The U.S. Court of Appeals for the Federal Circuit has let the air out of a Bayer Pharma AG erectile dysfunction drug.

A unanimous panel ruled Wednesday that a patent covering Bayer’s orally disintegrating version of Levitra is obvious in light of numerous previous patent applications and medical journal articles.

The decision reversed a ruling by U.S. District Judge Gregory Sleet of the District of Delaware, who had found following a six-day bench trial that the prior art “teaches away” from Bayer’s orally disintegrating formulation, known as Staxyn.

“We hold the district court clearly erred in finding a skilled artisan would not have been motivated to use the claim elements,” Judge Kimberly Moore wrote for the court. Judges Alan Lourie and Kathleen O’Malley concurred.

Bayer v. Watson is a win for Goodwin Procter partner William Jay, who argued the appeal for Teva Pharmaceutical Industries Ltd., which owns the named parties Watson Laboratories Inc. and Actavis Pharma Inc. Williams & Connolly partner David Berl argued for Bayer.

Levitra is a phosphodiesterase inhibitor similar to Viagra and Cialis, the two leading ED drugs on the market. Patents on all three are nearing expiration.

Bayer patented Staxyn, which combines Levitra’s active ingredient with mannitol and sorbitol, in 2013.

Bayer argued, and Sleet agreed, that other manufacturers would not have been motivated to combine the ingredients. Pfizer Inc. had announced plans to launch an orally dissolving version of Viagra in 1998, but had not brought the patent to market by 2005, when Bayer applied for the Staxyn patent. And Levitra’s active ingredient, vardenafil hydrochloride trihydrate, has a bitter, unpleasant taste.

Moore ruled that is not enough to defeat a claim for obviousness, especially given all the  literature available in 2005 about orally dissolving ED drugs.

“The motivation to combine inquiry is not limited to what products are forthcoming or currently available on the market,” Moore wrote. “Particularly given the lengthy FDA approval process, the pharmaceutical industry is no exception.”

Moore added that Sleet overlooked a sorbitol-based excipient that was advertised at the time as “impart[ing] a sweet taste and a unique texture to the mannitol, thereby improving the ODT formulation’s mouthfeel.”