Long-term follow-up on overall survival from the MM-009 and MM-010 phase III trials of lenalidomide plus dexamethasone in patients with relapsed or refractory multiple myeloma

We present a pooled update of two large, multicenter MM-009 and MM-010 placebo-controlled randomized phase III trials that included 704 patients and assessed lenalidomide plus dexamethasone versus dexamethasone plus placebo in patients with relapsed/refractory multiple myeloma (MM). Patients in both studies were randomized to receive 25 mg daily oral lenalidomide or identical placebo, plus 40 mg oral dexamethasone. In this pooled analysis, using data up to unblinding (June 2005 for MM-009 and August 2005 for MM-010), treatment with lenalidomide plus dexamethasone significantly improved overall response (60.6 vs 21.9%, P<0.001), complete response rate (15.0 vs 2.0%, P<0.001), time to progression (median of 13.4 vs 4.6 months, P<0.001) and duration of response (median of 15.8 months vs 7 months, P<0.001) compared with dexamethasone-placebo. At a median follow-up of 48 months for surviving patients, using data up to July 2008, a significant benefit in overall survival (median of 38.0 vs 31.6 months, P=0.045) was retained despite 47.6% of patients who were randomized to dexamethasone-placebo receiving lenalidomide-based treatment after disease progression or study unblinding. Low beta(2)-microglobulin and low bone marrow plasmacytosis were associated with longer survival. In conclusion, these data confirm the significant response and survival benefit with lenalidomide and dexamethasone.

Lenalidomide plus high-dose dexamethasone provides improved overall survival compared to high-dose dexamethasone alone for relapsed or refractory multiple myeloma (MM): Results of a North American phase III study (MM-009)

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Background: Lenalidomide is a novel, orally administered, immunomodulatory drug (IMiD) that has single-agent activity against MM and additive effects when combined with dexamethasone (Dex). Methods: In this phase 3, multicenter, double-blind trial, 354 patients (pts)with relapsed or refractory MM were treated with Dex 40 mg daily on days 1–4, 9–12, 17–20 every 28 days and were randomized to receive either lenalidomide (Len) 25 mg daily orally on days 1–21 every 28 days or placebo. Beginning with cycle 5, Dex was reduced to 40 mg daily on days 1–4 only, every 28 days. Patients were stratified with respect to B2M (≤ 2.5 vs. > 2.5 mg/mL), prior stem cell transplant (none vs. ≥ 1), and number of prior regimens (1 vs > 1). The treatment arms were well balanced for prognostic features. Results: The overall response rate was greater with Len-Dex than with Dex-placebo (59.4% vs. 21.1%; p < 0.001). Complete responses were achieved in 12.9% of pts treated with Len-Dex and 0.6% of pts treated with Dex-placebo. The median time to progression (TTP) for pts treated with Len-Dex was 11.1 months compared to 4.7 months for pts treated with Dex-placebo (p < 0.000001). Median overall survival was higher with Len-Dex (not reached) compared to Dex-placebo (24 months) (hazard ratio 1.76, p = .0125). Grade 3–4 neutropenia was more frequent with combination therapy than with Dex-placebo (24% vs. 3.5%), however ≥ grade 3 infections were similar in both groups. Thromboembolic events occurred in 15% of pts treated with Len-Dex and in 3.5% of pts treated with Dex-placebo. Atrial fibrillation occurred in 8 pts and CHF developed in 4 pts treated with Len-Dex. Conclusions: Considering the ease of oral administration, higher response rate, longer time to progression and overall survival benefit, the combination of lenalidomide-dexamethasone may very well represent the treatment of choice for early refractory or relapsing multiple myeloma. The relatively infrequent side effects should not detract from these improvements, but the use of prophylactic antithrombotic therapy should be considered for patients treated with the combination of lenalidomide and dexamethasone.

