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.