All patients initially treated with systemic corticosteroids alone: optional IV methylprednisolone pulse (15 mg/kg) at treatment start followed by oral prednisone (1 mg/kg/day) according to a tapering schedule. Treating physicians allowed to treat minor relapses with corticosteroids without referring the patient for randomization, as long as the prednisone dose did not exceed 0.5 mg/kg for 1 month.