Background: Preclinical work suggests SRC proteins have a role in the development of resistance to vascular endothelial growth factor (VEGF) targeted therapy in metastatic clear-cell renal cancer (mRCC). This hypothesis was tested in this trial using the SRC inhibitor saracatinib and the VEGF inhibitor cediranib.
Patients and methods: Patients with disease progression after ≥1 VEGF-targeted therapy were eligible to participate in this double-blind, randomized (1:1) phase II study. The study compared the combination cediranib 30 mg once daily (o.d.) and saracatinib 175 mg o.d. (CS) (n = 69) or cediranib 45 mg o.d. and placebo o.d. (C) (n = 69). Archived tissue was used for biomarker analysis [SRC, focal adhesion kinase (FAK), von Hippel-Lindau, protein tyrosine phosphatase 1b and hypoxia-inducible factor 2α : n = 86]. The primary end point was progression-free survival (PFS) by RECIST v1.1.
Results: Between 2010 and 2012, 138 patients were randomized across 16 UK sites. The characteristics of the two groups were well balanced. Partial responses were seen in 13.0% for C and 14.5% for CS (P > 0.05). There was no significant difference in PFS [5.4 months (3.6-7.3 months) for C and 3.9 (2.4-5.3 months) for CS; hazard ratio (HR) 1.18 (0.94-1.48)] or overall survival (OS) [14.2 months (11.2-16.8 months) for C and 10.0 (6.7-13.2 months) for CS; HR 1.28 (1.00-1.63)]. There was no significant difference in the frequency of key adverse events, dose reductions or drug discontinuations. None of the biomarkers were prognostic for PFS or OS. FAK overexpression correlated with an OS benefit [HR 2.29 (1.09-4.82), P > 0.05], but not PFS, for CS.
Conclusions: Saracatinib did not increase the efficacy of a VEGF-targeted therapy (cediranib) in this setting. Biomarker analysis did not identify consistent predictive biomarkers.
Keywords: SRC; VEGF; biomarker; renal cell carcinoma; tyrosine kinase inhibitor.
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