Progression-free survival by local investigator versus independent central review: comparative analysis of the AGO-OVAR16 Trial

Abstract

Background: Analysis of progression-free survival (PFS) as the primary endpoint in advanced epithelial ovarian, fallopian tube, and primary peritoneal cancer (AEOC) trials may be confounded by the difficulty of radiologic evaluation of disease progression and the potential for discrepancy between investigator and blinded independent central assessments. PFS as assessed by local investigator (INV) was the primary endpoint of AGO-OVAR16, a randomized, double-blind trial of pazopanib maintenance therapy in AEOC. To confirm the robustness of the primary analysis, PFS was also evaluated by blinded independent central review (BICR).

Methods: Patients with histologically confirmed AEOC (N = 940) were randomized 1:1 to receive pazopanib 800 mg/day or placebo for up to 24 months. Tumor response in the intent-to-treat population was evaluated by CT/MRI every 6 months and analyzed per RECIST 1.0.

Results: Pazopanib prolonged PFS versus placebo by INV (median 17.9 vs 12.3 months; hazard ratio [HR] = 0.766, 95% confidence interval [CI]: 0.643-0.911; P = 0.0021). Results for PFS by BICR were similar (median 15.4 vs 11.8 months; HR = 0.802, 95% CI: 0.678-0.949; P = 0.0084). Progression events were recorded later by INV in 23% of pazopanib-treated patients and 17% of placebo-treated patients. The overall concordance between INV and BICR assessments was 84% and 86% in the pazopanib and placebo arms, respectively.

Conclusions: By INV and BICR assessments, maintenance therapy with pazopanib in AEOC provided a significantly longer PFS than placebo. The good overall concordance between INV and BICR assessments, as well as HR and P value consistency, supports the reliability of investigator-assessed PFS as the primary endpoint in AGO-OVAR16.

Trial registration: ClinicalTrials.gov NCT00866697.

Keywords: Disease progression; Independent central review; Ovarian cancer; Progression-free survival.