Inclusion Criteria:

• Measurable or evaluable disease(evaluable according to CA125 criteria of GCIG) Cisplatin resistant ovarian cancer
• Persistent or progression to first line platinum-based chemotherapy
• Relapse within 6 months after completing first line platinum-based chemotherapy
• Platinum-sensitive disease who are failed to second line therapy based on platinum.
• Adequate organic function as defined by: hemoglobin >10 g/L, leukocytes >4000/mm3, platelets >100 000mm3; normal creatinine value and creatinine clearance >60 mL/min; total bilirubin < 1.5 upper normal limit value

Exclusion Criteria:

• History of allergy to hydralazine or valproate;
• Past or present condition of rheumatic disease, central nervous system disease, heart failure from aortic stenosis and postural hypotension as diagnosed by a physician;
• Newly diagnosed hypertension patients with or without pharmacological treatment are allowed as long as their treatment do not include hydralazine.
• Previous use of the experimental drugs (hydralazine and magnesium valproate) as well as if patients were pregnant or breast-feeding.

Other exclusion criteria are uncontrolled systemic disease or infection.