- Arm I (without rituximab): Patients receive pegfilgrastim subcutaneously (SC) on day 2 or 4 and CHOP comprising cyclophosphamide IV, doxorubicin hydrochloride IV, and vincristine IV on day 1, and oral prednisone on days 1-5. Treatment repeats every 2 weeks for up to 6-8 courses in the absence of disease progression or unacceptable toxicity.