Inconsistency Between Views of Two PTO Examiners Found Relevant to Obviousness Determination During Litigation

PatentlyOImage043Syntex v. Apotex (Fed. Cir. 2005).

Apotex filed an ANDA to begin marketing a generic version of ACULAR, an ophthalmic NSAID protected by a patent owned by Syntex.  Based on the Section IV filing, Syntex filed suit against Apotex for patent infringement.

After a bench trial, the district court determined that the proposed generic infringed the claims of the ACULAR patent and that the patent was not invalid.

Regarding invalidity, the district court concluded that Syntex had overcome obviousness issues by showing that the prior art taught away from the use of the drug/surfactant for opthalmic uses and that such a use created “unexpected results.” In its decision, district court noted that because the prior art at issue had been before the examiner during prosecution, the burden of proving the challenged claims obvious “is particularly high” — and that Apotex had failed to meet this heightened burden. 

On appeal, the CAFC reversed — finding “clear error by the district court in several of the grounds that led it to conclude that the invention claimed by the claims in suit would not have been obvious.” 

Of the several grounds for reversal, the issues of examiner discrepancy, expert testimony, and commercial success may be the most interesting:

Examiner Discrepancies:

Two different PTO examiners worked on various portions of the asserted application and its parent applications and had seemingly inconsistent views regarding patentability of the application.  The CAFC found this relevant to the obviousness determination.

This statement contradicted the express finding of the initial PTO examiner that Syntex’s earlier data failed to show unexpected results. Whether the second examiner was aware of the earlier rejection of Syntex’s claims is unknown. But the relevance of the inconsistency between the views of two examiners is not insignificant.

Although we conclude . . . that Syntex did not commit inequitable conduct . . . we think the unvarnished view of the prosecution history shows some weakness in the conclusion that the patentee established unexpected results for the claimed surfactant.

Expert Testimony:

The Appellate Panel found that the district court erred by failing to examine Apotex’s expert testimony on the question of motivation to combine and unexpected results.

Commercial Success:

The district court relied heavily on the commercial success of ACULAR in its nonobviousness decision.  However, the CAFC requested that the lower court revisit this issue in light of the recent case of Merck v. Teva.

In Merck, the court found that commercial success of an FDA restricted product “has minimal probative value on the issue of obviousness. . . . Financial success is not significantly probative . . . because others were legally barred from commercially testing the [] ideas.”


In a concurring opinion, Judge Prost disagreed with a portion of the majority opinion that made note of “inconsistency between the views of two examiners” who examined the asserted application and a parent application.

In general, I fail to see how the conduct of a patent applicant is relevant to an obviousness determination. Alleged misconduct at the PTO, in terms of either mischaracterizations or omissions, goes to the heart of an inequitable conduct inquiry but is simply irrelevant to an obviousness inquiry.