Introduction and Methods: Despite the development of new targeted therapies for treating AML, cytarabine (Ara-C) remains the most reliably effective agent, particularly when given in high dosage (HIDAC). The outcome of AML therapy in pts > 60 years of age remains dismal with slightly more than half of pts achieving remission, and < 15% becoming long term survivors. Elderly pts do not tolerate typical HIDAC regimens because of cerebellar and other toxicities, so we have employed a modified HIDAC regimen: Ara-C 2 gm/m2/day over 4 hours once daily on days 1–6, combined with daunorubicin 45 mg/m2 days 2,3,4 for induction. Consolidation consisted of one cycle of the same chemotherapy followed by two additional cycles of mHIDAC alone, unless the pt went on to autologous or allogeneic HPCT. We report a single institution experience with 59 consecutive pts ≥ 60 y/o (including 20 pts ≥ 70 y/o), and compare outcomes with 139 similarly treated pts < 60 y/o. Excluded were pts with antecedent MDS or chemotherapy-related AML, APL, and pts with major organ dysfunction.
Results and Discussion: The CR rate for pts age ≥ 60 was 66% vs 81% for those < 60 (p=0.02). The distribution of pts into cytogenetic risk categories was similar, except for an under-representation of good risk cytogenetics among older pts (3% vs 14%, p=0.025). Overall survival for older pts was worse than that for younger individuals primarily due to an excess of early deaths, however, disease free survival among complete responders was similar for the 2 age groups (see below). There were 11 (16%) early deaths within 60 days among older pts, 4 with residual leukemia and 7 during aplasia. Early death occurred in 7 (5%) of the younger pts, 2 with residual leukemia and 5 during aplasia. There were 4 deaths (3 infectious and 1 stroke) during consolidation, 3 in the older and 1 in the younger group. There were also 2 late deaths in remission (both older pts) which were unrelated to AML or therapy. Clinically significant cerebellar toxicity was observed in 4 (6.8%) of the older pts and 3 (2%) of the younger pts, for a total of 7 episodes associated with 535 courses of Ara-C delivered (1.3%). 60% of older pts were able to complete 2 or 3 courses of consolidation therapy. Our data confirm the challenges of treating older pts with AML, but suggest that a significant subgroup can tolerate and benefit from aggressive therapy which includes dose intensification of Ara-C. This mHIDAC regimen is effective and well tolerated, and repeated administration to older pts is feasible.