Zentalis Presents Azenosertib Data in TNBC and Ovarian Cancer at AACR 2026

Preclinical data show potential for azenosertib combinations in ADC-resistant TNBC, and real-world analysis highlights unmet need in Cyclin E1-positive ovarian cancer.

Apr. 20, 2026 at 4:06am

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A minimalist, neon-outlined illustration depicting the intricate molecular structure of a cancer cell, conveying the complex biological mechanisms that Zentalis' research aims to target.Zentalis' preclinical data on azenosertib combinations suggest the potential to expand treatment options for aggressive cancers like triple-negative breast cancer.San Diego Today

Zentalis Pharmaceuticals announced data from two posters being presented at the 2026 AACR Annual Meeting. The preclinical data show encouraging activity of azenosertib combinations in triple-negative breast cancer (TNBC) models, including those resistant to antibody-drug conjugates (ADCs). Additionally, real-world data demonstrate that Cyclin E1-positive ovarian cancer patients have significantly worse outcomes compared to Cyclin E1-negative patients, reinforcing the potential for azenosertib to address this unmet need.

Why it matters

The preclinical data in TNBC support the potential for azenosertib to be developed through differentiated combination strategies, which could help fill an emerging unmet need as ADCs advance toward first-line use in this cancer type. The real-world ovarian cancer data validate the poor prognosis of Cyclin E1-positive patients, providing important context for Zentalis' ongoing registration-intended studies evaluating azenosertib as a targeted approach for this biomarker-selected population.

The details

The preclinical data showed that azenosertib monotherapy demonstrated meaningful antitumor activity across a diverse panel of TNBC models. Importantly, combinations of azenosertib with TOPO1i-payload ADCs enhanced both the depth and duration of response compared to ADC monotherapy in ADC-naïve models. In a patient-derived xenograft model of TNBC resistant to the approved ADC sacituzumab govitecan, the azenosertib + enfortumab vedotin combination induced complete responses in 7 of 8 mice and prevented tumor progression for over 52 days, compared to 100% progression within 30 days with the ADC alone. The real-world data analysis from two independent cohorts consistently demonstrated that Cyclin E1-positive ovarian cancer patients, with or without CCNE1 gene amplification, had shorter time to next treatment and a trend toward reduced clinical benefit from standard-of-care platinum-resistant ovarian cancer (PROC) treatments compared to Cyclin E1-negative patients.

  • The AACR 2026 Annual Meeting is taking place from April 17-22, 2026 in San Diego, CA.
  • The preclinical TNBC data poster will be presented on Monday, April 20, 2026 from 2:00-5:00 PM PDT.
  • The real-world ovarian cancer data poster will be presented on Sunday, April 19, 2026 from 2:00-5:00 PM PDT.

The players

Zentalis Pharmaceuticals

A clinical oncology innovator developing a treatment approach for ovarian cancer and multiple tumor types, including the investigational WEE1 inhibitor azenosertib.

Julie Eastland

Chief Executive Officer of Zentalis Pharmaceuticals.

Ingmar Bruns, M.D.

Chief Medical Officer of Zentalis Pharmaceuticals.

Alexandra Levy, MS

Presenting author of the preclinical TNBC data poster.

Jinkil Jeong, PhD

Presenting author of the real-world ovarian cancer data poster.

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What they’re saying

“The preclinical data in triple-negative breast cancer being presented at AACR showed that azenosertib combinations can induce complete tumor responses in a model resistant to emerging ADC therapies, supporting the potential to broaden the impact of azenosertib beyond ovarian cancer.”

— Julie Eastland, Chief Executive Officer of Zentalis Pharmaceuticals

“The real-world data being presented at AACR provide important validation that Cyclin E1-positive ovarian cancer patients face a particularly challenging disease trajectory with standard-of-care therapies.”

— Ingmar Bruns, M.D., Chief Medical Officer of Zentalis Pharmaceuticals

What’s next

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The takeaway

This data highlights the potential for azenosertib to address unmet needs in both triple-negative breast cancer and Cyclin E1-positive ovarian cancer, two challenging tumor types with limited effective treatment options. The preclinical results in TNBC support exploring azenosertib combinations as a strategy to overcome resistance to emerging ADC therapies, while the real-world ovarian cancer analysis validates the poor prognosis of the Cyclin E1-positive population that Zentalis is targeting with its ongoing registration-directed studies.