Federal Circuit Invalidates Abbott's Sevoflurane Patent in Case Against Baxter

The Federal Circuit today reversed a district court decision that upheld the validity of Abbott's U.S. Patent No. 5,990,176, finding instead that Abbott's patent is inherently anticipated by U.S. Patent No. 5,684,211.  The '176 patent covers compositions of and processes for making sevoflurane, an inhalation anesthetic that Abbott sells under the brand names Ultane and Sevorane.  In 2001 Baxter filed an ANDA to market generic sevoflurane.

The '176 patent claims compositions comprising sevoflurane and a Lewis acid inhibitor (such as water) in an amount effective to prevent degradation of sevoflurane.  The '211 patent discloses a water-saturated sevoflurane composition, though the inventors did not recognize at the time that the water in the composition prevented degradation of sevoflurane.  At trial, the U.S. District Court for the Northern District of Illinois relied on Bristol-Myers Squibb v. Ben Venue in concluding that the '211 patent did not inherently anticipate the '176 patent because the purpose of the '211 patent was not to produce sevoflurane in its final usable form, in distinction to the purpose of the patent-in-suit.

The Federal Circuit's decision, written by Judge Garjarsa for a unanimous panel, noted initially that BMS v. Ben Venue applies only to process claims, and therefore is inapplicable to the composition claims of the '176 patent.  With regard to the process claims of the '176 patent, the Federal Circuit disagreed that the processes described in the '176 and '211 patents are directed to the same purpose.  The court stated:  "All that is contributed by the method claims of the '176 patent is the recognition of a new property of the prior art process."

Judge Gajarsa's opinion reaffirms the general principle that "a reference may anticipate even when the relevant properties of the thing disclosed were not appreciated at the time."  In support of this principle, the Federal Circuit cited its own 1985 opinion in Titanium Metals and an 1892 Supreme Court decision, Ansonia Brass & Copper Co.

RELATED READING:

• More on the case at Patent Docs

Comments

[Asok]

How do you draft a process claim with a "commercial finality" element? (See last sentence of the decision before the Conclusion section). How do you make it sound like a claim limitation rather than a "whereby" clause?

[Thalita]

I have some doubts referring to this case. I can notice that the '176 patent is invalid by very clear reasons. However there is no mention regarding to the continuation patents of the same.
Considering that the original patent is clearly invalid how do the court used to interpret the validity of the subsequent patents (continuations)? Are they automatically invalid, too?

Regards