Formation of DNA adducts and tumor growth delay following intratumoral administration of DTI-015

Intratumoral (IT) administration of DTI-015 (BCNU in 100% ethanol) utilizes solvent facilitated perfusion for the treatment of tumors. RIF-1 tumors were treated by IT injection of either ethanol alone or 0.05-1.0 mg of DTI-015 or by iv injection of 0.5 mg of BCNU. Treatment with ethanol alone or iv injection of 0.5 mg of BCNU did not produce a significant growth delay. In contrast, IT administration of DTI-015 produced a significant growth delay at each of the treatment doses (p<0.05 to p<0.001). We have quantified the levels of N7-(2-hydroxyethyl) guanine (N7-HOEtG) in RIF-1 tumors 24 h following either IT treatment with 0.5 mg DTI-015 or ip administration of 0.5 mg BCNU. Levels of N7-HOEtG (mumol/mol DNA) were less than or equal to0.08 for both untreated controls and following ip treatment with BCNU and 13.1 +/- 5.6 following IT administration of DTI-015. The levels of N7-HOEtG detected in RIF-1 tumors following IT administration of DTI-015 were 164-fold higher than the level(s) of N7-HOEtG in the ip BCNU treated tumor samples. These studies demonstrate that IT administration of DTI-015 produces high levels of DNA adducts in the tumor which correspond to a significant increase in tumor growth delay compared to the same dose of BCNU administered systemically.