On April 21, 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, reported that the American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) has accepted an abstract for presentation at the 2026 ASCO (Free ASCO Whitepaper) Annual Meeting, which will be held June 1-5, 2026, in Chicago, IL.
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"We are pleased that data from Part 1 of the MUIR trial focusing on azenosertib in combination with paclitaxel in platinum-resistant ovarian cancer (PROC) have been accepted for presentation at ASCO (Free ASCO Whitepaper)," said Julie Eastland, Chief Executive Officer of Zentalis. "Paclitaxel is a commonly used agent across multiple tumor types, including in ovarian cancer. The azenosertib-paclitaxel data from MUIR Part 1 will showcase combinability and activity in an all-comer setting, which we believe indicates the broad potential for azenosertib in multiple lines of ovarian cancer and other tumor types. With our core strategic focus on advancing azenosertib in registration-intended trials as a monotherapy in the biomarker-selected Cyclin E1-positive PROC population through our DENALI and ASPENOVA trials, the MUIR trial represents an important part of our broader pipeline strategy."
Accepted Abstract Title: Azenosertib Plus Paclitaxel for Platinum-Resistant Ovarian Cancer: Results From a Phase 1b Study
Abstract Number: 5529
Session Type / Title: Poster Session – Gynecologic Cancer
Poster Board: 195
Date/Time: June 1, 2026; 9am-12pm CDT
About MUIR Clinical Trial
MUIR (ZN-c3-002) is a multi-part, open-label Phase 1b clinical trial (NCT04516447) evaluating the safety, efficacy, and preliminary clinical activity of azenosertib in combination in patients with ovarian cancer.
Part 1 enrolled patients with platinum-resistant ovarian cancer (PROC) treated with azenosertib in combination with one of four chemotherapy regimens: carboplatin, gemcitabine, pegylated liposomal doxorubicin, or paclitaxel. Primary objectives are safety and tolerability, with key secondary objectives including clinical activity assessed by objective response rate, duration of response, and progression-free survival per RECIST v1.1.
Part 2 is evaluating azenosertib plus bevacizumab as maintenance regimen (first [1L] or second line [2L]) in patients with advanced ovarian, peritoneal, or fallopian tube cancer following platinum-based chemotherapy. The dose expansion portion will evaluate azenosertib at the recommended dose in combination with bevacizumab in patients with platinum-sensitive ovarian cancer in 2L who progressed while on a PARP inhibitor for 1L maintenance. The primary objective is safety and tolerability; secondary objectives include preliminary clinical activity of the combination as assessed by progression-free survival for the dose expansion portion.
About Azenosertib
Azenosertib is an investigational, potentially first-in-class, selective, and orally bioavailable inhibitor of WEE1 currently being evaluated in clinical studies in ovarian cancer and additional tumor types. WEE1 acts as a master regulator of the G1-S and G2-M cell cycle checkpoints, through negative regulation of both CDK1 and CDK2, to prevent replication of cells with damaged DNA. By inhibiting WEE1, azenosertib enables cell cycle progression, despite high levels of DNA damage, thereby resulting in the accumulation of DNA damage and leading to mitotic catastrophe and cancer cell death.
Azenosertib is in late-stage development as a potential treatment for Cyclin E1-positive platinum-resistant ovarian cancer (PROC). There is currently no approved treatment option specifically for this biomarker-selected population which comprises approximately 50% of PROC patients. Cyclin E1 protein overexpression has been established as a sensitive and specific predictive biomarker for identifying patients who could potentially derive benefit from azenosertib treatment, based on retrospective analysis of azenosertib studies in PROC. Validation of the Cyclin E1 companion diagnostic assay is ongoing in the DENALI and ASPENOVA trials.
Azenosertib has been granted Fast Track Designation by the U.S. FDA for the treatment of patients with Cyclin E1-positive platinum-resistant ovarian cancer. Fast Track Designation is intended to facilitate the development and expedite the review of therapies that have the potential to treat serious conditions and address unmet medical needs.
(Press release, Zentalis Pharmaceuticals, APR 21, 2026, View Source [SID1234664663])