The hypomethylating agents azacytidine and decitabine are unaffordable for many patients with MDS. The combination of the DNA methyltransferase inhibitor hydralazine and the histone deacetylase inhibitor valproate has shown preliminary efficacy in MDS. The aim of this study is to evaluate the clinical efficacy and safety of hydralazine/valproate in a case series of MDS patients treated in a compassionate manner. Hydralazine was dosed according to the acetylation genotype of patients (slow acetylators 83 mg daily; fast acetylators 182 mg daily), and valproate was dosed at 30 mg/kg/day. Both drugs were given daily until disease progression. Response and toxicity were evaluated with the International Working Group criteria and CTCAE, version 4, respectively. Survival parameters were estimated with the Kaplan-Meier method. From 2009 to 2012, 14 patients were treated. The median age ± SD was 55.2 ± 19.52 (range 23-87) years. According to the IPSS, cases were graded as intermediate-1 (n = 8/14; 57.2%) or intermediate-2 (n = 6/14; 42.8%). Responses were as follows: five (35.7%) complete response, one (7.1%) partial response, and two (14.28%) became transfusion independent. The mean duration of response ± SD was 60 ± 35.28 months (range 5-94). Three patients progressed to AML. At a median follow-up of 57 months (range 1-106), the median OS was 27 months. At that point, five patients remained on the treatment, one with partial response and four with complete response. The median OS was not reached in the eight patients who saw a clinical benefit from the treatment, in comparison to an OS of 7 months in the six patients who had no treatment. The combination of hydralazine and valproate is safe and effective in MDS, and its further testing is highly desirable.
Keywords: Epigenetic therapy; HDAC inhibitors; Hydralazine; Hypomethylating agents; Myelodysplastic syndrome; Valproate.