Not all bad: Drug-induced interstitial pneumonia in DLBCL patients is potentially fatal but could be linked to better survival

Abstract Background Interstitial pneumonitis (IP), a fatal complication of DLBCL treatment, can bring great challenges to clinicians. We retrospectively investigated clinical characteristics and risk factors of previous IP patients, and analyzed their survival data. Methods 556 DLBCL patients receiving CHOP-like regimens were enrolled between 2013 and 2018 in Sichuan Cancer Hospital. Findings The IP incidences were 4.9 % (27/556), 1.1 % (2/186), 5.2 % (10/191) and 8.4 % (15/179) in CHOP, R−CHOP and R-CDOP groups respectively (P = 0.005). When IP was diagnosed, monocyte and IL-6 were significantly higher while CD4 and CD4/CD8 significantly lower compared to baseline. 81.5 % (22/27) of IP patients were pathogen-negative with good response to glucocorticoid monotherapy. Only one patient died while the others recovered from IP and subsequently underwent previous chemotherapy. 19.2 % (5/26) of IP patients experienced IP recurrence, likely due to the reason of lower initial dose or faster withdrawal speed of glucocorticoid. Multivariate analysis identified male, in addition to G-CSF, rituximab and pegylated liposomal doxorubicin as risk factors. The 3-year PFS and OS were 74.1 % and 46.9 % respectively for patients with IP. Interpretation We suggest that IL-6, monocyte and CD4 should be monitored closely, especially in R−CHOP/R-CDOP group. Sufficient initial dose and slow decrease of glucocorticoid based on radiographic remissions were critical strategies to reduce IP recurrence. We speculate that drug-induced immune imbalance could be trigger of developing IP, causing a lower intensity cytokine storm, resulting in a potential immunotherapy. This complication might bring benefit in patients’ survival through a mechanism similar to PD-1.