A Randomized Phase II/III Study of Naptumomab Estafenatox + IFNα versus IFNα in Renal Cell Carcinoma: Final Analysis with Baseline Biomarker Subgroup and Trend Analysis

Purpose: To prospectively determine the efficacy of naptumomab estafenatox (Nap) þ IFNa versus IFN in metastatic renal cell carcinoma (RCC). Experimental Design: In a randomized, open-label, multicenter, phase II/III study, 513 patients with RCC received Nap (15 mg/ kg i. v. in three cycles of four once-daily injections) + IFN (9 MU s. c. three times weekly), or the same regimen of IFN monotherapy. The primary endpoint was overall survival (OS). Results: This phase II/III study did notmeetits primary endpoint. Median OS/PFS for Nap + IFN patients was 17.1/5.8 months versus 17.5/5.8 months for the patients receiving IFN alone (P = 0.56; HR, 1.08/P = 0.41; HR, 0.92). Post hoc exploratory subgroup and trend analysis revealed that the baseline plasma concentrations of antiSEA/E-120 (anti-Nap antibodies) for drug exposure and IL6 for immune status could be used as predictive biomarkers. A subgroup of patients (SG; n = 130) having concentrations below median of anti-SEA/E-120 and IL6 benefitted greatly from the addition of Nap. In SG, median OS/PFS for the patients treated with Nap þ IFN was 63.3/13.7 months versus 31.1/5.8 months for the patients receiving IFN alone (P = 0.02; HR, 0.59/P = 0.02; HR, 0.62). Addition of Nap to IFN showed predicted and transient immune related AEs and the treatment had an acceptable safety profile. Conclusions: The study did not meet its primary endpoint. Nap + IFN has an acceptable safety profile, and results from post hoc subgroup analyses showed that the treatment might improve OS/PFS in a baseline biomarker-defined RCC patient subgroup. The results warrant further studies with Nap in this subgroup

A Randomized Phase II/III Study of Naptumomab Estafenatox + IFNα versus IFNα in Renal Cell Carcinoma: Final Analysis with Baseline Biomarker Subgroup and Trend Analysis

Purpose: To prospectively determine the efficacy of naptumomab estafenatox (Nap) þ IFNa versus IFN in metastatic renal cell carcinoma (RCC). Experimental Design: In a randomized, open-label, multicenter, phase II/III study, 513 patients with RCC received Nap (15 mg/ kg i. v. in three cycles of four once-daily injections) + IFN (9 MU s. c. three times weekly), or the same regimen of IFN monotherapy. The primary endpoint was overall survival (OS). Results: This phase II/III study did notmeetits primary endpoint. Median OS/PFS for Nap + IFN patients was 17.1/5.8 months versus 17.5/5.8 months for the patients receiving IFN alone (P = 0.56; HR, 1.08/P = 0.41; HR, 0.92). Post hoc exploratory subgroup and trend analysis revealed that the baseline plasma concentrations of antiSEA/E-120 (anti-Nap antibodies) for drug exposure and IL6 for immune status could be used as predictive biomarkers. A subgroup of patients (SG; n = 130) having concentrations below median of anti-SEA/E-120 and IL6 benefitted greatly from the addition of Nap. In SG, median OS/PFS for the patients treated with Nap þ IFN was 63.3/13.7 months versus 31.1/5.8 months for the patients receiving IFN alone (P = 0.02; HR, 0.59/P = 0.02; HR, 0.62). Addition of Nap to IFN showed predicted and transient immune related AEs and the treatment had an acceptable safety profile. Conclusions: The study did not meet its primary endpoint. Nap + IFN has an acceptable safety profile, and results from post hoc subgroup analyses showed that the treatment might improve OS/PFS in a baseline biomarker-defined RCC patient subgroup. The results warrant further studies with Nap in this subgroup