This 2 arm study will compare the efficacy and safety of Avastin in combination with MabThera and CHOP chemotherapy (RA-CHOP) versus MabThera plus CHOP chemotherapy (R-CHOP) in previously untreated patients with CD20-positive diffuse large B-cell lymphoma (DLBCL). Patients will be randomized to 8 cycles of treatment with R-CHOP plus Avastin, or R-CHOP plus placebo. The treatment with Avastin/Placebo and R-CHOP will be given either as a 2 weekly or 3 weekly schedule, and Avastin will be given at a weekly average dose of 5mg/kg (10mg/kg for 2 weekly cycles and 15mg/kg for 3 weekly cycles). Responding patients will continue on Avastin monotherapy (15mg/kg every 3 weeks) for up to 1 year. The anticipated time on treatment is 3-12 months, and the target sample size is 500+ individuals.

• Drug: bevacizumab [Avastin]
  5mg/kg / week dosing equivalent iv
• Drug: R-CHOP
  As prescribed
• Drug: Placebo
  iv/week

• 1: Experimental
  Interventions:

  • Drug: bevacizumab [Avastin]
  • Drug: R-CHOP
• 2: Placebo Comparator
  Interventions:

  • Drug: R-CHOP
  • Drug: Placebo

Inclusion Criteria:

• adult patients, >=18 years of age;
• CD20-positive diffuse large B-cell lymphoma;
• low-intermediate, high-intermediate or high risk disease and/or bulky tumor (.7.5 cm);
• ECOG performance status 0-2.

Exclusion Criteria:

• prior treatment for diffuse large B-cell lymphoma;
• types of non-Hodgkin's lymphoma other than DLBCL;
• CNS involvement of lymphoma.