Abstract
BACKGROUND: Patients undergoing chemotherapy are known to be at risk for infection from myelosuppression by cytotoxic agents (CTAs) or immunosuppressive effects from mTOR inhibitors. The infection risk of newly developed anticancer agents has not been fully evaluated. It remains unknown how T-cell activation induced by immune checkpoint inhibitors (ICIs) relates to infection. METHODS: We retrospectively examined infection risk in patients with cancer treated with investigational agents in a phase I study. The investigational agents were classified into four groups: CTA, phosphatidylinositol 3 kinase/Akt/mammalian target of rapamycin inhibitor (PAM), molecular targeted agent (MTA) and ICI. All infection-related adverse events (AEs) during treatment were recorded. We compared the CTA, PAM and ICI with MTA, because MTA are already considered low risk and were used in the largest number of patients. RESULTS: A total of 641 patients were enrolled: 35 CTAs (5.5%), 61 PAMs (9.5%), 445 MTAs (69.4%) and 100 ICIs (15.6%). Among all patients, 132 (20.6%) experienced infection-related AEs and 46 (7.2%) developed 50 ≥grade 3 infection-related AEs. In any infection-related AEs, the ORs compared with MTAs were 2.19 (95% CI 1.03 to 4.66) for CTAs, 3.55 (95% CI 2.02 to 6.24) for PAMs and 1.05 (95% CI 0.60 to 1.85) for ICIs, respectively. In time to the first infection-related AE analysis, the risks for any infection-related AE from CTAs and PAMs were higher than those from MTAs (HR 1.84 (95% CI 0.82 to 4.11); p=0.05 and 3.96 (95% CI 2.18 to 7.22); p<0.001). The risk from ICIs was not significantly different from that of MTAs (HR 0.71 (95% CI 0.46 to 1.10); p=0.19). CONCLUSION: Our results validate that PAMs and CTAs carry a higher infection risk in patients with advanced solid tumours compared with MTAs. We suggest that the infection risk of ICIs is a similar infection risk to MTAs.