Abstract
Background: Lenalidomide has shown efficacy in patients with relapsed myeloma in phase II and III clinical trials, and is currently being investigated as initial therapy for the disease. We report results of a phase III trial comparing lenalidomide plus high-dose dexamethasone (Dex) versus lenalidomide plus low-dose Dex as first line therapy in newly diagnosed multiple myeloma (MM).
Methods: Pts with newly diagnosed, untreated, symptomatic MM were eligible. Pts in both arms received lenalidomide 25 mg/day PO on days 1–21 every 28 days. In addition, patients in the high-dose Dex arm (Arm A) received Dex 40 mg on days 1–4, 9–12, and 17–20 PO every 28 days, while pts in the low-dose Dex arm (Arm B) received Dex 40 mg on days 1, 8, 15, and 22 PO every 28 days. The primary endpoint was best response at 4 months on intent to treat basis. At 4 months pts could go off study for stem cell transplant or elect to continue therapy until progression. Response was defined as a decrease in serum and urine monoclonal (M) protein by 50% or higher. If the serum M protein was unmeasurable, a 90% or higher decrease in urine M protein was required. Responses need to be confirmed at least 4 weeks apart. Patients with disease progression or not responding to lenalidomide within 4 months switched to thalidomide with the same dose of dexamethasone they were receiving (Arms C and D, respectively). An independent Data Monitoring Committee approved release of these results.
Results: 445 pts were enrolled: 223 randomized to Arm A and 222 to Arm B. Median age was 65 yrs. Serious adverse event data based on expedited reporting (AdEERS) is available on all pts (see table). Common adverse events of Grade 3 or higher were thromboembolism (18.4% in arm A vs 5.4% in Arm B), infection/pneumonia (18.8% vs 9.0%) and hyperglycemia (5.8% vs 1.8%). Incidence of any grade 4 or higher toxicity was 22.0% in Arm A vs 12.6% in Arm B. Response data is being analyzed.
Conclusions: Lenalidomide plus two different schedules of Dex was investigated in this phase III trial. Preliminary results suggest that toxicity rates are higher in the high-dose Dex arm. The differences in the response rates between the two arms will dictate future trials and clinical practice.
Major Toxicties (AdEERS) Toxicity Arm A (n=223) Arm B (n=222) Cardiac ischemia (Grade >=3) 2.7% 0.5% Hyperglycemia (Grade >=3) 5.8% 1.8% Infection/Pneumonitis (Grade >=3) 18.8% 9.0% Neuropathy (Grade >=3) 0.9% 0.9% Thromboembolism (Grade >=3) 18.4% 5.4% Any non-Hem toxicity (Grade >=3) 53.4% 36.0% Any toxicity (Grade >=4) 22.0% 12.6% Death (Grade 5) 4.5% 1.4%
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