A phase II trial of gefitinib in patients with non-metastatic hormone-refractory prostate cancer

OBJECTIVE To investigate, in a phase II trial, the use of the epidermal growth factor receptor (EGFR) inhibitor gefitinib as monotherapy in patients with non-metastatic hormone refractory prostate cancer (HRPC), as current treatment options for this disease are limited, and agents which target the EGFR should be assessed because EGFR is highly expressed in prostate cancer and associated with a poor prognosis. PATIENTS AND METHODS Patients with histologically or cytologically confirmed cancer of the prostate with no evidence of metastatic disease were enrolled into this open-label, multicentre study of monotherapy with gefitinib 500 mg/day. The primary endpoint of the study was biochemical response, defined as a ≥50% decrease in serum prostate-specific antigen (PSA) level. RESULTS Fifty-eight men were enrolled across 10 centres in the USA; none of the 40 evaluable patients had a PSA response. Gefitinib was generally well tolerated, with diarrhoea being the most common treatment- related adverse event, in 71% of patients. There was treatment-related grade 3 diarrhoea in 5% of patients, with no grade 4 adverse events or deaths during the course of the study. CONCLUSIONS Gefitinib has no single-agent activity in non-metastatic HRPC, as assessed by decreases in serum PSA level. This phase II study also confirmed the well-established favourable tolerability profile of gefitinib monotherapy.