Valproic acid and all-trans retinoic acid: meta-analysis of a palliative treatment regimen in AML and MDS patients.

Currently, no standard treatment is available for elderly patients with de novo/secondary acute myeloid leukemia (AML) who are not eligible for intensive chemotherapy. New, less aggressive therapies are therefore needed. Histone deacetylase inhibitors (HDACi) are known to reduce proliferation and induce differentiation in hematological malignancies. With all-trans retinoic acid (ATRA) these effects have been reported to be even enhanced. Valproic acid (VPA) is an HDACi and has been known as anti-epileptic agent for many years. We treated 21 patients with de novo/secondary AML and 1 patient with myelodysplastic syndrome with ATRA (45 mg/m(2)/day in 2 doses, 14 days, q29 days) and VPA (150 mg/day 1 week, then 300 mg/day, continuously). Treatment was tolerated well with moderate side effects. 4 patients revealed hematological improvement and another 4 patients experienced a reduction in transfusion dependency. The overall response rate was 27%. Our study is presented together with an overview of the literature on the topic.