Messick v. Novartis Pharmaceuticals Corp.

Under Federal Rule of Evidence 702, an expert’s testimony may only identify a substantial factor contributing to a condition and need not identify the cause of a condition to be reliable, also given the liberal thrust favoring admission the testimony is relevant if it based in knowledge with a valid connection to the condition at issue.

Linda Messick appealed the district court’s ruling of summary judgment based on the fact that she had no expert causation testimony after the district court excluded expert testimony provided to show causation between her bisphosphonate treatment and osteonecrosis (“BRONJ”) of her jaw. The district court excluded the testimony because it found it to be irrelevant and unreliable. After developing osteoporosis as a result of chemo and steroid therapies, the Messick took Zometa, a bisphophonate produced by Novartis. Messick developed BRONJ thereafter and brought suit against Novartis. The Ninth Circuit reviewed the district courts ruling for abuse of discretion. Under Federal Rule of Evidence 702, the panel concluded that the district court had applied too high of a bar for relevancy. The relevancy bar only requires that “the evidence logically advances a material aspect of the proposing parties case.” Here, the expert was able to testify that the plaintiff’s bisphosphonate treatment was at least a substantial factor in her development of BRONJ and therefore relevant. The panel also found that the expert was reliable. A differential diagnosis is a reliable basis of causation, if it also provides reason for rejecting other causes. It is not required that an expert identify the sole cause of the condition for the testimony to be reliable. Therefore, the district court abused its discretion in excluding the expert’s testimony. Because the panel found that it was improper to exclude this expert testimony, there was an issue of material fact. Therefore summary judgment in favor of the defendant was improper. REVERSED and REMANDED.