ACELYRIN, INC. Announces Positive Top-line Results from Its Global Phase 2b/3 Clinical Trial of Izokibep in Psoriatic Arthritis

Study met primary endpoint of ACR50 at 16 weeks versus placebo with high statistical significance and is expected to be the first of two registrational trials in psoriatic arthritis

Robust clinical responses achieved for the high hurdles of ACR70, PASI100, as well as composite endpoints ACR50/PASI100 and Minimal Disease Activity

Favorable safety profile consistent with the IL-17A class and previous izokibep experience

LOS ANGELES, March 11, 2024 (GLOBE NEWSWIRE) -- ACELYRIN, INC. (Nasdaq: SLRN), a late-stage clinical biopharma company focused on accelerating the development and delivery of transformative medicines in immunology, today announced its global Phase 2b/3 clinical trial of izokibep in psoriatic arthritis (PsA) met the primary endpoint of ACR50 at week 16 with high statistical significance. Results from the 160 mg weekly (QW) and every other week (Q2W) arms showed improved magnitude of responses on higher hurdle endpoints such as ACR70, PASI100, and Minimal Disease Activity relative to the Phase 2 80 mg Q2W dose. This is notable given a higher baseline disease burden in the Phase 2b/3 trial population relative to the Phase 2 trial.

Izokibep was well-tolerated with a favorable safety profile consistent with previous experience and the IL-17A class, without evidence of the safety liabilities observed with targeting IL-17A&F. The trial had a low study discontinuation rate of < 3%. Mild-to-moderate injection site reactions (ISRs) were observed with discontinuations due to ISR < 2%. There were two cases of mild candida – one in the placebo arm and one in the 160 mg QW arm – and no cases of suicidal ideation/behavior.

Pre-specified analyses continue to support the potential for differentiation in enthesitis resolution. Consistent high magnitude absolute responses were demonstrated in the Phase 2-comparable population (baseline Leeds Enthesitis Index (LEI) 1 or 2) although enthesitis resolution overall was not statistically significant due to high placebo response. Izokibep achieved clinically meaningful resolution in patients with the highest burden of enthesitis (baseline LEI 3-6) relative to placebo an effect not previously reported by other agents.

Additional information about these results can be found at ACELYRIN.com. Further data from this trial will be presented at future scientific meetings.

“These positive Phase 2b/3 data reinforce the potential demonstrated in Phase 2 for izokibep to provide meaningful benefit in treating the debilitating signs and symptoms of active psoriatic arthritis in the joints and skin, as well as enthesitis where the results in the most severe patients are encouraging and warrant further study,” said Philip Mease, MD, MACR, Director of Rheumatology Research at Swedish Medical Center. “We have observed from the Phase 2 46-week data that there is no safety limitation to long-term treatment with izokibep and that longer duration of therapy demonstrated the potential for even further improvements over time.”