Gemcitabine and oxaliplatin in patients with metastatic breast cancer resistant to or pretreated with both anthracyclines and taxanes - Clinical and pharmacokinetic data

Objectives: To evaluate the efficacy, the toxicity and the pharmacokinetics of a gemcitabine (GEM) and oxaliplatin (OXA) combination in metastatic breast cancer patients (MBC), previously treated with anthracycline and taxanes. Methods: A total of 40 women were enrolled; 37 patients had visceral metastases as dominant site of disease, including 20 patients with liver metastases and 14 with multiple visceral metastases. Three patients received neo-adjuvant chemotherapy, 13 patients adjuvant chemotherapy alone, 24 patients chemotherapy for MBC alone. Gemcitabine was given at 1000 mg/m(2) on days 1, 8 followed by oxaliplatin at 100 mg/m(2) iv on day 2 every 2 weeks (GEM-OXA sequence). Possible pharmacokinetic interactions were studied in 10 patients, by administering on cycle I gemcitabine d1/oxaliplatin d2 (GEM-OXA) and on cycle 2 oxaliplatin d1/gemcitabine d2 (OXA-GEM). Results: After a median of 8 cycles, 10 partial response (PR) (25%) 16 stable disease (SD) (40%), and 14 progressive disease (PD) (35%) were obtained. The median duration of response was 6 months (3-9) for responding patients and 4.9 months (2-7.5) for patients with stable disease. For PR, SD and PD patients, median survival was 18 (10-23+), 13 (8-18), and 6 months (4-13), respectively. G34 neutropenia occurred in 20% of patients (febrile G3 neutropenia in 2.5%), G3-4 thrombocytopenia and anemia in 15% and 7.5%. The most frequent G3-4 northematologic toxicity was represented by peripheral neuropathy (20%), always reversible. The GEM-OXA and OXA-GEM schedules showed a similar phanrmacokinetic behavior, with no sequence-dependent interaction. Conclusions: The combination gemcitabine plus oxaliplatin has moderate activity in anthracycline and taxanes resistant/relapsed heavily treated patients, mild toxicity and no administration sequence-dependent pharmacokinetic interactions.