Affibody, ACELYRIN, and Inmagene Biopharmaceuticals Announce Data from Global Phase 2 Trial of Izokibep in Patients with Psoriatic Arthritis Presented During 2022 European Alliance of Associations for Rheumatology Congress

• Data suggest efficacy over standard of care for the treatment of psoriatic arthritis
• Izokibep was well-tolerated, having a safety profile consistent with previous studies and the IL-17A inhibitor therapeutic class
• Supports hypothesis that izokibep offers greater efficacy with high potency and small size, as well as strategy of evaluating IL-17A inhibition’s potential for transformative efficacy across many disease states

Solna, Sweden, Los Angeles, USA, and Shanghai, China, June 3, 2022 – ACELYRIN, INC., Affibody AB, and Inmagene Biopharmaceuticals today announced data from a 16-week, global, Phase 2 clinical trial of izokibep in 135 patients with psoriatic arthritis (PsA) presented by Frank Behrens, MD, director of the Center of Innovative Diagnostics and Therapeutics Rheumatology/Immunology at the Goethe University in Frankfurt, Germany and a founding member of the Group of Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA), during a podium session at the 2022 European Alliance of Associations for Rheumatology (EULAR) Congress in Copenhagen.

The randomized double-blind, placebo-controlled, Phase 2 clinical trial evaluated the safety and efficacy of izokibep dosed 80 mg every two weeks (Q2W) or 40 mg Q2W, versus placebo Q2W, in adult patients with active PsA. The global study assessed various endpoints at 16 weeks including the American College of Rheumatology (ACR) response, the Leeds Enthesitis Index (LEI), the Psoriasis Area and Severity Index (PASI) score and Quality of Life via the Psoriatic Arthritis Impact of Disease (PsAID) questionnaire.

¹ FAS, observed data for LEI > 0 at baseline – N=43 (32%) – post-hoc analysis
² FAS, observed data for psoriasis BSA ≥ 3% at baseline – N=74 (55%) – post-hoc analysis

“Psoriatic arthritis is a painful and debilitating inflammatory disease of the peripheral joints, skin, and nails, and it can also affect the spine,” said Professor Behrens. “Furthermore, residual entheseal pain and inflammation, which occurs in approximately 60% of patients, is often associated with more severe disease, poorer quality of life and is considered one of the most significant unmet needs of psoriatic arthritis patients. The data presented at EULAR demonstrate there is potential opportunity for increased therapeutic efficacy in joints, entheseal pain and inflammation resolution and improved quality of life, all of which would be meaningful for patients living with psoriatic arthritis.”

Izokibep was well-tolerated in the study, having a favorable safety profile consistent with that previously observed for izokibep and the IL-17A inhibitor therapeutic class. The most commonly reported AEs were injection site reaction and injection site erythema, the majority of which was mild.

“The improvements demonstrated in arthritis, psoriasis and enthesitis are exciting relative to responses reported for the current standard of care,” observed Professor Peter Taylor, Norman Collison chair of musculoskeletal sciences at the University of Oxford. “Combined with the clinically meaningful improvement in disease-specific quality of life and well-tolerated safety profile, izokibep seems promising for patients living with the painful and debilitating symptoms of psoriatic arthritis, and I am eager to see its continued development for patients.”

ACELYRIN holds worldwide rights to izokibep except development and commercialization rights by Inmagene in selected Asian countries, including China, Hong Kong, South Korea, and Taiwan, and excluding Japan. Affibody holds commercialization rights in the Nordic countries.