Regional differences in the treatment approaches for relapsed multiple myeloma: An IMF study.

Abstract

8095 Background: Multiple myeloma (MM) remains incurable and invariably relapses after initial therapy. There is no uniform approach to management of relapsed MM and is dictated by type of initial therapy and the response seen, and availability of new drugs. The outcomes associated with current approaches have not been systematically examined. Methods: We enrolled 383 patients (pts) with myeloma who had a documented relapse between Jan 2007 and June 2010, including 220 from Europe, 106 from Asia, and 31 from South America and 26 from North America. Time Zero (T0) was defined as date of treatment after first relapse. Results: Across the study, 61% were male and 49% were over 65 years at T0. ISS stage distribution at diagnosis included 26, 40 and 33% of patients in stages 1, 2 and 3, respectively. Among regimens used at first relapse; bortezomib (Btz) containing regimens were most common (54%), followed by lenalidomide (Len, 25%) and cyclophosphamide (21%). The overall response rate (>=PR) to first therapy after relapse was 58% including 14% with a CR. There was a progressive decrease in the response rates with successive regimen; 45%, 30% and 15% for regimens 2, 3 and 4 respectively. Len use was considerably lower in the Asian cohort, while Btz use was comparable across the regions. The median PFS from T0 was 13 mos and OS was 35 mos, for the entire cohort. The PFS to first salvage regimen was similar across the regions, while OS was shorter for the Asian and South American cohorts. In a univariate analysis, ISS stage 3, presence of cytogenetic abnormalities, history of plasma cell leukemia or extramedullary disease (EMD), bone marrow PC% > 33% and presence of renal insufficiency were all associated with a shorter PFS as well as shorter OS (P<=0.01). In a multivariate model, ISS stage 3 and presence of EMD were most associated with short OS. Conclusions: Median PFS for current second line regimens, typically containing Btz or Len appear to be 1 yr with an OS from first relapse of about 3 yrs. The OS from first relapse is nearly double that seen in a cohort of patients in first relapse prior to introduction of new drugs. Clear-cut regional differences can be seen in terms of patterns of drug use and likely reflect drug availability and healthcare costs.