High-risk clear cell RCC survival not ASSUREd with sunitinib, sorafenib
medwireNews: Adjuvant treatment with sunitinib or sorafenib does not prolong disease-free survival (DFS) or overall survival (OS) in clear cell renal cell carcinoma (RCC) patients classed as high risk, shows a post hoc analysis of the placebo-controlled ASSURE trial.
The primary analysis of the total study cohort comprising 1943 patients who underwent surgery for clear cell or non-clear cell disease did not find a DFS benefit with adjuvant sunitinib or sorafenib relative to placebo.
But in light of the recent S-TRAC trial results that showed improved DFS with sunitinib versus placebo in a clear cell RCC cohort with predominantly high-risk patients, Naomi Haas (Abramson Cancer Center of the University of Pennsylvania, Philadelphia, USA) and team conducted an updated analysis of the ASSURE cohort focusing on the 1069 participants with pT3, pT4, or node-positive disease.
At 5 years, 47.7% of the 358 patients randomly assigned to receive sunitinib remained disease-free, as did 49.9% of the 355 patients given sorafenib, and 50.0% of the 356 given placebo, with no significant difference between treatment arms.
As reported in JAMA Oncology, OS was also comparable, with 5-year rates of 75.2%, 80.2%, and 76.5% for participants treated with sunitinib, sorafenib, and placebo, respectively.
Haas et al also evaluated the effect of dose intensity as the ASSURE protocol had undergone an amendment due to intolerance, such that the starting dose of sunitinib was reduced from 50 mg daily in 2006 to 37.5 mg daily in 2009; the corresponding starting doses for sorafenib were 800 mg daily and 400 mg daily.
However, the lack of efficacy of the vascular endothelial growth factor–tyrosine kinase inhibitors was not attributable to low dose intensity as the researchers observed “no difference in outcome by dose quartile.”
They acknowledge that this post hoc analysis was not powered to detect differences between treatment arms in the high-risk and dosing subgroups, but believe that “the sample size was large enough that a clinically meaningful difference would be observable in the graphical portrayal of DFS.”
The study authors conclude: “Based on this analysis, a rationale for adjuvant therapy in this high-risk population is not elucidated.”
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