What You Say Can Hurt You

May 21, 2019 – Article

            Often in writing applications there is a tendency to denigrate prior art techniques. This is not risk free as the patentee in Nuvo Pharmaceuticals (Ireland) v. Dr. Reddy’s Laboratories, Inc. (Fed. Cir. May 15, 2019) discovered. 

            The issue involved whether the claims of U.S. Patent 6,926,907 (‘907) and 8,557,285 (‘285) had an adequate written description of the claimed subject matter even though the claim language found support in patent as filed. The ‘285 patent was a C-I-P of the ‘907 patent but in the aspects important to the case shared the same problem. The ‘285 claim 1 is representative of the claims at issue:

1. A pharmaceutical composition in unit dosage form comprising therapeutically effective amounts of:

(a) esomeprazole, wherein at least a portion of said esomeprazole is not surrounded by an enteric coating; and

(b) naproxen surrounded by a coating that inhibits its release from said unit dosage form unless said dosage form is in a medium with a pH of 3.5 or higher;

wherein said unit dosage form provides for release of said esomeprazole such that upon introduction of said unit dosage form into a medium, at least a portion of said esomeprazole is released regardless of the pH of the medium.

            The objective of the claimed invention was to provide an NSAID (naproxen) which did not cause bleeding or ulcers which were common side effects of NSAIDs. It was known that if the pH in the stomach was elevated above pH 3.5 the NSAID propensity to cause bleeding and ulcers was reduced. The issue was whether the specification had an adequate written description of using esomeprazole in the immediate release form to raise the pH to this level. PPIs were well-known to raise the pH of the gastric system. The application contained examples where the esomeprazole was present only in an immediate release form. However, these examples did not disclose whether the exemplified formulations had the stability necessary to provide a pH in the stomach of 3.5 or higher. The problem was the background of the invention.

            The background of the invention explained that prior attempts to use proton pump inhibitors (PPI) like esomeprazole to protect against gastrointestinal tract from the NSAID had either failed or not provided adequate protection even using PPIs in slow release form. Further, the background described PPIs as being administered in slow release forms to avoid destruction of the PPI by the stomach acid. That is, those of ordinary skill in the art would not expect the immediate release form of the PPI to work. The examples using PPIs contained no stability data on the PPIs when administered. The only data in the ‘607 patent was for famotidine. Famotidine is not a PPI but is a histamine H2 receptor antagonist known to increase gastric pH. The data demonstrated that the naproxen formulation containing immediate release famotidine achieved the desired result, no information was provided for the esomeprazole formulation.

The written description requirement is met only if the specification:

conveys with reasonable clarity to those skilled in the art that, as of the filing date sought, he or she was in possession of the invention,’ and demonstrate[s] that by disclosure in the specification of the patent.” Centocor Ortho Biotech, Inc. v. Abbott Labs., 636 F.3d 1341, 1348 (Fed. Cir. 2011) (quoting Carnegie Mellon Univ. v. Hoffmann–La Roche Inc., 541 F.3d 1115, 1122 (Fed. Cir. 2008)). “The essence of the written description requirement is that a patent applicant, as part of the bargain with the public, must describe his or her invention so that the public will know what it is and that he or she has truly made the claimed invention.” AbbVie Deutschland GmbH & Co. v. Janssen Biotech, Inc., 759 F.3d 1285, 1298 (Fed. Cir. 2014). [Slip opinion at 12.]

            Here the Court found that the written description while enabling the invention, the examples, did not contain the required written description because of the Background of the Invention taught one of ordinary skill in the art that the use of the immediate release PPI would lead to failure. The Court said that the inventor needed to use techniques to show that this expectation did not hold for his formulation. Since there was nothing in the specification describing why the immediate release PPI combined with delayed release NSAID would work, there was nothing to show the inventor was in possession of the invention as broadly as claimed. 

            The takeaway is that be careful what you write in the Background as it can lead to written description issues. While it is true that no one prior to the ‘607 and ‘285 patents had developed a successful formulation, that was no reason for the patentee to assert that the PPI was destroyed in the stomach when the patentee was presenting claims to this very concept. Alternatively, the patentee should have presented data to show his formulation did not experience this problem.