Zentalis Pharmaceuticals (ZNTL) investor relations material

Strategic focus and development plans

• Primary focus is on advancing azenosertib for patients with cyclin E1 high protein expression in platinum-resistant ovarian cancer (PROC), with plans to expand into other tumor types and combination regimens.

• Azenosertib is positioned as a differentiated agent due to its tolerability and potential efficacy in cyclin E1 overexpressing populations, which are underserved by current therapies.

• The company is actively exploring combinations with chemotherapies and ADCs, with paclitaxel highlighted as a promising partner due to synergy and manageable toxicity.

• Ongoing and future trials are designed to optimize dosing, with 250 mg identified as the optimal dose in combination with paclitaxel, though further expansion cohorts are planned.

• Expansion into combinations with bevacizumab and exploration of activity in PARP inhibitor progressors are underway, aiming to address broader patient populations.

Market dynamics and clinical landscape

• The PROC market is evolving as new agents, especially ADCs, move up the treatment line, potentially expanding the addressable patient population and duration on therapy.

• Response rates for single-agent chemo in PROC are low (4–13%), highlighting the need for more effective and tolerable options.

• There is uncertainty about the efficacy of repeated topo payload ADCs due to emerging resistance, with evidence from other solid tumors suggesting diminishing returns.

• Differences in PFS and ORR between ADCs and WEE1 inhibitors are observed, with cyclin E1 high patients showing particularly short PFS on current ADCs.

• Combination strategies are informed by mechanistic synergy, with taxanes and DNA-damaging agents seen as strong partners for WEE1 inhibition.

Clinical data and biomarker strategy

• ASCO data from the MUIR trial showed a 50% ORR and nine-month duration of response for azenosertib plus paclitaxel at 250 mg, exceeding historical paclitaxel outcomes.

• Safety data indicate that most paclitaxel discontinuations were due to neuropathy, not azenosertib, supporting the agent’s tolerability.

• Monotherapy trials in cyclin E1 high, platinum-refractory patients show consistent ORR above 30% and PFS around five to six months.

• Enrichment strategies include focusing on PARP inhibitor progressors, who often have elevated cyclin E1 and may respond better to WEE1 inhibition.

• Approximately 25–30% of patients in the ongoing phase III monotherapy trial are fast PARP progressors, a key subgroup for efficacy analysis.