Subgroup analyses of a randomized sequential open-label study (SWITCH) to evaluate efficacy and safety of sorafenib (SO)/sunitinib (SU) versus SU/SO in the treatment of metastatic renal cell cancer (mRCC).

Abstract

4567 Background: Results of the sequential randomized phase III SWITCH study comparing SO/SU and SU/SO have been reported previously (ASCO GU 2014, abstract 393) showing no significant difference in the primary endpoint total PFS (T-PFS, Hazard Ratio [HR] 1.01) nor the secondary endpoints overall survival (OS, HR 1.0) and 1st-line PFS (HR 1.19). We here report results of SWITCH study subgroup analyses per endpoints T-PFS, OS, and 1st-line PFS. Methods: Pts with mRCC unsuitable for cytokines without prior systemic therapy, ECOG PS 0/1, MSKCC score low or intermediate, and ≥1 measurable lesion were randomized to receive open-label SO/SU (arm A) or SU/SO (arm B) in standard dosage. Retrospective subgroup analyses according to age, sex, MSKCC score, and ECOG PS were performed to identify any subgroup that profits more from one sequence or the other by comparing both groups using Cox proportional hazard regression model and log-rank testing. Results: A total of 365 pts were enrolled: 182 arm A, 183 arm B.At time of final T-PFS analysis 220 events had occurred (A, n=117 [64%]; B, n=103 [56%]). The Table shows the subgroup analyses comparing group A vs group B including HR and p value of tests for difference. Conclusions: There was no significant difference in T-PFS, OS, and 1st-line PFS in the evaluated subgroups between the two sequential treatments apart from OS per age group in which different results have been found. Both drugs provided overall benefit regardless of sequence and subgroup. However, the analyses were exploratory and hypothesis-generating as they were retrospective and the significance analysis was not corrected for multiple testing. Clinical trial information: NCT00732914. Subgroup T-PFS HR (p value) OS HR (p value) PFS in 1st-line HR (p value) Age < 65 yrs 1.17 (0.37) 1.57 (0.04) 1.25 (0.18) Age ≥ 65 yrs 0.84 (0.40) 0.60 (0.04) 1.10 (0.63) Male 1.04 (0.80) 0.99 (0.94) 1.27 (0.09) Female 0.86 (0.59) 1.08 (0.81) 0.96 (0.86) ECOG PS 0 1.02 (0.91) 1.05 (0.82) 1.33 (0.08) ECOG PS 1 1.04 (0.84) 0.97 (0.90) 1.08 (0.14) MSKCC low 0.98 (0.91) 1.24 (0.48) 1.30 (0.20) MSKCC intermediate 1.01 (0.95) 0.83 (0.34) 1.14 (0.44)