Renal cell carcinoma (RCC) primary tumor shrinkage on vascular endothelial growth factor (VEGF)-targeted therapy (TT): A pooled analysis.

Abstract

629 Background: Cytoreductive nephrectomy (CRN) is an important treatment modality in patients (pts) with advanced RCC, however the role and timing in the context of VEGF-TT remains under investigation. The aim of this study is to determine the efficacy of VEGF-TT to induce primary tumor shrinkage in advanced RCC. Methods: We conducted a pooled analysis of 12 Pfizer-sponsored trials in pts with metastatic RCC treated with sunitinib, sorafenib, axitinib, bevacizumab, termsirolimus or interferon-α. Primary endpoint was the primary tumor objective response rate (ORR) by RECIST in pts who have not undergone prior nephrectomy. Kaplan-Meier method was used to estimate median overall survival (OS) of responders (PR or CR) v. non-responders. Cox regression adjusting for demographics, histology type, prior therapy, metastasis sites, IMDC risk factors and neutrophil-to-lymphocyte ratio was used to compare OS between pts with and without primary tumor ORR. Results: 565 (12%) out of 4736 pts included had their primary tumors intact, of which 360 (8%) received VEGF-TT. In pts with primary tumor intact, 87% had clear-cell RCC and IMDC risk group were 4% favourable, 33% intermediate, 39% poor, 24% unknown. 35% had bone metastasis and 32% had liver metastases. 65% had ECOG performance status ≥1. Compared to pts with prior nephrectomy, primary tumor intact pts were more likely to have bone or liver metastases or to be IMDC poor risk. Primary tumor ORR was 17% (95% exact CI, 14, 20) in all pts, 19% (95% exact CI, 16, 23) in first line treated pts and 23% (95% Exact CI, 19, 28) in pts treated with VEGF-TT (any line). Primary tumor ORR was 20% (95% exact CI, 15, 26) in IMDC intermediate risk pts and 9% (95% exact CI, 5 – 13) in the poor risk. No pts had PD as best response in their primary tumor at the time they stopped systemic therapy. Median OS was 33.98 months in pts with primary tumor ORR and 9.8 months in pts without ORR, adjusted HR 0.42 [95%CI, 0.28, 0.6; p < 0.0001]. Conclusions: VEGF-TT resulted in primary tumor shrinkage in 23% of pts with IMDC intermediate and poor risk advanced RCC who have not undergone CRN. VEGF-TT may potentially facilitate future CRN in select pts. Trials assessing the utility of CRN are underway.