The Activity for a Novel Niteosourea (TCNU) in Human Lung Cancer Xenografts

The activity of a novel water-soluble taurine-containing nitrosourea 1-(2-chloroethyl)-3-/2-(dimethylaminosulfonyl)-ethyl/-1-nitrosourea (TCNU) was assessed in 3 human bronchial carcinoma xenografts grown in immunodeficient mice. Animals were prepared by neonatal thymectomy and total body irradiation after a priming dose of cytosine arabinoside. Groups of 6-9 tumours were randomly allocated to either treatment with a single MTD dose of TCNU (20 mg/kg orally) or to a control group. Tumours were measured 3 times per week and the activity of the drug expressed in terms of the specific growth delay (SGD) derived from the median doubling times of treated and control groups. Activity was seen in 2 non-small cell tumours, an adenocarcinoma and a squamous carcinoma (SGDs of 0.67 and 0.96, respectively). In a small cell tumour TCNU was curative at this dose.