Prognostic significance of radiologic features of pneumonitis induced by anti-PD-1 therapy.

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9065 Background: Anti-PD-1 therapy is now a standard treatment for patients with NSCLCs. Pneumonitis induced by immune-check point inhibitors is potentially fatal; however, some studies have shown that antitumor effects were enhanced in patients with pneumonitis. Although several radiologic patterns of pneumonitis induced by anti-PD-1 therapy have been reported, the association between radiologic features and clinical outcomes, especially enhancement of antitumor effects remains unclear. Methods: We retrospectively evaluated data of NSCLC patients treated in 1st to 3rd line with anti-PD-1 antibodies (nivolumab or pembrolizumab) at Niigata Lung Cancer Treatment Group. Pneumonitis was diagnosed by the treating investigators. The chest CT scans of patients with pneumonitis were independently reviewed by one radiologist and two pulmonologists to classify pneumonitis into 5 subtypes: cryptogenic organizing pneumonia-like (COP), ground glass opacities (GGO), interstitial, hypersensitivity and pneumonitis not otherwise specified (NOS). Results: Of 231 patients who received anti-PD-1 antibodies, pneumonitis developed in 33 patients (14.3%) at 7 institutions between January 2016 to October 2017. Of 33 patients with pneumonitis, the median age was 66 (range 45 to 82 years), 7 were female, 25 received nivolumab, and 8 received pembrolizumab. Sixteen patients were classified as GGO, 16 patients had COP-like appearance and one patient had NOS. The median survival time was significantly longer among patients with COP than among those with GGO (not reached vs. 7.8 months; HR 0.29, 95% CI 0.09-0.81; p = 0.0071). Pneumonitis improved in 94% (31 of 33) of cases, and one patient died from pneumonitis. The overall response ratio (CR+PR) was 44% in patients with COP and 31% in patients with GGO (p = 0.47). There was no statistical difference in OS between patients with systemic corticosteroid therapy for pneumonitis and those without (not reached vs. 14.8 months; HR 1.4, 95% CI 0.52-4.1; p = 0.51). Conclusions: Patients with pneumonitis classified as COP had significantly longer survival time than those with pneumonitis classified as GGO. Radiologic features of pneumonitis may reflect clinical outcomes after anti-PD-1 therapy.