Durable Responses to Lenalidomide (Revlimid®) in Patients with AL Amyloidosis: Follow Up of a Phase II Trial.

Abstract

AL amyloidosis is a clonal plasma cell dyscrasia in which misfolded immunoglobulin light chains deposit in tissues and produce organ failure and death. Untreated, median survival is short. Melphalan-based regimens can produce hematologic remissions and improvement in organ function; more than 20% of patients treated with high dose melphalan and autologous stem cell transplantation (HDM/SCT) have survived more than 10 years (Blood, in press). The combination of lenalidomide and dexamethasone can also produce partial and complete hematologic responses (Blood 2007; 109:492–496). Here we report on remission duration and long-term results of treatment in the original 34 patients and an additional 9 patients, with median follow up of 26.5 m. The median age of the 43 patients was 64 (range, 44–84), 70% were male, 67% were lambda isotype, 46% had multi-organ involvement, and 42% had cardiac involvement. 90% had received prior melphalan-based therapy; in 60% this was HDM/SCT. 14% of patients had received thalidomide and 5%, bortezomib. 10% had no prior treatment. Patients were begun at 15 mg lenalidomide per day for 21 days per month; the median tolerated dose was 10 mg. The response rate was 60% (24% CR, 36% PR); an additional 15% of patients had minor responses. Of the 8 patients who achieved a CR, 6 occurred at 3–6 months of treatment, but 2 were late (18m, 19m). 7 of 8 are alive; one died of cardiac allograft rejection. 3 of 8 have relapsed. 5 of 8 maintain remissions for 6–30 m, of which 4 of 8 continue in CR off therapy for 6–21m. Kaplan-Meier survival for all 43 patients is shown. 7 of 8 patients achieving CR had significant proteinuria: in 2 patients (29%), proteinuria resolved (2 g to 120 mg, 8.8 g to 140 mg); in 3 (43%) it improved by 50% or more; and in 2 there has been no change. Thus, lenalidomide can produce beneficial hematologic and organ responses in AL amyloidosis patients, and remissions can be durable off therapy. Further trials should be done to determine how and when to incorporate lenalidomide into treatment protocols for AL amyloidosis. [Display omitted]