Phase III study comparing exemestane with tamoxifen as first-line hormonal treatment of metastatic breast cancer in postmenopausal women: the European Organisation for Research and Treatment of Cancer Breast Cancer Cooperative Group

Robert J Paridaens, Luc Y Dirix, Louk V Beex, Marianne Nooij, David A Cameron, Tanja Cufer, Martine J Piccart, Jan Bogaerts, Patrick Therasse

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

This phase III randomized open-label clinical trial was designed to evaluate the efficacy and safety of the steroidal aromatase inactivator exemestane versus the antiestrogen tamoxifen as first-line treatment for metastatic breast cancer (MBC) in postmenopausal women.

Patients and Methods

The study was conducted at 81 centers and enrolled postmenopausal patients with measurable hormone-sensitive metastatic or locally advanced breast cancer. Prior adjuvant chemotherapy and/or tamoxifen were allowed. One previous chemotherapy regimen and no prior hormone therapy for advanced disease were permitted. Patients were randomly assigned to receive exemestane 25 mg or tamoxifen 20 mg orally once daily until disease progression or unacceptable toxicity occurred.

Results

A total of 371 patients enrolled at 79 sites (182 exemestane, 189 tamoxifen) were included in the analysis. Both treatments were generally well tolerated without major toxicity. Overall response rate was greater for exemestane than for tamoxifen treatment (46% v 31%; odds ratio = 1.85; 95% CI, 1.21 to 2.82; P = .005). Median progression-free survival (PFS) was longer with exemestane (9.9 months; 95% CI, 8.7 to 11.8 months) than with tamoxifen (5.8 months; 95% CI, 5.3 to 8.1 months). However, these early differences (Wilcoxon P = .028) did not translate to a longer-term benefit in PFS, the primary study end point (log-rank P = .121). There was also no difference in survival between both study arms.

Conclusion

Exemestane is an effective and well-tolerated first-line hormonal treatment for postmenopausal women with MBC and offers significant early improvement in time to tumor progression when compared with tamoxifen.
Original languageEnglish
Pages (from-to)4883-90
Number of pages8
JournalJournal of Clinical Oncology
Volume26
Issue number30
DOIs
Publication statusPublished - Oct 2008

Keywords / Materials (for Non-textual outputs)

  • Adult
  • Aged
  • Aged, 80 and over
  • Androstadienes
  • Antineoplastic Agents
  • Aromatase Inhibitors
  • Bone Neoplasms
  • Breast Neoplasms
  • Disease-Free Survival
  • Drug Resistance, Neoplasm
  • Estrogen Antagonists
  • Female
  • Humans
  • Lymphatic Metastasis
  • Middle Aged
  • Postmenopause
  • Soft Tissue Neoplasms
  • Tamoxifen
  • Treatment Outcome

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