• Nov 22 2019
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  • Category: CAFC Updates

Pharma Tech sued LifeScan for infringement of its U.S. Patent Nos. 6,153,069 and 6,413,411, which concern blood glucose monitoring systems for home use by individuals with diabetes. After Pharma Tech dismissed its literal infringement allegations, LifeScan filed a motion for summary judgment of no infringement under the doctrine of equivalents, and the district court held that amendment-based prosecution history estoppel barred Pharma Tech’s claims of infringement under the doctrine of equivalents. The CAFC holds that amendment-based and argument-based prosecution history estoppel bar Pharma Tech’s infringement claims under the doctrine of equivalents because the inventors’ arguments accompanying and following an October 1997 amendment clearly and un-mistakably surrendered systems that do not convert Cottrell current readings to analyte concentration measurements and compare those analyte concentration measurements, establishing argument-based estoppel and negating Pharma Tech’s reliance on the tangential relation exception. Concluding that the district court did not err in determining that prosecution history estoppel bars Pharma Tech from succeeding on its infringement claims under the doctrine of equivalents, the CAFC affirms the district court’s order granting LifeScan’s motion for summary judgment.

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