Next-generation IgG protease candidate Xork to be licensed for development with AT845, an investigational Astellas Gene Therapies’ product, for the treatment of Pompe Disease

Selecta to receive a $10M upfront payment and eligible to receive up to $340M for certain additional development and commercial milestones plus royalties on commercial sales

WATERTOWN, MA, USA and TOKYO, Japan I January 9, 2023 I Selecta Biosciences, Inc. (NASDAQ: SELB, President and CEO: Carsten Brunn, Ph.D., “Selecta”), and Astellas Pharma Inc. (TSE: 4503, President and CEO: Kenji Yasukawa, Ph.D., “Astellas” or “Astellas Gene Therapies”) today announced an exclusive licensing and development agreement for IdeXork (Xork). Xork is being studied as a potential next generation immunoglobulin G (IgG) protease that will be developed by Astellas for use with AT845, an investigational, adeno-associated virus (AAV)-based treatment for Late-Onset Pompe disease (LOPD) in adults.

“Currently many patients are ineligible for clinical trials with investigational AAV gene therapy products due to the presence of naturally occurring antibodies against AAV gene therapy capsids,” said Carsten Brunn, Ph.D., President and Chief Executive Officer of Selecta. “Xork has the potential to expand access to life-changing gene therapies by addressing pre-existing immunity to AAV. Most other IgG proteases in development are derived from common human pathogens, and as a result there is a high prevalence of pre-existing antibodies against these proteases that can restrict their use. Xork is differentiated by its low cross-reactivity to pre-existing antibodies in human serum. We are thrilled to partner with Astellas as they advance their robust gene therapy portfolio through the clinic.”

Naoki Okamura, Chief Strategy Officer of Astellas added, “We are looking forward to partnering with Selecta as we strive to expand our therapies to a broader range of patients living with debilitating diseases, who have limited treatment options. This agreement provides an opportunity to deliver potentially transformative gene therapy treatments to a specific population of LOPD adult patients who might otherwise be ineligible for clinical trials or treatment with Astellas’ investigational product.”

Under the terms of the agreement, Selecta will receive a $10M upfront payment and is eligible to receive up to $340M for certain additional development and commercial milestones plus royalties on any potential commercial sales where Xork is used as a pre-treatment for AT845. Selecta is responsible for the development and manufacturing of Xork and will maintain the rights for the development of additional indications beyond Pompe disease. Astellas would have the sole and exclusive right to commercialize Xork for use in Pompe disease with an Astellas gene therapy investigational or authorized product, with a current focus on AT845.

About Selecta Biosciences, Inc.
Selecta Biosciences Inc. (NASDAQ: SELB) is a clinical stage biotechnology company leveraging its ImmTOR™ platform to develop tolerogenic therapies that selectively mitigate unwanted immune responses. With a proven ability to induce tolerance to highly immunogenic proteins, ImmTOR has the potential to amplify the efficacy of biologic therapies, including redosing of life-saving gene therapies, as well as restore the body’s natural self-tolerance in autoimmune diseases. Selecta has several proprietary and partnered programs in its pipeline focused on enzyme therapies, gene therapies, and autoimmune diseases. Selecta Biosciences is headquartered in the Greater Boston area. For more information, please visit www.selectabio.com.

About AT845 for the treatment of Late-Onset Pompe Disease (LOPD) 
Astellas is developing AT845, a novel gene replacement therapy using an AAV8 vector under a muscle-specific promotor to deliver a functional copy of the GAA gene, for the treatment of adult LOPD. AT845 is being investigated to determine whether it can deliver a functional GAA gene that is efficiently transduced to express GAA directly in tissues affected by the disease, including skeletal and cardiac muscle.

About Astellas
Astellas Pharma Inc. is a pharmaceutical company conducting business in more than 70 countries around the world. We are promoting the Focus Area Approach that is designed to identify opportunities for the continuous creation of new drugs to address diseases with high unmet medical needs by focusing on Biology and Modality. Furthermore, we are also looking beyond our foundational Rx focus to create Rx+® healthcare solutions that combine our expertise and knowledge with cutting-edge technology in different fields of external partners. Through these efforts, Astellas stands on the forefront of healthcare change to turn innovative science into VALUE for patients. For more information, please visit our website at https://www.astellas.com/en.

About Astellas Gene Therapies
Astellas Gene Therapies is an Astellas Center of Excellence developing genetic medicines with the potential to deliver transformative value for patients. Our gene therapy drug discovery engine is built around innovative science, a validated AAV platform, and industry leading internal manufacturing capability with a particular focus on rare diseases of the eye, CNS and neuromuscular system. Astellas Gene Therapies will also be advancing additional Astellas gene therapy programs toward clinical investigation. Astellas Gene Therapies is based in San Francisco, with manufacturing and laboratory facilities in South San Francisco, Calif., Sanford, N.C. and Tsukuba, Japan.

SOURCE: Astellas Pharma