Association of Azacitidine and Lenalidomide (Combined vs Sequential Treatment) in High-Risk Myelodysplastic Syndromes. Final Results of a Randomized Phase II Multicenter Study

Abstract

Introduction. Azacitidine (AZA) is able to induce hematologic responses in 50-60 % of patients (pts) with Myelodysplastic Syndromes (MDS) and moreover to prolong survival in higher risk MDS pts. Recently, several studies have evaluated the efficacy and safety of combining, in high-risk MDS pts, AZA with Lenalidomide (LEN), either administered concurrently (Sekeres, 2010; 2012), or sequentially (Platzbecker, 2013), in both cases showing promising results, although in a limited number of pts. The aim of this study was to evaluate the efficacy and safety of the combination vs the sequential use of AZA and LEN in high-risk MDS pts (IPSS score risk: High or INT-2). Primary endpoint: ORR, defined as the Rate of Complete Remission (CR), Partial Remission (PR), Marrow Complete Remission (mCR), and Hematological Improvement (HI), following the International Working Group (IWG) criteria (Cheson, 2006).Methods. This is a randomized, phase II, multicenter, open label study, including pts with MDS (WHO 2008 classification) with International Prognostic Scoring System (IPSS) risk High or Intermediate-2, without previous treatment with AZA or LEN. ARM 1 (combined treatment): AZA: 75 mg/m2/day (days 1-5) I.C. + LEN: 10 mg/day (days 1-21), orally, every 4 weeks. ARM 2 (sequential treatment): AZA: 75 mg/m2/day (days 1-5) I.C. + LEN: 10 mg/day (days 6-21), orally, every 4 weeks. The induction treatment was planned for 8 cycles (32 weeks). For responder patients (CR, PR, mCR, or HI) the same treatment was continued until disease progression or unacceptable toxicity. A sample size of 44 pts was planned.Results. From March 2013, 44 pts (27 males), with a median age of 72 (48-83 yrs) were enrolled, from 13 hematologic italian Centers. At baseline, WHO diagnosis was: RCMD: 2 pts; RCMD-RS: 1 pt ; RAEB-1: 11 pts; RAEB-2: 30 pts; IPSS risk was: Intermediate-2: 31 pts; High: 9 pts; not determined (N.D.) (because of lack of cytogenetic data): 2 pts. (all with RAEB-2). In 2 pts IPSS risk was Intermediate-1, but they were enrolled because of severe thrombocytopenia and neutropenia, respectively. IPSS-R risk was: intermediate: 8 pts; High: 16 pts; Very-High: 18 pts; N.D.: 2 pts; IPSS cytogenetic risk was: Good: 17 pts; Intermediate: 11 pts; Poor: 14 pts; N.D.: 2 pts. 21 pts were randomly assigned to ARM 1, and 23 pts to ARM 2. At the time of this analysis, enrolment of the planned 44 pts was completed. 34/44 pts (77.3%) completed ≥ 6 cycles of treatment, and are evaluable for response. The remaining 10 pts (4 in ARM 1 and 6 in ARM 2) are not evaluable for response, as they discontinued treatment before completing the 6th cycle because of adverse events (6 pts, 13.6%), consent withdrawal (2 pts, 4.5%) or medical decision (2 pts, 4.5%), respectively. Treatment was given for a median of 8 (1-28) cycles; in ARM 1: 9 (1-22) cycles, in ARM 2: 8 (1-28) cycles, respectively. Among the 34 pts evaluable for response, 26/34 pts (ORR: 76.5 %) showed a favourable response to treatment. The Best Response achieved was: CR: 8 pts (23.5%), PR: 1 pt (2.9%), mCR: 3 pts (8.8%), HI: 8 pts (23.5%), mCR+HI: 6 pts (17.6%). The remaining 8 pts showed either Stable Disease (SD) (6 pts, 17.6%) or Disease Progression (DP) (2 pts, 5.9%). First Response was detected after a median of 2 (1-8) cycles. Responder pts were: 13/17 (ORR: 76.5 %) in ARM 1 (3 CR; 1 PR; 1 mCR; 4 HI, 4 mCR+HI), and 13/17 (ORR: 76.5 %) in ARM 2 (5 CR; 2 mCR; 4 HI; 2 mCR+HI), respectively. Overall, the median duration of response was 8.5 (2-23) months: 6 (2-19) months in ARM 1; 16 (2-23) months in ARM 2. A grade > 2 non hematologic toxicity was observed in 24/44 (54.5 %) pts (ARM 1: 66.7%; ARM 2: 43.5%). 27/44 pts (61.4 %) (ARM 1: 61.9%; ARM 2: 60.9%) had a dose reduction of LEN because of hematologic or non-hematologic toxicity. 22 pts (50%) died (ARM 1: 47.6%; ARM 2: 52.2%). 14 pts (31.8%) (ARM 1: 23.8%; ARM 2: 39.1%) showed progression to AML. Overall, median survival was 13 (1-28) months; ARM 1: 13 (1-25) months; ARM 2: 14 (2-28) months.Conclusions. Our results confirm the efficacy of both AZA + LEN treatment regimens in high-risk MDS pts. Moreover, at a molecular level, a significant increase of phosphoinositide-specific phospholipase C (PI-PLC) beta1 and/or PI-PLCgamma1 expression was associated with a favourable clinical response to treatment. Responder cases also showed an increase of Beta-globin expression, hinting at a specific contribution of LEN on erythroid activation DisclosuresFinelli:Janssen: Other: Speaker; Novartis: Other: Speaker; Celgene: Other: Speaker, Research Funding. Visani:Celgene: Research Funding. Cavo:Janssen-Cilag, Celgene, Amgen, BMS: Honoraria.