Selecta and Astellas Enter Exclusive Licensing and Development Agreement for Xork IgG Protease

Selecta Biosciences and Astellas Pharma have entered an exclusive licensing and development agreement for IdeXork (Xork), which is being studied as a potential next generation immunoglobulin G protease that will be developed by Astellas for use with AT845, an experimental, adeno-associated virus (AAV)-based treatment for late-onset Pompe disease in adults.

Photo: Carsten Brunn, president and CEO of Selecta

“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, president and CEO 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.”

Selecta leverages its ImmTOR platform to develop tolerogenic therapies that selectively mitigate unwanted immune responses with 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.

Under the terms of their agreement, Selecta will receive a $10 million in an upfront payment and is eligible to receive up to $340 million 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.

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 late-onset Pompe disease (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.

Pompe disease is a rare, lysosomal disease caused by variations in the acid alpha-glucosidase (GAA) gene. These variations lead to a deficiency in GAA protein, which limits the body’s ability to break down glycogen in the lysosomes. This buildup of glycogen damages the body’s muscles, affecting mobility. As the muscles that control breathing become affected, respiratory problems can begin.

“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,” said Naoki Okamura, chief strategy officer at Astellas.

Author: Rare Daily Staff