6 November 2013Americas

Pfizer wins IL-13 priority over Sanofi

The US Court of Appeals for the Federal Circuit affirmed on Tuesday that pharmaceutical company Pfizer can patent a DNA polynucleotide ahead of rival Sanofi-Aventis.

Both companies were researching IL-13, a regulatory molecule called a cytokine, for diagnostic and therapeutic purposes. Cytokines function by interacting with cytokine receptors located on target cells.

At the centre of this dispute is a DNA polynucleotide that encodes the protein-binding chain of the IL-13 receptor. Both companies have tried to patent the polynucleotide, Sanofi claiming priority to December 6, 1995 and Pfizer filing an application on March 1, 1996.

Pfizer showed that it had isolated and identified the polynucleotide before Sanofi’s priority date but that, due to sequencing errors, it did not have a completely accurate analysis of the entire nucleotide sequence until February 1996.

The Board of Patent Appeals and Interferences, now the Patent and Trial Appeal Board, has previously awarded Pfizer priority. It said Pfizer’s patent contained the correct analysis of the entire nucleotide sequence and had “established conception and actual reduction to practice” of the polynucleotide before Sanofi.

But on appeal Sanofi argued, citing Federal Circuit precedent, that until Pfizer had correctly analysed the polynucleotide, neither conception nor reduction to practice could occur.

The Federal Circuit disagreed. It said the cases – including Amgen v Chugai Pharmaceutical – which Sanofi relied on do not hold that conception requires the complete and correct sequencing of the isolated DNA.

“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 said.

It added: “We conclude that the board applied the correct law. The award of priority to Pfizer is affirmed.”

Bill Baton, partner at Saul Ewing LLP, said the most interesting aspect of the ruling is that a patent application may receive priority even if it is not entirely accurate. “So long as the claims indicate that the inventor actually was the first to make the invention and that the inventor ‘understood his creation to have the features that comprise the inventive subject matter at bar’,” he added.

“Here, Pfizer's original assertion of the invention described a gene sequence of 1143 nucleotides with eight errors in the nucleotide sequence that was claimed to have been isolated in October 1995. In other words, Pfizer claimed it had been 99.3 percent correct before Sanofi's assertion of priority. Pfizer's errors were not corrected and submitted until March 1996. The Federal Circuit found that this was good enough to obtain priority over Sanofi's December 6, 1995 priority date.”

Sanofi could appeal to the US Supreme Court based on an alleged error of law, but the Supreme Court has the discretion to deny such a request.

Counsel at Sanofi’s representative Lucas & Mercanti LLP could not be reached for comment.

UPDATE (07/11/13): Jim Haley and Ying Li of Ropes & Gray LLP, who represented Pfizer, provided the following statement: "The Federal Circuit’s decision clarifies the important question of whether conception of a nucleic acid molecule (or other molecules) requires knowledge of the complete and correct structure of the molecule. This decision makes clear that there is no bright line rule. What is important is whether there was enough known about the molecule to distinguish it from any other molecule.

"Even though the Federal Circuit’s decision was in a priority-of-invention context, it has important implications under the AIA as well, for example, in the context of prior disclosure, written description, and derivation."

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