as a "de novo and incorrect contrary ruling."  She stated, "My colleagues ignore the district court's analysis, offering neither deference nor acknowledgement."  Specifically, Judge Newman said the court should have deferred to the district court's finding that the substitution of azithromycin with clarithromycin was merely "obvious to try."  She wrote, in summary, "My colleagues conclude that claim 4 of the [patent in suit] is 'vulnerable to allegations of invalidity,' and find 'a substantial argument' as to other claims.  These are not the criteria of likelihood of success."

The suit was initiated in March 2005.  A bench trial is scheduled for March of next year.  Teva has yet not indicated when it intends to launch its generic version of Biaxin XL.