Phase I-II study of the somatostatin analogue lanreotide in hormone-refractory prostate cancer.

Lanreotide (BIM 32014), a somatulin analogue, was found to be as effective as castration in a rat prostate tumor model. Therapeutic benefit was also demonstrated in the hormone-resistant phase of this tumor model. The activity of lanreotide may be due to a reduction in the levels of growth factors such as insulin growth factor 1 (IGF1). A total of 30 patients with hormone-refractory prostate cancer were treated with a slow-release formulation of lanreotide. The mean age was 71 years. Patients were treated with one intramuscular injection of 30 mg BIM 23014 once a week and were followed for prostate-specific antigen (PSA) level evolution until disease progression or WHO grade 3 or 4 toxicity and for survival. The patients were treated for a mean duration of 12 weeks (range, 2-60 weeks). The performance status and bone pain were improved in 40% and 35% of patients respectively. In all, 20% of the patients had a decrease of > or = 50% in PSA levels and 16% showed a stabilization. The biological response was correlated with clinical improvement. The 1-year global survival rate was 72%, with the rate being 89% in the group of patients who were responders on PSA plasma level and 64% in patients with progressive disease. The response duration ranged from 16 to 60 weeks. Toxicity was minor, with transient grade I digestive side effects being noted in a few patients. Lanreotide given at 30 mg once a week to patients with metastatic hormone-refractory prostate cancer was well tolerated. The response rate was higher than that reported in recent published series. Higher doses of lanreotide should be evaluated.