The findings of the second interim overall survival (OS) analysis of the IMpassion130 study has suggest there might be a clinically meaningful benefit with atezolizumab plus nab-paclitaxel as first-line treatment for PD-L1 immune cell-positive unresectable, locally advanced or metastatic triple-negative breast cancer (BCa).
The randomised, placebo-controlled, double-blind, phase 3 IMpassion130 trial was carried out in 246 centres in 41 countries. It randomised 902 adults with previously untreated, histologically documented, locally advanced, or metastatic triple-negative ECOG 0-1 to receive atezolizumab 840 mg or matching placebo (intention-to-treat) on day 1 and day 15 of every 28-day cycle and nab-paclitaxel 100 mg/m2 of body surface area on days 1, 8, and 15 until progression or unacceptable toxicity.
Median OS in the intention-to-treat group was 21.0 months with atezolizumab and 18.7 months with placebo (stratified HR 0.86; 95% CI 0.72-1.02; P=0.078).
In the exploratory overall survival analysis in patients with PD-L1-positive tumours, median OS was 25.0 months with atezolizumab versus 18.0 months with placebo (stratified HR 0.71).
As of Sept 3, 2018 (the date up to which updated safety data were available), the most common grade 3-4 adverse events were neutropenia (8% with atezolizumab vs 8% with placebo group, peripheral neuropathy (6% vs 3%), decreased neutrophil count (5% vs 4%), and fatigue (4% vs 3%).
There were two treatment-related deaths in the atezolizumab group and one patient in the placebo group.
The findings of this second interim analysis are consistent with the first analysis and show no significant OS difference between groups in the intention-to-treat population but suggests an OS benefit with atezolizumab plus nab-paclitaxel in patients with PD-L1 immune cell-positive disease.
The study is published in the Lancet Oncology.