BioPATH: A Biomarker Study in Asian Patients with HER2+ Advanced Breast Cancer Treated with Lapatinib and Other Anti-HER2 Therapy

Sung Bae Kim, In Gu Do, Janice Tsang, Tae You Kim, Yoon Sim Yap, Gerardo Cornelio, Gyungyub Gong, Soonmyung Paik, Suee Lee, Ting Ying Ng, Sarah Park, Ho Suk Oh, Joanne Chiu, Joohyuk Sohn, Moonhee Lee, Young Jin Choi, Eun Mi Lee, Kyong Hwa Park, Christos Nathaniel, Jungsil Ro

Research output: Contribution to journalArticlepeer-review

Abstract

PURPOSE: BioPATH is a non-interventional study evaluating the relationship of molecular biomarkers (PTEN deletion/downregulation, PIK3CA mutation, truncated HER2 receptor [p95HER2], and tumor HER2 mRNA levels) to treatment responses in Asian patients with HER2+ advanced breast cancer treated with lapatinib and other HER2-targeted agents. Materials and Methods: Female Asian HER2+ breast cancer patients (n=154) who were candidates for lapatinib-based treatment following metastasis and having an available primary tumor biopsy specimen were included. The primary endpoint was progression-free survival (PFS). Secondary endpoints were response rate, overall survival on lapatinib, correlation between biomarker status and PFS for any previous trastuzumab-based treatment, and conversion/conservation rates of the biomarker status between tissue samples collected at primary diagnosis and at recurrence/metastasis. Potential relationships between tumor mRNA levels of HER2 and response to lapatinib-based therapy were also explored. RESULTS: p95HER2, PTEN deletion/downregulation, and PIK3CA mutation did not demonstrate any significant co-occurrence pattern and were not predictive of clinical outcomes on either lapatinib-based treatment or any previous trastuzumab-based therapy in the metastatic setting. Proportions of tumors positive for p95HER2 expression, PIK3CA mutation, and PTEN deletion/down-regulation at primary diagnosis were 32%, 31.2%, and 56.2%, respectively. Despite limited availability of paired samples, biomarker status patterns were conserved in most samples. HER2 mRNA levels were not predictive of PFS on lapatinib. CONCLUSION: The prevalence of p95HER2 expression, PIK3CA mutation, and PTEN deletion/downregulation at primary diagnosis were similar to previous reports. Importantly, no difference was observed in clinical outcome based on the status of these biomarkers, consistent with reports from other studies.

Original languageEnglish
Pages (from-to)1527-1539
Number of pages13
JournalCancer research and treatment : official journal of Korean Cancer Association
Volume51
Issue number4
DOIs
Publication statusPublished - 2019 Oct 1

Keywords

  • Biomarkers
  • Breast neoplasms
  • HER2
  • Lapatinib
  • Trastuzumab

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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