Use of Lenalidomide (Revlimid® +/− Corticosteroids in Relapsed/Refractory Multiple Myeloma Patients with Elevated Baseline Serum Creatinine Levels.

Lenalidomide (Revlimid®; Rev) is an important novel agent for the treatment of multiple myeloma (MM) patients (pts). Since MM pts are at risk for renal insufficiency, we evaluated whether an abnormal serum creatinine (cr) level affected the outcome of pts treated with Rev +/− corticosteroids (CS). Between 12/05 and 07/06, 69 MM pts who had progressed after at least 1 line of prior therapy were treated in our center with Rev +/− CS as part of Celgene’s Expanded Access Program in Canada. Eligibility criteria included a platelet count (pl ct) ≥ 30 x 10⁹/L and neutrophil count ≥ 1.0 x 10⁹/L; a cr level of ≤220 umol/L was required unless a waiver was obtained. Protocol therapy consisted of Rev + dexamethasone (dex) in 44, Rev + prednisone in 7, Rev + dex and prednisone at different time points in 5 and Rev alone in 13. The median age was 60 yrs (35–79); 36 (52%) were male; median β2-microglobulin was 214 nm/L (114–1420); Ig subtype was IgG in 42, IgA in 12, IgM in 1 and light chain only in 14. Prior therapy included ASCT in 59 pts (86%), thalidomide in 51 (74%), bortezomib in 21 (30%) and oral cyclophosphamide in 52 (75%); the median number of prior regimens was 2 (1–5). Twenty-three pts (33%) had an elevated baseline cr level (> 89 umol/L for females and 109 umol/L for males in our center). The median cr was 138 umol/L (110–412) in these pts (group 1), compared with 80 umol/L (51–109) in group 2 (control) (p=0.001). Five pts in group 1 had a cr level ≥ 177 umol/L (2 mg/dL). Both groups were similar except that group 1 had more males (p=0.04) and the baseline platelet count (pl ct) was lower (35% vs. 4% with pl ct less than 50 x 10⁹/L; p=0.0007).

RESULTS: The median number of cycles of Rev +/− CS given to date was 4 (1–8) in both groups, and the median follow-up is 4 mos (0.5–8). After 3 cycles of Rev, the median cr was 104 umol/L (61–372) in group 1 and 79 umol/L (53–180) in group 2. In group1, cr decreased in 39% and increased in 26%, compared with 39% and 32% in group 2, respectively (p=0.56). The incidence of grade 3–4 neutropenia was 43% vs. 46%, febrile neutropenia 13% vs. 9%, any infection 17% vs. 20% and G-CSF use 66% vs. 57% among pts in group 1 vs. 2 (p=NS for all comparisons). More in group 1 experienced grade 3–4 thrombocytopenia and required at least 1 pl transfusion (52% vs. 17%; p=0.003). In group 1, 6 (26%) pts required pl transfusion in only 1 cycle, 5 (22%) in 2 cycles and 1 (4%) in 3 cycles. However, the only 2 significant bleeding complications were seen in group 2. There were 2 deaths (8.7%) in group 1 and 4 (8.7%) in group 2. Table 1 summarizes the preliminary anti-myeloma results in these 2 groups.

CONCLUSIONS:

1. Rev +/− CS can be given safely to selected patients with an elevated baseline cr level;

2. pts with an elevated cr had lower baseline pl cts, and required more pl transfusions;

3. the response rate, PFS and OS to date are similar in patients with a normal vs. elevated cr level.