Mitoxantrone and etoposide for acute myeloid leukemia in first relapse.

6563 Background: Achievement of complete remission (CR) for relapsed acute myeloid leukemia (AML) is crucial for improving prognosis and survival. However, there are no established standard therapies for AML in first relapse. Our purpose was to evaluate the efficacy and toxicity of a regimen of mitoxantrone and etoposide for relapsed AML and assess factors that may be predictive of response. Methods: Patients were identified from a database of patients with AML treated at the University of Pittsburgh Cancer Institute from 1999-2011. Subjects were patients with AML in first relapse treated with mitoxantrone 10mg/m2 and etoposide 100mg/m2 daily on days 1-5. An exploratory analysis was performed to determine CR rate, overall survival, toxicities, and predictive factors. Results: The study cohort consisted of 66 patients with AML in first relapse, median age 56.5 years (range 21-75). At time of relapse, 12 were classified as having poor cytogenetics, 39 had intermediate cytogenetics, and 5 had favorable cytogenetics (9 patients did not have karyotype analysis). 34.8% (23/66) of patients achieved CR, and 16 went on to have allogeneic hematopoietic cell transplantation. Patients with favorable, intermediate, and poor cytogenetics had CR rates of 60% (3/5), 35.9% (14/39) and 50% (6/12), respectively. Median survival was 8.1 months (95% CI 5.1-11.9). Patients who achieved CR had significantly improved survival compared to those who did not (20.0 months vs. 5.2 months, p<0.0001). Median days to neutrophil and platelet recovery were 37.5 (range 19-81) and 40 (range 21-81), respectively. There were no grade 3/4 hepatic toxicities. The 4-week and 8-week mortality rates were 4.5% and 13.6%, respectively. Duration of first remission greater than 12 months was predictive of CR (p<0.001), whereas age, cytogenetics, bone marrow blast percentage, and white blood cell count at relapse were not. Conclusions: In an unselected heterogeneous patient population with relapsed AML, mitoxantrone and etoposide was an effective regimen with acceptable toxicity, and those who achieved CR had significantly improved overall survival. Duration of first remission greater than 12 months was the only predictive factor, and response was seen among all cytogenetic risk groups.