e19509 Background: CAN2007 was the first prospective study of single-agent btz in relapsed AL. We describe 4 pts in CAN2007 (NCT00298766) who received btz treatment for up to 5.6 yrs. Methods: 70 pts received btz 0.7–1.6 mg/m2, d 1, 8, 15, 22, 35-d cycles (QW), or 0.7–1.3 mg/m2, d 1, 4, 8, 11, 21-d cycles (BIW), for up to 8 cycles; prolonged treatment was permitted at the discretion of the treating physician for pts showing ongoing clinical benefit. Results: Pt #1 (male, age 53 yrs; IgA lambda AL with cardiac and renal involvement; 16 mos since diagnosis; prior therapy: melphalan plus ASCT) received btz 1.3 mg/m2 QW for 57 cycles (5.6 yrs). Cumulative dose was 190.5 mg/m2. He had a hematologic CR to initial btz therapy and a complete renal response to sustained therapy, without grade 3/4 adverse events (AEs). Pt #2 (male, age 53 yrs; IgG kappa AL with gastrointestinal [GI] involvement; 38 mos since diagnosis; prior therapy: ASCT) received btz 0.7 mg/m2 BIW for 47 cycles (4.3 yrs; cumulative dose 77.7 mg/m2), had a hematologic response of stable disease, and had a renal response, with no grade 3/4 AEs. The pt progressed and is in remission on alternative therapy. Pt #3 (female, age 55 yrs; IgG lambda AL with GI and other-site involvement; 14 mos since diagnosis; prior therapy: ASCT) received btz 1.6 mg/m2 QW for 39 cycles (3.7 yrs; cumulative dose 167.7 mg/m2). She had grade 3 paralytic ileus in cycle 8 with dose adjustment to 1.3 then 1.0 mg/m2. She had a hematologic PR. Pt #4 (female, age 54 yrs; lambda light-chain AL with cardiac and GI involvement; 44 mos since diagnosis; prior therapy: cardiac allograft followed by ASCT) received 57 cycles (3.5 yrs; cumulative dose 173.7 mg/m2); starting dose was 1.3 mg/m2 BIW, reduced to 1.0 (cycle 3) and 0.7 mg/m2 (cycle 16) due to grade 3 AEs of vasculitis and volvulus, respectively. Other grade 3 AEs included pneumonia, hemoptysis, and C. difficile diarrhea. Best hematologic response was PR; a renal response was also achieved. Conclusions: This case series indicates the feasibility and activity of btz for long-term disease control in relapsed AL, particularly in pts who did not achieve a CR to initial btz therapy. Pts 1, 3, 4 remain progression-free and are ongoing on btz. Clinical trial information: NCT00298766.