- Initial therapy: Patients receive prednisone and vinblastine as in arm I initial therapy. Patients also receive methotrexate IV over 24 hours on days 1, 15, and 29 and oral leucovorin calcium twice daily on days 2,16, and 30. Patients achieving NAD after course 1 proceed to continuation therapy. Patients achieving intermediate response or disease regression receive a second course* of initial therapy. Patients achieving NAD or disease regression after course 2 proceed to continuation therapy.