A phase II study of atezolizumab for pretreated advanced/recurrent non-small cell lung cancer with idiopathic interstitial pneumonias: rationale and design for the TORG1936/AMBITIOUS study

Background: Approximately 10% of patients with non-small cell lung cancer (NSCLC) are complicated with comorbid interstitial pneumonia (IP) with a poor prognosis. The pharmacotherapy for advanced lung cancer occasionally induces fatal acute exacerbation of pre-existing IP. Due to the lack of prospective studies, there is an urgent need to establish a safe and effective pharmacotherapy, especially for second-line or later settings. Atezolizumab, an anti-programmed cell death-ligand 1 antibody, is thought to be the safest candidate for second-line therapy among various immune checkpoint inhibitors. Moreover, compared with patients without IP, the patients with comorbid IP may have higher tumor mutation burden (TMB) or microsatellite instability (MSI), which are partly associated with a more favorable response to immune checkpoint inhibitors.

Methods: The Thoracic Oncology Research Group 1936/AMBITIOUS study is an ongoing, multicenter, single-arm, phase II trial to assess the safety and efficacy of atezolizumab for pretreated advanced/recurrent patients with NSCLC complicated with idiopathic, chronic fibrotic IP with a forced vital capacity of >70%. The patients will receive atezolizumab (1200 mg, day 1) every 3 weeks until the discontinuation criteria are met. The primary end point of this study is the 1-year survival rate, and a sample size of 38 patients is set. As a translational research, we will perform the analysis of TMB, somatic mutations, and MSI for nucleic acids extracted from archival tumor samples.

Discussion: Since there is no standard second-line or later therapy of advanced NSCLC with IP, the results of this study are expected to have a major impact on clinical practice.

Trial registration: Japan Registry of Clinical Trials, jRCTs031190084, registered 26 August 2019 - retrospectively registered, https://jrct.niph.go.jp/en-latest-detail/jRCTs031190084.