---
schema_version: "secwatch.filing_event.v1"
accession: "0001725160-26-000045"
form_type: "8-K"
ticker: "ZNTL"
cik: "0001725160"
company_name: "Zentalis Pharmaceuticals, Inc."
filed_at: "2026-05-21T21:29:34+00:00"
generated_at: "2026-05-21T21:33:34.646606+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Zentalis reports 39% ORR, 7.3-month median PFS for azenosertib+paclitaxel in PROC at ASCO

## Summary
- Phase 1b MUIR trial: all-comer PROC (n=46), ORR 39.1%, CBR 58.7%, median DOR 5.6 mo, median PFS 7.3 mo.
- At 250 mg intermittent dose (n=12): ORR 50.0%, median DOR 9.2 mo, median PFS 5.5 mo, manageable safety.
- Cyclin E1-positive (ORR 41.4%) and -negative (ORR 35.7%) patients showed comparable activity.
- Grade ≥3 TRAEs: neutropenia 30.4%, anemia 19.6%; one Grade 5 sepsis event previously reported.
- Data supports combo expansion; core focus remains azenosertib monotherapy in Cyclin E1+ PROC.

## SEC filing metadata
- accession: 0001725160-26-000045
- form_type: 8-K
- ticker: ZNTL
- cik: 0001725160
- company_name: Zentalis Pharmaceuticals, Inc.
- filed_at: 2026-05-21T21:29:34+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1725160/000172516026000045/0001725160-26-000045-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1725160/000172516026000045/zntl-20260521.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001725160-26-000045
- JSON: https://secwatch.observer/filing/0001725160-26-000045.json
- Plain text: https://secwatch.observer/filing/0001725160-26-000045.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.