Risk factors for and characteristics of pneumonitis in patients treated with anti-programmed death-1 therapy.

Abstract

128 Background: Pneumonitis is an uncommon but potentially fatal toxicity of anti–programmed death-1 (PD-1) monoclonal antibodies (mAbs), but its prevalence, risk factors and clinical features are poorly described. Methods: The medical records of 234 patients with advanced cancer who underwent anti–PD-1mAbs therapies between September 2015 and September 2017 at the Cancer Center of the Chinese PLA (People’s Liberation Army) General Hospital were analyzed with regard to patient background and clinical features. Pneumonitis was diagnosed by the treating investigator; cases with confirmed malignant lung infiltration or infection were excluded. Univariate and multivariate analyses were performed to identify independent predictive factors for pneumonitis. Clinical features, management and prognosis of pneumonitis were also collected. Results: A total of 55 patients (23.5%) developed pneumonitis. Anti–PD-1mAbs induced pneumonitis was significantly associated with male sex, a history of prior thoracic radiotherapy, combination therapy and underlying lung condition (odds ratios 3.380, 3.081, 2.538 and 2.559, respectively). Time to onset of pneumonitis ranged from 2 days to 277days (median time was 85days). 85.4% (47 of 55) of cases were grade 1 to 2, 25.5% (14 of 55) were treated with steroid therapy, of which 85.7% (12 of 14) resolved/ improved. Nine (16.4%) patients worsened clinically and one died during the course of pneumonitis treatment. Conclusions: Pneumonitis associated with anti–PD-1 mAbs is a serious adverse effect in the clinical setting that cannot be ignored. However, patient selection based on sex, history of prior thoracic radiotherapy, combination therapy and underlying lung condition can minimize pneumonitis risk. Most events are low grade and resolved/ improved with steroid therapy. Rarely, pneumonitis worsens despite steroid therapy, and may result in death.