Aumilto Silva, Medical Oncologist, Senior Research Investigator Brazilian Clinical Research Institute, shared. a post on X:
“The recent SUMMIT TNBC analysis adds another piece to an evolving concept in precision oncology: activating HER2 mutations may define a therapeutically relevant subgroup even in HER2-nonamplified disease.
Earlier studies such as MutHER and the HR-positive SUMMIT cohorts already showed that HER2-mutant, HER2-nonamplified metastatic breast cancer can respond to HER2-directed kinase inhibition, particularly with dual blockade strategies combining neratinib with trastuzumab-based approaches.
The TNBC cohort extends this rationale into a biologically aggressive setting traditionally considered difficult to target molecularly.
The signal is interesting:
- Confirmed ORR around 35-40%.
- Longer disease control with neratinib + trastuzumab.
- ctDNA dynamics tracking response and resistance evolution in real time.
What makes the study particularly relevant is not simply the response rate.
ctDNA analyses demonstrated suppression of HER2-mutant clones during response, followed by molecular re-emergence at progression, alongside acquisition of potential resistance alterations involving ERBB3, KRAS, PIK3CA, MTOR, and TP53.
- Genomic drivers may matter more than conventional receptor labels alone.
- Rare molecular subsets can still support drug development strategies.
- Basket trials remain highly relevant in modern oncology.
- ctDNA is increasingly becoming a functional biomarker of therapeutic pressure and clonal evolution.
The study is small and nonrandomized, so interpretation must remain cautious.
But conceptually, it represents another step away from static pathology labels and toward dynamic molecular oncology.”
Title: Efficacy and Genomic Analysis of HER2-Mutant Metastatic Triple-Negative Breast Cancer Treated with Neratinib Alone or with Trastuzumab in the SUMMIT Basket Trial
Authors: Komal Jhaveri, Lisa D. Eli, Sara A. Hurvitz, Adam Brufsky, Ron Bose, María de Miguel, Nisha Unni, Sonya Reid, David I. Quinn, Devalingam Mahalingam, Cristina Saura Manich, José Ángel García-Sáenz, Alejandro Martínez-Bueno, Angel Guerrero-Zotano, Olivier Trédan, Hans Wildiers, Georg F. Bischof, Judith Bebchuk, David B. Solit
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