EDINBURGHIdarubicin (Idamycin) paired with capecitabine (Xeloda) and
administered orally is well tolerated and active as a first-line treatment for
older women with breast cancer, according to results of a recent dose-finding
study. The oral idarubicin/capecitabine regimen was associated with 8 responses
among 16 postmenopausal women who had chemotherapy-naive locally advanced or
metastatic breast cancer, according to David Cameron, MD, senior lecturer in
oncology at Western General Hospital, University of Edinburgh.
"We were trying to find an entirely oral combination for treatment, and this
investigation was really to find the optimum dose," Dr. Cameron said. "We were
not looking for how active it was, although we did see responses at every dose
Capecitabine has been shown to be at least as effective as paclitaxel or the
regimen of cyclophosphamide, methotrexate, fluorouracil (CMF) in advanced
breast cancer, according to Dr. Cameron. The oral anthryacline idarubicin is
active as a single agent in breast cancer, and has similar efficacy compared
with doxorubicin, but with less cardiotoxicity, he added.
Women in the phase I dose-finding study had to be less than 75 years of age;
the actual age range was 53 to 75 years. The patients could not have received
prior chemotherapy, except for adjuvant CMF completed at least a year earlier.
Prior endocrine therapy was also allowed.
Patients received idarubicin on the first 3 days and capecitabine on the
first 14 days of a 21-day cycle. Idarubicin was given initially at 10 mg/m2
daily, and capecitabine in divided doses as 1,500, 2,000, or 2,500 mg/m2
per day. The maximum tolerated dose level was idarubicin 10 mg/m2/day
and capecitabine 1,250 mg/m2 twice daily. Dose-limiting toxicities
included diarrhea and myelotoxicity.
Subsequently, investigators evaluated the 1,000 mg/m2 twice daily
dose of capecitabine with a somewhat higher dose of idarubicin (12 mg/m2/day),
and found the combination to be tolerable. This dose level is currently being
explored in an extended cohort of 12 patients to confirm activity. "This is
potentially an active regime that is well tolerated," Dr. Cameron said.