Last week, the Federal Circuit affirmed a decision by the Patent Trial and Appeal Board (PTAB) finding claims of U.S. Patent No. 7,064,197 to be invalid for anticipation or obviousness, in Enzo Life Sciences, Inc. v. Becton, Dickinson and Co. (Fed. Cir. 2019). Because Enzo raised the issue du jour, that subjecting a patent granted prior to enactment of the Leahy-Smith America Invents Act (AIA) to inter partes review (IPR) was unconstitutional, the U.S. government joined the appeal to defend the constitutionality of PTAB proceedings under these circumstances.
Representative claims of the '197 patent read as follows:
1. A non-porous solid support comprising one or more amine(s), hydroxyl(s) or epoxide(s) thereon, wherein at least one single-stranded nucleic acid is fixed or immobilized in hybridizable form to said non-porous solid support via said one or more amine(s), hydroxyl(s) or epoxide(s).
17. An array comprising various single-stranded nucleic acids fixed or immobilized in hybridizable form to a non-porous solid support.
(wherein italicized terms were important to the PTAB decision).
The Board held in a Final Written Decision that all the claims in IPR were invalid for being anticipated by a prior art reference to Fish or obvious by the combination of Fish and secondary references, or a reference to van Prooijen-Knegt ("VPK") with (obviousness) or without (anticipation) reliance on secondary references. The basis for these determinations based on the VPK reference relied, inter alia, on the Board finding that the '197 patent was not entitled to its earliest priority date for failure of the priority application to satisfy the written description requirement for the "non-porous solid support" limitation recited in challenged claims. Enzo appealed.
The Federal Circuit affirmed, in an opinion by Judge Lourie joined by Judges O'Malley and Chen. The panel characterized the teaching of the Fish reference as "a microradioimmunoassay for detecting antibodies that bind to double-stranded DNA ('dsDNA') . . . us[ing] poly-L-lysine ('PLL') 'to facilitate the binding of pure dsDNA to plastic surfaces' [and that] single-stranded DNA ('ssDNA') [was used] in the form of a mixture of synthetic polymers deoxyadenosine ('poly-dA') and deoxycytidine ('poly-dC') or 'denatured calf thymus DNA.'" According to the opinion, all challenged claims required single-stranded DNA to be "capable of binding through Watson-Crick base pairing" (italics in opinion), using a construction the parties agreed upon. This construction was the basis for the Board to decide that the Fish reference anticipated all of the '197 challenged claims, despite Enzo's argument that Fish did not show hybridization (the Board saying that the Fish disclosure just needed to be capable of hybridization according to the claim language). Enzo's expert countered (unpersuasively) that there were interactions that could arise using the methods disclosed in Fish that would preclude hybridization, and without the reference disclosing actual hybridization it was incorrect to presume that hybridization could occur (as required in Enzo's claims). Becton's expert disagreed, basing his testimony on the presumed interaction between the phosphate backbone of the DNA and the positively charged polylysine coating, which would presumably leave the bases available for hybridization.
The Federal Circuit agreed with the Board that the evidence supported their conclusion, characterizing the capacity to hybridize as an inherent property and citing Eli Lilly & Co. v. Barr Labs., Inc. for the proposition that "[a] reference includes an inherent characteristic if that characteristic is the 'natural result' flowing from the reference's explicitly explicated limitations." 251 F.3d 955, 970 (Fed. Cir. 2001) (quoting Cont'l Can Co. USA, Inc. v. Monsanto Co., 948 F.2d 1264, 1269 (Fed. Cir. 1991)). The panel held that the evidence from the experts, as well as the inherent property of single-stranded DNA to hybridize under appropriate conditions, supported the Board's decision that Fish anticipated the challenged claims. The panel also rejected Enzo's allegation that Fish did not disclose an "array" of single-stranded DNA molecules, saying that the Board's determination to the contrary was supported by substantial evidence.
Turning to the Board's decision that certain of the challenged claims were rendered obvious by Fish in view of secondary references, the panel agreed that the additional limitations recited in these claims ("wherein said nucleic acid comprises a nucleic acid sequence complementary to a nucleic acid sequence of interest sought to be identified, quantified or sequenced," or, "wherein said nucleic acid is RNA," or, "wherein said nucleic acids comprise a gene sequence or pathogen sequence") resulted in claims obvious in view of the Fish teachings. With regard to the Board's obviousness determination based on the combination of Fish with other references, the Court affirmed the Board's decision that there was substantial evidence that the skilled worker would have had a motivation to combine the references and a reasonable expectation of success. These references bolstered the teachings in Fish to include covalent linkage between the non-porous support (motivated by greater stability) and to substitute the polyvinyl tray supports disclosed in Fish with properly treated glass supports. The substantial evidence provided by the cited references was supported, according to the panel, by the testimony of Becton's expert witness.
Finally, the panel dealt summarily with Enzo's argument that subjecting patents granted prior to enactment of the AIA to the IPR provisions of the AIA was unconstitutional:
We recently addressed this issue in Celgene Corp. v. Peter, No. 18-1167, 2019 WL 3418549, at *12–16 (Fed. Cir. July 30, 2019), which is now precedent that governs this case. Celgene held that "retroactive application of IPR proceedings to pre-AIA patents is not an unconstitutional taking under the Fifth Amendment." Accordingly, we hold that the retroactive application of IPR proceedings to the '197 patent, which issued before the enactment of the AIA, is not an unconstitutional taking under the Fifth Amendment.
The Supreme Court invited patentees to explore the extent to which IPRs could constitute a Taking under the Fifth Amendment, in its Oil States Energy Services, LLC. v. Greene's Energy Group, LLC decision ("our decision should not be misconstrued as suggesting that patents are not property for purposes of the Due Process Clause or the Takings Clause"). Several patentees having taken the Court up on its invitation, it seems the time is ripe for Supreme Court review of the Federal Circuit's determination that IPRs do not raise constitutional takings issues.
Enzo Life Sciences, Inc. v. Becton, Dickinson and Co. (Fed. Cir. 2019)
Nonprecedential disposition
Panel: Circuit Judges Lourie, O'Malley, and Chen
Opinion by Circuit Judge Lourie
