A phase II trial of imatinib mesylate monotherapy in patients with metastatic breast cancer.

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Modi S, Seidman AD, Dickler M, Moasser M, D'Andrea G, Moynahan ME, Menell J, Panageas KS, Tan LK, Norton L, Hudis CA

A phase II trial of imatinib mesylate monotherapy in patients with metastatic breast cancer.

Breast Cancer Res Treat. 2005 Mar;90(2):157-63.

PubMed ID

15803362 [ View in PubMed

]

Abstract

BACKGROUND: Imatinib mesylate is a potent inhibitor of Abl, KIT, and PDGFR tyrosine kinases. Breast cancer has variable expression of KIT and PDGFR therefore we conducted a phase II trial to evaluate the safety and efficacy of imatinib in patients with metastatic breast cancer (MBC). PATIENTS AND METHODS: Eligible patients had measurable and progressive MBC, with no limits on prior chemo- or hormonal therapy. Imatinib was initially administered at a dose of 400 mg orally twice a day with provisions for dose reductions based on toxicities. The primary endpoint was clinical benefit based on RECIST criteria. Tumor specimens were tested for expression of KIT and PDGFR tyrosine kinases. RESULTS: Sixteen patients were enrolled and treated. Median age was 55 years (range: 35-73); median number of prior chemotherapy regimens for MBC was 4 (range 1-8). The main non-hematologic toxicities were (Grades 1/2; Grade 3): fatigue (56%; 6%), edema (38%; 19%), nausea (31%; 19%), vomiting (38%; 0%), anorexia (38%; 0%), diarrhea (19%; 6%), and rash (25%; 6%). Grade 3/4 hematologic and biochemical abnormalities were minimal. There was no evidence of clinical benefit. The median duration of therapy on trial was 28 days (range 2-71). Of the 13 testable cases: 1 was KIT positive and 4 were PDGFR positive. CONCLUSION: Imatinib therapy at doses of 800 mg/day was associated with significant toxicity in patients with heavily pre-treated MBC. Our results do not indicate activity for imatinib monotherapy in these unselected patients.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Imatinib	Platelet-derived growth factor receptor beta	Protein	Humans	Yes	Antagonist	Details