Cardiff Oncology Presents Preclinical Data on Onvansertib Combined with HER2-Targeted ADC at 2026 AACR Annual Meeting

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Cardiff Oncology presented preclinical data at the AACR Annual Meeting 2026 (April 17–22, San Diego) on its oral PLK1 inhibitor onvansertib combined with trastuzumab deruxtecan (T-DXd) in HER2-low breast cancer models.14

The combination demonstrated synergistic inhibition of cell viability in HER2-low breast cancer cell lines, including fulvestrant- and CDK4/6i-resistant cells, robust antitumor activity, tumor regression, and overcame resistance.124

In resistant triple-negative and hormone receptor-positive models, the combo drove tumor regression in nearly all mice, with complete response rates up to 62%, improved growth inhibition, extended event-free survival, and favorable tolerability.145

Poster titled 'PLK1 inhibitor onvansertib potentiates the antitumor efficacy of trastuzumab deruxtecan (T-DXd) and reverses its resistance in therapy-resistant HER2-low breast cancer models' presented April 19, 2026, 2:00–5:
00 PM PT (Abstract #329).24

Sources:

1. https://www.marketscreener.com/news/cardiff-oncology-presents-preclinical-data-on-its-plk1-inhibitor-onvansertib-in-combination-with-a-h-ce7e50d3da8bf620

2. https://www.biospace.com/press-releases/cardiff-oncology-to-present-preclinical-data-with-highly-specific-plk1-inhibitor-onvansertib-at-the-2026-aacr-annual-meeting

4. https://investors.cardiffoncology.com/news-releases/news-release-details/cardiff-oncology-presents-preclinical-data-its-plk1-inhibitor

5. https://www.stocktitan.net/news/CRDF/cardiff-oncology-presents-preclinical-data-on-its-plk1-inhibitor-exank18cmya1.html