Money EpiPen maker Mylan, Pfizer’s Upjohn off-patent drug business to merge July 29, 2019 Nathan Bomey, USA TODAY Comments Off on EpiPen maker Mylan, Pfizer’s Upjohn off-patent drug business to merge Pfizer's off-patent drug business, Upjohn, is set to merge with Mylan, maker of emergency allergic reaction treatment EpiPen.