Incidence and Outcomes of a Rare Translocation t(3,5) in Patients (pts) with Acute Myeloid Leukemia (AML) and Myelodysplastic Syndrome (MDS)

Abstract Abstract 1456 Background: Cytogenetic analysis of large pt cohorts allows us to evaluate the prognostic impact of rare and unique translocations. Little is known about the clinical outcomes of pts with t(3,5), which generally results in fusion of NPM and MLF1 in pts with MDS and AML. Methods: We retrospectively reviewed the charts of 8,215 pts with a diagnosis of MDS or AML evaluated at our institution from 1985–2011. Results: A total of 17 pts with a t(3,5) either at diagnosis or post-treatment were identified (10 pts, as the sole cytogenetic abnormality, and 7 pts, as part of other/complex karyotype). Among evaluable cases (15/17), frequently occurring breakpoints included q25;q34 (n=4), p21;q15 (n=2), and p21;q13 (n=2).10 pts had MDS with IPSS of Int-1(n=5) and Int-2(n=5), and 7 pts had AML. Four pts had therapy-related MDS (3 pts with prior lymphoma, 1 pt small cell lung cancer) and one pt with MDS had PNH. Median age was 56 years (range, 20–78) at diagnosis. Four pts (24%) had a FLT3-ITD mutation (3 with AML and 1 with MDS), 1 of these FLT3-mutated pts had additional mutations in c-KIT and NRAS mutation, 9 pts were tested and negative for molecular abnormalities, and 4 pts did not have molecular analysis available. Therapies were diverse, with two most common: cytarabine-based regimens (n=6) and hypomethylating agent-based therapy (n=6). Overall, median number of therapies for all pts was 1 (range, 0–5), including 2 pts treated with upfront stem cell transplant (SCT) and 1 pt treated with only growth factors/supportive care. Six pts (35%) (MDS 3 pts, AML 3 pts) underwent SCT during their course of therapy (including 1 cord blood, 1 SCT with NK cells, and 4 allogeneic MUD SCT). Overall median survival for pts with MDS was 8.1 months (range, 1–57) and for pts with AML, 21 months (range, 2–53). CR was achieved overall in 12 pts (71%) with median CR duration of 3.2 months (range, 1–60 months). Three (18%) pts were refractory to all chemotherapy and one pt died during induction chemotherapy (infection and diffuse alveolar hemorrhage). One pt never received treatment. Conclusions: Survival is particularly poor among patients with MDS and t(3;5) while those with AML have survival comparable to normal karyotype (NK) AML. Further investigation with novel treatment approaches is warranted in this subpopulation of MDS/AML pts. Disclosures: No relevant conflicts of interest to declare.