Ethicon Inc., a Johnson & Johnson subsidiary facing 18,000 cases involving its pelvic mesh in federal multidistrict litigation, wants to block discovery of the compensation it paid to a non-retained expert who works as a medical-affairs director at the company.

The compensation to Dr. Piet Hinoul should not be discoverable just because he is employed by Ethicon, the manufacturer said in a recent court filing. His pay would only be discoverable if he were paid specifically for his expert testimony, to let the plaintiffs expose any personal interest he might have in arriving at his opinion, Ethicon said.