Exhibit 99.1 Zentalis Pharmaceuticals Reports First Quarter 2025 Financial Results and Operational Progress First patient dosed in DENALI Part 2a clinical trial of azenosertib in patients with Cyclin E1+ PROC Topline data from DENALI Part 2 anticipated by year end 2026 with the potential to support an accelerated approval, subject to FDA feedback $332.5 million cash, cash equivalents and marketable securities supports operational runway into late 2027 SAN DIEGO, Calif. — May 14, 2025 — Zentalis® Pharmaceuti ...