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U.S. Patent Office Issues Initial Rejection of Pfizer’s Reissue Patent Application on Lipitor

As The Wall Street Journal reported last week, the U.S. Patent and Trademark Office has issued an initial rejection of Pfizer’s application for a reissue patent of U.S. Patent No. 5,273,995–one of two Pfizer patents covering Lipitor.

In a decision last August, the Court of Appeals for the Federal Circuit upheld one Pfizer patent on Lipitor (U.S. Patent No. 4,681,893) and invalidated another (the ‘995 patent).  Specifically, the court invalidated claim 6 of the ‘995 patent, covering the hemicalcium salt of atorvastatin acid (the active ingredient in Lipitor), because it failed to specify a further limitation to the claim from which it depended.  Pfizer sells about $12 billion worth of Lipitor annually.  The ‘995 patent (if valid) was set to expire more than a year later than the ‘893 patent will expire, so naturally Pfizer filed a reissue patent application to try to correct the ‘995 patent.

In a preliminary amendment filed as part of its reissue application in January, Pfizer amended claim 6 of the ‘995 patent to be an independent claim, and indicated that "this was one of the options . . . approved by the Federal Circuit in its decision."

Ranbaxy–the first ANDA filer for generic Lipitor and the defendant in the patent litigation decided by the Federal Circuit–filed a protest against Pfizer’s reissue application in May.  Among Ranbaxy’s arguments was that the defect in claim 6 is not correctable through a reissue patent.

The Patent Office mailed a first Office Action on Pfizer’s reissue application last Thursday.  While the Patent Office stated that the defect in claim 6 is in fact correctable through a reissue application, the Office rejected all 14 claims of Pfizer’s reissue application on grounds of anticipation, obviousness, or obviousness-type double patenting.  In particular, the Office rejected claim 6 for obviousness-type double patenting in view of U.S. Patent Nos. 6,605,729 and 5,969,156.

The proceedings over Pfizer’s reissue patent application are far from over.  Pfizer will certainly file a response to last week’s Office Action, after which the Patent Office might issue a final Office Action.  If Pfizer is unsatisfied at that point, it might request continued examination or file an appeal to the Patent Office Board of Appeals.  If rebuffed there, Pfizer could appeal to the Federal Circuit.  Given how much money is at stake, Pfizer is likely to pursue all its options before giving up on the reissue application.

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2 responses to “U.S. Patent Office Issues Initial Rejection of Pfizer’s Reissue Patent Application on Lipitor”

  1. anon Avatar
    anon

    Analysis:
    The critical claims at issue (6,13 and 14 i.e. those claiming atorvastatin calcium) were held allowable by the examiner except for a obviousness type double-patenting over two patents. But both cited patents have expiration dates well past the expiration date for the ‘995 patent. Which means that filing a terminal disclaimer over those two patents will not have any adverse effect.
    Thus, Pfizer can simply cancel the other rejected claims (perhaps pursue them in a continuation of the reissue), and get the crucial claims reissued expeditiously.
    On the other hand, Pfizer may strategically choose to continue pursuing the other (unimportant) rejected claims simply to delay the issuance of the reissue patent, and thereby delay the anticipated litigation by Ranbaxy. This may have the effect of pushing the litigation well past the 15-month period between the expirations of the ‘893 and the ‘995 patents.
    But then, if Pfizer lets the allowable claims sit too long in the PTO, other events may change in the interim that may cause the examiner to change his position on allowability.
    The Federal Curcuit refused to review the district court’s findings of patentability, other than the “dependent claims issue” (i.e. s. 112 p. 4), holding that single issue was dispositive of the case. However, the CAFC unwillingness to review the other issues, may now come back to haunt Ranbaxy. Perhaps these issues can never be relitigated because of collateral estoppel. Even if estoppel won’t be applied (at least at the circuit court level), nevertheless the delayed litigation will certainly hurt Ranbaxy.
    It’s a shame the Federal Circuit did not anticipate these turn of events.

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  2. Cary Avatar
    Cary

    The good news for Pfizer is that it was a “non final rejection.” According to Pfizer spokesman Bryant Haskins, “An initial rejection is not uncommon in reissue application proceedings. Once we receive the decision we’ll review it and respond appropriately to address any issues that were raised by the examiner.”
    If the US Patent and Trademark Office rules against Pfizer, they will be reeling. Lipitor is the best-selling drug in the world, selling around $12.9 billion last year alone. Losing the patent on Lipitor and having no new drug in the pipeline to take its place will be a tough blow for Pfizer to take.

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