Inhibition of IL‐17A by secukinumab shows no evidence of increased <i>Mycobacterium tuberculosis</i> infections

Secukinumab, a fully human monoclonal antibody that selectively neutralizes interleukin-17A (IL-17A), has been shown to have significant efficacy in the treatment of moderate to severe psoriasis, psoriatic arthritis and ankylosing spondylitis. Blocking critical mediators of immunity may carry a risk of increased opportunistic infections. Here we present clinical and <i>in vitro</i> findings examining the effect of secukinumab on <i>Mycobacterium tuberculosis</i> infection. We re-assessed the effect of secukinumab on the incidence of acute tuberculosis (TB) and reactivation of latent TB infection (LTBI) in pooled safety data from five randomized, double-blind, placebo-controlled, phase 3 clinical trials in subjects with moderate to severe plaque psoriasis. No cases of TB were observed after 1 year. Importantly, in subjects with a history of pulmonary TB (but negative for interferon-γ release and receiving no anti-TB medication) or positive for latent TB (screened by interferon-γ release assay and receiving anti-TB medication), no cases of active TB were reported. Moreover, an <i>in vitro</i> study examined the effect of the anti-tumor necrosis factor-α (TNFα) antibody adalimumab and secukinumab on dormant <i>M. tuberculosis</i> H37Rv in a novel human three-dimensional microgranuloma model. Auramine-O, Nile red staining and rifampicin resistance of <i>M. tuberculosis</i> were measured. <i>In vitro</i>, anti-TNFα treatment showed increased staining for Auramine-O, decreased Nile red staining and decreased rifampicin resistance, indicative of mycobacterial reactivation. In contrast, secukinumab treatment was comparable to control indicating a lack of effect on <i>M. tuberculosis</i> dormancy. To date, clinical and preclinical investigations with secukinumab found no evidence of increased <i>M. tuberculosis</i> infections.