Phase II study of irinotecan plus capecitabine in anthracycline- and taxane- pretreated patients with metastatic breast cancer

To evaluate the efficacy and tolerability of combined treatment with irinotecan (I) and capecitabine (X), we conducted a phase II study of the IX combination in anthracycline- and taxane-pretreated patients with metastatic breast cancer (MBC). Patients received 80 mg/m² I on days 1 and 8 and 1,000 mg/m² X twice daily on days 1–14 of 21-day cycles until disease progression. The primary endpoint was the objective response rate (ORR), and the secondary endpoints were progression-free survival (PFS), overall survival (OS), and safety. Thirty-six patients were enrolled between September 2006 and April 2008. The median follow-up was 47.6 months. The ORR was 58.3 % (95 % CI, 42.2–72.9), with 3 complete responses and 18 partial responses. The median PFS was 7.6 months (95 % CI, 5.0–10.2), and the median OS was 20.0 months (95 % CI, 11.6–28.4). Neutropenia was the most common adverse event (grade 3, 30.6 %; grade 4, 27.8 %) with febrile neutropenia in 2 patients (5.6 %). Three patients (8.3 %) had grade 3 diarrhea, 3 patients (8.3 %) had grade 3 asthenia, and 1 patient (2.8 %) had grade 3 hand-foot syndrome. The IX combination was effective and tolerable for anthracycline- and taxane-pretreated patients with MBC. A phase III trial of this combination is ongoing.