ACELYRIN, INC. Provides Update on Izokibep Clinical Development Program - Seite 2

Work is ongoing to determine the implications of the sequencing errors in the 160mg Q2W and 80mg Q4W arms. Based on ACELYRIN’s review to date and the fact that the placebo and 160mg QW arms were designed for consistent weekly dosing, the Company has no reason to believe the 160mg QW and placebo arms are impacted.

Next Steps

ACELYRIN’s wide-ranging review of the ongoing izokibep trials, including operational execution by the CRO, is continuing. ACELYRIN will contract with a third-party to conduct an independent audit of the trials being conducted by the CRO for ACELYRIN, including the HS trial and the PsA trial. ACELYRIN will not use this CRO for any new trials that it conducts. Based on the outcome of its ongoing evaluation and the planned audit, the Company will determine the best path forward for the development of izokibep on behalf of patients. This will include a determination of whether to transition its ongoing trials to a new CRO or complete the trials with the current CRO.

Pending completion of the evaluation from the third-party auditor, ACELYRIN plans to report top-line data from its PsA trial in the first quarter of 2024.

The Company previously presented differentiated 16- and 46-week data up to 80mg every other week from a Phase 2 trial of izokibep in PsA that was not conducted by the CRO. These results demonstrated dose-ordered responses as early as one month into treatment and increasing over time. Long-term efficacy results from the same trial presented recently at the American College of Rheumatology annual meeting showed that with longer duration of treatment, patients experienced durable and deepening resolution of disease across clinical manifestations of PsA, leading to further improvements in quality of life as measured by the Psoriatic Arthritis Impact of Disease questionnaire. Modeling from the Phase 2 PsA data predicted the potential for increased efficacy with higher doses over the 80mg Q2W. The ongoing PsA trial includes higher doses designed to evaluate the potential to further maximize responses for patients.

“We are disappointed by these developments, especially for the patients who need better treatment options for psoriatic arthritis and hidradenitis suppurativa,” said Shao-Lee Lin, MD, PhD, founder and CEO of ACELYRIN. “However, we are a company founded on truth and transparency, and we are grateful that through the tenacity of our internal team we were able to identify these errors. We are committed to delivering the best possible outcome for patients, physicians and shareholders as we continue to pursue development of izokibep as a potentially differentiated treatment for multiple immunologic conditions.”