Modified Capizzi maintenance regimen in children with relapsed acute lymphoblastic leukaemia

Improved survival of children with acute lymphoblastic leukaemia who relapse during therapy has been reported using the Capizzi maintenance regimen. We have treated ten such patients, without histocompatible donors, with this regimen, which consisted of fortnightly doses of vincristine (1.5 mg/m2) and an escalating dose of intravenous methotrexate (90-470 mg/m2) followed 24 hours later by asparaginase (15,000 units). Remission of disease had been successfully achieved in all patients using conventional therapy prior to the start of maintenance treatment. Cerebrospinal fluid concentrations of methotrexate were estimated serially in several patients but remained relatively low despite dose escalation. It appears that additional intrathecal chemotherapy is therefore necessary. Treatment was generally well tolerated but there is concern about the incidence of neurotoxicity in patients who had previously received cranial irradiation and intensive intrathecal therapy. The median duration of bone marrow remission was only 35 weeks (range 18-50). Two patients who had not been receiving IT therapy had early isolated CNS relapses. In conclusion, it appears that contrary to early expectations this treatment approach is unlikly to offer a significantly better outlook for these patients, in whom the chance of early marrow relapse remains high.