Ab0873 Development of Il17a Vaccine Targeting Axial Spondyloarthritis

Background: Ankylosing spondylitis is known as a typical disease of axial spondyloarthritis, in which progressive chronic inflammation of the axial joints leads to bony ankylosis of the limb joints and severe physical disability due to joint destruction. Recently, antibody therapy targeting IL17A has become an effective treatment option because the IL23/IL17A pathway is involved in the mechanism of arthritis pathogenesis. However, antibody therapy is expensive and requires frequent administration, placing a heavy financial and physical burden on patients. Therefore, we focused on therapeutic vaccines in the hope that the antibodies induced by the vaccines would produce long-term therapeutic effects. We evaluated the efficacy of the vaccine in a rat model of spondylitis, and found that the vaccine was effective in treating arthritis and spondylitis. Objectives: In this study, we conducted a phase I study in healthy adults to evaluate the safety of the vaccine in humans. Methods: A single-center, randomized, placebo-controlled, double-blind study was conducted in healthy adults aged 20-65 years. The actual drug group was divided into two groups, low-dose and high-dose, and each group consisted of 8 subjects each, administered three times every 4 weeks. Each group had a placebo group of 2 subjects. The vaccine group was followed up for 20 weeks after the first administration, and the safety and antibody titer increase were examined. Results: 100% of the vaccine group had adverse events. Almost all were injection site reactions. No serious adverse events were observed in all patients. Antibody titers increased after 4 weeks and remained at the same level from 8 to 20 weeks (Figure 1). Conclusion: These results confirm the safety of the IL17A vaccine in humans and the antibody titer increase. REFERENCES: [1] Hayashi H, Tomita T, Nakagami H, et al. Peptide-based vaccine targeting IL17A attenuates experimental spondyloarthritis in HLA-B27 transgenic rats. RMD Open 2023, 9(1): e002851 Acknowledgements: This work was supported by a grant from the Japan Agency for Medical Research and Development (23ek0109565h0003). Disclosure of Interests: Tetsuya Tomita: None declared, Hiroshi Mikami: None declared, Hideki Tomioka FunPep.Co, Shigeyoshi Tsuji: None declared, Hironori Nakagami financially supported by FunPep.