Hematologic improvement and response in elderly AML/RAEB patients treated with valproic acid and low-dose Ara-C

The histone deacetylase inhibitor (HDACi) valproic acid (VPA) has been shown to be active on acute myeloid leukemia (AML) and refractory anemia with excess of blasts (RAEB). Thirty-one elderly AML/RAEB patients (AML n=25; RAEB n=6) with a high rate of comorbidity were entered in a phase II study with low-dose cytarabine (Ara-C) and VPA. Fitness was evaluated by means of the Comprehensive Geriatric Assessment (CGA), including the Cumulative Illness Rating Scale (CIRS) score, the self-sufficiency scores of Activity of Daily Living (ADL) and Instrumental Activity of Daily Living (IADL). Eight patients obtained a lasting complete remission and 3 other patients obtained hematologic improvement for a total response rate of 35%. Five of 11 responding patients were relapsed or resistant after a previous treatment with Ara-C. Seven of 11 responding patients were assessed as frail at enrollment and/or had IADL impairment. Grades 3 and 4 toxicities were mainly hematological. Low-dose Ara-C and VPA is a relatively non-toxic combination with good therapeutic activity in elderly patients with AML/RAEB. This therapeutic approach represents an alternative treatment for patients who cannot undergo standard induction therapy.