New breast cancer PDX models, including with acquired resistance

XenTech is delighted to announce 18 new Breast Cancer models

• 14 triple-negative models, including one with a BRCA1 mutation and highly sensitive to the PARP inhibitor Olaparib.
• 3 ER+ models, including 2 sensitive to estrogen deprivation.
• 1 HER2+ model sensitive to T-DM1 and carrying an ERBB2 mutation leading to Lapatinib resistance.

The successful transition of a drug candidate into clinical phases requires its preclinical evaluation in the most predictive experimental models. That’s why all our models are characterized by deep molecular and pharmacological signatures, according to their mechanisms of action and targeted pathways.

Today, our breast cancer PDX panel is among the most representative and recognized worldwide. It supports both preclinical drug candidate evaluation and responder model identification through Mouse Clinical Trials (MCT).

Spotlight on 8 brand-new PDX models with acquired resistance

✅ 6 of these new models exhibit acquired resistance to Olaparib (PARP inhibitor) after long-term exposure. Resistance is associated with:

• Increased expression of DNA repair genes (HR, NHEJ pathways) and TP53 mutated
• In one case, reversion of a BRCA1 mutation

✅ 2 additional models were derived from in vivo exposure of a highly sensitive model to Enhertu (HER2 ADC), until resistant derivatives emerged. Key findings:

• Retained HER2 expression
• Overexpression of DNA repair genes (BRCA1/2, RAD51, CHEK1) highlighting transcriptional plasticity

These resistant PDX models offer powerful tools to explore mechanisms of acquired resistance and support the design of more effective therapies.

Looking for more information about these models, our MCT platform, or collaboration opportunities? 👉 Contact us today at bdteam@xentech.eu