|The following article features coverage from the American Society of Clinical Oncology 2020 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.|
Treatment with the anti-TIGIT antibody tiragolumab plus atezolizumab resulted in clinically meaningful improvement in overall response rate and progression-free survival compared with placebo plus atezolizumab among patients with treatment-naive, PD-L1-selected non-small cell lung cancer (NSCLC), according to phase 2 data from the CITYSCAPE study presented as part of ASCO20 Virtual Scientific Program.
TIGIT is a novel inhibitory immune checkpoint present on activated T cell and natural killer cells in multiple cancers including NSCLC, explained study researcher Melissa Johnson, MD, of Sarah Cannon Research Institute in Nashville, Tennessee.
TIGIT expression strongly correlates with PD-1 expression, sometimes even on same tumor-infiltrating T cells in lung cancer, she said. Therefore, the hypothesis of CITYSCAPE (ClinicalTrials.gov Identifier: NCT03563716) was that anti-TIGIT antibodies, which prevent TIGIT from binding to its ligand, could restore antitumor response and complement the activity of anti-PD-L1/PD-1 antibodies.
In the updated CITYSCAPE study results, 135 patients randomly assigned to tiragolumab plus atezolizumab maintained the overall response rate and progression-free survival benefits seen at the primary analysis. With a median follow-up of 10.9 months, the overall response rate was 37% for tiragolumab plus atezolizumab compared with 21% for placebo. When patients were selected based on PD-L1 status, the drug combination benefited those with TPS score of 50% or greater with overall response rate of 66% for tiragolumab plus atezolizumab compared with 24% for placebo. Patients with PD-L1 TPS score of 1% to 49% saw no difference between the 2 arms.
Median progression-free survival for the combination was 5.55 months compared with 3.88 months for placebo (HR, 0.58; 95% CI, 0.38-0.89). In patients with PD-L1 TPS scores of 50% or greater, the median progression-free survival was not reached for the combination compared with 4.11 months for placebo (HR, 0.30; 95% CI, 0.15-0.61).
Grade 3 or worse adverse events occurred in 48% of patients assigned the combination compared with 44% of patients assigned placebo. Adverse events leading to treatment withdrawal occurred in 10% of patients who received the combination compared with 9% of those who received placebo.
All included patients had EGFR/ALK wild-type disease and had a PD-L1 tumor proportion score of 1% or greater.
Read more of Cancer Therapy Advisor‘s coverage of the ASCO 2021 meeting by visiting the conference page.
Rodriguez-Abreu D, Johnson ML, Hussein MA, 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). Presented at: ASCO20 Virtual Scientific Program. J Clin Oncol. 2020;38(suppl):abstr 9503.