Bayer Patent on Yasmin Affirmed Invalid

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Bayer Schering v. Barr Labs, No. 2008-1282 (Fed. Cir. 2009)

A divided panel of the Federal Circuit affirmed a district court decision holding Bayer's (OTC:BYERF) U.S. Patent No. 6,787,531 invalid due to obviousness. The '531 patent, which claims pharmaceutical compositions of drospirenone and ethinyl estradiol, protects Bayer's popular birth-control pill Yasmin. In today's decision, the majority (Judges Mayer and Friedman) held that "the invention would have been obvious to try." Judge Newman dissented.

Drospirenone is an acid-sensitive and poorly soluble compound. The use of drospirenone with ethinyl estradiol was known in the prior art, but, according to Bayer, formulations of micronized drospirenone in a normal (not enteric coated pill) would not have been obvious, especially since the prior art taught that an enteric coating is necessary to protect drospirenone from the acidic environment of the stomach.

The majority, however, disagreed. Citing KSR, the majority stated that a person having ordinary skill in the art would have chosen

between two known options: delivery of micronized drospirenone by a normal pill . . . or delivery of drospirenone by an enteric-coated pill . . . . This is a finite number of identifed, predictable solutions. The prior art would have funneled the formulator toward these two options; he would not have been required to try all possibilities in a field unreduced by the prior art . . . .

In dissent, Judge Newman argued that the actual experience of the Bayer scientists should be dispositive. They testified, without contradiction, "that it was not reasonably expected that uncoated micronized drospirenone would be 99+% effective as an oral contraceptive when ingested into the acid stomach, when it was known to degrade rapidly in acid." According to Judge Newman, "the exercise of judicial expertise to override the clear evidence of how persons of skill in this field actually behaved, is inappropriate."

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