The U. S. Court of Appeals for the Federal Circuit, reversing a bench ruling on the issue of validity, relied on the long-held rule that prior art compositions anticipate even when there was no knowledge of the relevant properties of the composition to find the patent-in-suit anticipated. Abbott Laboratories and Central Glass Company, Ltd. v. Baxter Pharmaceutical Products, Inc., Case No. 06-1021 (Fed. Cir., Nov. 9, 2006) (Gajarsa, J.).
Baxter Pharmaceutical filed an Abbreviated New Drug Application (ANDA) to market sevoflurane, an inhalation anesthetic, certifying that Abbott Laboratories' patent on the compound was non-infringed and invalid. Abbott's patent solved the problem that sevoflurane was highly susceptible to Lewis acids degradation occurring during shipping and storage and claimed compositions and methods of combining water and sevoflurane to prevent Lewis acid degradation.
Following a bench trial finding of the patent to be not invalid but not infringed, both sides appealed. Baxter argued invalidity based on a prior art patent that described sevoflurane saturated with water as an interim step in the technique for preparing purified sevoflurane for use as an inhalation anesthetic. The Federal Circuit rejected the argument that because the beneficial nature of the water-sevoflurane mix to inhibit Lewis acid degradation was unknown at the time, the prior art did not anticipate the claims. The Federal Circuit noted that it has consistently held a reference anticipates even when the relevant properties of the thing disclosed were not appreciated at the time.
In rejecting the argument based on Bristol-Myers Squibb, that new uses of known processes may be patentable, the Federal Circuit explained that in both the prior art and the claimed invention, the description of the process of using a water/sevoflurane mixture had the purpose of ensuring that sevoflurane would be of high purity at the time it was administered to patients, and both relied upon the same method of achieving that end, i.e., adding water. The Court found the fact that the addition of water described in the patent included a newly discovered property of also guarding against impurities generated by the presence of Lewis acids was immaterial, since the steps of the method and its objective were the same as those of the prior art. An inventor may not obtain a patent on a process having the same steps as a prior art process, in which the new process merely identifies a new, advantageous property of the prior art process.
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