Acelyrin Reports $248.2 Million Net Loss for 2024, Announces Merger with Alumis Inc.

Acelyrin, Inc., a late-stage clinical biopharmaceutical company, reported a net loss of $248.2 million for the year ended December 31, 2024, compared to a net loss of $381.6 million in 2023. The 2024 net loss included $37 million in other income, $45 million in stock-based compensation expense, $14.3 million in termination costs, $11.4 million in restructuring charges, and a $31 million one-time payment to Pierre Fabre. Research and development expenses decreased by $117.8 million year-over-year, primarily due to lower license fees and in-process research and development expenses. General and administrative expenses increased slightly by $0.6 million.

Significant changes in 2024 included the implementation of a restructuring plan in August, resulting in a workforce reduction of approximately one-third and the suspension of internal investment in izokibep for hidradenitis suppurativa, psoriatic arthritis, and axial spondyloarthritis. The company also terminated its license agreements with Novelty Nobility for SLRN-517 and Affibody for izokibep. In February 2025, Acelyrin entered into a merger agreement with Alumis Inc., leading to a delay in the initiation of the Phase 3 LONGITUDE program for lonigutamab until the merger closes. The company also announced additional interim data from its Phase 1/2 dose-ranging trial of lonigutamab in thyroid eye disease (TED), showing clinically meaningful improvements.

Acelyrin's current portfolio consists solely of lonigutamab for the treatment of TED. As of March 14, 2025, the company employed 83 full-time employees. The company holds global development and commercialization rights to lonigutamab outside of oncology, but none of its product candidates are currently approved for sale. Acelyrin relies on third-party contract manufacturing organizations (CMOs) for the supply of its product candidates and anticipates continuing this reliance for commercial manufacturing if its candidates receive marketing approval. The company also holds various license agreements, including one with Pierre Fabre for lonigutamab, which includes milestone payments and royalties.

Key operational developments include the completion of the Phase 1 proof-of-concept portion of the lonigutamab trial and the ongoing Phase 2 dose-ranging portion. The company announced its intention to initiate a Phase 3 trial in the first quarter of 2025, but this was subsequently delayed pending the merger. The company's Phase 2b/3 trial of izokibep in uveitis did not meet its primary endpoint. As of March 11, 2025, Acelyrin's owned and exclusively licensed patent portfolio included ten issued U.S. patents, 211 issued foreign patents, and numerous pending applications.

Acelyrin's outlook is contingent upon the successful completion of the merger with Alumis and the successful development and commercialization of lonigutamab. The company anticipates incurring substantial and increasing losses for the foreseeable future and will require substantial additional financing to achieve its goals. The company's financial performance and future prospects are subject to numerous risks and uncertainties, including those related to clinical trial outcomes, regulatory approvals, competition, and market conditions, as detailed in the 10-K filing.