Infringement of analyte measurement device claims under DOE barred by prosecution history estoppel

Pharma Tech Solutions, Inc. et al. v. LifeScan, Inc. (Johnson and Johnson)

Docket Nos. 2019-1163
November 22, 2019

Brief Summary: DC grant of SJ of no infringement under DOE affirmed due to prosecution history estoppel.

Summary: Pharma Tech (PT) appealed DC’s grant of summary judgment (SJ) of non-infringement, finding prosecution history estoppel (PHE) bars the doctrine of equivalents (DOE) infringement claims. PT’s asserted US 6,153,069 and 6,413,411 relate to “blood glucose monitoring systems” that measure “Cottrell current(s) through [a] sample fluid” and comparing the “first analyte concentration measurement with…at least one additional concentration measurement to confirm that they are within a prescribed percentage of each other”. “LifeScan’s OneTouch® Ultra® system, a blood glucose meter for home use” that “measures current from two working electrodes during a five-second countdown period” and a “Current Difference Test” was alleged to infringe. The FC panel opinion explains that “[i]t is undisputed that LifeScan’s meters neither convert multiple Cottrell current readings to analyte concentration measurements nor compare multiple analyte concentration measurements” and “do not literally infringe the claims” but that the product infringes under DOE. It also explains that expert testimony shows that PT’s originally-filed claim “cover[ed] any test strip with two working electrodes”. The claim was subsequently amended after a prior art rejection to require taking “at least two Cottrell current readings” and converting and comparing the same, and that PT “emphasized the new claim language and distinguished the asserted prior art thereon” (and again after a subsequent prior art-based rejection (e.g., “the present invention compares analyte concentration readings at different times”, prior art does not “disclose or suggest comparing…based on first and second Cottrell current readings”). LifeScan argued to the DC in its SJ motion that these arguments “constituted clear and unambiguous disclaimers of meters that do not perform the claimed conversion and comparison steps”. PT argued its amendment “was tangential to the real purpose of the amendment, which was to require a linear comparison of multiple measurements”. The DC agreed with LifeScan, finding that “that the tangentiality exception did not apply” and “that argument-based estoppel likewise barred” PT’s claims. The FC panel agreed with the DC’s conclusions, writing that “[t]he inventors’ clear statements not only establish argument-based estoppel, but also negate [PT’s] reliance on the tangential relation exception” (Int. Tech., FC 2013; Festo, FC 2003; PODS, FC 2007; Pioneer Magnetics, FC 2003) since, e.g., “[t]he inventors repeatedly and unequivocally described ‘the present invention’ as ‘a system which takes’” and compares “two different Cottrell current readings” and “continually argued that these features distinguished their invention over the prior art” (“a clear and unmistakable surrender”, “[t]hat the…amendment may have ceded more claim scope than necessary…does not mean the tangential relation exception applies here” (Int’l Rectifier, FC 2008; Schwarz Pharm., FC 2007; Eli Lilly, FC 2019; Insituform Techs., FC 2004; Ajinomoto, FC 2019). The DC grant of SJ was therefore affirmed.

This entry was posted in Doctrine of equivalents, Infringement, Prosecution History Estoppel, Uncategorized. Bookmark the permalink.

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