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A multicenter, randomized, double-blind, placebo-controlled trial of thalidomide plus dexamethasone versus dexamethasone alone as initial therapy for newly diagnosed multiple myeloma

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Background: Thalidomide plus dexamethasone (Thal/Dex) yields superior response rates versus dexamethasone (Dex) but its impact as primary therapy for multiple myeloma (MM) is unknown. Methods: Patients (pts) with previously untreated, symptomatic MM were eligible and were randomized in this double-blind trial to Thal/Dex (Arm A) or placebo plus Dex (Arm B). Pts in Arm A received Thal 50 mg PO daily, escalated to 100 mg on day 15, and to 200 mg from day 1 of cycle 2; Dex 40 mg PO was given on days 1–4, 9–12, and 17–20. Pts in Arm B received placebo instead of Thal, and Dex as in Arm A. Cycles were 28 days long, repeated until progression or undue toxicity. The primary endpoint was time to progression (TTP) defined using EBMT criteria. All analyses were intent to treat. Planned sample size was 218 eligible pts in each arm. Full information for one-sided log rank test with significance level of 0.025 (allowing for 1interim analysis) to have 80% power to detect a 40% improvement in TTP (16.8 mo in Arm A vs. 12 mo in Arm B) would be achieved when 282 pts have progressed. A pre-planned interim analysis of the primary endpoint and safety was performed by an independent Data Monitoring Committee (DMC). P value < 0.0015 at this interim analysis would indicate that Arm A is superior to Arm B based on an alpha-spending function of the O’Brien-Fleming type. The DMC recommended release of results. Results: 470 pts were enrolled: 235 randomized to Thal/Dex and 235 to placebo/Dex. Median follow-up was 25 months. Median age was 65 yrs. TTP was significantly superior with Thal/Dex vs placebo/Dex, median TTP 17.4 months (95% CI: 8.1 months-NE) vs 6.4 months (95% CI: 5.6–7.4 months), respectively, P < 0.000065, crossing the upper boundary for superiority. DVT was higher with Thal/Dex vs placebo/Dex, 15.4% vs 4.3%, respectively. Median survival was not reached in either arm. Conclusions: Thal/Dex is significantly superior to Dex alone as first-line therapy for multiple myeloma.

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Comparison of lenalidomide in combination with dexamethasone to dexamethasone alone in patients who have received prior thalidomide in relapsed or refractory multiple myeloma

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Background: Lenalidomide (len), an analog of thalidomide (thal) is a novel, oral immunomodulatory agent that is effective against multiple myeloma (MM). Two randomized, Phase III trials (MM009 and MM010) have recently demonstrated superior responses and overall survival (OS) for patients (pts) treated with len and dexamethasone (dex) in comparison with dex-placebo. This is a prospective subgroup analysis to assess the impact of prior therapy with thal on the sensitivity of MM to subsequent lenalidomide. Methods: We evaluated 692 pts from both trials (MM009 and MM010). The pts had relapsed/refractory MM, were not refractory to dex and were randomized to receive either len (25 mg daily for 3 weeks (wks) every 4 wks) plus dex (40 mg on days 1–4, 9–12, 17–20 every 4 wks for 4 cycles, then 40 mg on days 1–4 every subsequent cycle) or placebo plus dex. Standard criteria were used to evaluate response and TTP. Results: Pooled data from 692 pts showed superior median TTP (48.1 vs 20.1 wks) and OR (59.2% vs 22.5%) in pts treated with len/dex compared to dex-placebo (p <0.001). Although subgroup analysis of pts with prior thal therapy revealed that pts who received len/dex had significantly improved OR, PR CR and median TTP than pts who received dex-placebo, OR, CR and TTP were highest in len/dex pts not previously treated with thal. Multivariate analysis indicates that after controlling for the treatment factor and baseline disease characteristics, whether or not pt had prior exposure to thal is a marginally significant variable to predict TTP. The risk of deep venous thrombosis and pulmonary embolism in these subgroups will be updated on further analysis. Conclusions: Lenalidomide in combination with dexamethasone is more effective than dexamethasone-placebo regardless of prior thalidomide in relapsed/refractory multiple myeloma.

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