From June 1988 to January 1990, 28 patients with primary brain tumours were operated and treated with radiotherapy (RT) (50 Gy whole brain + 10 Gy boost to tumour bed) + cyclohexylnitrosourea (CCNU) 130 mg/msq p.o. every 6 weeks + the radiosensitizer Lonidamine (LND) (150 mg T.I.D. for the whole duration of treatment). Myelotoxicity of this regimen was acceptable, with two cases of grade IV leukopenia and thrombocytopenia requiring discontinuation of treatment. LND was discontinued in 6 patients for major toxicity (myalgias and/or testicular pain), and 3 additional patients required dose reduction of this drug. The median follow-up time of the patients on study was 12 months. The median survival time (MST) was 5 months for grade IV astrocytomas (n = 8) and 16 months for grade III lesions (= 20). No correlation was seen between survival of patients and DNA content, measured by flow cytometry, or levels of O6- alkylguanine-DNA alkyltransferase, an enzyme that repairs the CCNU-induced DNA damage.