Last week the Federal Circuit decided the case of Santarus, Inc. v. Par Pharmaceutical, Inc., which dealt with whether a drug covered by an Abbreviated New Drug Application (ANDA) infringed the patents owned by that patent owner relative to the proton pump inhibitors (PPI) product omeprazole. The big issue in the case is what might at first glance seem to be a rather innocuous statement relative to the support necessary in a patent specification for a negative claim limitation. But after reading the Newman dissent (which joins in the other aspects of the Court’s decision) it starts to become clear that this could be a much larger issue of significant consequence.
The appeal came to the Federal Circuit from the judgment of the United States District Court for the District of Delaware. The plaintiff, Santarus, Inc., is the exclusive licensee of patents on specified formulations of benzimidazole PPI – a class of chemical compounds that inhibit gastric acid secretion and help prevent and treat stomach acid-related diseases and disorders. The patents are for the inventions of Dr. Jeffrey Phillips, and are assigned to the University of Missouri. Santarus provides the PPI product omeprazole in the formulations covered by the Phillips patents, with the brand name Zegerid®.
Prescription omeprazole is used to treat gastroesophageal reflux disease (GERD), a condition in which backward flow of acid from the stomach causes heartburn and possible injury of the esophagus (the tube between the throat and stomach). Prescription omeprazole allows the esophagus to heal and prevents further damage, and can also be used to treat conditions in which the stomach produces too much acid. See Omeprazole from NIH.gov.
The defendant Par Pharmaceutical, Inc. filed an ANDA seeking FDA approval to sell a generic counterpart of the Santarus Zegerid® products. This, of course, invokes the Hatch-Waxman Act, which allows a procedure known as a “Paragraph IV certification,” 21 U.S.C. § 355(j)(2)(A)(vii)(IV), whereby an entity that seeks to market a generic counterpart of a patented drug product or method of use, before the patent has expired, may challenge the patent before actually marketing the drug. The patent owner is allowed to treat an ANDA with a Paragraph IV certification as an act of infringement despite no truly infringing activities. In other words, the mere filing of a Paragraph IV certification is an act of technical infringement as defined by the statute. As with all Paragraph IV related patent infringement cases, the parties litigated the issues of infringement, validity, and enforceability of the Phillips patents.
The district court found that Par’s ANDA products infringed the Phillips patents, but held all of the asserted claims invalid on the ground of obviousness, 35 U.S.C § 103. The district court also held certain claims invalid on the ground of inadequate written description, 35 U.S.C. § 112. On the defense of unenforceability, the district court held that there was not inequitable conduct by Dr. Phillips, the University of Missouri, or their counsel in procuring the patents.
Both parties appealed the various adverse rulings with one notable exception. Par did not appeal the finding of infringement.
The Federal Circuit, per Chief Judge Rader and with Judges Moore and Newman, concluded that the district court erred by holding that some of the thirty-six asserted claims would have been obvious over the prior art; these rulings are reversed. The court’s other rulings were affirmed.
Of particular note is the disagreement between Judge Newman and the majority on one seemingly minor point related to written description. Chief Judge Rader wrote:
“Negative claim limitations are adequately supported when the specification describes a reason to exclude the relevant limitation.”
Judge Newman characterized this as “a gratuitous fillip,” saying that this is the creation of a “new rule that the specification must ‘describe a reason’ for the claim limitation, or the claims are invalid on written description grounds.” Judge Newman went on to explain: “Negative claim limitations may often be appropriately stated in claims al- though the reason for the limitation is not set forth in the specification.”
Judge Newman identified several situations where negative limitations are allowed although no specific reason for the limitation may be found in the patent specification:
- “a negative limitation may be prudently placed in a claim in response to an exam- iner’s rejection, perhaps to distinguish a reference that was given its “broadest reasonable interpretation” for purposes of examination.
- “A claim limitation may distinguish the prior art al- though the reason is not in the specification.”
- “there may be situations in which comparative data are provided during prosecution in order to respond to an examiner’s rejection, see MPEP §716, and the distinction from the prior art may lead to a claim limitation.”
Judge Newman concluded:
“The applicant’s obligation is to describe and claim the invention in accordance with 35 U.S.C. §112. Thereafter, patent examination may lead to amendments to the claims. The MPEP §2173.05(i) advises that: “If alternative elements are positively recited in the specification, they may be explicitly excluded in the claims.” The MPEP does not require that the reason for such exclusion must be stated in the specification. The panel majority creates a new and far-reaching ground of invalidity, a ground that received no deliberation and advice from the concerned communities.”
A seemingly small issue, but one of potentially large significance. If Chief Judge Rader meant to say that the only way for a specification to support a negative limitation is to announce a reason for the limitation then that would seem to be an important departure from written description law as we have known it to exist and would create a scenario where it would be exceptionally difficult to have support for many negative limitations that need to be inserted in claims as the result of the natural ebb and flow of prosecution with the patent examiner.
So did that one line in the opinion usher in a new written description requirement? If Chief Judge Rader and Judge Moore did not intend to say this quite as definitively as it might be interpreted one could easily speculate that the language would have been softened or somehow changed after Judge Newman drafted her opinion. The fact that the language persists in the released opinion would seem to be strong support for the proposition that the statement was intentional and does potentially usher in a new regime insofar as disclosure of negative claim limitations is concerned.