by Dennis Crouch
Senju v. Lupin (Fed. Cir. 2015)
In a split decision, the Federal Circuit has affirmed a district court judgment that Senju’sU.S. Patent No. 6,333,045 is invalid as obvious. The patent covers an eye-drop formulation that is mixture gatifloxacin and EDTA (sold as Zymar) and has an interesting litigation history. In particular, this case represents the fourth time that the patent has been asserted in a lawsuit before Judge Sue Robinson (D.Del.). That history includes a prior finding by Judge Robinson that the claims were invalid as obvious. Following that original obviousness decision, Senju successfully shepherded the claims through an ex parte reexamination. In that process, the PTO confirmed the patentability of the claims once amended to include a specified concentrations of the aforementioned ingredients (e.g., “about 0.3 to about 0.8 w/v%” of gatifloxacin and “about 0.01 w/v%” of EDTA). Following reexamination, the court blocked Senju from asserting the reexamined claims against the same party (Apotex) who won the first obviousness decision — finding that claim to be precluded. However, the court did allow assertion of the new claims against new parties – here Lupin and Hi-Tech Pharma. However, after considering the same prior art as the USPTO, Judge Robinson found the revised claims still obvious based upon -again – the same prior art.
On appeal, the Federal Circuit affirms – holding that the district court’s conclusion of obviousness was correct. In the process the Federal Circuit appeared to give no deference to the USPTO reexamination determinations other than to require clear and convincing proof of the factual underpinnings of the obviousness determination. See Sciele Pharma Inc. v. Lupin Ltd., 684 F.3d 1253, 1260 (Fed. Cir. 2012) (“Whether a reference was previously considered by the PTO, the burden is the same: clear and convincing evidence of invalidity.”). The appellate court did agree that the amendments during reexamination did refresh the patent claims so as to reestablish the presumption of validity in the face of the prior invalidity ruling.
Regarding the added concentration limitation of “0.01 w/v% EDTA,” the two sides fought over whether that concentration level was suggested by the prior art studies. The court writes:
At bottom, the district court’s analysis rests largely on a determination that Lupin’s experts were more credible than Senju’s experts. Based on this determination, the district court found that [the Prior Art] Grass 1988-I, along with the other cited references, taught that 0.01 w/v% EDTA would be effective to increase corneal permeability. On the evidence before us, that determination by the district court falls well within the wide discretion the court has to weigh expert credibility. Ordinarily, and absent compelling reason otherwise, an appellate court defers to such credibility determinations.
With that (and some further analysis), the court affirmed the obviousness finding.
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Judge Plager drafted the majority opinion that was joined by Judge Moore. Writing in dissent, Judge Newman argued that the courts should “give deference” to the PTO’s review of the narrowed claim scope and its conclusions regarding the unexpected results associated with the newly narrowed claims. Judge Newman further writes:
The prior art is crowded. . . . However, no combination of prior art references shows or suggests the use of very low concentrations of EDTA to enhance the corneal permeability of antibiotic formulations of gatifloxacin, or of any other quinolone. . . . The panel majority relies on the unsupported opinion of Lupin’s expert witness, and gives that unsupported opinion greater weight than the experimental data.
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Although PTO reexamination decisions are not given deference in this type of third-party challenge, there are some reasons to think that IPR/PGR decisions should be given deference under the APA. However, it is unlikely that the Federal Circuit would come to that conclusion without first being led by either Congress or the Supreme Court.