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Abstract Aim: A phase III trial of lenalidomide plus high (standard) dose dex (RD) versus lenalidomide plus low dose dex (Rd) in newly diagnosed myeloma (MM). Methods: Pts with untreated, symptomatic MM were eligible. Pts in the RD arm (Arm A) received lenalidomide 25 mg/day PO days 1–21 every 28 days plus dex 40 mg days 1–4, 9–12, and 17–20 PO every 28 days; pts in the Rd arm (Arm B) received lenalidomide at the same dose plus dex 40 mg days 1, 8, 15, and 22 PO every 28 days. The primary endpoint was response rate at 4 months, with the null hypothesis being that the response rates in the two 2 arms are equivalent. Planned sample size was 196 eligible pts per arm with one-sided 0.10 Type I and 0.05 Type II error rate. All analysis were performed on an intent to treat basis. An independent DMC recommended release of study results. Results: 445 pts (median age, 65 yrs) were accrued; 223 randomized to RD, 222 to Rd. Median follow-up time is 17 months. Arms were well balanced for age, gender, stage, bone lesions, hemoglobin, beta-2 microglobulin, performance status, bone marrow plasma cells, and M protein levels at baseline. Major grade 3 or higher toxicities, including DVT/PE and infections, were significantly higher in the high dose dex arm (see Table). Overall survival (OS) at the second pre-planned interim analysis was significantly superior with lenalidomide plus low dose dex, P<0.001; one year survival 96% (Rd) versus 87% (RD). The 18 month survival rate is 91% versus 80%, respectively. OS differences in favor of the low dose dex arm were seen in pts <65 (P=0.022; one year rate 97% vs 92%) as well as pts 65 and older (P=0.002; one year rate 94% vs 83%), respectively. Sixty-one patients have died; 42 in the RD arm and 16 in Rd arm. The cause of death has been verified by detailed chart review in 38 patients. Of 29 verified deaths in the RD arm, 13 were due to disease progression, 6 thrombosis/embolism, 3 infection, 3 cardiac ischemia, 1 stroke, and 1 respiratory failure. Of 9 verified deaths in the Rd arm, 5 were due to disease progression, 2 infection, 1 thrombosis/embolism, and 1 cardiac arrest. Response rate data are expected to be available at the time of the meeting. Conclusions: Lenalidomide plus low-dose dexamethasone (Rd) is associated with superior OS compared to lenalidomide plus high-dose dexamethasone (RD) in newly diagnosed MM. The increased mortality in Arm A is due to disease progression (myeloma deaths) as well as increased toxicity. This study has major implications for the use of high-dose dexamethasone in the treatment of newly diagnosed MM. Major Grade 3 or Higher Adverse Events Toxicity Arm A % Arm B % P value Neutropenia 10 19 0.01 DVT/PE 25 9 <0.001 Infections 16 6 <0.001 Any grade 3 or higher non-hematologic 49 32 <0.001 Any grade 4 or higher non-hematologic 20 9 <0.001 Deaths in first 4 months 5 0.5 0.006
Rajkumar et al. (Fri,) studied this question.