A Phase 2 Study of Atezolizumab for Pretreated NSCLC With Idiopathic Interstitial Pneumonitis

INTRODUCTION: Interstitial pneumonia (IP) is one of the most common and poor prognostic comorbidities in patients with NSCLC and a known risk factor for pneumonitis. Atezolizumab monotherapy is an established treatment for recurrent NSCLC and reported to have a lower risk of pneumonitis than programmed cell death protein 1 inhibitors. This study aimed to assess the safety and efficacy of atezolizumab monotherapy in patients with pretreated advanced or recurrent NSCLC with idiopathic IP. METHODS: Patients with advanced or recurrent NSCLC with comorbid idiopathic, chronic fibrotic IP with % forced vital capacity of greater than 70% and no history of immune checkpoint inhibitors were enrolled. The patients received atezolizumab (1200 mg) every 3 weeks until the discontinuation criteria were met. The primary end point of this study was the 1-year survival rate. A sample size of 38 patients was set. RESULTS: This study was terminated early owing to high incidence of pneumonitis. A total of 17 patients were enrolled, with a median age of 70 years. The median % forced vital capacity and % diffusing capacity for carbon monoxide at baseline were 85.4% and 54.4%, respectively. The incidence of pneumonitis was 29.4% (5 of 17) for all grades, 23.5% (4 of 17) for grade greater than or equal to 3, and 5.9% (1 of 17) for grade 5. A total of 57.1% patients (4 of 7) with honeycomb lung developed pneumonitis with a grade greater than or equal to 3, whereas only one patient (10%) without honeycomb lung (n = 10) with grade 1 pneumonitis was found. CONCLUSIONS: Patients with NSCLC with comorbid IP as defined by the selection criteria for this study might have an increased risk of immune checkpoint inhibitor–induced pneumonitis.