PURPOSE: Lenalidomide (CC-5013, Revlimid; Celgene Corporation, Summit, NJ), a 
thalidomide analogue, was granted approval by the U.S. Food and Drug 
Administration (FDA) on June 29, 2006, for use in combination with dexamethasone 
in patients with multiple myeloma (MM) who have received at least one prior 
therapy. The FDA approved lenalidomide with a restricted distribution program, 
RevAssist.
EXPERIMENTAL DESIGN: In two randomized, double-blind, multicenter studies, the 
combination of lenalidomide and dexamethasone (LD) was compared with placebo and 
dexamethasone (PD) in patients with MM who had received at least one prior 
therapy. The primary endpoint was time to progression (TTP).
RESULTS: Following a prespecified interim analysis of TTP, an independent 
data-monitoring committee advised the sponsor to halt the two studies. For both 
studies, the interim analysis for efficacy revealed a statistically significant 
longer TTP with LD than with PD. The most clinically relevant grade 3 and 4 
adverse events that occurred more frequently in the LD arm were neutropenia, 
thrombocytopenia, deep vein thrombosis, pulmonary embolism, and atrial 
fibrillation. Thrombotic or thromboembolic events, including deep vein 
thrombosis, pulmonary embolism, thrombosis, and intracranial venous sinus 
thrombosis were reported more frequently in patients treated with LD than with 
PD.
CONCLUSIONS: The FDA approved lenalidomide based on interim results from two 
multicenter, placebo-controlled, randomized trials comparing the combination of 
LD with PD that revealed a longer TTP with LD than with PD. The major toxicity 
observed during these trials was myelosuppression. The serious toxicities 
included thromboembolic events. Lenalidomide is only available under the 
RevAssist Program.