 Brentuximab vedotin will be administered as a single IV infusion on Day 1 of each 21-day cycle. Measures of anti-cancer activity will be assessed using the revised response criteria for malignant lymphoma. CT scans chest, neck, abdomen, and pelvis will be performed at baseline and Cycles 2, 4, 7, 10, 13, and 16 and PET scans will be done at baseline and Cycles 4 and 7. Patients will have an EOT assessment 30 7 days after receiving their final dose of study drug. Long-term follow-up assessments including survival and disease status information will be performed every 12 weeks until either patient death or study closure, whichever occurs first. Patients who discontinue study treatment with stable disease or better will have CT scans done every 12 weeks until disease progression. 