Pfizer ( PFE ) received a request for documents as part of a U.S. investigation into quality-control problems at a subsidiary that makes the EpiPen device for Mylan ( MYL ), according to a regulatory filing. In 2017, the Meridian Medical Technologies unit was cited by regulators for a failure to investigate "serious" problems associated with an unspecified number of patient deaths. Within days of an FDA inspection, Mylan began recalling EpiPen devices from the U.S., Europe, Asia, and North and South America due to a product defect that, at the time, Mylan claimed "occurs rarely."