Santarus,Inc. v. Par Pharmaceutical,Inc. : Is there a new written description requirement for negative limitations?

Case history

With respect to the ‘772 patent, Santarus asserted independent claim 1 and several dependent claims that all contain the negative limitation of “no sucralfate.” After the fourth day of trial, the District Court found that Par’s ANDA products infringed the asserted claims. Id. at 435-36. The other issues raised at trial included invalidity for lack of written description and obviousness as well as unenforceability for inequitable conduct.

Lack of written description

Par argued that the specification of the ‘772 patent did not provide adequate written description to support the negative limitation “wherein the composition contains no sucralfate” and as such, all the claims which require that negative limitation were invalid. Id. at 443-44. Santarus retorted that the patent specification did provide adequate written description because the specification indicated that sucralfate had adverse effects and as such a person of ordinary skill in the art would have understood that sucralfate was contraindicated. Id. at 444. The District Court disagreed, finding that “no evidence was presented as to why a person of ordinary skill in the art reading the application would believe that sucralfate was ‘contraindicated’ in the claimed composition.” Id.

Accordingly, the District Court concluded that Par had established that all of the asserted claims of the ‘772 patent were invalid for lack of written description because the patent specification did not support the “no sucralfate” claim limitation. Id. Moreover, of import to the obviousness analysis below, the District Court also concluded that “the asserted claims of the ‘772 Patent are only entitled to the filing date of the ‘346 application” as opposed to being able to claim priority back to the application for the ‘737 patent or the provisional application.

Obviousness

Par contended that the ‘772 patent claims were also invalid for obviousness. Id. at 445. The District Court agreed, finding that the asserted claims were obvious, regardless of whether or not they were entitled to claim priority to the application for the ‘737 patent or the provisional application. Id.

The District Court began its analysis by noting that the prior art by 1996 included “buffered, non-enteric-coated solutions or suspensions containing omeprazole and sodium bicarbonate.” Id. at 446. The District Court pointed to a 1985 article published by Pilbrant et al. in the Scandinavian Journal of Gastroenterology (“Pilbrant”) as an example of such prior art. Id. at 447. The District Court found that this and other references rendered the claims obvious. Id. at 449.

Furthermore, in view of its aforementioned ruling that the ‘772 patent claims are only entitled to the filing date of the ‘346 application in the year 2000, the District Court concluded that the asserted claims were obvious in light of the ‘737 patent which issued in 1998. Id. at 452. The District Court noted that the ‘737 patent (which was, accordingly, intervening prior art since it was issued more than one year before the effective filing date for the ‘772 patent claims) disclosed a method of treating gastric disorders by administering an aqueous solution or suspension of omeprazole and sodium bicarbonate and that the composition could be made into a tablet, capsule or granule “by methods well known to those skilled in the art.” Id. The District Court concluded that these disclosures of the ‘737 patent “either anticipate or render obvious each asserted claim” of the ‘772 patent. Id.

With respect to secondary considerations of non-obviousness, the District Court found that: Zegerid^® had not achieved commercial success (id. at 453); there was no “close nexus between the asserted merits of the invention and the sales and growth of Zegerid” (id. at 454); “[i]f there was a ‘need’ in the PPI market that Zegerid resolved, the need was not for advancements on the existing prior art, but rather for a drug manufacturer to recognize the commercial potential of what already existed in the prior art.” (id. at 455); Santarus failed to present persuasive evidence of skepticism (id. at 457); the claimed composition did not produce unexpected results (id.); “a showing of copying is not compelling evidence of non-obviousness in Hatch-Waxman cases due to the nature of the ANDA process” (id. at 458); and “Santarus has not presented evidence sufficient to persuade [the court] that the patents-in-suit [including the ‘772 patent] have gained substantial industry recognition or acceptance, or that any acceptance it has achieved has a nexus to the merits of the claimed inventions.” Id. at 459.

Accordingly, the District Court concluded that Par had established that the ‘772 patent claims were invalid for obviousness regardless of whether the ‘737 patent was intervening prior art.

Inequitable conduct

Par further alleged that the ‘772 patent, and the other patents-in-suit, were unenforceable due to inequitable conduct committed by Dr. Phillips. Id. Specifically, Par alleged that “Dr. Phillips publicly used and disclosed the combination of sodium bicarbonate and omeprazole claimed in the priority applications, and that Dr. Phillips and his legal representatives intentionally withheld this information from the PTO.” Id.

