Phase II study of low-dose methotrexate in advanced osteosarcoma followed by escalation after disease progression: a study of the Soft Tissue and Bone Sarcoma Group of the European Organization for Research on Treatment of Cancer.

Twenty-seven patients with osteosarcoma and measurable metastases were treated with low-dose methotrexate (LDMTX) (80 mg/m2), followed by high-dose methotrexate (HDMTX) (7.5 g/m2) after disease progression in 14 patients. LDMTX was administered on Days 1, 8, and 15; if response or stable disease occurred, it was repeated on Days 29 and 43. If response occurred by Day 57, LDMTX was continued every 2 weeks until disease progression. If stable disease occurred by Day 57, the patient crossed over (optional) to HDMTX. HDMTX was given weekly during the first 3 weeks and continued once every 14 days until disease progression. Twenty-five of the patients were evaluable for response. Three patients (12%) achieved complete remission, with durations of 5, 14, and 34 weeks, respectively. The time to disease progression from the start of treatment was 19, 28, and 42 weeks. Twelve patients (48%) had stable disease, with a median duration of 7.5 weeks (range, 6-20). Ten patients (40%) had disease progression. In general, toxicity with LDMTX was mild. The most frequent toxic effect was stomatitis. Twelve of 14 patients who crossed over to HDMTX were evaluated for response. Six patients had stable disease and six had disease progression. We conclude that the results achieved with LDMTX seem inferior to the results achieved with HDMTX described in the literature.