Last week, in Novartis, et al., v. West-Ward Pharmaceuticals International Limited, the District of Delaware denied Defendant’s motion in limine seeking to exclude “post art” evidence, i.e. references published after the critical date, as irrelevant and prejudicial.  In its order, the court remarked that though there are some limitations, post art can be offered for a number of purposes.

Specifically, even though references published after the critical date do not qualify as prior art, such “post art” may be admissible “(1) to show circumstantially what was known or unknown earlier—if something was an open question in 2002, it could be inferred that it was an open question in 2001; (2) to corroborate what an expert says—[e.g., post art might support an expert’s statement that there was a motivation to combine]. . .; and (3) to show directly something that was known at an earlier time.” The court did caution, however, that “the further away in time one gets from the relevant date, the less likely the post art is relevant.” Even with these restrictions, “post art” could prove to be valuable evidence for parties supporting or challenging the validity of patents in Hatch Waxman litigation.

The district court also confirmed that, at least in Delaware, the Court expects defendants’ experts to have a chance to respond to plaintiffs’ invalidity experts. “[I]n the normal course, [the invalidity experts] should have the last word.”