Mycobacterial infections due to PD-1 and PD-L1 checkpoint inhibitors

Background Immune checkpoint inhibitors that block programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1) have improved outcomes for many cancer subtypes but do exhibit toxicity, in the form of immune-related adverse events. Objective The aim of this study was to investigate the emerging toxicities of PD-1 and PD-L1 inhibitors including acute or reactivation of tuberculosis (TB) and atypical mycobacterial infection (AMI). Methods This study was completed as a retrospective review using the US Food and Drug Administration Adverse Events Reporting System (FAERS) for incidence of TB and AMI due to PD-1 and PD-L1 inhibitors compared with other FDA (Food and Drug Administration) approved drugs. The statistical methods included disproportionality signal analysis using the reporting OR (ROR) to compare cases. The 95% Wald CI was reported to assess the precision of the ROR. Results Out of the 10 146 481 adverse events (AEs) reported to FAERS for all drugs between 1 January 2015 and 31 March 2020, 73 886 AEs were due to the five FDA approved PD-1/PD-L1 inhibitors. Seventy-two cases of TB were due to PD-1/PD-L1 inhibitors. Specifically, 45 cases (62.5%) due to nivolumab, 18 (25%) due to pembrolizumab, 5 (7%) due to atezolizumab and 4 (5.5%) due to durvalumab. There were 13 cases of AMI: 9 (69.3%) due to nivolumab, 2 (15.3%) due to pembrolizumab and 1 (7.7%) each due to durvalumab and atezolizumab. Avelumab was not attributed to any AE of TB or AMI. From analysis of the FAERS database, the calculated ROR for TB due to PD-1/PD-L1 inhibitors was 1.79 (95% CI, 1.42 to 2.26) (p<0.0001) and for AMI was 5.49 (95% CI, 3.15 to 9.55) (p<0.0001). Conclusion PD-1/PD-L1 inhibitors used in the treatment of cancer subtypes is associated with increased TB and AMI risk. Although this complication is rare, clinicians using PD-1/PD-L1 inhibitors should be aware of the risks.