Comparison of risks of cancer, infection, and MACEs associated with JAK inhibitor and TNF inhibitor treatment: a multicentre cohort study.

OBJECTIVES: The objective of this study was to compare the incidence rates (IRs) of infectious diseases, major adverse cardiovascular events (MACEs), and malignancies in RA patients treated with tofacitinib, baricitinib or a TNF inhibitor. METHODS: We retrospectively analysed the cases of 499 RA patients treated with tofacitinib (n = 192), baricitinib (n = 104), or a TNF inhibitor (n = 203). We determined the IRs of infectious diseases and the standardized incidence ratio (SIR) of malignancies and investigated factors related to infectious diseases. After adjusting the clinical characteristic imbalance by propensity score weighting, we compared the incidence of adverse events between the Janus kinase (JAK)-inhibitor and TNF-inhibitor groups. RESULTS: The observational period was 959.7 patient-years (PY), and the median observational period was 1.3 years. The IRs within the JAK-inhibitor treatment group were: serious infectious diseases other than herpes zoster (HZ), 8.36/100 PY; HZ, 13.00/100 PY. Multivariable Cox regression analyses revealed independent risk factors: the glucocorticoid dose in serious infectious diseases other than HZ, and older age in HZ. Two MACEs and 11 malignancies were identified in JAK-inhibitor-treated patients. The overall malignancy SIR was (non-significantly) higher than that of the general population (1.61/100 PY, 95% CI: 0.80, 2.88). The IR of HZ in the JAK-inhibitor-treated group was significantly higher than the TNF-inhibitor-treated group, but there were no significant differences in the IRs of other adverse events between the JAK-inhibitor-treated group and the TNF-inhibitor-treated group, or between the treatment groups of the two JAK inhibitors. CONCLUSIONS: The infectious disease IR in RA was comparable between tofacitinib and baricitinib, but the IR for HZ in these treatment groups was high compared with that in the TNF inhibitor treatment group. The malignancy rate in the JAK-inhibitor-treated group was high but not significantly different from that of the general population or that of the TNF-inhibitor-treated group.

Akt is an endogenous inhibitor toward tumor necrosis factor-related apoptosis inducing ligand-mediated apoptosis in rheumatoid synovial cells.

Akt is known to be activated in the rheumatoid synovial tissues. We examined here functional role of Akt during tumor necrosis factor-related apoptosis inducing ligand (TRAIL)-mediated apoptosis in rheumatoid synovial cells. Rheumatoid synovial cells in vitro were rapidly committed to apoptosis in response to TRAIL in mitochondria-dependent manner whereas Akt and extracellular signal-regulated kinase (ERK) were also phosphorylated. TRAIL-mediated apoptosis in synovial cells was significantly increased through inactivation of Akt by LY294002, however, that process was not so changed by adding ERK inhibitor, PD98059. Platelet-derived growth factor (PDGF) clearly phosphorylated both Akt and ERK in synovial cells, and PDGF pretreatment markedly suppressed TRAIL-mediated synovial cell apoptosis. The use of not PD98059 but LY294002 abrogated PDGF-mediated inhibitory effect toward TRAIL-induced apoptosis in synovial cells. The above protective effect of Akt was confirmed by the use of short interfering RNA (siRNA)-directed inhibition of Akt. Our data suggest that Akt is an endogenous inhibitor during TRAIL-mediated synovial cell apoptotic pathway, which may explain that synovial cells in situ of the rheumatoid synovial tissues are resistant toward apoptotic cell death in spite of death receptor expression.