Impact of Chromosomal Abnormalities Del(13), T(4;14), and Del(17p) and Prior Treatment on Outcomes in Patients with Relapsed or Refractory Multiple Myeloma Treated with Lenalidomide

The chromosomal abnormalities of del(13), t(4;14), and del(17p) are associated with poor progression-free survival (PFS) and shorter overall survival (OS) in newly diagnosed multiple myeloma (MM) treated with traditional chemotherapy. In patients with relapsed or refractory MM, a recent study demonstrated that lenalidomide (Revlimid^®) can overcome poor prognosis conferred by del13q and t(4;14) but not del17p13 (Bahlis et al 2007). Here, we performed a retrospective analysis of medical records obtained from 49 clinical centers participating in the French Autorisation Temporaire d’Utilisation program. Patients with relapsed or refractory MM received dexamethasone 40 mg orally (days 1–4; 9–12 and 17–20 for 4 cycles, then days 1–4 beginning with cycle 5) and lenalidomide 25 mg orally on days 1–21 of a 28 day cycle. CD138-purified plasma cells were analyzed with fluorescent in-situ hybridization (FISH) for del(13), t(4;14), and del(17p) at diagnosis. Response and disease progression endpoints were evaluated using the European Group for Blood and Marrow Transplantation criteria. A multivariate analysis was performed to assess the impact of the following 7 variables on outcomes: any chromosomal change, prior bortezomib use, prior thalidomide use, prior transplant, progression on thalidomide, age, and number of lines of previous therapy. In total, 207 patients were included in the analysis; the median number of treatment cycles was 5 (range, 1–22). Most patients in the current study had received prior thalidomide (87%) or bortezomib (81%). The overall response rate (ORR) was 59%, including 7% complete response and 14% very good partial response. Median progression-free survival (PFS) and overall survival (OS) were 9.6 months and 15.1 months, respectively. These values are comparable to the recently published phase III trials (Weber et al., 2007; Dimopoulos et al., 2007), despite the higher median number of prior therapies in this analysis (5 vs. 3). Overall, 41% of patients had del(13), 14% had t(4;14) and 5% had del(17p). The ORR was significantly lower, and PFS and OS significantly shorter, in patients with del(13) compared with patients without del(13) (ORR: 43% vs. 71%, P<0.001; PFS: 5.0 months vs. 12.5 months, P<0.0001; OS: 10.4 months vs. 17.4 months, P=0.001). A similar pattern was observed in patients with t(4;14) versus patients without t(4:14) (ORR 39% vs. 62%, p=0.04; PFS 5.5 months vs. 10.6 months, p<0.01; OS 9.4 months vs. 15.4 months, p=0.005). Multivariate analysis identified hemoglobin (<10 g/dL), progression on thalidomide, and del(13) as independent predictors of reduced PFS (Table). There was a trend towards reduced PFS with prior bortezomib use and number of prior therapies. Age, sex, prior transplant, prior thalidomide use, and t(4;14) did not affect PFS. The results from the analysis indicate that del(13), progression on thalidomide, and hemoglobin levels ≥10 g/dL have a significant impact on outcomes in heavily pre-treated patients with relapsed or refractory MM. Randomized trials are needed to further assess these findings.