Abstract BACKGROUND: Metronomic chemotherapy (MC) is defined as the frequent administration of chemotherapy at doses below the maximal tolerated dose and with no prolonged drug-free break. As off-patent chemotherapeutic drugs can be used and given the low toxicity profile of this approach, MC seems to be well adapted to low-income countries.

OBJECTIVE: The aim of this study was to assess the efficacy and safety of a vincristine/cyclophosphamide/methotrexate MC regimen given to children with refractory cancer of various tumor types.

METHODS: This prospective, pilot, single-center study evaluated the use of MC with a first cycle consisting of weekly vincristine (1.5 mg/m) on days 1, 8, 15, and 22, daily cyclophosphamide (25 mg/m) on days 1 to 21, and twice weekly methotrexate (15 mg/m) on days 21 to 42, followed by a 1-week break. For the following cycles, vincristine was administered only at weeks 1 and 5 of the cycle. This treatment was proposed to children with refractory cancer following treatments with the standard protocols available in our institution and to patients who were not eligible for the protocol. Adverse events were determined through laboratory analyses and investigator observations.

RESULTS: From November 2008 to December 2009, 12 children (median age, 3.7 y; range, 2 to 7 y) were included. The most frequent diagnoses were Wilms tumors (6) and retinoblastoma (5). No objective response was observed, but 7 patients experienced disease stabilization (58%) and continued their treatment for 15 to 24 weeks. After a median follow-up of 39 weeks, 6 patients (50%) were alive. Most importantly, in 3 patients (25%), disease remained stable for at least 6 months after completion of treatment. One grade 4 anemia was observed in 1 patient and 1 grade 4 nonfebrile neutropenia in 1 patient. No other grade 3 or 4 toxicities were noted.

CONCLUSION: The MC regimen that we report here was well tolerated and was associated with disease stabilization. Most importantly, stabilization could be maintained for over 6 additional months after completion of treatment in 3 patients. The potential of MC in children and young adults in low-income countries warrants further studies.