US CAFC upholds Aventis Lovenox (enoxaparin) patent enforceability

(Aventis Pharma SA v Amphastar Pharmaceuticals [2006] CAFC - 10 April 2006)

Copyright Thursday, April 13, 2006 Duncan Bucknell Company

On 10 April 2006, Judges Radar, Schall and Prost of the United States Court of Appeal for the Federal Circuit handed down their decision in Aventis Pharma SA v Amphastar Pharmaceuticals [2006] CAFC - 10 April 2006.

Take home

While Aventis’s failure to disclose the correct comparative data was material, there was insufficient evidence before the District Court to base a finding of intent to deceive the USPTO on summary judgment.

Facts

In the latest round of a Hatch-Waxman paragraph IV dispute, Aventis appealed a decision of the US District Court for the Central District of California which granted summary judgment in favour of Amphastar and Teva and held US Patent No. 5,389,618 and US Reissue Patent No. 38,743 unenforceable. The ‘618 and ‘743 patents claim mixtures of low molecular weight heparins used to prevent blood clots and cover Aventis’s Lovenox product.

The district court had granted a motion for summary judgment of unenforceability without holding a hearing and based on repeated representations by Aventis of patentability based on the purported half-life of the claimed products. The court found Aventis at fault for comparing data based on different doses to show an improved half-life when a comparison of available data using the same doses actually showed that there was little if any difference between the half lives of the prior art and the purported invention.

The Court found the omission by Aventis to meet the test for materiality but held that based on the evidence before the District Court, it was inappropriate to find an intent to deceive the USPTO on summary judgment.

The lower court’s decision was reversed and remanded for further consideration.

Comment

A patent challenger seeking summary judgment in relation to inequitable conduct will do well to establish as far as possible an intent to deceive the USPTO.It will always be open to the patentee, however, to challenge the motion by pointing to any one of a potentially large number of remaining genuine issues of fact.