Inclusion Criteria:

- Histological diagnosis of malignant mesothelioma

- Unresectable or inoperable malignant mesothelioma failing after at least one prior
chemotherapy regimen including platinum derivatives (cisplatin or carboplatin)

- At least one evaluable or measurable CT-lesion

- Availability for participating in the detailed follow-up of the protocol

- Signed informed consent

Exclusion Criteria:

- Patients who are candidates for surgery with curative intent

- Patient who were previously treated with anthracyclin derivatives

- Performance status < 60 on the Karnofsky scale

- A history of prior malignant tumour, except non-melanoma skin cancer or in situ
carcinoma of the cervix and cured malignant tumour (more than 5-year disease free
interval)

- A history of prior HIV infection

- Polynuclear cells < 2,000/mm³

- Platelet cells < 100,000/mm³

- Abnormal coagulation tests (aPTT, PTT, prothrombin time) and/or decreased fibrinogen

- Serum bilirubin >1.5 mg/100 ml

- Transaminases more than twice the normal range

- Serum creatinine > 1.5 mg/100 ml

- Recent myocardial infarction (less than 3 months prior to date of diagnosis)

- Congestive cardiac failure (ejectional fraction of the left ventricle < 50%) or
uncontrolled cardiac arrhythmia

- Uncontrolled infectious disease

- Active epilepsy needing a specific treatment

- Concomitant treatment with IMAO, carbamazepine, mefloquine, phenobarbital, primidone,
phenytoïn, lamotrigine, zidovudine

- Pregnancy or refusal to use active contraception

- A known allergy to valproate acid and/or doxorubicin

- Serious medical or psychological factors which may prevent adherence to the treatment
schedule