The District Court agreed that “[t]he evidence clearly and convincingly established that Dr. Phillips publicly and repeatedly used and disclosed the composition described in the priority applications more than a year before the filing of the Provisional Application.” Id. at 461. The District Court noted, however, that Dr. Phillips “believed at the time he prosecuted the patents-in-suit that his duty to disclose did not extend to uses and disclosures of his invention that were not both printed and published.” Id. While the District Court admitted that Dr. Phillips’ testimony “strains credibility” in that “[i]t seems highly unlikely that for five years, Dr. Phillips was not aware that his early uses and disclosures of [simplified omeprazole solution] might be relevant to patentability, and that his attorneys remained ignorant of this information throughout the same period,” the District Court nonetheless found that “the evidence presented is not sufficient to establish by clear and convincing evidence that Dr. Phillips acted with an affirmative intent to deceive.” Id.

Accordingly, the District Court concluded that Par had not established that the patents-in-suit, including the ‘772 patent, were unenforceable for inequitable conduct despite testimony that “strain[ed] credibility.”

Santarus’s Opening Appeal Brief

With respect to written description, Santarus argued that the District Court’s analysis of the “no sucralfate” limitation “was legally flawed.” Brief of Plaintiffs-Appellants Santarus, Inc. and the Curators of the University of Missouri, 2010 WL 3048426, Santarus, Inc. v. Par Pharmaceutical, Inc., 694 F.3d 1344 (Fed. Cir. 2012) at *54. Specifically, Santarus argued that “[t]he district court’s analysis focused on whether the specification disclosed that sucralfate was ‘contraindicated,’ i.e. banned from use. This written description standard is improperly high and at odds with [Federal Circuit] precedent.” Id. Based on Federal Circuit precedent Santarus further argued that “it is erroneous to require the specification to ‘necessarily exclude’ all elements other than those claimed. Instead, the test for limitations that exclude elements from the claim is whether the specification conveyed with reasonable clarity to one of ordinary skill that the inventor had invented what is claimed – a test the present specification passes.” Id. at *56 (emphasis in original). According to Santarus, “[a] proper written description analysis reveals that the ‘772 patent specification and its prior applications support the ‘no sucralfate’ limitation.” Id. at *57.

With respect to obviousness based on references other than the ‘737 patent, Santarus argued, inter alia, that the District Court “erroneously failed to include the substantial history and references teaching away from the patented inventions” in its analysis. Id. at *25. Specifically, Santarus argued that the complex liquid administration disclosed in Pilbrant discouraged anyone from attempting to modify and arrive at the uncoated solid dosage forms of the invention. Id. at *29. In addition, Santarus argued that even references after Pilbrant taught that solid dosage forms must have an enteric coating, unlike the claimed solid dosage forms. Id. at *32. Rather, argued Santarus, “the court’s analysis was limited to select citations from a subset of Par’s chosen prior art that could, if one squints, be read to teach that enteric coating might be optional.” Id. at *33. Santarus maintained that “[o]nly through hindsight, and by picking and choosing elements from various disclosures, while ignoring all art teaching away from and discouraging [the inventor’s] approach, would one be lead to select the elements necessary to construct what [the inventor] invented and have any reasonable belief in success.” Id. at *44.

As for obviousness based on the ‘737 patent as intervening prior art, Santarus stated that the ‘737 patent was simply not prior art because, in view of the aforementioned written description analysis, the ‘772 patent claims were “entitled to priority to [the application for] the ‘737 Patent.” Id. at *45.

Par’s Responsive/Cross Appeal Brief

In responding to Santarus’s argument on written description, Par contended that the District Court had properly invalidated the ‘772 patent claims because the specification did not support the “no sucralfate” limitation. Brief of Defendant/Cross-Appellant Par Pharmaceutical, Inc. at *45, 2010 WL 3762112, Santarus, Inc. v. Par Pharmaceutical, Inc., 694 F.3d 1344 (Fed. Cir. 2012). Par noted that “[t]he district court’s citation to ‘contraindication’ was in reference to what [Santarus] advocated at trial. Thus, the district court’s mention of the word ‘contraindication’ was merely in response to [Santarus’s] own arguments regarding alleged written support for the limitation.” Id. Par further argued that the ‘772 patent never described compositions with and without sucralfate, such that it would convey with reasonable clarity to a person of ordinary skill in the art that a ‘limited genus’ of compositions without sucralfate was intended to be part of the invention. Instead, Par contended that the patent specification merely referred to sucralfate in general and not in the context of the claimed invention. Id. at *46.

