The safety of anti-programmed cell death 1 (PD-1) antibody for patients with preexisting interstitial lung disease (ILD) remains unknown. The aim of this study was to evaluate the dependence of preexisting ILD on anti-PD-1 antibody-induced pneumonitis in non-small cell lung cancer (NSCLC) patients. We retrospectively reviewed the association of preexisting ILD with the incidence, radiographic pattern, and outcome of pneumonitis in NSCLC patients receiving anti-PD-1 antibody. A total of 331 patients were included in this study. Of these patients, 17 had preexisting ILD. The incidence of pneumonitis was higher among the patients with preexisting ILD than among those without preexisting ILD (29% vs. 10%, P = 0.027). The distributions of the CT appearances at the onset of anti-PD-1 antibody-induced pneumonitis were as follows: for the patients with preexisting ILD, two patients (40%) had diffuse alveolar damage (DAD), one patient each with organizing pneumonia-like (OP), hypersensitivity pneumonitis (HP), and other patterns (20% each); for the patients without preexisting ILD, 19 patients (61%) had OP, 8 (26%) had HP, 3 (10%) had DAD, and 1 (3.2%) had other patterns. The median onset time from the initiation of anti-PD-1 antibody treatment until the development of pneumonitis was 1.3 months (range 0.3-2.1 months) for the patients with preexisting ILD and 2.3 months (range 0.2-14.6 months) for the patients without preexisting ILD. Careful attention to the development of pneumonitis is needed, especially within the first 3 months after the start of anti-PD-1 antibody treatment, when using anti-PD-1 antibody to treat patients with preexisting ILD.
Keywords: Anti-PD-1 antibody; Immune checkpoint inhibitor; Immune-related adverse event; Interstitial lung disease; Non-small cell lung cancer; Pneumonitis.