Elacestrant plus alpelisib in an ESR1 and PIK3CA co-mutated and heavily pretreated metastatic breast cancer: the first case report for combination efficacy and safety


Tokat Ü. M., Bilgiç Ş. N., Aydın E., Adibi A., Özgü E., TUTAR O., ...More

Therapeutic Advances in Medical Oncology, vol.16, 2024 (SCI-Expanded, Scopus)

  • Publication Type: Article / Article
  • Volume: 16
  • Publication Date: 2024
  • Doi Number: 10.1177/17588359241297101
  • Journal Name: Therapeutic Advances in Medical Oncology
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Directory of Open Access Journals
  • Keywords: alpelisib, cancer genomics, case report, elacestrant, ESR1/PIK3CA co-mutations, HR-positive/HER2-negative metastatic breast cancer, selective estrogen receptor degrader (SERD)
  • Istanbul University Affiliated: No

Abstract

Breast cancer (BC) is the leading cause of cancer-related mortality among women, and hormone receptor (HR)-positive subtype makes up the majority of all cases. The standard of care in HR+/HER2− metastatic BC (MBC) is endocrine therapy (ET) plus a CDK4/6 inhibitor (CDK4/6i). ESR1 mutations could impair the clinical efficacy of the ETs. Similarly, PIK3CA mutations may serve as a negative prognostic marker. Furthermore, MBC is challenging to treat despite new drug approvals. Our patient received multiple lines of ET ± CDK4/6i and chemotherapy but persistently progressed after each or stopped the treatment due to adverse events. Here we showed for the first time that an all-oral combination of elacestrant plus alpelisib was feasible, tolerable, and clinically active in an ESR1 and PIK3CA co-mutated and heavily pretreated patient. We achieved a remarkable response in the metastatic lesions with minor toxicity issues. This case highlights the importance of utilizing up-to-date therapeutic agents and reactive decision-making during personalized cancer treatment.