Pfizer v. Ranbaxy (Fed. Cir. 2006).
In an infringement suit arising from Ranbaxy’s ANDA filing, Pfizer’s two patents covering Lipitor (atorvastatin) were upheld as infringed and not-invalid by the district court Judge Farnan. On appeal, the CAFC affirmed on one patent (leaving Lipitor covered), but found the asserted claim of the second patent (the ‘995 patent) invalid under Section 112, paragraph 4 because of an improper dependent claim structure.
Section 112 of the Patent Act requires, inter alia, that a dependent claim incorporates by reference all the limitations of the parent claim and also specifies a further limitation.
Pfizer’s asserted claim 6 depends from claim 2, which depends from claim 1. The subject matter of the claims is as follows:
Claim 1: (1) atorvastatin acid; or (2) atorvastatin lactone; or (3) pharmaceutically acceptable salts thereof.
Claim 2: atorvastatin acid but not atorvastatin lactone or a pharmaceutically acceptable salts.
Claim 6: the hemicalcium salt of the compound of claim 2.
Thus, claim 6 fails to "specify a further limitation of the subject matter" of the parent claim (as requred by 112) because the subject matter of claim 6 is completely outside the scope of claim 2.
Consequently, based on violation of the statute, the court found that the claim was invalid.
Although the district court was reluctant to find the fourth paragraph of § 112 to be an invalidating provision, doing so does not exalt form over substance. Rather, it is consistent with the overall statutory scheme that requires applicants to satisfy certain requirements before obtaining a patent, some of which are more procedural or technical than others.
Reversed in part. Pfizer may be able to correct this defect through a reissue application, although there is some question as to whether the defect here falls within an identified category.