Exhibit 99.1 Xencor Reports First Quarter 2025 Financial Results -- Recent interim Phase 1 study results for XmAb942 (Xtend™ anti-TL1A) support a 12-week maintenance dosing interval in XENITH-UC, a Phase 2b study in participants with ulcerative colitis, to begin in the second half of 2025 -- -- Chief development officer and former independent director, Nancy Valente, M.D., to transition to senior advisory role -- PASADENA, Calif.-- May 7, 2025-- Xencor, Inc. (NASDAQ:XNCR), a clinical-stage biopharmaceutical ...