Patent Law

Pfizer v. Teva (Fed. Cir. 2008)

A family of three Pfizer patents covers aspects of the bestselling drug Celebrex. Seeing some possible holes* in the patents, Teva field an Abbreviated New Drug Application (ANDA) with the FDA with a Paragraph IV certification challenging the patents as invalid and unenforceable.

Continuation-in-Part After Restriction: 35 USC 121 blocks the use of a parent application “as a reference … against a divisional application” if the divisional was the result of a restriction requirement. 

One of the Pfizer patents (the ‘068) is a continuation-in-part (CIP) filed after a restriction requirement. On appeal, the CAFC confirmed that Section 121 does not apply to CIPs: “a divisional application contains an identical disclosure to its parent application, but a CIP introduces new matter. . . . [T]he protection afforded by section 121 . . . is limited to divisional applications.”

Thus, the parent application of a CIP will potentially be used for an obviousness-type double patenting rejection. Here, the CAFC held that the CIP claims were indeed obvious when compared to the parent application.

Pfizer’s Strategy: From Dan Feigelson’s comment below:

Pfizer could have cured the problem with the '068 patent - even during the trial or the appeal - by filing a terminal disclaimer in that patent. I'm guessing they chose not to b/c they had nothing to lose and everything to gain by having the court adjudicate the question of 35 USC 121 to CIPs.

Best Mode: A patent is invalid when the applicant fails to satisfy the best mode requirement of Section 112. The requirement can be broken down into two elements:

1. Whether the applicant subjectively “possessed” a best mode for practicing the invention at the time the application was filed; and, if so,
2. Whether the disclosure would objectively enable a PHOSITA to practise the best mode.

Like other invalidity issues, best mode is determined on a claim-by-claim basis.  There was no real question here that the COX-specific claims did satisfy the best mode requirement. The appellate panel refused to speculate further on the moot issue of how the best mode requirement is met for claims covering a larger class of compounds.

Note:

• * The post was updated to ensure that Patently-O remains non-controversial (See comments below).