This is a multicenter, open-label study to evaluate single-agent brentuximab vedotin (SGN-35) treatment in patients who previously participated in a brentuximab vedotin study, including Studies SGN35-005 (NCT01100502), SGN35-007 (NCT01026233), and SGN35-008 (NCT01026415). Patients treated on this study (SGN35-006) could re-enroll on study if eligible. The study consisted of 2 arms, as follows: