Azacitidine in the Treatment of Elderly Patients with Acute Myelogenous Leukemia.
Authors: Benjamin Heather L. , Rossetti James M. , Lampkin Aaron J. , Hilton Christie , Sahovic Entezam , Abdulhaq Haifaa , Shadduck Richard K. , Vemulapalli Namratha , Hercules Amanda , Lister John 
Published: October 2019

Abstract
Abstract 4164

BACKGROUND
Effective treatment of the elderly patient with acute myelogenous leukemia (AML) remains a challenging task. Elderly patients with AML usually respond poorly to standard induction chemotherapy. Response rates in elderly patients are in the range of 30–50% compared to 80–90% in younger patients. Moreover, prolonged hospitalization with treatment related mortality as high as 30% is typical in this older population. In a prior retrospective analysis done at our institution, azacitidine showed an overall response rate of 60% with limited toxicity when administered to patients older than 55 years of age with AML. We present an interim analysis of the first 13 patients enrolled in our prospective, phase II open label study using single agent azacitidine for elderly patients with AML.

METHODS
This is a prospective, phase II open label study using azacitidine in patients ≥ 60 years with AML. Inclusion criteria: Newly diagnosed AML (de novo or secondary, WHO criteria) and ECOG≤ 2. Promyelocytic (M3) phenotype was excluded. Patients with circulating blast count ≥ 30,000/mcl were treated with hydroxyurea until < 30,000/mcl. Azacitidine was given at a dose of 100 mg/m2 subcutaneously for 5 consecutive days every 28 days until disease progression or significant toxicity. G-CSF was given to patients with neutropenia (ANC < 1000/mcl) during all cycles excluding cycle one.

RESULTS
Thirteen patients have been enrolled to date. The mean age of patients is 75 years (range: 66–84). The mean baseline ECOG performance score was 1 with a mean during treatment of 1. Mean baseline bone marrow blast count was 57% (range: 21–100%). Overall response rate using the NCI response criteria (IWG criteria for patients with hematological improvement (HI) only) was 46% (6/13): complete response (CR; n=3; 23%), partial response (PR; n=1; 8%), and HI (n=2; 15%). One additional patient had a 94% reduction in marrow blasts, but failed to achieve transfusion independence. The mean number of days on treatment was 171+ (range: 13–606). The mean number of days hospitalized for diagnosis plus treatment or disease related complication was 21 (range: 7–72) with the majority of therapy being given in the outpatient setting. One patient required prolonged hospitalization after going on to allogeneic transplantation. The mean overall survival from diagnosis for all patients was 246+ days (range: 13–606). The mean overall survival for responders was 399+ days (range: 212–606). One patient continues on therapy with azacitidine at 606 days (CR). Of the other responders, one progressed at 420 days and is considering other options (CR), one died from an intra-cranial hemorrhage after receiving Mylotarg for disease progression at 454 days (CR), one progressed at 119 days and went on to another clinical trial (PR), and two died with disease at 212 and 347 days (HI). Non-hematological toxicity was limited to mild injection site skin reaction and fatigue in 77% (10/13) each. No treatment related deaths were observed. The dose and schedule of therapy remained constant in all but three patients: One patient required a 25% dose reduction after cycle 3 followed by another 25% reduction after cycle 11 due to drug induced marrow suppression, one patient required a 25% dose reduction after cycle 2 due to drug induced marrow suppression, and one patient required and tolerated a 25% dose escalation to recapture a CR after cycle 15.

CONCLUSION
This interim analysis suggests that the administration of subcutaneous azacitidine in an accelerated dosing schedule to elderly patients with acute myelogenous leukemia is a feasible and well-tolerated alternative to standard induction chemotherapy.

Disclosures:
Benjamin: Celgene Corporation: Research Funding. Off Label Use: Use of azacitidine in AML.. Rossetti:Celgene Corporation: Honoraria, Research Funding, Speakers Bureau. Sahovic:Celgene Corporation: Honoraria, Research Funding, Speakers Bureau. Abdulhaq:Celgene Corporation: Research Funding. Shadduck:Celgene Corporation: Honoraria, Research Funding, Speakers Bureau. Lister:Celgene Corporation: Research Funding.