In Spectrum Pharmaceuticals, Inc. v. Sandoz Inc., Appeal No. 2014-1407, the Federal Circuit affirmed the district court’s grant of summary judgement of noninfringement because Sandoz’s product would not meet the dosage claim limitation and Spectrum was estopped from invoking the doctrine of equivalents.  The Federal Circuit also affirmed the district court’s holding that other claims directed to a substantially pure compound were obvious when both the 50/50 compound mixture and the pure compound were known in the art.

Sandoz submitted an ANDA in October 2011 seeking FDA approval for a levoleucovorin drug product.  Spectrum sued Sandoz for infringement of a patent related to pharmaceutical compositions of substantially pure levoleucovorin.  The claims at issue were directed to pharmaceutical compositions comprising a mixture of (6S) and (6R) leucovorin isomers, with at least 92% or 95% of the (6S) isomer (levoleucovorin).

After construing the claims, the district court granted Sandoz’s motion for summary judgment of noninfringement for certain claims.  It later held that other claims were invalid for obviousness.  Spectrum appealed, and the Federal Circuit affirmed.  The Federal Circuit concluded that the district court did not clearly err in finding that the product Sandoz planned to sell would not literally infringe the claims.  Sandoz’s product would only contain up to 250 mg of levoleucovorin, much less than the two doses of 2000 mg required by the construed claims.  There was also no clear error in concluding that Sandoz was estopped from invoking the doctrine of equivalents.  The claims were added in an amendment and the applicants had distinguished the prior art by pointing to the claimed quantities of the specific mixtures.  

As for obviousness, the Federal Circuit again concluded that the district court did not clearly err in finding certain claims invalid.  The district court had found that two prior art references disclosed processes for separating leucovorin isomers, and these processes would have “invariably” produced a mixture containing the (6R) isomer as an impurity.  The Federal Circuit noted that both the 50/50 mixture and the pure compound were known in the art and Spectrum did not provide any evidence of unexpected results for the claimedsubstantially pure compound. The Federal Circuit also concluded that the district court did not err in finding that Spectrum failed to provide sufficient factual evidence of other secondary considerations (including long-felt need) to rebut the prima facie case of obviousness.