Outcome Of Patients (pts) With Low and Intermediate-1 Risk Myelodysplastic Syndrome (MDS) After Hypomethylating Agent (HMA) Failure

Abstract

▪ BackgroundHMA are standard of care in pts with high-risk MDS and commonly used in pts with lower risk. Pts with high-risk disease post HMA failure have a poor prognosis with a median survival of 4-6 months. The prognosis of pts with low and intermediate-1 risk MDS by the International Prognostic Scoring System (IPSS) after HMA failure is not known. AimsTo assess outcome of pts with low and intermediate-1 risk disease post HMA failure that might benefit from specific strategies or investigational agents. MethodsData from 423 pts with low (n= 141, 33%) and intermediate-1 risk disease (n=282, 67%) by IPSS score treated with HMA at MD Anderson Cancer Center (MDACC; n=144) and Moffitt Cancer Center (MCC; n=279) between 2000 and 2011 were analyzed. ResultsMedian age was 69 years. 294 (69%) pts had a diploid cytogenetic analysis. 63 (15%) pts had therapy-related MDS. 282 (67%) pts received azacitidine, 87 (21%) decitabine, and 54 (12%) both. Median number of cycles of HMA administered was 6 (range, 1-64) for a median duration of therapy of 7 months (range, 1- 74). Best response to HMA was complete response (CR) in 39 (9%) pts, partial response (PR) in 13 (3%), a bone marrow CR in 6 (1%), and hematologic improvement (HI) in 90 (21%) pts. Pts had discontinued HMA because of primary resistance in 198 (47%) pts, loss of response in 141 pts (33%), intolerance in 13 pts (3%) and other reasons in 71 pts (17%). At the time of HMA failure, 81 (19%) pts transformed into acute myeloid leukemia (AML). Of the 302 remaining pts evaluable by IPSS, 67 (22%) pts were of low-risk, 158 (53%) of intermediate-1 risk, 48 (16%) of intermediate-2 risk, and 29 (9%) of high-risk disease. By the revised IPSS (R-IPSS), the percentage of pts with low, very low, intermediate, high, and very high risk disease were 11%, 29%, 30%, 20%, and 10%, respectively. By the MDACC global prognostic scoring system (MDGPSS) 18%, 35%, 29%, and 18%, of the pts were of low-risk, intermediate-1, intermediate-2, and high-risk disease, respectively. After a median follow-up of 16 months from HMA failure, 117 (28%) pts remained alive. The median overall survival (OS) was 15 months (95% CI: 12-18) with estimated 1- and 3-year OS rates of 55% and 27%, respectively. Both, the R-IPSS and the MDGPSS were predictive of survival post HMA failure (Table 1Table 1Survival from HMA failure by risk groupSurvivalRisk groupCategoryPercentageMedian (mos)% 1-year% 3-yearp-valueMDGPSSLow18346848p<0.001Intermediate-135297539Intermediate-229124914High187318R-IPSSVery low11518360p<0.001Low29317638Intermediate30216030High2093912Very high1062511). ConclusionIn the largest cohort of lower risk MDS pts treated with HMA, the outcome after HMA failure is poor. Treatment of those patients remains an unmet medical need. OS is a reasonable primary endpoint for clinical studies targeting this population. Disclosures:Lancet:Celgene: Research Funding. Sekeres:Celgene: Consultancy; Amgen: Consultancy. List:Celgene: Research Funding. Komrokji:Celgene: Research Funding, Speakers Bureau.