Efficacy
pain
DISEASE, EVENTS, EVENT
Due to discordance between investigator and independent assessment of PFS, it was determined that 40 PFS events based on independent assessment would not occur. As such, the primary analysis was conducted after approximately 40 PFS events per investigator assessment; nevertheless, primary analysis was still based on independent assessment.At the time of analysis, 17 patients (32.7%) in the xentuzumab arm and 15 (29.4%) in the placebo arm had experienced a PFS event per independent assessment. Median PFS was 12.7 (95% CI 6.8–29.3) months with xentuzumab and 11.0 (7.7–19.5) months with placebo (hazard ratio 1.19; 95% CI 0.55–2.59; p = 0.6534; Fig. Progression-free survival for xentuzumab plus everolimus and exemestane versus everolimus and exemestane. Subgroup analyses of PFS were generally consistent with the overall analyses with no statistically significant differences (Figs. Five (9.6%) patients in the xentuzumab group and eight (15.7%) in the placebo group had died at data cut-off. OS data were immature and median OS was not calculable in either treatment group. Preliminary analysis indicated that there was no statistical difference in OS between the two arms (p = 0.1983).Per independent review, disease control was achieved in 29 (55.8%) patients in the xentuzumab arm versus 25 (49.0%) patients in the placebo arm (odds ratio [OR] 1.31; 95% CI 0.60–2.86). Median duration of disease control was 14.6 and 18.4 months, respectively. Per investigator assessment, disease control rate was 57.7% in the xentuzumab arm and 51.0% in the placebo arm (OR 1.31; 95% CI 0.60–2.87). In line with the predominantly non-measurable bone-only disease setting, the objective response rate was 11.5% and 9.8% in the xentuzumab and placebo arms, respectively, per independent assessment (OR 1.20; 95% CI 0.34–4.43; p = 0.7759).Time to pain progression or increase in pain treatment was not significantly different between the treatment groups (median of 5.6 versus 3.0 months for xentuzumab and placebo, respectively; hazard ratio 0.97; 95% CI 0.54–1.76; p = 0.9279).