ACELYRIN, INC. Announces Izokibep Achieves HiSCR100 Responses at 12 Weeks in Moderate-to-Severe Hidradenitis Suppurativa

• Data from the open label Part A of a Phase 2b/3 trial to be presented today at the American Academy of Dermatology (AAD) Annual Meeting
• At 12 weeks, participants achieved high orders of HiSCR (HiSCR75 and above), including 33% achieving HiSCR100
• Izokibep was generally well-tolerated, and no candida events were reported through week 12

LOS ANGELES, March 18, 2023 /PRNewswire/ -- ACELYRIN, INC., a late-stage clinical biopharma company focused on accelerating the development and delivery of transformative medicines in immunology, today announced data from the open label Part A of a Phase 2b/3 trial in patients with moderate-to-severe Hidradenitis Suppurativa (HS) that demonstrated treatment with izokibep led to high orders (HiSCR75 and above) of HiSCR response at 12 weeks, including HiSCR100 responses in 33% of participants. HS is a chronic, inflammatory skin disease characterized by abscesses, nodules, fistulae, pain, scarring and malodor, all contributing to a devastating impact on quality of life. The data will be presented in a Late-Breaking session at the AAD Annual Meeting on March 18, 2023. 

"Hidradenitis suppurativa is a devastating disease, and as clinicians we are continuously searching for therapies that can improve quality of life and ideally even provide for resolution of disease," said Shao-Lee Lin, MD, PhD, founder and CEO of ACELYRIN. "We've long known that drug exposures in HS are lower compared to other inflammatory conditions and had hypothesized that the high potency of izokibep to IL-17A, as well as its small molecular size – about 1/10 the size of a monoclonal antibody – could generate deep levels of clinical response due to robust tissue penetration and potent target engagement. We are delighted to see izokibep delivering high order HiSCR responses through 12 weeks and are pleased to see this hypothesis for izokibep unfolding now across two disease states, as shared today in HS and previously for Psoriatic Arthritis."

In the trial conducted at multiple sites in the United States, participants with Hurley Stage II and III disease received 160 mg of izokibep dosed subcutaneously every week. Results as observed at week 12 showed 71% of participants achieved HiSCR50, 57% achieved HiSCR75, 38% achieved HiSCR90 and 33% achieved HiSCR100; achievement of HiSCR100 responses at Week 12 does not appear to have been previously reported for any other product.

At HiSCR75 and above, placebo response rates have been historically reported by other agents as low-to-none. For example, in a phase 3 study of adalimumab, the placebo response rate for HiSCR90 was 7% and in a phase 2 study of bimekizumab, the placebo response rate for HiSCR90 was 0%.

Izokibep was generally well-tolerated with localized mild-to-moderate injection site reactions being the most common adverse event. Three serious adverse events were observed in two subjects: inflammatory bowel disease, an exclusionary criterion, in one subject with pre-existing symptoms (which was reported as possibly related) and peri-colonic abscess/sepsis in another subject with pre-existing symptoms and known diverticulosis (which was reported as not related). There were no candida events reported through week 12.

The double-blind, placebo-controlled Part B of this Phase 2b/3 trial is ongoing and based on the Part A results, ACELYRIN plans to accelerate initiation of the second Phase 3 trial in HS.

About Izokibep
Izokibep is a small protein therapeutic designed to inhibit interleukin-17A (IL-17A) with high potency and the potential for robust tissue penetration due to its small molecular size, about one-tenth the size of a  monoclonal antibody. Izokibep has been administered across numerous clinical trials for multiple immunological indications including hidradenitis suppurativa (HS), psoriatic arthritis (PsA), axial spondyloarthritis (AxSpA) and uveitis to more than 400 participants, including at doses up to 160 mg, and in some for up to three years.

About Hidradenitis Suppurativa
Hidradenitis Suppurativa (HS) is a chronic Inflammatory skin disease causing scarring, abscesses, malodor and pain. HS typically occurs in areas with high concentrations of sweat glands and is typically accompanied by pain, malodor, drainage, and disfigurement that contribute to disability and a devastating impact on quality of life. Patients with HS miss a greater number of days of work and have increased disability compared to the average population. In  2019, there were an estimated 317,000 HS patients in the U.S., of which 50-60% were moderate-to-severe HS patients.

About ACELYRIN
ACELYRIN, INC. is a Los Angeles area-based late-stage clinical biopharmaceutical company – with additional operations in the San Francisco Bay area – focused on providing patients life-changing new treatment options by identifying, acquiring, and accelerating development and commercialization of promising drug candidates. For more information, please visit www.acelyrin.com.

Forward Looking Statements
Some statements in this press release are, or may be considered,  forward-looking statements, including statements regarding ACELYRIN's progress, business plans and clinical trials, as well as the potential future benefits of our product candidates. While ACELYRIN, INC. considers any projections to be based on reasonable assumptions, these forward-looking statements are subject to risks and uncertainties that may cause actual results to differ materially from those anticipated in such forward-looking statements.

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