Obinutuzumab and ICE Chemotherapy in Refractory/Recurrent CD20+ Mature NHL

This study is testing a combination of a targeted antibody drug called obinutuzumab with a standard chemotherapy regimen in children and young adults whose aggressive B-cell lymphoma or leukemia has come back or did not respond to initial treatment. **You may be eligible if...** - You have a CD20-positive B-cell blood cancer (such as diffuse large B-cell lymphoma, Burkitt lymphoma, or follicular lymphoma grade III) that has returned or did not respond to first-line treatment - You have not received the drug obinutuzumab before - Your body is functioning reasonably well - Your organ function is adequate - At least 2 weeks have passed since your last chemotherapy **You may NOT be eligible if...** - You have a newly diagnosed B-cell cancer that has not been treated yet - You have a known immune deficiency (inherited or acquired) - You have had a previous organ transplant - You had a bone marrow transplant less than 60 days ago, or have active severe graft-versus-host disease - You have had a severe allergic reaction to a monoclonal antibody drug before - You have uncontrolled hepatitis B or C Talk to your doctor to see if this trial is right for you.