CAFC affirms obviousness and unenforceability of Sanofi’s docetaxel (TAXOTERE) formulation patents

The Court of Appeals for the Federal Circuit recently affirmed a District Court’s finding that claim 5 of U.S. patent No. 5,750,561 and claim 7 of U.S. patent No. 5,714,512 are invalid for obviousness and that these patents are unenforceable for inequitable conduct.  The relevant claims (with simplifying substitutions between square brackets in the ‘512 Patent), read in relevant part:

‘561 Claim 5 – A perfusion, which contains approximately 1 mg/ml or less of compound of formula as defined in claim 1, and which contains less than 35 ml/l of ethanol and less than 35 ml/l of polysorbate, wherein said perfusion is capable of being injected without anaphylactic or alcohol intoxication manifestations being associated therewith.

‘512 Claim 7 – A composition comprising a compound of the formula [genus of chemical structures including docetaxel], said composition being dissolved in [polysorbate], said composition being essentially free or free of ethanol.


On appeal, Sanofi challenged the District Court’s construction of “perfusion” and “essentially free or free of ethanol.”  Sanofi submitted that “perfusion” requires the formulation to also be effective for treatment, safe and stable for at least 8 hours. The Court “easily” rejected the first two proposed limitations holding that neither the specification nor the prosecution history suggested that the claimed perfusion must satisfy certain safety or efficacy standards.   In support of the third limitation, Sanofi relied on language within the specification disclosing that “no precipitation phenomenon is seen to appear within approximately 8 hours” and that the perfusion examples disclosed in the ‘561 patent have stabilities exceeding eight hours.  The Court, following the stringent standard for narrowing a claim term adopted in Thorner v. Sony Computer Entertainment America L.L.C., refused to read the eight hour stability limitation into claim 5, holding:

In sum, we conclude that the patentee did not narrow  the ordinary meaning of “perfusion” in claim 5 of the ’561 patent by either acting as its own lexicographer or disclaiming claim scope and therefore agree with the district court that a “perfusion” is simply “an injectable solution containing the active pharmaceutical ingredient and an aqueous infusion fluid.

During oral argument before the CAFC, Sanofi did not dispute that claim 5, as construed by the District Court, was obvious in light of certain prior art.  Because the CAFC affirmed the District Court’s construction of “perfusion”, it also affirmed that claim 5 of the ‘561 patent was invalid for obviousness.

Sanofi submitted that “essentially free or free of ethanol” in the ‘512 patent means “the same amount of ethanol as a stock solution with no more than 5% ethanol by volume.”  The CAFC concluded that it did not need to resolve the proper construction of this term because Sanofi’s opening brief had not addressed the District Court’s obviousness finding with respect to stock solutions and affirmed the District Court’s unchallenged finding of obviousness of claim 7.

Inequitable Conduct

The CAFC also affirmed that the ‘512 and ‘561 patents were unenforceable for inequitable conduct arising from an inventor’s failure to disclose two material prior art references.  Although the District Court had reached its conclusion before the CAFC’s en banc decision in Therasense, Inc. v. Becton, Dickinson & Co., the CAFC held that the District Court had properly applied the more rigorous “but-for” materiality analysis adopted in Therasense.  The CAFC further concluded that the District Court’s finding that one of the inventors acted with a specific intent to deceive the USPTO was not clearly erroneous and affirmed the District Court’s finding of unenforceability.

A copy of the CAFC’s opinion may be found here.