- Arm B: CHVP + alpha2a-interferon + rituximab. Patients will receive 6 monthly courses of CHVP (cyclophosphamide 600 mg/m², adriamycin 25 mg/m², etoposide 100 mg/m² on day 1 and prednisolone 40 mg/m² for 5 days) associated with 6 infusions of rituximab (375 mg/m2) associated with alpha2a-interferon 4.5 millions units sub-cutaneously three times a week for 18 months.