The primary aim of this study is to determine if the addition of valproic acid to a combination of adriamycin, cyclophosphamide and vindesine could increase progression-free survival in patients relapsing after first-line chemotherapy including platinum derivatives, cisplatin or carboplatin, and etoposide.

Inclusion Criteria:

• Histological or cytological diagnosis of small-cell lung cancer (SCLC)
• SCLC refractory to prior chemotherapy regimen including platinum derivatives (cisplatin or carboplatin) and etoposide, either primary refractory (immediate progression or recurrence less than 3 months after the end of previous chemotherapy) or secondary refractory (sensitive patients to platinum plus etoposide in first-line, progressing or recurring less than 3 months after reintroduction of the same chemotherapy).
• At least one evaluable or measurable lesion
• Availability for participating in the detailed follow-up of the protocol
• Signed informed consent.

Exclusion Criteria:

• Patient who were previously treated with anthracyclin or vinca-alcaloid derivatives or cyclophosphamide
• 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 or of the bladder or 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 (ejection 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 valproic acid and/or doxorubicin, cyclophosphamide, vindesine
• Serious medical or psychological factors which may prevent adherence to the treatment schedule.