Bone Care Int’l, LLC v. Pentech Pharma., Inc.
April 09, 2012
Drug Product and Patent(s)-in-Suit: Hectoral® (doxercalciferol); U.S. Pat. No. 5,602,116 ("the '116 patent").
Nature of the Case and Issue(s) Presented: A bench trial was held to determine the priority date of claim 7 of the '116 patent, whether the '116 patent was operable and/or obvious, and whether the patentees engaged in inequitable conduct while prosecuting the '116 patent. Defendants stipulated to infringement. Following a bench trial, the Court held that (i) claim 7 had a priority date of August 2, 1988 because, even though it issued from a continuation-in-part filed in 1995, it was enabled by the application's parent filed in 1988; (ii) the claimed invention was operable and not obvious; and (iii) the patentee's failure to disclose references after August 2, 1988 was not inequitable conduct.
Why Plaintiffs Prevailed: The '116 patent application was a continuation-in-part application filed in 1995. During prosecution, the inventors amended the application so that the disclosure in claim 7 would be supported by the specification of a 1988 parent application (the "Original Application"). Claim 7 of the '116 patent claims "a method of using an effective amount of doxercalciferol to lower and maintain lowered parathyroid hormone ("PTH") levels in human patients who suffer from hyperparathyroidism ("HPT" or "SHPT") secondary to end-stage renal disease ("ESRD")." Defendants contended that the 1988 priority date for claim 7 of the '116 patent was improper because (i) the patentees failed to file an oath or declaration when they amended the '116 patent application relate-back clause; (ii) the Examiner did not have evidence that claim 7 was conceived and reduced to practice; and (iii) the Examiner did not explicitly state that claim 7 should have the 1988 priority date. Plaintiffs countered that the Examiner implicitly relied upon the 1988 priority date when it allowed claim 7 because the relate-back amendment precluded prior art that the Examiner relied on to reject similar claims in the '116 patent application.
The Plaintiffs had the initial burden to show that the Original Application's written description supported claim 7. If shown, the Defendants then had the burden to prove, by clear and convincing evidence, that the priority date was beyond 1988. Relying on an example in the Original Application as conception and reduction to practice, the Court found that the Original Application's written description enabled claim 7. The Court evaluated example four in light of expert testimony and other evidence to find that its description sufficiently enabled one skilled in the art to practice claim 7. Therefore, the Court found that claim 7 was entitled to the 1988 priority date.
Defendants next contended that example four was inoperable by offering three articles to show that doxercalciferol did not cause less hypercalcemia than related vitamin D3 drugs (which example four relied upon to show the benefits of doxercalciferol). To rebut those studies, Plaintiffs offered expert testimony that doxercalciferol does in fact reduce hypercalcemia and that physicians used it for precisely that reason. Based on this latter testimony, the Court found that claim 7 was operable.
The Court then addressed whether the '116 patent was obvious as of the 1988 filing date. The Defendants argued that a person of ordinary skill in the art would appreciate that doxercalciferol was a treatment for SHPT and ERSD to lower PTH levels because doxercalciferol increases calcium absorption which results in lower PTH, and that it was known that similar substances like vitamin D3 lowered PTH. The Defendants also contended that a person of ordinary skill in the art in 1988 would have known that doxercalciferol was safer than vitamin D3 compounds based on a 1985 study. The Plaintiffs countered that numerous vitamin D3 compounds were known in 1988, and Defendants failed to show why a person of ordinary skill in the art would choose doxercalciferol over others. Plaintiffs also argued that in 1988, a person of ordinary skill in the art would be taught away from using doxercalciferol because of the risk that doxercalciferol caused an increase in hypercalcemia. The Court agreed with Plaintiffs. Among other reasons, there were too many unknowns regarding doxercalciferol, and that the related vitamin D3 compounds were not similar enough to those compounds to understand how a person would react to doxercalciferol.
Finally, the Court found there had been no inequitable conduct because the references at issue were published after the Original Application's filing date.
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