Exhibit 99.1 Repligen Corporation 41 Seyon Street Building #1, Suite 100 Waltham, Massachusetts 02453 Repligen Reports First Quarter 2024 Financial Results • Reports first quarter revenue of $151 million • Increased new modalities revenue by 16% year-over-year • Increased Filtration (non-COVID) revenue by 12% year-over-year • Achieved a nine-month book-to-bill ratio of 1.03 WALTHAM, Mass., May 1, 2024 — Repligen Corporation (NASDAQ:RGEN), a life sciences company focused on bioprocessing technology leadershi ...