Treatment of myelodysplastic syndromes with valproic acid alone or in combination with all-trans retinoic acid

Valproic acid (VPA) has been shown to inhibit histone deacetylase activity and to synergize with all-trans retinoic acid (ATRA) in the differentiation induction of acute myelogenous leukemia (AML) blasts in vitro. We treated 18 patients with myelodysplastic syndromes (MDS) and AML secondary to MDS (sAML/MDS) with VPA monotherapy (serum concentrations 346693 muM [50-100 mug/mL]). Five patients received VPA and ATRA (80 mg/m(2)/d, days 1-7, every other week). Response according to international working group (IWG) criteria was observed in 8 patients (44%) on VPA monotherapy, including 1 partial remission. Median response duration was 4 months (range, 3-9 months). Four of 5 patients relapsing were treated with VPA + ATRA, 2 of them responding again. Among 5 patients receiving VPA + ATRA from the start, none responded according to IWG criteria, but 1 patient with sAML/MDS achieved a marked reduction in peripheral and marrow blasts. Thus, VPA is of therapeutic benefit for patients with MDS, and ATRA may be effective when added later. (C) 2004 by The American Society of Hematology.