A PTO Decathlon

Cancer Research Technology Ltd. v. Barr Laboratories, Inc.

Forget shot put and the long jump. The latest Olympian achievement in the annals of patent law comes from a patent which defeated a claim of prosecution laches despite a decade-long prosecution history replete with the filing and abandonment of ten successive patent applications and continuances. None of this was enough to entitle an accused infringer to a prosecution laches defense. The infringer won in the district court. The judge held that the patent holder had no credible reason or explanation for its prosecution delays. But a divided panel of the Federal Circuit reversed. The majority held that a defense of prosecution laches also requires a showing of prejudice in the specific form of intervening rights during the period of delay-which the accused infringer could not prove. A vigorous dissent by Judge Prost challenged the particularized prejudice required by the majority, perhaps signaling an en banc review that could reveal that someone jumped the gun.

In Cancer Research Technology Ltd. v. Barr Laboratories, Inc., a British pharmaceutical company filed its original patent application on August 23, 1982. The patent application covered a genus of compounds intended to treat cancer. The PTO had its first office action on the application on November, 18, 1983, when it rejected some of the pending claims. Instead of responding, the original applicant abandoned the application and filed a continuation application-a course of conduct it would repeat ten more times over the next ten years. After assignment of ownership rights and the patent application to Cancer Research, the ultimate patent holder, prosecution of the eleventh application finally occurred and the patent issued in November 1993.

In 2007, Barr Laboratories, Inc. and Barr Pharmaceuticals, Inc. (collectively, "Barr") challenged the validity of the patent and sought permission from the FDA to make a generic version of the drug covered by the patent. Cancer Research then sued Barr for infringement. The parties stipulated to infringement, leaving the district court to decide the sole remaining issue: Barr's assertion that prosecution laches and inequitable conduct made the patent unenforceable. The district court concluded that the decade-long string of continuances and abandonments constituted a sufficiently egregious misuse of the patent system to bar enforcement of Cancer Research's patent. The district court also held the patent unenforceable for inequitable conduct because of the inventor's failure to tell the PTO about research results he published elsewhere.

Reversing on appeal, the panel majority found that a prosecution-laches defense requires a showing of prejudice as well as an unreasonable and unexplained delay. The majority held that to prove prejudice, an accused infringer must provide evidence showing that the delay in prosecution adversely affected others working in the same field during the delay period. Without evidence showing that someone invested in, worked on, or used the claimed technology during the period of delay, no prosecution laches can exist. Here, Barr could not show any instances of such intervening rights, leaving the majority to conclude that the only effect of the delay was a limitation on Cancer Research's own patent term. The dissent criticized the majority's temporal restriction on prejudice as well as the reversal of Barr's inequitable conduct affirmative defense.

Patent terms can no longer be delayed through multiple application re-filings because the controlling statute now measures patent terms from the effective filing date with only limited opportunities for extensions. Still Cancer Research's result is one for the record books. Any accused infringer hoping to experience the thrill of victory that comes with establishing the affirmative defense will need to follow the decision and demonstrate that the prosecution delay caused some prejudice to someone other than the patent holder during the time of the delay. Only by seeking that evidence early and being ready to include third-party discovery efforts to find proof of intervening rights can a prosecution-laches defense avoid Barr's fate-and the agony of defeat.

The articles on our Website include some of the publications and papers authored by our attorneys, both before and after they joined our firm. The content of these articles should not be taken as legal advice.