Hypothesis: Combined treatment with valproic acid and ATRA can be used to achieve disease stabilization for a subset of patients with acute myelogenous leukemia (AML), and this effect can be improved without serious toxicity by adding low-dose cytarabine to this treatment.

Adult patients >18 years of age who can be included:

Elderly patients who cannot achieve standard chemotherapy, patients with relapsed or resistant AML.

Treatment: Combined therapy with:

Valproic acid, continuous therapy until disease progression ATRA, oral therapy for 14 days every three months Low-dose cytarabine 10 mg/m2 up to 10 injections during week 2 and 3, repeated every 3 months.

Patients to be included:

1. Elderly patients (>60 years of age) or other patients unfit for conventional intensive chemotherapy with newly diagnosed acute myelogenous leukemia (AML).
2. Adult patients of any age (>18 years of age) with relapsed or resistant AML who cannot receive conventional therapy.

Treatment:

Valproic acid to be started on day 1 as continuous therapy until disease progression.

ATRA administered from day 8 orally as 22.5 mg/m2 twice daily for 14 days, repeated every third month.

Low-dose cytarabine 10 mg/m2 from day 14 and continued as daily injections for up to 10 days, repeated every third month.

Supportive therapy is given according to the hospitals general guidelines.

Followup: The first 2 days treatment in hospital, later regular out-patient treatment. Controls will include clinical examination, peripheral blood parameters (including serum valproic acid levels), bone marrow samples.

Inclusion Criteria:

• Recently diagnosed AML in patients unfit for intensive chemotherapy
• Patients with relapsed or refractory AML

Exclusion Criteria:

• No informed consent
• Intolerance to study drugs
• Serious liver disease