Federal Circuit interprets the term “batches” in patent claims to require a specific process of “efficient mixing” from specification

The patentee sued the alleged infringer for infringing patents claiming pharmaceutical formulations of bivalirudin. The ‘727 patent claimed pharmaceutical “batches” of bivalirudin with a particular impurity profile. The ‘343 patent claimed pharmaceutical “batches” of bivalirudin made by a particular process and having a particular impurity profile. The district court construed the ‘343 patent claim language but not the ‘727 patent claim language to require “efficient mixing.” Based on the “efficient mixing” limitation, the district court found that the ‘343 patent was not infringed. Because the ‘727 patent did not include the “efficient mixing” limitation, the district court found it was infringed.

The Federal Circuit held that the claim language of both the ‘727 and ‘343 patents required “efficient mixing.” The word “batches” in the claim language “requires the use of a compounding process that achieves batch consistency” and the compounding process must use “efficient mixing.” If the batches limitation did not require “efficient mixing,” the limitation was otherwise disclosed by the prior art.

The patents disclose two embodiments in the specification—Example 4, describing “inefficient mixing,” and Example 5, describing “efficient mixing.” The district court construed “efficient mixing” as “not using inefficient mixing conditions as described in Example 4.” The Federal Circuit noted that while there is no per se rule against negative constructions, “efficient mixing” is defined and limited by the process described in Example 5 of the specification. The Federal Circuit relied on Example 5 to ensure the patent claim was definite and because it is the only description that enables potential infringers to determine if their conduct infringes on the patents.

Thus, the patents would be infringed only if batches were produced using a process that employs the efficient mixing conditions of Example 5. Because the alleged infringer’s ANDA product did not, on its face, use a process that employs the efficient mixing conditions of Example 5, such as using multiple mixing devices, the alleged infringer’s ANDA product did not infringe the patents.