The Federal Circuit has affirmed an ITC decision finding two asserted patents invalid because they did not satisfy the best mode requirement of 35 U.S.C. §112.

The two patents relate to improved methods of producing L-lysine using genetically modified E. coli.  (L-lysine is a dietary supplement in animal feed and has a multi-billion dollar market worldwide.)  The patent disclosed one method of creating the L-lysine producing E. coli.  However, before the patent applications were filed, the inventors created another, better strain.  (The evidence also established that the better strain was intentionally withheld from the patent applications.)

§112 requires that the inventor disclose the preferred embodiment of the invention and any preferences that materially affect the claimed invention, but only to the extent that information is known by the inventor when an application is filed.

The patentee unsuccessfully argued that the improvements in the better E. coli strain related to other, non-patentable, improvements that were not related to the “inventive aspects” of the claimed invention.

Here, the best mode requirement was not met due to the breadth of the claims.  The asserted claim recited the step of “cultivating a bacterium belonging to the genus [E. coli] … having mutation to desensitize feedback inhibition of L-lysine.”  Because the scope of the claimed invention included “cultivating a bacterium,” the failure to disclose the preferred, and in one case, only bacterial strain used by the patentee to practice the claimed invention the best mode requirement was not met and the asserted patents were held invalid.

See Ajinomoto Co., Inc. v. International Trade Commission (Fed. Cir. 2010).  

Thus, it is important to keep your attorney apprised of any modification to the invention, particularly if you believe the modification is preferred, up to the filing date your patent application.

Note: the current version of the Patent Reform Act of 2010 eliminates the invalidity defense for failing to disclose the best mode, which would likely have  flipped the verdict in a case such as this.