Prognostic Factors of Long-Term Outcomes In Low- or Int-1-Risk MDS with del5q Treated with Lenalidomide (LEN): Results From a Randomized Phase 3 Trial (MDS-004)

Transfusion dependence is a significant negative predictor of overall survival (OS) and risk of AML-progression in MDS (Malcovati L, et al. JCO 2007;25:3503-10). LEN 5 mg and 10 mg induced significant RBC-transfusion independence (TI) versus placebo (PBO) in a randomized, phase 3, multicenter, double-blind (DB) study (MDS-004) in RBC transfusion-dependent patients (pts) with Low- or Int-1-risk MDS with del5q (Fenaux P, et al. Blood 2009;114:Abstract 944). The aim of this analysis is to identify prognostic factors for AML-free survival and OS during LEN treatment in the MDS-004 study after prolonged follow-up (pts enrolled between July 8, 2005 and July 26, 2007; last pt visit June 14, 2010; final data cutoff July 9, 2010).

LEN-naïve pts with RBC transfusion-dependent Low- or Int-1-risk del5q MDS were randomized to receive LEN 5 mg on days 1–28 or LEN 10 mg on days 1–21, both of every 28-day cycle, or PBO. First response was assessed at 16 wks. Responders continued DB treatment for up to 52 wks, until erythroid relapse or disease progression. Pts who completed 52 wks of therapy could enter an open label (OL) extension phase at their current LEN dose. PBO and LEN 5 mg recipients who did not respond by wk 16 or who had erythroid relapse could receive LEN 5 or 10 mg, respectively, in the OL phase. This analysis included data through completion of the OL phase for pts randomized to LEN 5 and 10 mg combined in the DB phase; pts randomized to PBO were excluded as all except 11 pts crossed-over to LEN 5 mg. LEN 5 and 10 mg dose groups were comparable, allowing data for the two groups to be combined. A Cox proportional hazard model was used to evaluate effect of potential baseline risk factors, with RBC-TI ≥ 26 wks and cytogenetic response (CyR) as time-dependent covariates on AML-free survival and OS. The full model with all covariates and the final model, based on backward model selection method, are presented.

All 138 pts randomized to LEN who received ≥ 1 dose were included: median age 68 y (range 36–86); 74% of pts were female; 66% had an isolated del5q abnormality and 28% had ≥ 1 additional abnormality; and 43% of pts had WHO-based Prognostic Scoring System (WPSS) low/int risk, 32% high/very high, and 25% missing data. At baseline, median time since diagnosis was 2.7 y (range 0.2–29.2) and median RBC transfusion requirement was 6 units/8 wks (range 1–25). Duration of LEN was 12.9 mo (range 0.3–36.7); 54 of 62 responders entered the OL phase. Median follow-up for the cohort was 36 mo (range 0.4–59.4). Overall, 31 (22%) pts progressed to AML (median time to AML progression 4.01 y; 95% confidence interval [CI] 3.17–4.03) and 66 (48%) died (median OS 3.68 y; 95% CI 2.93–not estimable). The cumulative 3-year AML-progression rate was 34.8% and the 3-year OS rate was 56.0%. Multivariate results are presented in the Table. Achieving RBC-TI ≥ 26 wks was associated with a 45% and 51% reduction in the risk of AML progression (P=0.022) and death (P=0.008), respectively. Lower baseline ferritin level and younger age were associated with a reduced risk of AML-progression and death.

Achievement of RBC-TI with LEN was associated with a significantly reduced risk of AML progression and death. Other predictors for longer AML-free survival and OS were lower baseline ferritin levels and younger age.

Fenaux:Celgene: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; J&J: Honoraria; Merck: Honoraria; Cephalon: Honoraria; Novartis: Honoraria. Giagounidis:Celgene: Consultancy, Honoraria. Beyne-Rauzy:Amgen: Consultancy; Celgene: Consultancy, Research Funding; Roche: Research Funding; Novartis: Consultancy. Mufti:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Mittelman:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Muus:Celgene: Membership on an entity's Board of Directors or advisory committees; Alexion: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Sanz:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Backstrom:Celgene: Employment, Equity Ownership. Fu:Celgene: Employment, Equity Ownership. Hellström-Lindberg:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding.