In Sanofi-Aventis v. Pfizer, Inc., the Federal Circuit affirmed the USPTO’s determination that Pfizer had proven an earlier date of invention of the DNA sequence at issue, even though it did not have the full, correct nucleotide sequence at the time. Because the subject matter at issue relates to cDNA, it remains patent-eligible under the Supreme Court’s Myriad decision. While the America Invents Act will phase out interference proceedings, new interferences still can arise between first-inventor-to-file patents and applications, and similar issues will remain relevant to questions of inventorship.

The Invention at Issue

This case arose out of an interference proceeding with the following count:

The isolated protein of 6,268,480 claim 4


The isolated polynucleotide of 5,710,023 claim 1, selection (b) (an isolated polynucleotide comprising a nucleotide sequence of SEQ ID NO:3 from nucleotide 103 to nucleotide 1242).

As the Federal Circuit explained, “[n]ucleotides 103 to 1242 constitute the protein-encoding portion of the complementary deoxyribonucleic acid (“cDNA”) for the human interleukin-13 receptor binding chain (“IL-13bc”).”

The Sanofi-Aventis application was awarded the benefit of its December 6, 1995 priority date, while Pfizer’s earliest filing date was March 1, 1996. Thus, in order to prevail, Pfizer had to prove a date of conception earlier than December 6, 1995.

Pfizer’s Activities

As summarized by the Federal Circuit, “Pfizer presented documentary and testimonial evidence that it had isolated and identified the desired cDNA [and appreciated its function] before the Sanofi benefit date.” However, Pfizer’s initial work included sequencing errors, so it did not have the full, correct nucleotide sequence. Although the USPTO Board found that Pfizer’s work was sufficient, “Sanofi argue[d] that as a matter of law Pfizer did not have a complete conception until Pfizer had the full correct nucleotide sequence.”

The Federal Circuit Opinion

The Federal Circuit opinion was authored by Judge Newman and joined by Judge Lourie and Chief Judge Davis, United States District Court for the Eastern District of Texas, sitting by designation.

Judge Newman framed the issue as follows:

It is not disputed that the Pfizer scientists had isolated and obtained the IL-13bc DNA; the issue is whether conception is negated because the nucleotide sequence was not corrected until after the Sanofi benefit date of December 6, 1995.

The Federal Circuit agreed that Pfizer had established possession of the cDNA at issue:

We conclude that the Board correctly based conception and reduction to practice on the possession of the isolated DNA segment that was shown to have the desired properties.

The court explained:

When the subject matter is a DNA segment, conception requires possession and appreciation of the DNA segment that is claimed.

The USPTO Board had found that “Pfizer had successfully searched for and isolated the IL-13bc DNA segment, and possessed and appreciated the isolated IL-13bc DNA before the Sanofi benefit date.” While the Board stated that having the sequence “is the gold standard” for identifying proteins and nucleotide sequences, “a sequence is [not] the only way to identify the composition precisely.” Because Pfizer could “define [the IL-13bc] so as to distinguish it from other materials, and to define how to obtain it,” it had shown conception and reduction to practice.

Without further analysis, the Federal Circuit affirmed that determination.

Interference Law Remains Relevant

Footnote 2 of the Federal Circuit opinion states that the America Invents Act “obviated patent interferences,” but notes, “[p]ursuant to AIA§ 3(n)(2)(A), this interference remains governed by the prior laws.” Indeed, all patents and applications that claim subject matter with an effective filing date earlier than March 16, 2013 are subject to the “prior” interference laws. According to the USPTO Data Visualization Center, there are 45 interference proceedings pending a t the USPTO. Moreover, similar issues of conception and reduction to practice arise in the context of inventorship and patent ownership. Thus, interference law is likely to remain relevant for the foreseeable future.