Phase II study of everolimus in patients with locally advanced or metastatic transitional cell carcinoma of the urothelial tract: clinical activity, molecular response, and biomarkers

Background: This phase II study assessed the safety and efficacy of everolimus, an oral mammalian target of rapamycin inhibitor in advanced transitional carcinoma cell (TCC) after failure of platinum-based therapy. Patients and methods: Thirty-seven patients with advanced TCC received everolimus 10 mg/day until progressive disease (PD) or unacceptable toxicity. The primary end point was the disease control rate (DCR), defined as either stable disease (SD), partial response (PR), or complete response at 8 weeks. Angiogenesis-related proteins were detected in plasma and changes during everolimus treatment were analyzed. PTEN expression and PIK3CA mutations were correlated to disease control. Results: Two confirmed PR and eight SD were observed, resulting in a DCR of 27% at 8 weeks. Everolimus was well tolerated. Compared with patients with noncontrolled disease, we observed in patients with controlled disease a significant higher baseline level of angiopoietin-1 and a significant early plasma decrease in angiopoietin-1, endoglin, and platelet-derived growth factor-AB. PTEN loss was observed only in patients with PD. Conclusions: Everolimus showed clinical activity in advanced TCC. The profile of the plasma angiogenesis-related proteins suggested a role of the everolimus antiangiogenic properties in disease control. PTEN loss might be associated with everolimus resistance.