Lenalidomide and Dexamethasone for the Treatment of Refractory/relapsed Multiple Myeloma: Dosing of Lenalidomide According to Renal Function and Effect on Renal Impairment

Objectives: Lenalidomide and dexamethasone (LenDex) is an active regimen for relapsed/refractory multiple myeloma (MM). However, there is limited data for the effect of LenDex on renal impairment (RI) and on renal reversibility.

Patients & Methods: Fifty consecutive patients with relapsed/refractory MM received LenDex in 28-d cycles. Median lines of previous therapies were 2 (range: 1-6). Lenalidomide was administered on days 1-21 according to creatinine clearance (CrCl), while dexamethasone was given at a dose of 40 mg on days 1-4 and 15-18 for the first four cycles and only on days 1-4 thereafter.

Results: Twelve patients (24%) had RI at baseline, defined as CrCl < 50 mL/min. Most patients were pretreated with either thalidomide or bortezomib and > 50% of them were refractory to both drugs. At least partial response was documented in 60.5% and 58% of patients with and without RI. Median progression-free survival (PFS) and overall survival (OS) for all patients was 9 and 16 months, respectively. RI was not associated with an inferior PFS or OS. There were no differences in the incidence of adverse events among patients with and without RI. Three of 12 patients with RI (25%) achieved complete renal response and two (16%) achieved minor renal response with LenDex.

Conclusions: We conclude that LenDex is an active treatment even in heavily pretreated MM. With dosing of lenalidomide according to renal function, LenDex can be administered to patients with RI (who may not have other treatment options) without excessive toxicity. Furthermore, LenDex may improve the renal function in approximately 40% of patients with RI.