Abbott Labs. v. Baxter Pharm. (Fed. Cir. 2006).
Way-back-when, Abbott went through a recall of its inhalation anesthetic sevoflurane because of excess Lewis acid buildup. Abbott’s scientists figured-out that mixing water in the solution would bind an deactivate Lewis acids, and stabilize the product. Abbott changed its product and also obtained patent protection.
When Baxter filed its Abbreviated New Drug Application (ANDA) to begin selling its version of a sevoflurane inhaler, Abbott sued for infringement. After a bench trial, the patent was found valid, but not infringed. Abbott appealed.
The CAFC pointed its laser vision on the question of validity. A prior reference had indicated that water could be combined with sevoflurane, but had not realized that the composition would work to prevent the acid buildup. Framed in this manner, the prior-art was found to be anticipatory:
Our cases have consistently held that a reference may anticipate even when the relevant properties of the thing disclosed were not appreciated at the time.
The CAFC went-on to find that a claim directed to the newly discovered property of the prior art cannot support a patent because it is inherently disclosed by the art.
This rule holds equally well to process claims:
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.
Reversed on validity.