Secukinumab, a fully human anti‐interleukin‐17A monoclonal antibody, exhibits low immunogenicity in psoriasis patients treated up to 5 years

BACKGROUND: Secukinumab is a fully human monoclonal antibody that selectively neutralizes IL-17A, a key cytokine involved in psoriasis and psoriatic arthritis development, and has shown rapid and long-lasting efficacy and safety in the complete spectrum of psoriasis manifestations. Monoclonal antibody therapies may be associated with the production of treatment-emergent antidrug antibodies (TE-ADAs) that can affect drug pharmacokinetics, diminish clinical responses via inhibition of target binding or cause hypersensitivity reactions. Secukinumab exhibited minimal immunogenicity up to 52 weeks in patients with moderate-to-severe plaque psoriasis, as evidenced by TE-ADA in <1% patients. OBJECTIVE: To investigate the immunogenicity of secukinumab treatment up to 5 years in two phase 3 extension studies (NCT01640951 and NCT01365455) in patients with moderate-to-severe plaque psoriasis. METHODS: Immunogenicity was evaluated up to Week 268 (5 years). TE-ADAs were defined as positive antidrug antibody (ADA) signals detected in post-treatment samples from patients with negative baseline signals. Confirmed positive samples were further analysed for their neutralizing potential. RESULTS: In total, 1821 patients entered the extension studies. Among patients receiving secukinumab and evaluated for ADAs (n = 1636), 32 developed TE-ADA, which resulted in an incidence of new TE-ADA cases below 1% per year. Neutralizing antibodies were detected in 9/32 (28%) patients with TE-ADA. Half of ADA-positive cases were transient. Among pharmacokinetic samples measured at the times of immunogenicity determination (n = 9992), 544 (5.4%) had secukinumab concentrations higher than the drug tolerance level of 53.8 μg/mL. There was no effect of TE-ADA, including neutralizing antibodies, on efficacy, safety or pharmacokinetics of secukinumab. CONCLUSION: The yearly secukinumab immunogenicity incidence over 5 years of treatment was consistently below 1% in patients with moderate-to-severe plaque psoriasis. Any TE-ADAs, including neutralizing antibodies, were not associated with loss of secukinumab efficacy or with clinical concerns.