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In an ANDA case, the court affirmed the district court’s grant of summary judgment that claims 1-2 of the patent-in-suit were invalid as being obvious and that claims 5-9 were not infringed either literally or under the doctrine of equivalents.  The patent claimed a substantially pure form leucovorin having 92% of the (6S) diastereoisomer.  The court held that such a composition was obvious because 50-50 mixtures of the (6R) and (6S) versions of the compound were known, preparations of purified (6S) version were known, and it was known that the (6S) version provided the therapeutic usefulness.  Spectrum argued that, despite this knowledge, there was no evidence of any motivation to obtain the claimed mixture having 92% of the (6S) compound.  The court found that starting with the 50-50 mixture and knowing that the (6S) version was more desirable, one would have been motivated to purify that mixture to provide more of the (6S) version.  The court further found that the slightly impure mixture of the claims did not possess unexpected advantages over the prior art pure material and therefore it cannot be found to be nonobvious.  

Spectrum Pharmaceuticals, Inc. v. Sandoz Inc., Case No. 2015-1407 (October 2, 2015); Opinion by: Lourie, joined by Wallach and Hughes; Appealed From: District Court for the District of Nevada, Navarro, J.  Read the full opinion here.

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