Issue 139 | December 3, 2003
Ranbaxy Pharmaceuticals, Inc.,
et. al. v. Apotex, Inc.
 In Ranbaxy Pharmaceuticals, Inc., et. al. v. Apotex, Inc., No. 02-1429 (Fed. Cir. Nov. 26, 2003), the court affirmed a district court's denial of a preliminary injunction to patentee Apotex, for failure to establish a likelihood of success on the merits in establishing infringement under the doctrine of equivalents.

Apotex's '118 patent was directed to a process for preparing amorphous cefuroxime axetil. After Ranbaxy began marketing and selling the covered product, it sought a declaratory judgment of noninfringement of the ’118 patent; Apotex filed a counterclaim for infringement based solely on the doctrine of equivalents and moved for a preliminary injunction. Ranbaxy argued that prosecution history estoppel precluded a finding of infringement, because Apotex had, during prosecution, rewritten four claims (one independent - reciting “highly polar solvents,” and three dependent - reciting three specific solvents) into a single claim reciting only three solvents. The changes were specifically made in response to rejections under §103 and §112.

The district court agreed, concluding that prosecution history estoppel precluded Apotex from relying on the doctrine of equivalents because either: (1) it had entered a narrowing amendment for reasons related to patentability invoking the complete bar of Festo, or (2) it had surrendered coverage of solvents of the same polarity as acetone, which it found acetic acid was.

On appeal, the Federal Circuit analyzed the reasons for surrender, and concluded they were for patentability:
In this case the surrender is particularly clear. While Apotex was merely rewriting a dependent claim into independent form, the effect on the subject matter was substantial. The dependent claims that were redrafted into independent form did more than simply add an additional limitation; they further defined and circumscribed an existing limitation for the purpose of putting the claims in condition for allowance. The additional language limited “highly polar solvent” to a defined group of solvents: sulfoxides, amides, and formic acid. In so doing, the patentee is presumed to have surrendered the equivalents that may have been encompassed by “highly polar solvent.”
The court next considered whether Apotex had overcome the presumption that it had surrendered equivalents. Because acetic acid was a foreseeable equivalent to formic acid that could have and should have been included in the original claim, and acetic acid and acetone (acknowledged prior art) were similar in polarity, the court concluded that Apotex had not overcome the presumption that it surrendered coverage of acetic acid.

To discuss this topic further, please feel free to contact the author Michael R. Dzwonczyk, (mdzwonczyk@sughrue.com), at Sughrue Mion, PLLC in Washinton DC., USA.

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