Zentalis reported that azenosertib monotherapy yielded 10% high-grade neutropenia and predominantly low-grade gastrointestinal and fatigue adverse events, which were managed with supportive care. The clinical team employs a daily data-driven review to proactively contact trial sites and address emerging side effects, aiming to differentiate azenosertib’s tolerability from other WEE1 inhibitors.

The DENALI registration study is in Part 2A, having enrolled up to 60 platinum-resistant ovarian cancer patients split evenly between 300 mg and 400 mg once-daily dosing on a 5-days-on/2-days-off schedule. Following follow-up, Zentalis will select a single registration dose in H1 2026, then expand to approximately 100 patients in Part 2B, with a top-line readout expected by year-end 2026.

Zentalis plans to enroll the first patient in the ASPENOVA Phase 3 confirmatory trial in H1 2026, using the same eligibility criteria as DENALI Part 2 to satisfy accelerated approval requirements. The adaptive three-arm design allows immediate initiation of the randomized control arm and aims for a target overall response rate near 30% and a duration of response between 5 and 6 months.

The company developed an immunohistochemistry assay for cyclin E1 expression, with a cutoff derived from retrospective analyses of several hundred patients; roughly 50% of PROC patients meet this threshold. While a uterine serous carcinoma study (TETON) is fully enrolled, priority remains on PROC, and broader combination strategies and longer-term pipeline initiatives will be considered after key clinical milestones.