Zentalis reports 39.1% ORR and 7.3-month PFS with azenosertib-paclitaxel combo
Zentalis Pharmaceuticals’ Phase 1b MUIR trial of azenosertib plus paclitaxel in 46 platinum-resistant ovarian cancer patients showed a 39.1% overall response rate and median progression-free survival of 7.3 months. The 250 mg intermittent cohort achieved 50% ORR, 9.2-month median duration of response and low frequency of high-grade adverse events.
1. Trial Design and Patient Population
The Phase 1b MUIR trial enrolled 46 patients with platinum-resistant ovarian cancer who had all received prior paclitaxel. Four dose cohorts of azenosertib were evaluated: 200 mg daily continuous and 200 mg, 250 mg, 300 mg daily intermittent (5 days on, 2 days off), each combined with paclitaxel 80 mg/m².
2. Efficacy Results
Across all cohorts, the overall response rate was 39.1% with a median progression-free survival of 7.3 months and clinical benefit rate of 58.7%. In the 250 mg intermittent cohort, a 50% ORR and 9.2-month median duration of response were observed, outcomes in Cyclin E1-positive and -negative tumors were broadly similar.
3. Safety Profile and Next Steps
Most common treatment-related adverse events were fatigue (60.9%), anemia (58.7%), nausea (52.2%), and neutropenia (50%), with Grade ≥3 neutropenia and anemia at 30.4% and 19.6%. Serious events occurred in 20% of patients and one sepsis-related fatality was reported. Data will be presented June 1 at the ASCO poster session and further combination arms will be disclosed later.