In addressing Santarus’ criticism of the District Court’s obviousness ruling based on references other than the ‘737 patent, Par argued that the District Court had correctly found that the prior art, including Pilbrant, did not teach away or discourage the use of non-enteric-coated solid dosage forms. Id. at *21-*24.

As for obviousness based on the ‘737 patent as intervening prior art, Par pointed out that “Appellants do not dispute the district court’s prior determination. Instead they devote less than one page of their brief to their contention that the ‘737 Patent does not invalidate ‘most’ of the “Exemplary Claims.’” Id. at *37.

In cross-appealing the District Court’s decision of no inequitable conduct, Par argued that the District Court had “looked on the overwhelming evidence of intent with a too lenient lens.” Id. at *50. Par contended that “the ‘inventor did not know the law and the lawyer did not know the facts’ argument is exactly the type of circle of ignorance this Court has rejected on numerous occasions.” Id. at *55. Par concluded by stating that “[t]he district court’s acceptance of the circle of ignorance argument to refuse to find intent to deceive has no legally supportable basis and must be reversed.” Id. at *56.

Santarus’s Responsive and Reply Brief

With respect to written description, Santarus admitted that it had argued before the District Court that the ‘772 patent specification taught that sucralfate is “contraindicated.” According to Santarus, “a specification that contraindicates sucralfate goes well beyond the minimum support for a ‘no sucralfate’ limitation” and “[t]he district court’s language shows that it believed the sufficiency of written description turned on whether there was evidence of contraindication. This was error.” Response and Reply Brief of Plaintiff-Appellants Santarus, Inc. and the Curators of the University of Missouri, 2010 WL 4853315, Santarus, Inc. v. Par Pharmaceutical, Inc., 694 F.3d 1344 (Fed. Cir. 2012) at *34-*35 (emphasis added). Santarus continued, arguing that in view of the “numerous examples that have no sucralfate, nothing more is required to establish that Dr. Phillips possessed a composition without sucralfate.” Id. at *36.

Santarus also reiterated its arguments that the District Court erred in finding the asserted claims invalid as obvious based on references other than the ‘737 patent. In particular, Santarus explained why the prior art explicitly taught away from non-enteric-coated solid dosage forms. Id. at *7-8. As for obviousness based on the ‘737 patent as intervening prior art, Santarus reiterated that the application for the ‘737 patent provides adequate written description of the “no sucralfate” limitation. Id. at 31. The upshot of Santarus’ position is that the ‘737 patent (issued in 1998) could not be intervening prior art (if the ‘772 patent claims are only entitled to the year 2000 filing date of the ‘346 application) because the ‘772 patent claims are entitled to a priority date going back to 1996.

With respect to the issue of inequitable conduct raised in Par’s cross-appeal, Santarus argued, inter alia, that while the District Court noted that certain aspects of the inventor’s and the prosecuting attorney’s testimony “strain[] credibility,” the District Court did not find that the testimony was untrue – and “found no clear and convincing evidence of deceptive intent. Moreover, nothing should strain credibility about any aspect of the testimony based on the unrefuted facts.” Id. at *47.

Par’s Reply Brief

In its reply brief, Par emphasized that the District Court had indeed erred in not concluding that inequitable conduct was committed. Reply Brief of Defendant/Cross-Appellant Par Pharmaceutical, Inc., 2010 WL 3762112, Santarus, Inc. v. Par Pharmaceutical, Inc., 694 F.3d 1344 (Fed. Cir. 2012). In particular, Par noted that “Appellants studiously ignore that Par has not alleged just a single, isolated act of inequitable conduct, or even just two or three. Rather, Dr. Phillips and his counsel, Mr. Mahoney, engaged in a pattern of systematic inequitable conduct spanning several years and multiple patents.” Id. at *1. As such, Par urged the Federal Circuit to reverse the District Court’s holding of no inequitable conduct. Id. at *17-*18.

