Introduction: As new therapeutics for metastatic renal cell carcinoma (mRCC) are quickly introduced to market, comparative randomized trial evidence guiding treatment decisions is lacking, especially in the second treatment exposure and beyond. As a demonstration case, we studied mRCC in real-world clinical settings by creating a joint community-academic retrospective mRCC registry to assess outcomes.
Materials and methods: For this overall survival (OS) analysis, the analytic cohort included all patients in the registry diagnosed between January 1, 2007, to May 31, 2011 (N = 384). Patients were grouped by up to three treatment exposures according to each drug's mechanism of action: vascular endothelial growth factor tyrosine kinase inhibitor (VEGFR TKI), mammalian target of rapamycin inhibitor (mTOR), or no systemic treatment (NSTx, which could include radiation or surgery). OS by exposure sequence was evaluated using Kaplan-Meier, pairwise comparison, and Cox regression analyses.
Results: Median OS was 17.2 months. OS (months) for one exposure was: mTOR 5.4, TKI 18.2, NSTx 18.4; for two exposures: mTOR/TKI 9.3, TKI/mTOR 13.9, TKI/TKI 35.2; and for three exposures: TKI/mTOR/TKI 20.9, TKI/TKI/mTOR 33.1. By pairwise comparison, OS for TKI, mTOR/TKI, TKI/mTOR, TKI/TKI, TKI/mTOR/TKI and TKI/TKI/mTOR sequences was greater than mTOR (all P < .04); demographics confirmed that individuals treated with early mTOR inhibition more commonly had adverse prognostic features. In Cox regression analysis, compared with the referent (TKI), TKI/TKI (hazard ratio = 0.53; P = .03) had a lower risk of death, and mTOR (hazard ratio = 2.16; P = .002) had a higher risk of death.
Conclusions: mRCC survival outcomes are different by pattern, with general findings consistent with trial-based expectations in similar patient populations. Real-world data can provide context around patterns of care and impact when experimental trial data are lacking.