Aim: This study aimed to evaluate the safety, pharmacokinetics and treatment effects of an alpha(nu)beta(3) integrin inhibitor on bone turnover and disease activity in men with hormone-refractory prostate cancer (HRPC) and bone metastases.
Methods: A total of 21 patients with bone metastases and HRPC were randomized to receive MK-0429 200 mg b.i.d. or 1600 mg b.i.d. for 4 weeks. Toxicity, pharmacokinetics and markers of bone turnover and tumor activity were examined.
Results: Nausea was the most common adverse event: one (200-mg group) and 11 (1600-mg group) patients. At 4 weeks, mean AUC(0-12 h) was 210 mmol*h (200-mg group) and 673 mmol*h (1600-mg group); mean C(max) values were 42 mmol/L (200-mg group) and 154 mmol/L (1600-mg group). Urinary cross-linked N-telopeptides of type I collagen to creatinine ratio (uNTx), a bone turnover biomarker, showed a change from baseline of -43.4 percent (200-mg group) and -34.1 percent (1600-mg group). There was an increase in serum prostate specific antigen (PSA), a marker for disease activity, of 54.1 percent (200-mg group) and 44.5 percent (1600-mg group).
Conclusion: MK-0429 was generally well tolerated, with the most common side-effect being nausea. There was some evidence of an early reduction of bone turnover, indicating a potential for clinical use in the treatment of MBD although serum PSA was unexpectedly increased during the study.