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

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.

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.

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.

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.