An interim analysis of the Phase III IMpower132 study with programmed death ligand 1 (PD-L1) inhibitor atezolizumab (Tecentriq®, Roche/Genentech) showed that addition of atezolizumab to platinum-based chemotherapy (cisplatin or carboplatin) plus pemetrexed improves the median progression-free survival (PFS) in treatment-naïve patients with non-squamous non-small cell lung cancer (NSCLC). The median PFS for atezolizumab plus pemetrexed and a platinum salt was 7.6 months vs 5.2 months with chemotherapy alone (HR=0.60, 95% CI: 0.49-0.72; p<0.0001).

The data were presented at the International Association for the Study of Lung Cancer (IASLC) 2018 World Conference on Lung Cancer (WCLC) on Monday 24 September (Abstract OA05.07 Oral).

The open-label, Phase III IMpower132 randomised 578 treatment-naïve patients with non-squamous NSCLC 1:1 to receive four or six cycles of atezolizumab plus platinum-based chemotherapy (cisplatin or carboplatin) with pemetrexed vs platinum-based chemotherapy with pemetrexed alone. Patients who showed clinical benefit during the initial four to six cycles of chemotherapy received maintenance therapy until disease progression. The co-primary endpoints were investigator-assessed PFS (RECIST v1.1) and overall survival (OS).

Although the co-primary PFS endpoint was met, the co-primary OS endpoint had not yet been reached. The OS showed a numerical improvement of 4.5, the median OS in the experimental arm was 18.1 months vs 13.6 months in the control arm (HR=0.81, 95% CI: 0.64-1.03; p=0.0797). The final OS results are expected next year.

Table 1 shows the results of the interim analysis in the general study population, and Table 2 shows the PFS results of the study by PD-L1 expression.

The investigators did not report new safety signals with the combination, the safety for atezolizumab plus chemotherapy appeared consistent with the documented safety profiles of the individual drugs. Grade 3-4 treatment-related adverse events were reported in 53.6% of patients receiving atezolizumab plus chemotherapy vs 39.1% of people receiving platinum-based chemotherapy with pemetrexed alone.

Reference

Papadimitrakopoulou VA, et al. Presented at the IASLC 2018 WCLC; 2018 Sept 24; Toronto, Ont, Canada. Abstract #OA05.07