In an effort to improve survival in patients with high-grade brain tumours, it was hypothesised that local delivery of carmustine (BCNU) to these tumours would prolong survival. By implanting a polymer impregnated with carmustine into the tumour resection cavity, it was hoped that high local drug concentrations could be achieved over a sustained time period with minimal systemic concentrations or toxicity.This hypothesis was tested in the laboratory, and the use of a carmustine polymer was found to be safe and efficacious in a rodent brain tumour model. Based on the preclinical laboratory studies, a series of clinical studies were carried out to evaluate the safety and efficacy of this treatment.Two phase III randomised, placebo-controlled studies have been completed evaluating the use of a carmustine polymer in patients at the time of recurrence and as initial therapy. Both studies demonstrated that carmustine polymers resulted in prolonged survival. These studies establish the principle that local delivery by a polymer is an efficacious drug delivery strategy. Furthermore, these studies demonstrate that local delivery of carmustine by the polymer is an effective treatment for patients with high-grade gliomas.