Abstract 4123
The incidence of acute myeloid leukemia (AML) increases with advancing age. At present, there are limited treatment options available for older patients because of lack of efficacy and increased toxicity. In a previously reported Phase II AML trial (n = 55), older patients not previously treated for AML experienced an overall response rate of 25% with decitabine (Cashen et al. Blood 2008). Response rate was similar in patients with poor or intermediate cytogenetic risk at baseline. In addition, 5 (15%) of the 34 patients who had cytogenetic abnormalities at baseline achieved a complete cytogenetic response in this trial. As older AML patients are more likely to present with unfavorable cytogenetic profiles, it was of interest to review the patient characteristics and describe the responses of the 5 patients who had a complete cytogenetic response.
The patients for this analysis were from a multicenter, Phase II study. In this study, patients over the age of 60 with AML (>20% bone marrow blasts) and no prior therapy for AML were treated with decitabine, 20 mg/m2 IV for 5 consecutive days of a 28-day cycle until disease progression or unacceptable adverse event. Cytogenetic profile was assessed at screening and after every cycle, beginning with cycle 2.
The 5 patients (2 males, 3 females; 5 white; 2 M1, 1 each for M2, M6, and M7) with a complete cytogenetic response had baseline characteristics that are associated with high risk. Three were >70 yrs of age, and all 5 had AML secondary to prior therapy (n=2) or MDS (n=3). Four patients had poor-risk cytogenetics: 2 pts with -7, -5q, and ≥ 3 abnormalities and 2 pts with deletions of chromosome 5 and ≥ 3 abnormalities. One patient had intermediate-risk cytogenetics. The median baseline bone marrow myeloblast count was 33% (range 21 to 60). These patients were treated with a median 10 cycles (range 6 to 19) of decitabine. The median time to a complete cytogenetic response was 5 cycles (range 2.3 to 6). The median time to relapse from a complete cytogenetic response was 8.1 cycles (range 3.4 to 19.8). The overall median survival was 21.6 months (95% CI: 9.5, 24.7), which compares favorably to the median overall survival of the entire study cohort (21.6 months vs. 7.7 months, Cashen et al. Blood 2008).
Treatment with decitabine can induce complete and durable cytogenetic responses, even in older patients with high risk disease characteristics and poor risk cytogenetics. Patients who achieve a cytogenetic response may have a survival benefit. A presently ongoing Phase III survival trial with decitabine will help further characterize the effect of decitabine on cytogenetic responses in older AML patients.
Cashen:Eisai, Inc.: Consultancy.
Asterisk with author names denotes non-ASH members.
