Zentalis Pharmaceuticals to Present at the European Society for Medical Oncology (ESMO) Congress 2026

Zentalis ® Pharmaceuticals, Inc. (Nasdaq: ZNTL), a clinical oncology innovator advancing late-stage development of investigational first-in-class WEE1 inhibitor azenosertib as a biomarker-driven treatment approach for ovarian cancer, today announced two presentations at the European Society for Medical Oncology (ESMO) Congress 2026, taking place October 23-27, 2026, in Madrid, Spain.

Rapid oral presentation: Title: “Azenosertib in platinum-resistant ovarian cancer (PROC): overall survival analysis from Part 1b of the DENALI study (GOG-3066)” Date/Time: Friday, October 23, 2026, 4:15 p.m. - 5:45 p.m. CEST Presentation Number: 1242RO

Trial-in-progress poster presentation: Title: “ASPENOVA: A phase 3 study of azenosertib monotherapy versus standard of care chemotherapy in cyclin E1-positive platinum-resistant ovarian cancer (PROC)” Date/Time: Monday, October 26, 2026, 12:00 p.m. - 12:45 p.m. CEST Presentation Number: 1339TiP

About DENALI Clinical Trial DENALI is a multi-part Phase 2 registration-intended clinical trial (NCT05128825) studying azenosertib in PROC patients. Part 1b enrolled patients with PROC regardless of Cyclin E1 protein expression, all treated at 400mg QD 5:2 (5 days once-daily administration of azenosertib, followed by 2 days without azenosertib). Part 2 is prospectively enrolling PROC patients with Cyclin E1 protein overexpression based on Zentalis' proprietary immunohistochemistry cutoff. Part 2, in total, is designed to support accelerated approval, pending positive study outcomes and further discussions with the FDA. The study design consists of the following parts: Part 2a: Dose confirmation evaluated two doses, 300mg QD 5:2 and 400mg QD 5:2, with approximately 30 patients enrolled per dose group. 400mg QD 5:2 was selected as the optimal monotherapy dose. Recruitment at the 300mg QD 5:2 dose level has been discontinued. All patients enrolled in Part 2a will contribute to the overall safety database submitted to the FDA. Part 2b: Enrollment expansion at the selected 400mg QD 5:2 dose up to approximately 100 patients, including patients at this dose in Part 2a. This cohort is currently enrolling. Part 2c: Broadening study population, which is expected to include approximately 40 patients previously treated with a taxane-containing regimen for PROC. This cohort is currently enrolling. For physician and patient information about the DENALI trial, please visit www.denalitrial.com .

About ASPENOVA Clinical Trial ASPENOVA is a Phase 3 randomized, confirmatory clinical trial designed to support full approval of azenosertib in patients with Cyclin E1-positive PROC. The trial is expected to enroll approximately 420 patients and compare azenosertib monotherapy at 400mg QD 5:2 to investigator's choice of standard-of-care single-agent chemotherapy (paclitaxel, pegylated liposomal doxorubicin [PLD], gemcitabine, or topotecan) in this biomarker-selected population. The primary endpoint is progression-free survival (PFS); key secondary endpoints include overall survival (OS) and overall res...