A phase II study of imatinib mesylate and capecitabine in metastatic breast cancer: Southwest oncology group study 0338

Helen Chew, William Barlow, Kathy Albain, Danika Lew, Allen Gown, Daniel Hayes, Julie Gralow, Gabriel Hortobagyi, Robert Livingston

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Background: Imatinib mesylate is a potent inhibitor of the Bcr-Abl, c-Kit, and platelet-derived growth factor receptor (PDGFR) tyrosine kinases. On the basis of variable expression of c-Kit and PDGFR in breast cancer and of in vitro data supporting synergy between imatinib and capecitabine, the Southwest Oncology Group conducted a phase II trial of the combination in metastatic breast cancer. Patients and Methods: Eligible patients had progressive, measurable metastatic breast cancer and received - 2 previous chemotherapy regimens for metastatic disease. Previous 5-fluorouracil or capecitabine for metastatic disease was not allowed. Patients were accrued on a 2-stage design and received imatinib mesylate 400 mg by mouth daily and capecitabine at 1000 mg/m2 by mouth twice daily for 14 days of a 21-day cycle. The primary endpoint was the confirmed response rate (RR). Tumors were evaluated for c-Kit, PDGFR-β, and hormone receptor expression. Results: Nineteen fully evaluable patients were enrolled, with a confirmed RR of 11% (95% CI, 1%-33%). Eleven percent had unconfirmed partial responses, and 42% had stable disease. The trial did not accrue to the second stage. The estimated 6-month progression-free survival was 16% (95% CI, 0%-32%), and the median overall survival was 14 months (95% CI, 7-15 months). The combination was well tolerated. Of 8 available tumor samples, 2 stained for c-Kit, and all had stromal staining for PDGFR-β. Conclusion: In unselected patients, the combination of imatinib mesylate and capecitabine was well tolerated but did not result in improved RRs compared to those reported with capecitabine alone.

Original languageEnglish (US)
Pages (from-to)511-515
Number of pages5
JournalClinical Breast Cancer
Issue number6
StatePublished - Dec 1 2008


  • C-Kit
  • Platelet-derived growth factor
  • Targeted therapy receptor

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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