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Relationship between Tumor Biomarkers and Efficacy in EMILIA, a Phase III Study of Trastuzumab Emtansine in HER2-Positive Metastatic Breast Cancer.
Baselga, José; Lewis Phillips, Gail D; Verma, Sunil; Ro, Jungsil; Huober, Jens; Guardino, Alice E; Samant, Meghna K; Olsen, Steve; de Haas, Sanne L; Pegram, Mark D.
Affiliation
  • Baselga J; Memorial Sloan Kettering Cancer Center, New York, New York. baselgaj@mskcc.org.
  • Lewis Phillips GD; Genentech, Inc., South San Francisco, California.
  • Verma S; Sunnybrook Odette Cancer Centre, Toronto, Canada.
  • Ro J; National Cancer Center, Goyang, Korea.
  • Huober J; Breast Center, Kantonsspital St. Gallen, St. Gallen, Switzerland.
  • Guardino AE; Genentech, Inc., South San Francisco, California.
  • Samant MK; Genentech, Inc., South San Francisco, California.
  • Olsen S; Genentech, Inc., South San Francisco, California.
  • de Haas SL; F. Hoffmann-La Roche Ltd, Basel, Switzerland.
  • Pegram MD; Stanford Cancer Institute, Palo Alto, California.
Clin Cancer Res ; 22(15): 3755-63, 2016 08 01.
Article in En | MEDLINE | ID: mdl-26920887
ABSTRACT

PURPOSE:

HER2-positive breast cancer is heterogeneous. Some tumors express mutations, like activating PIK3CA mutations or reduced PTEN expression, that negatively correlate with response to HER2-targeted therapies. In this exploratory analysis, we investigated whether the efficacy of trastuzumab emtansine (T-DM1), an antibody-drug conjugate comprised of the cytotoxic agent DM1 linked to the HER2-targeted antibody trastuzumab, was correlated with the expression of specific biomarkers in the phase III EMILIA study. EXPERIMENTAL

DESIGN:

Tumors were evaluated for HER2 (n = 866), EGFR (n = 832), and HER3 (n = 860) mRNA expression by quantitative reverse transcriptase PCR; for PTEN protein expression (n = 271) by IHC; and for PIK3CA mutations (n = 259) using a mutation detection kit. Survival outcomes were analyzed by biomarker subgroups. T-DM1 was also tested on cell lines and in breast cancer xenograft models containing PIK3CA mutations.

RESULTS:

Longer progression-free survival (PFS) and overall survival (OS) were observed with T-DM1 compared with capecitabine plus lapatinib in all biomarker subgroups. PIK3CA mutations were associated with shorter median PFS (mutant vs. wild type 4.3 vs. 6.4 months) and OS (17.3 vs. 27.8 months) in capecitabine plus lapatinib-treated patients, but not in T-DM1-treated patients (PFS, 10.9 vs. 9.8 months; OS, not reached in mutant or wild type). T-DM1 showed potent activity in cell lines and xenograft models with PIK3CA mutations.

CONCLUSIONS:

Although other standard HER2-directed therapies are less effective in tumors with PI3KCA mutations, T-DM1 appears to be effective in both PI3KCA-mutated and wild-type tumors. Clin Cancer Res; 22(15); 3755-63. ©2016 AACR.
Subject(s)

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Breast Neoplasms / Biomarkers, Tumor / Receptor, ErbB-2 / Trastuzumab / Antineoplastic Agents, Immunological / Maytansine Type of study: Observational_studies / Prognostic_studies / Risk_factors_studies Limits: Animals / Female / Humans Language: En Journal: Clin Cancer Res Journal subject: NEOPLASIAS Year: 2016 Document type: Article

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Breast Neoplasms / Biomarkers, Tumor / Receptor, ErbB-2 / Trastuzumab / Antineoplastic Agents, Immunological / Maytansine Type of study: Observational_studies / Prognostic_studies / Risk_factors_studies Limits: Animals / Female / Humans Language: En Journal: Clin Cancer Res Journal subject: NEOPLASIAS Year: 2016 Document type: Article