Clinical relevance of mutations in patients with myelodysplastic syndromes and myelodysplastic/myeloproliferative neoplasms with normal karyotype.

Abstract

7053 Background: Clinical outcomes of patients with myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) are heterogeneous. Specific mutations and mutation patterns are known to define prognostic groups in normal karyotype acute myeloid leukemia. Whether this is the case in MDS and MDS/MPN remains unknown. Methods: We evaluated 325 previously untreated patients with MDS or MDS/MPN with normal karyotype evaluated from 2012 to 2016. Next generation sequencing (NGS) on whole bone marrow DNA analyzing a panel of 28 or 53 genes was performed at the time of diagnosis. Results: A total of 225 (69%) patients had MDS and 100 (31%) had MDS/MPN including 77 (24%) patients with chronic myelomonocytic leukemia (CMML). Median age was 69 years (31-92). Among patients with MDS, 189 (84%) had lower-risk and 36 (16%) had higher-risk based on IPSS. NGS data was obtained by 53-gene panel in 93 (29%) patients and by 28-gene panel in 232 (71%). A total of 202 (62%) patients had detectable mutations. Median number of mutations was 1 (range 0-6). Detected mutations are detailed in Table 1. A total of 111 (34%) patients, 70 with MDS and 41 with MDS/MPN, received therapy with hypomethylating agents. Median follow up was 12 months (0-167). By univariate analysis, NRAS (HR 3.28, CI 1.25-8.62, p=0.016) and TP53 (HR 4.9, CI 1.44-16.67, p=0.011) predicted for shorter overall survival (OS) among MDS patients. After multivariate analysis including IPSS-R, only TP53retained its impact in OS (HR 5.25, CI 1.44-19.13, p=0.012). Among MDS/MPN patients, no mutation was found to significantly impact OS. Conclusions: With the exception of TP53mutations, no other identified mutation seemed to independently define prognosis of patients with MDS or MDS/MPN with normal karyotype. In view of the high proportion of lower-risk patients, longer follow up is required to better define prognostic impact of mutations in this population. [Table: see text]