Decitabine in Myelodysplastic Syndromes: Argentine Initial Multi-Institutional Clinical Experience
Authors: Iastrebner Marcelo , Prates Virginia , Arbelbide Jorge , Fernandez Isolda , Flores Gabriela , Milone Gustavo , Sackmann Federico , Saba Silvia , Orlando Sergio , Basso Alfredo , Pavlovsky Astrid , Taborda Gustavo , Korin Jorge , Pose Julio 
Published: April 2020

Abstract
Epigenetic therapy with a hypomethylating agent is becoming the standard of care in some intermediate and high-risk myelodysplastic syndromes (MDS). The DNA-targeted hypomethylating agent, decitabine (DACOGEN, Janssen Cilag Farmaceutica S.A. and Eisai Inc.), has been approved for patients (pts) with intermediate-1 (INT-1), intermediate-2 (INT-2), and high-risk MDS in Argentina. An alternative regimen with decitabine 20 mg/m2 IV over 1 hour once daily for 5 consecutive days repeating every 4 weeks, permits its use in the outpatient clinic. Clinical and hematological response and safety were analyzed retrospectively for pts with all FAB subtypes of MDS who had received this dosing regimen at 17 centers in our country between July 2007 and June 2008. Inclusion criteria were: ≥18 years of age; de novo or secondary MDS; and International Prognosis Scoring System (IPSS) score ≥0.5. Exclusion criteria were: diagnosis of acute myeloid leukemia (AML) or other progressive malignant disease. Patients with prior therapy were not excluded. The primary endpoint was overall response, assessed by IWG 2006 criteria. Thirty-eight pts were enrolled: median age 67 years; 71% male and 29% female. The diagnosis was de novo MDS in 34 pts (89%) and secondary MDS in 4 (11%). The median time from diagnosis to first dose of decitabine was 7 months. Eastern Cooperative Oncology Group performance status scores were 0 (21%), 1 (47%), 2 (26%) and 3 (5%). IPSS scores were INT-1 (50%), INT-2 (8%), and high-risk (42%). Cytogenetic abnormalities were found in 37% of pts. FAB classification was: RA (21%), RARS (8%), RAEB (18%), RAEB-T (24%) and CMML (29%). A median of 3.5 cycles (range, 1–8) were given. Dosage had to be reduced in 7 pts (18%) due to comorbidity and cytopenias. Overall improvement rate in the intent-to-treat population was 45% (Table), including: 9% complete response (CR), 5% marrow complete response (mCR), 5% partial response (PR) and 26% hematological improvement (HI). Two pts (5%) had stable disease. Four pts (11%) were non-evaluable for response. Most pts had their first hematological response by cycle 2 and their best response by cycle 4. The mean ± SD time to best response was 2.7±3 months. No differences in clinical and hematological response were observed between pts with INT-2/High compared to INT-1 (8/19 and 9/19, respectively); red cell and platelet transfusion requirements resolved during the first 2 cycles in 13/16 and 7/8 pts, respectively. Overall improvement rates were similar in pts with more and less than 1 year since MDS diagnosis (9/18 and 8/20, respectively). Overall survival was 71% during the observational period (up to 11 months). The most frequent adverse events were neutropenia without fever (47%) and with fever (21%), especially during cycle 2, and thrombocytopenia (23%). This study showed prompt clinical activity for an alternative 5-day dosing schedule of decitabine in the outpatient setting and an overall improvement rate of 45%, with an initial response by cycle 2, the best response by cycle 4, and acceptable tolerability.
&lt;&gt;Table. Response to 5-Day Decitabine Dosing Schedule
IWG 2006 Criteria ITT (N=38) Overall Improvement Rate (CR+mCR+PR+HI) 17 (45%) CR (Complete Response) 3 (9%) mCR (Marrow Complete Response) 2 (5%) PR (Partial Response) 2 (5%) HI (Hematological Improvement) 10 (26%) SD (Stable Disease) 2 (5%) Failure (Progressive Disease or Death) 15 (39%) Non-Evaluable 4 (11%)