Westlake Village Biopartners - Acelyrin

Westlake-backed ACELYRIN, INC., a biopharma company focused on providing patients life-changing new treatment options by identifying, acquiring, and accelerating development and commercialization of promising drug candidates, today announced the closing of its hugely successful Series B round of financing.

LOS ANGELES, Nov. 16, 2021 /PRNewswire/ — ACELYRIN, INC., an innovative clinical-stage biopharma company that identifies, acquires, and accelerates the development and commercialization of life-changing therapies, today announced the completion of a $250 million Series B financing led by AyurMaya, an affiliated fund of Matrix Capital Management (“Matrix”), Surveyor Capital (a Citadel company), and Westlake Village BioPartners (“Westlake”). Additional new investors include Cowen Healthcare Investments, Decheng Capital, Marshall Wace, OrbiMed, RTW Investments, LP, Samsara BioCapital, Tybourne Capital Management, and venBio Partners.

ACELYRIN also announced it has entered into an agreement with Affibody AB to develop and commercialize izokibep, a unique, antibody mimetic, interleukin-17A (IL-17A) inhibitor designed to overcome the limitations of monoclonal antibodies and provide potential for meaningfully differentiated efficacy in several autoimmune diseases. The exquisite potency and small size of izokibep enables enhanced tissue penetration and high exposures in a single subcutaneous injection; exposures monoclonal antibodies require IV administration to approach.

The proceeds from the Series B financing will be used to fund licensing and acquisition of additional programs, with a focus in immunology, and accelerate the development of izokibep.

“We are pleased this syndicate of blue-chip investors has committed to ACELYRIN and our mission to identify, license, and develop transformative therapies for patients with serious diseases and unmet needs,” said Shao-Lee Lin, MD, PhD, co-founder and chief executive officer (CEO) of ACELYRIN. “This financing catalyzes our ability to rapidly advance the late-phase development of izokibep and demonstrate its potential for differentiation within the class of IL-17 inhibitors, both by unlocking new indications as well as achieving differentiated efficacy in existing blockbuster indications, where significant unmet needs persist. The financing also catapults our ability to proactively build the company and aggressively pursue the expansion of our portfolio to meaningfully improve patients’ lives.”

“As the lead Series A investor, we want to thank and welcome this impressive group of Series B investors in joining us to support ACELYRIN. This is a management team we know well and have every confidence will achieve its goal of building a fully integrated biopharma company with a robust pipeline and broad research, development, and commercialization capabilities,” said Westlake’s co-founding managing director and ACELYRIN Board member, Sean Harper, MD.

“ACELYRIN’s founders have a long track record of bringing life-changing medicines to patients with immunologic diseases. These medicines are amongst some of the most successful drugs, reflecting the team’s ability to identify significant unmet medical need and bring innovative solutions to meet those needs,” said Alan Colowick, MD, managing director, Matrix. “We believe izokibep is the first of many assets that the company will develop to transform patients’ lives, and we are excited to be a partner in that journey along with the other investors and management team.”

The Company is currently enrolling izokibep in a pivotal trial for the treatment of uveitis, a vision-threatening form of inflammation inside the eye, and a Phase 2b trial for the treatment of axial spondyloarthritis (AS), a chronic form of arthritis that primarily affects the spine and enthesites, specialized tissue that connects ligaments and tendons to bone. In addition, ACELYRIN plans to initiate a Phase 2b trial for hidradenitis suppurativa (HS), a devastating, chronic inflammatory disease of the exocrine sweat glands characterized by painful, malodorous nodules and abscesses in the axilla, groin, and gluteal areas that can become scarred and disfiguring.

“As the innovators of izokibep, we’re honored to work with ACELYRIN to unlock this molecule’s potential and address promising new indications and solve unmet needs,” said David Bejker, CEO of Affibody AB. “In addition, we look forward to working with the ACELYRIN team to select additional targets and build new programs, in parallel with the development of izokibep.”

Under the terms of the transaction with Affibody AB, ACELYRIN has obtained worldwide rights to izokibep except development and commercialization by Inmagene Biopharmaceuticals Co., Ltd. in selected Asian countries, including China, Hong Kong, South Korea, and Taiwan, and excluding Japan, and commercialization by Affibody in the Nordic Countries. The agreement with Affibody AB also includes an option for ACELYRIN to license additional molecules developed by Affibody AB.

The Company is adding Richard Gaster, MD, of venBio Partners and Dr. Colowick to its board of directors.

About Izokibep

Izokibep is a unique, antibody mimetic, interleukin-17A (IL-17A) inhibitor designed to overcome the limitations of monoclonal antibodies. With extraordinary potency and small molecular size, izokibep can reach high drug exposure levels through a single subcutaneous injection that monoclonal antibodies require IV administration to achieve. In addition, the molecule’s small size—about a tenth the size of a monoclonal antibody—also enables its potential to reach targeted tissues that may otherwise be inaccessible to the much larger monoclonal antibodies. More than 300 patients have been exposed to izokibep to date, many for up to three years. These data confirm the safety profile of izokibep and support the strategy of fully evaluating IL-17A inhibition in pursuit of transformative efficacy across many disease states.


ACELYRIN, INC. is a biopharma company focused on providing patients life-changing new treatment options by identifying, acquiring, and accelerating development and commercialization of promising drug candidates and by leveraging its expertise to rapidly advance these medicines to patients. The company was founded in late 2020. For more information, visit www.acelyrin.com.