Response to Tetanus and Pneumococcal Vaccination Following Administration of Ixekizumab in Healthy Participants

Background Ixekizumab (IXE) is an interleukin (IL)-17A antagonist approved for the treatment of adults with moderate-to-severe psoriasis. Objective The objective of this study was to determine if the immune response to tetanus and pneumococcal vaccines in healthy subjects administered IXE was noninferior to control. Methods In a randomized, open-label, parallel-group study, adult subjects received vaccinations alone (N = 42, control) or in combination with 160 mg IXE subcutaneously 2 weeks prior to vaccination and 80 mg IXE on the day of vaccination (N = 41, IXE). Response to tetanus vaccination was defined as anti-tetanus antibodies >= 1.0 IU and a >= 1.5-fold increase if baseline was <= 1.0 IU or a >= 2.5-fold increase if baseline was > 1.0 IU. Response to pneumococcal vaccination was defined as a >= 2-fold increase from baseline in anti-pneumococcal antibodies against > 50% of the 23 serotypes. The primary outcomes were the percentages of patients with a response to the tetanus and pneumococcal vaccines 4 weeks after vaccination. A noninferiority analysis of IXE to control using a 40% margin was evaluated for the primary outcomes. Safety and pharmacokinetics were also assessed. Results IXE (38 completers) was noninferior to control (41 completers) based on the difference in the proportion of responders to tetanus [1.4%; 90% confidence interval (CI) -16.6 to 19.2] and pneumococcal (-0.8%; 90% CI -12.9 to 11.0) vaccines. Twenty subjects (14 IXE, six control) reported 43 mild treatment-emergent adverse events. Conclusion IXE does not suppress the humoral immune response to non-live vaccines and was well tolerated in healthy subjects. ClinicalTrial.gov identifier: NCT02543918.