ACELYRIN is a late-stage clinical biopharma company focused on identifying, acquiring and accelerating the development and commercialization of transformative medicines. We are driven by our sense of urgency to bring life-changing therapies to patients globally, a core value that we refer to as “courageous caring.” (Incorporated in Delaware)

Our initial focus is on the treatment of diseases with pathology related to excess activation of the immune system, an area where our management and team bring industry-leading expertise. We acquired our portfolio of product candidates with the intent to develop and commercialize novel therapies that we believe may provide the opportunity to offer clinically meaningful, differentiated benefits for patients by improving upon the efficacy and/or safety of existing therapeutics directed against established targets, such as currently marketed anti-interleukin (IL)-17A agents, or by targeting new modalities. In each case, our strategy is to identify candidates we believe are “diamonds in the rough,” where, based on molecule characteristics, our collective experience and expertise, and the evolving scientific and medical understanding, we can establish a clinical development plan that tests our hypotheses as to what those benefits could mean for patients. Subsequently, we plan to utilize the results from initial clinical trials and the learnings we obtain from emerging biology to potentially expand the application of our candidates to other indications in which there are significant unmet needs.

Our current portfolio consists of multiple clinical and preclinical stage product candidates being investigated across several indications representing multi-billion-dollar opportunities in the aggregate.

Our lead product candidate is izokibep, a small protein therapeutic designed to inhibit IL-17A with high potency through tight binding affinity and the potential for robust tissue penetration due to its small molecular size, about one-tenth the size of a monoclonal antibody. Izokibep is in Phase 2b/3 clinical trials to treat patients with hidradenitis suppurativa (HS); psoriatic arthritis (PsA)  and uveitis.

We are also advancing lonigutamab, a humanized immunoglobulin G1 (IgG1) monoclonal antibody against insulin-like growth factor 1 receptor (IGF-1R). Lonigutamab has shown high potency against IGF-1R in both binding and functional laboratory assays. We are evaluating lonigutamab in thyroid eye disease with the intent to increase depth and durability of clinical response, maximize tolerability, and deliver as a convenient subcutaneous injection.

In addition, we are developing SLRN-517, which is a fully human IgG1 monoclonal antibody targeting c-KIT. SLRN-517 is designed as a highly potent inhibitor (antagonist) of the c-KIT pathway, targeting mast cell proliferation and degranulation, without stimulating (agonist) mast cell degranulation. Due to its fully human design, we believe SLRN-517 may limit immunogenicity relative to monoclonal antibodies that are not fully human.

(Note: Acelyrin, Inc. upsized its IPO again at pricing – to 30.0 million shares – from  26.5 million shares in the upsized terms in the SEC filing on May 3, 2023 – and priced the IPO at $18.00 – the top of its $16.00-to-$18.00 range – to raise $540.0 million. Background: Acelyrin, Inc. upsized its IPO to 26.5 million shares – from 20.6 million shares – in an S-1/A filing dated May 3, 2023 – to raise $450.5 million. Acelyrin, Inc. disclosed its IPO terms in an S-1/A filing dated May 1, 2023: 20.6 million shares at a price range of $16.00 to $18.00 to raise $350.0 million. Acelyrin, Inc. filed its S-1 on April 13, 2023. It submitted confidential documents to the SEC on Feb. 10, 2023.)