Atezolizumab for Pretreated Non-Small Cell Lung Cancer with Idiopathic Interstitial Pneumonia: Final Analysis of Phase II AMBITIOUS Study

BACKGROUND: Interstitial pneumonia (IP) is a poor prognostic comorbidity in patients with non-small cell lung cancer (NSCLC) and is also a risk factor for pneumonitis. The TORG1936/AMBITIOUS trial, the first known phase II study of atezolizumab in patients with NSCLC with comorbid IP, was terminated early because of the high incidence of severe pneumonitis. METHODS: This study included patients with idiopathic chronic fibrotic IP, with a predicted forced vital capacity (%FVC) of >70%, with or without honeycomb lung, who had previously been treated for NSCLC. The patients received atezolizumab every 3 weeks. The primary endpoint was the 1-year survival rate. RESULTS: A total of 17 patients were registered; the median %FVC was 85.4%, and 41.2% had honeycomb lungs. The 1-year survival rate was 53.3% (95% CI, 25.9-74.6). The median overall and progression-free survival times were 15.3 months (95% CI, 3.1-not reached) and 3.2 months (95% CI, 1.2-7.4), respectively. The incidence of pneumonitis was 29.4% for all grades, and 23.5% for grade ≥3. Tumor mutational burden and any of the detected somatic mutations were not associated with efficacy or risk of pneumonitis. CONCLUSION: Atezolizumab may be one of the treatment options for patients with NSCLC with comorbid IP, despite the high risk of developing pneumonitis. This clinical trial was retrospectively registered in the Japan Registry of Clinical Trials on August 26, 2019, (registry number: jRCTs031190084, https://jrct.niph.go.jp/en-latest-detail/jRCTs031190084).