The Federal Circuit decision

In its decision, the Federal Circuit first addressed Par’s inequitable conduct claim. The Federal Circuit noted that “[o]n this appeal Par stresses the district court’s remark of ‘strained credibility’ and argues that this court should disbelieve Dr. Phillips, and that the only reasonable inference is that he and his legal representatives acted in bad faith and with intent to deceive.” Santarus, 694 F.3d at 1349. However, the Federal Circuit quickly concluded that it agreed with the District Court that intent to deceive had not been shown by clear and convincing evidence, and accordingly affirmed the District Court’s ruling of no inequitable conduct. Id.

The Federal Circuit then turned to the written description issue relating to the “no sucralfate” limitation in the ‘772 patent claims. The Federal Circuit first noted that the District Court had held that “it is necessary for the ‘772 specification to include evidence demonstrating that sucralfate is ‘contraindicated,’ in order to meet the written description requirement of § 112 ¶ 1” and that it is inadequate for the specification to state that the claimed composition is “advantageous” over compositions which contain sucralfate. Id. at 1350. The Federal Circuit disagreed, noting that “[n]egative claim limitations are adequately supported when the specification describes a reason to exclude the relevant limitation. Such written description support need not rise to the level of disclaimer. In fact, it is possible for the patentee to support both the inclusion and exclusion of the same material.” Id. at 1351 (emphasis added). Accordingly, the Federal Circuit reversed the District Court’s holding that the ‘772 patent claims were invalid for lack of written description. Moreover, the Federal Circuit held that the ‘772 patent claims were entitled to claim priority to the application for the ‘737 patent and thus the ‘737 patent could not be used as intervening prior art against those claims. Id.

Turning to the question of obviousness based on references other than the ‘737 patent, the Federal Circuit noted that the disclosure of Pilbrant “would discourage a person of ordinary skill in the art from pursuing conventional oral dosage forms such as tablets, capsules, or granules with non-enteric-coated PPIs, and thus teaches away from such formulations. As a result, we hold that the district court erred by concluding that claims directed to such conventional dosage forms would have been obvious over Pilbrant or [other cited prior art].” Id. at 1355 (emphasis in original).

Accordingly, the Federal Circuit reversed the District Court’s ruling that the ‘772 patent claims were obvious in view of either the ‘737 patent (held not to be intervening prior art) or pre-1996 prior art such as Pilbrant. Id. at 1358.

Judge Newman’s position on written description

At the onset, Judge Newman noted that she agreed with the majority that “the district court clearly erred in finding that since the specification did not contain evidence of ‘contraindication’ of sucralfate, the patent failed the written description requirement.” Id. Judge Newman further noted that on appeal “correction of this erroneous finding is all that is needed. However, my colleagues add a gratuitous fillip, and devise a new rule that the specification must ‘describe a reason’ for the claim limitation, or the claims are invalid on written description grounds.” Id. (emphasis added). Judge Newman argued that this is incorrect and that “[n]egative limitations may often be appropriately stated in claims although the reason for the limitation is not set forth in the specification.” Id. at 1359. For example, negative limitations may be introduced in response to an examiner’s rejection, and “[t]he specification need not foresee and describe the reason for every possible examination response.” Id. Thus, Judge Newman contended that “[t]he panel majority creates a new and far-reaching ground of invalidity, a ground that received no deliberation and advice from the concerned communities.” Id. Moreover, argued Judge Newman, “[t]his new ground of invalidity ignores the factual nature of the written description requirement, and impugns the presumption of validity of a duly granted patent. The court’s new rule simply adds to the uncertainty of the patent grant, to the detriment of invention and commerce.” Id. at 1360.

Par’s Petition for Rehearing and Rehearing En Banc

Dissatisfied with the panel’s decision, Par filed a petition with the Federal Circuit for rehearing and rehearing en banc. Par Pharmaceutical, Inc.’s Combined Petition for Panel Rehearing and Rehearing En Banc at 1, Santarus, Inc. v. Par Pharmaceutical, Inc., 694 F.3d 1344 (Fed. Cir. 2012). However, Par did not raise any arguments relating to the panel’s holding that the ‘772 patent claims were not invalid for either lack of written description or obviousness based on the ‘737 patent as intervening prior art. Ultimately, on December 12, 2012, Par’s petition was denied without opinion leaving Par in the position of having infringed claims of the ‘772 patent that it had failed to prove were invalid and/or unenforceable.