Tiragolumab and atezolizumab showed improved objective response rate over tiragolumab and placebo in chemotherapy-naïve locally advanced or metastatic non-small cell lung cancer (NSCLC).
Dr Delvys Rodriguez-Abreu (NYU Perlmutter Cancer Center, New York, USA) presented the phase 2 CITYSCAPE trial, which tested patients with chemotherapy-naïve PD-L1-positive locally advanced or metastatic NSCLC, at the virtual ASCO Annual meeting . Participants were randomized to the combination of tiragolumab and atezolizumab (n=67) versus placebo plus atezolizumab (n = 68). Co-primary endpoints were investigator-assessed objective response rate (ORR) and progression-free survival (PFS).
The primary analysis indicated that tiragolumab/atezolizumab improved ORR and median PFS compared with tiragolumab/placebo. The ORR was 31.3% in the tiragolumab arm versus 16.2% in the placebo arm. The median PFS was 5.4 months and 3.6 months in the tiragolumab and placebo arms, respectively (HR: 0.57).
According to the updated analysis, the ORR was 37.3% versus 20.6% in the tiragolumab and placebo arms, respectively. Investigators also stratified patients according to PD-L1 tumor proportion score (TPS, between 1- 49% versus > 50%). Patients with a PD-L1 TPS of at least 50% derived even more benefit from tiragolumab/atezolizumab with an ORR of 66% versus 24% with atezolizumab alone, whereas there was no difference between the treatment arms in the group whose tumors had a TPS between 1-49% PD-L1 positive cells.
- Rodriguez-Abreu, D et al. Primary analysis of a randomized, double-blind, phase II study of the anti-TIGIT antibody tiragolumab (tira) plus atezolizumab (atezo) versus placebo plus atezo as first-line (1L) treatment in patients with PD-L1-selected NSCLC (CITYSCAPE) ASCO Virtual Meeting, 29-31 May 2020, Abstract 9503.