Gambro Lundia AB v. Baxter Healthcare Corp.

Gambro Lundia AB (Gambro) (plaintiff) owned a patent for a system for measuring impurities removed from blood during dialysis, using censors that were recalibrated during the treatment. Measuring impurities using sensors was known dialysis technology when Gambro engineers designed the system claimed in its patent. Known technology was increasingly inaccurate due to clogging of outflow sensors. Gambro’s technology accounted for that inaccuracy by recalibrating the sensors during dialysis. In the late 1970s, a British bioengineering company led advancement in the art with a monitoring system designed by Keith Wittingham. Wittingham’s system used two sensors for its measurements that were only calibrated before dialysis, a calibration method that did not account for the increasing inaccuracies. While developing the system, Gambro engineers met with Wittingham twice to discuss his technology and Gambro acquired a four-page proposal Wittingham wrote after acquiring the intellectual property of the British company Wittingham worked for. Wittingham’s proposal briefly discussed an “Auto Zero/Start” feature that would “zero” the sensors before automatically starting dialysis. The proposal contained one sentence indicating the system may have required a zero button that did not automatically start the dialysis after zeroing. However, a parenthetical questioned whether a start signal could be allowed within 20 minutes of powering the system on using an independent zero button. By December 1987, Baxter Healthcare Corp. (Baxter) (defendant) had acquired dialysis technology and begun marketing its own monitoring device. Gambro sued Baxter, claiming the device infringed Gambro’s patent. Baxter defended by asserting that the patent was invalid and unenforceable. The district court found Gambro’s patent was invalid as derived from Wittingham’s technology, among other reasons, and was therefore unenforceable. Gambro appealed.