IP Law Daily, TOP STORY—Fed. Cir.: Pfizer’s priority award affirmed in dispute over isolation of DNA segment, (Nov 5, 2013)

By Mark Engstrom, J.D.

An award of priority to Pfizer for conceiving and reducing to practice a DNA polynucleotide that encoded a protein binding chain for interleukin-13 receptors was affirmed by the U.S. Court of Appeals for the Federal Circuit (Sanofi-Aventis v. Pfizer Inc., November 5, 2013, Newman, P.).

Background. Interleukin-13 (IL-13) is a regulatory molecule called cytokine, a protein that functioned by interacting with a target cell’s cytokine receptors (IL-13R). The subject of the interference proceeding was a DNA polynucleotide that encoded the protein binding chain of IL-13R. Both Sanofi and Pfizer conducted IL-13 research, for therapeutic and diagnostic purposes, and both discovered and filed patent applications that described the polynucleotide that encoded the IL-13 binding chain of IL13R.

Interference proceeding. The Board of Patent Appeals and Interferences awarded Sanofi the benefit of a December 6, 1995 priority date. Because Pfizer’s filing date was three months later (March 1, 1996), Pfizer bore the burden of proving a conception date that was earlier than Sanofi’s benefit date.

Pfizer presented documentary and testimonial evidence that it had isolated and identified the desired complementary DNA before Sanofi’s benefit date. Although sequencing errors prevented Pfizer from having “a completely accurate analysis of the entire nucleotide sequence” at that time, the Board found that Pfizer nevertheless had the polynucleotide “in hand,” with “some additional identifying information,” including a partial sequence. In light of that finding, the Board ruled that Pfizer had conceived of the relevant polynucleotide and reduced it to practice before Sanofi’s benefit date.

Appeal. Sanofi argued that Pfizer could not be credited with a conception date that was prior to Sanofi’s benefit date because Pfizer’s sequence analysis on the benefit date was incorrect as to 8 of the polynucleotide’s 1143 monomers. According to Sanofi, Federal Circuit precedent required a full and correct nucleotide sequence to establish conception because reduction to practice, whether actual or constructive, required the full and correct nucleotide sequence. The issue thus became whether Pfizer’s conception was negated because the incorrect nucleotide sequence was not corrected until after Sanofi’s benefit date.

The court concluded that the Board had correctly based Pfizer’s conception and reduction to practice on its possession of an isolated DNA segment that was shown to have the desired properties. When the subject matter was a DNA segment, the court explained, conception required possession and appreciation of the DNA segment that was claimed. In this case, the Board found that Pfizer had successfully searched for and isolated the IL-13R binding chain segment, and had possessed and appreciated the isolated segment before the Sanofi benefit date.

Discussing the consequences of Pfizer’s flawed sequence analysis, which was corrected after Sanofi’s priority date, the Board noted that, “[f]or proteins and polynucleotide species, a sequence [wa]s the gold standard for identifying species with precision … It d[id] not, however, thereby follow that a sequence [wa]s the only way to identify the composition precisely.”

Ultimately, the Board found that Pfizer had sufficiently identified the relevant composition by selecting, isolating, and characterizing the IL-13 binding chain before Sanofi’s benefit date. In addition, Pfizer had defined the binding chain, “so as to distinguish it from other materials, and to define how to obtain it.” According to the court, those findings were supported by substantial evidence.

In light of those findings, the Board held that Pfizer had conceived the isolated polynucleotide, and reduced it to practice, before Sanofi’s benefit date. Because the court concluded that the Board had applied the correct law, Pfizer’s priority award was affirmed.

The case is No. 2012-1345.

Attorneys: Thomas J. Vetter (Lucas & Mercanti, PP) for Sanofi-Aventis. Z. Ying Li (Ropes & Gray, LLP) for Pfizer Inc.

Companies: Sanofi-Aventis; Pfizer, Inc.

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