ASCO 2016

http://abstracts.asco.org/176/AbstView_176_166037.html

SIRFLOX study: Novel approach to define depth of response (DpR) within a volumetric model in patients with metastatic colorectal cancer (mCRC).


Abstract:

Background: DpR has recently been proposed as a measure of efficacy that predicts the long-term treatment outcome for mCRC. DpR is a continuous measure that defines the nadir of tumor response, typically by the sum of the longest diameters of all target lesions compared to baseline. A novel volumetric model was applied to the independent blinded reader RECIST data from SIRFLOX, a multicenter RCT of 530 patients with non-resectable, liver-only or liver-dominant mCRC that compared first-line FOLFOX (± bev) plus Y-90 resin microspheres [SIRT] to FOLFOX (± bev) alone [Control]. Methods: Spherical tumor volume was estimated from the longest unidimensional length for ≤ 5 target hepatic lesions (RECIST 1.0) in the SIRFLOX ITT population. Finite mixture modelling was used to assess baseline tumor distribution and identify the optimal cut-point for subpopulations within which any potential predictors of DpR could be described. Results: There was a 7% greater decrease in median liver tumor volume in SIRT vs. Control (-75% vs. -68%; P = 0.036). Deepest response (median time to nadir) occurred 60 days later in SIRT than Control (266 vs. 206 days; P < 0.001). A larger treatment effect and longer time to nadir were observed in patients with > 12% hepatic tumor burden (median DpR -90% in SIRT vs. -77% in Control, P = 0.003; median nadir 298 vs. 196 days, P < 0.001), compared to those with ≤ 12% tumor burden (median DpR -93% vs. -94%, P = 0.763; median nadir 243.5 vs. 220 days, P = 0.152). PFS in the liver by competing risk analysis was significantly longer in patients with > 12% hepatic tumor burden receiving SIRT vs. Control (median 27.2 vs. 13.1 months, P = 0.003), whereas complete response [CR] for SIRT vs. Control was more common in patients with ≤ 12% liver tumor burden (12.9% vs.3.5%; P = 0.001). Conclusions: The present study integrates baseline tumor volume into the analysis of volumetric DpR modelled from existing unidimensional target lesion assessment. In SIRFLOX, the addition of SIRT to standard chemotherapy significantly increased hepatic DpR. The impact of SIRT on PFS was greatest in patients with a baseline tumor burden > 12%, whereas the impact on CR rate was greater where tumor burden was < 12%. Clinical trial information: NCT0072450

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Interesting that the heading is SIRFLOX, but the link NCT0072450 is -
^{FOLFOX Plus SIR-SPHERES MICROSPHERES Versus FOLFOX Alone in Patients With Liver Mets From Primary Colorectal Cancer (SIRFLOX)}