Long-term follow-up from a phase 1/2 study of single-agent bortezomib in relapsed systemic AL amyloidosis

Abstract

CAN2007 was a phase 1/2 study of once- and twice-weekly single-agent bortezomib in relapsed primary systemic amyloid light chain amyloidosis (AL) amyloidosis. Seventy patients were treated, including 18 and 34 patients at the maximum planned doses on the once- and twice-weekly schedules. This prespecified final analysis provides mature response and long-term outcomes data after 3-year additional follow-up since the last report. In the once-weekly 1.6 mg/m(2) and twice-weekly 1.3 mg/m(2) bortezomib groups, final hematologic response rates were 68.8% and 66.7%; 80% of patients in each group sustained their response for ≥1 year. One-year progression-free rates were 72.2% and 76.8%. Median overall survival (OS) was 62.1 months and not reached; 4-year OS rates were 75.0% and 63.0%. Low baseline difference in κ/λ free light-chain level was associated with higher hematologic complete response rates and longer OS. At data cutoff, 40 (57%) patients had received subsequent therapy, including 19 (27%) retreated with bortezomib, 11 (58%) of whom achieved complete or partial hematologic responses. Four patients received prolonged bortezomib for between 3.5 and 5.6 years, with no new safety concerns, highlighting the feasibility of long-term therapy. Single-agent bortezomib produced durable hematologic responses and promising long-term OS in relapsed AL amyloidosis. This trial was registered at www.clinicaltrials.gov as #NCT00298766.

© 2014 by The American Society of Hematology.

Figures

Figure 1

Kaplan-Meier analysis of overall survival in the bortezomib 1.6 mg/m2 QW, 1.3 mg/m2 BIW, and lower-dose QW/BIW groups.

Figure 2

Kaplan-Meier analysis of OS. Overall survival was analyzed in patients grouped according to (A) high (>124.2 mg/L) vs low (≤124.2 mg/L) baseline dFLC or (B) high (>59%) vs low (≤59%) percentage decrease in dFLC during cycle 1. Cutoffs based on median baseline dFLC and median percentage dFLC decrease from baseline to the last visit of cycle 1, respectively.