R75251 in prostate cancer patients in progression after first-line hormonal treatment

The therapeutic potential of R75251, a ketoconazole derivative which has shown marked antitumor activity in animals and in men, was investigated in 16 patients with advanced prostatic cancer progressing after one or more lines of hormone therapy.

Patients were given the drug at 150 mg/b.i.d. for one month. After the first month of treatment, the dose was increased to 300 mg/b.i.d. In all patients, treatment was continued until disease progression or the development of sever toxicity. Clinical and biochemical assessments were performed on days 0, 14 and 28 and then repeated on a monthly basis.

Of the 13 evaluable patients, 12 showed stable disease by strictly employing US-NPCP criteria. However, in 3 patients a clear effect was observed on the volume of their measurable lesions. In addition, 2 of them showed a more than 50% decrease of prostate-specific antigens (PSA). Overall, 50% of patients showed some decrease in PSA baseline levels. Overall tolerance to treatment was good.

Our results, although achieved in a small number of patients, suggest that R75251 has a moderate but definite activity in patients with hormone-refractory prostate cancer and that the value of this drug as second-line treatment in these patients should be further investigated.