Impact of risk stratification on outcome among patients with multiple myeloma receiving initial therapy with lenalidomide and dexamethasone

Abstract

The outcome of patients with multiple myeloma is dictated primarily by cytogenetic abnormalities and proliferative capacity of plasma cells. We studied the outcome after initial therapy with lenalidomide-dexamethasone among 100 newly diagnosed patients, risk-stratified by genetic abnormalities and plasma cell labeling index. A total of 16% had high-risk multiple myeloma, defined by the presence of hypodiploidy, del(13q) by metaphase cytogenetics, del(17p), IgH translocations [t(4;14), or t(14;16)] or plasma cell labeling index more than or equal to 3%. Response rates were 81% vs 89% in the high-risk and standard-risk groups, respectively. The median progression-free survival was shorter in the high-risk group (18.5 vs 36.5 months, P < .001), but overall survival was comparable. Because of unavailability of all tests for every patient, we separately analyzed 55 stringently classified patients, and the results were similar. In conclusion, high-risk patients achieve less durable responses with lenalidomide-dexamethasone compared with standard-risk patients; no significant differences in overall survival are apparent so far. These results need confirmation in larger, prospectively designed studies.

Figure 1

Survival analysis of patients with newly diagnosed MM who received Len-Dex as initial therapy. (A) PFS by risk stratification; median PFS is 18.5 months for high-risk versus 36.5 months for standard-risk patients (P < .001). (B) OS by risk stratification (high-risk vs standard-risk patient); median OS not reached (P = not significant). (C) PFS of strictly categorized patients (N = 55) who either had all the 3 tests (metaphase cytogenetics, fluorescence in situ hybridization [FISH], and PCLI) or at least 1 test that led to their inclusion in the high-risk group; median PFS = 18.5 months for the high-risk group and 36.5 months for the standard-risk group (P < .001). (D) OS of strictly categorized patients (N = 55) who either had all the 3 tests (cytogenetics, FISH, and PCLI) or at least 1 test that led to their inclusion in the high-risk group; median OS not reached for either high-risk or standard-risk group.