Relationship between biomarkers and everolimus efficacy in the phase III RECORD-1 trial of patients with metastatic renal cell carcinoma (mRCC).
352 Background: Compared with placebo, everolimus provided significant improvement in median PFS in the RECORD-1 study of VEGFr-TKI-refractory mRCC. To investigate the role of angiogenesis pathway molecules as potential biomarkers of everolimus efficacy in RECORD-1, plasma levels of sVEGFR-2, VEGF-A, and bFGF were estimated. Methods: In addition to best supportive care, patients received everolimus 10 mg/day (n = 277) or placebo (n = 139). Placebo patients who progressed were offered everolimus. Predose blood samples were collected on day 1 of the first four 28-day treatment cycles. Plasma levels of sVEGFR-2, VEGF-A, and bFGF were assessed by ELISA. Effect of treatment over time on each biomarker was assessed by a mixed effects model. Hazard ratios (HR) for prognostic effects were obtained using log baseline biomarker values as continuous variables in a stratified Cox proportional hazards model. Results: Plasma levels of sVEGFR-2, VEGF-A, and bFGF were available for 45%, 45%, and 39% of everolimus patients and 50%, 50%, and 45% of placebo patients. Patients with biomarker data had baseline characteristics similar to those of the overall population. Mean baseline levels (pg/mL) of sVEGFR-2, VEGF-A, and bFGF were similar for everolimus (8945, 245, and 8, respectively) and placebo (8985, 253, and 13, respectively). Everolimus significantly improved median PFS over placebo irrespective of baseline levels of the analyzed biomarkers (p < 0.001), indicating they are not predictive of everolimus efficacy. Prolonged PFS in the biomarker population was associated with lower VEGF-A baseline level (HR, 1.27; 95% CI, 1.03-1.57; p = 0.028), suggesting VEGF-A may be prognostic for mRCC. Compared with placebo, everolimus significantly reduced bFGF (p = 0.0095) and sVEGFR-2 (p< 0.001) levels over the time course of the study; no effect on VEGF-A levels was observed. Conclusions: Everolimus significantly improved PFS compared with placebo, regardless of baseline biomarker levels. Lower VEGF-A levels may be a potential prognostic factor for longer PFS. Everolimus treatment significantly downregulated plasma levels of bFGF and sVEGFR-2 from baseline. Clinical trial information: NCT00410124.