Phase II study of atezolizumab for pretreated advanced / recurrent non-small cell lung cancer with idiopathic interstitial pneumonia (TORG1936 / AMBITIOUS study)

Abstract

Background: Interstitial pneumonia (IP) is one of the most common and poor prognostic comorbidities in patients with non-small cell lung cancer (NSCLC) and is also a known risk factor for pneumonitis. Approximately 10% of patients have concomitant IP diagnosed at the time of cancer diagnosis. IP is associated with smoking, microsatel-lite instability (MSI) and higher tumour mutation burden (TMB). Atezolizumab monotherapy is an established treatment for recurrent NSCLC. PD-L1 inhibitors are reported to have a lower risk of pneumonitis than PD-1 inhibitors. This study aims to assess the safety and efficacy of atezolizumab monotherapy for pretreated advanced or recurrent NSCLC patients with idiopathic IP. Trial design: The Thoracic Oncology Research Group (TORG) 1936/AMBITIOUS study is a multicentre, single-arm, phase II trial. The key inclusion criteria are (1) histologically or cytologically proven NSCLC, (2) unresectable stage III/IV or recurrent disease, (3) prior chemotherapy, including platinum doublet chemotherapy, (4) chronic, fibrotic and idiopathic IP with a predicted vital capacity > 70%, (5) age > 20 years and (6) ECOG performance status 0,1. The enrolled patients will receive atezolizumab (1200 mg) every 3 weeks until the discontinuation criteria are satisfied. The primary end point is the 1-year survival rate. We set an expected value of 40% and a threshold value of 15%. Taking statistical points (two-sided a = 0.05; 1 - b = 0.9) and ineligible patients into account, the sample size was set at 38 based on the exact binomial test. The key secondary end points are the incidence of acute exacerbation of IP within 1 year after treatment initiation, overall survival, progression-free survival, objective response rate and safety. As atranslational research, we will perform analysis of TMB, somatic mutations and MSI from tumour samples.