Phase I clinical and pharmacodynamic evaluation of oral CI-1033 in patients with refractory cancer.

PURPOSE: To determine the tolerability and pharmacokinetics of CI-1033 given daily for 7 days of a 21-day cycle. Tumor response and changes in erbB receptor tyrosine kinase activity in tumor and skin tissue were examined, and modulation of potential biomarkers in plasma was explored. DESIGN: This was a dose-finding phase I study in patients with advanced solid malignancies. Patients were evaluated for safety, pharmacokinetics, and tumor response. Pharmacodynamic markers, such as Ki67, p27, and erbB receptor status, were assessed in tumor and skin tissue using immunohistochemical and immunoprecipitation methodologies. Plasma biomarkers HER2, vascular endothelial growth factor, interleukin-8, and matrix metalloproteinase-9 were evaluated using immunologic techniques. RESULTS: Fifty-three patients were enrolled in the study. Dose-limiting toxicity (emesis, persistent rash, and mouth ulcer) was observed at 750 mg. The maximum tolerated dose was 650 mg. There were no confirmed objective responses. CI-1033 treatment showed down-regulation of epidermal growth factor receptor, HER2, and Ki67 in a variety of tumor tissues and up regulation of p27 in skin tissue. Plasma HER2 was reduced following CI-1033 administration, but no consistent change in vascular endothelial growth factor, interleukin-8, or matrix metalloproteinase-9 was noted. CI-1033 plasma concentrations were proportional to dose. CONCLUSION: The safety and pharmacokinetic profile of CI-1033 was favorable for multidose oral administration. Evidence of modulation of erbB receptor activity in tumor and skin tissue was accompanied by changes in markers of proliferation and cell cycle inhibition. Additional clinical trials are warranted in defining the role of CI-1033 in the treatment of cancer and further assessing the utility of antitumor markers.

Prostate-specific antitumor activity by probasin promoter-directed p202 expression.

p202, an interferon (IFN) inducible protein, arrests cell cycle at G1 phase leading to cell growth retardation. We previously showed that ectopic expression of p202 in human prostate cancer cells renders growth inhibition and suppression of transformation phenotype in vitro. In this report, we showed that prostate cancer cells with stable expression of p202 were less tumorigenic than the parental cells. The antitumor activity of p202 was further demonstrated by an ex vivo treatment of prostate cancer cells with p202 expression vector that showed significant tumor suppression in mouse xenograft model. Importantly, to achieve a prostate-specific antitumor effect by p202, we employed a prostate-specific probasin (ARR2PB) gene promoter to direct p202 expression (ARR2PB-p202) in an androgen receptor (AR)-positive manner. The ARR2PB-p202/liposome complex was systemically administered into mice bearing orthotopic AR-positive prostate tumors. We showed that parenteral administration of an ARR2PB-p202/liposome preparation led to prostate-specific p202 expression and tumor suppression in orthotopic prostate cancer xenograft model. Furthermore, with DNA array technique, we showed that the expression of p202 was accompanied by downregulation of G2/M phase cell-cycle regulators, cyclin B, and p55cdc. Together, our results suggest that p202 suppresses prostate tumor growth, and that a prostate-specific antitumor effect can be achieved by systemic administration of liposome-mediated delivery of ARR2PB-p202.