Duration of OS. Results are presented for the safety population: (A) by randomized treatment group, by 6-month landmark analyses of OS, (B) by cytogenetic response (complete + partial), and (C) by RBC-TI (≥ 8 weeks) in patients randomized to lenalidomide (LEN). The placebo group includes 56 patients (83.6%) who had not achieved at least minor response by week 16 and were therefore crossed over to LEN 5 mg.