Selecta Biosciences and AskBio Initiate First-in-Human Dose-Escalation Study to Evaluate ImmTOR™ in Gene Therapy

- Clinical trial commences in healthy adult volunteers to determine appropriate dose of ImmTOR to mitigate formation of antibodies to AAV capsids used in gene therapy -

WATERTOWN, MA, and Research Triangle Park, NC, USA I February 17, 2021 I Selecta Biosciences, Inc. (NASDAQ: SELB) and Asklepios BioPharmaceutical, Inc. (AskBio), a wholly owned and independently operated subsidiary of Bayer AG, today announced the initiation of a Phase 1 dose-escalation trial of SEL-399, an adeno-associated viral serotype 8 (AAV8) empty vector capsid (EMC-101) containing no DNA combined with ImmTOR™. The trial aims to determine the optimal dose of ImmTOR to mitigate the formation of antibodies to AAV8 capsids used in gene therapies.

"We are pleased to further evaluate ImmTOR's ability to reduce the formation of antibodies to AAV capsids and potentially enable gene therapy redosing by having initiated this dose-escalation study of SEL-399," said Carsten Brunn, Ph.D., president and chief executive officer of Selecta. "This trial builds upon our strong preclinical data in non-human primates and marks the first time that ImmTOR in conjunction with an AAV capsid has been dosed in humans, which is a significant milestone. Data from this study will inform the design of future clinical trials in patients as we seek to unlock the full potential of gene therapy."

The dose-escalation trial of SEL-399 is designed to evaluate the safety and preliminary efficacy of ImmTOR in gene therapy. The study, being conducted in healthy volunteers at the SGS Life Sciences Clinical Pharmacology Unit in Antwerp, Belgium, plans to enroll up to 45 subjects to investigate increasing doses of ImmTOR and EMC-101. Subjects will be randomized in a 3:1 ratio of ImmTOR plus empty AAV8 capsid to empty capsid alone. Preliminary efficacy will be measured by assessing levels of AAV8-specific neutralizing antibodies.

Jude Samulski, Ph.D., chief scientific officer and co-founder of AskBio said, "By determining the dose at which ImmTOR is able to inhibit the formation of AAV-specific antibodies, this study could be a significant first step toward overcoming some of the unwanted immune responses associated with gene therapies. We look forward to using these findings to inform future studies as we work to develop strategies for repetitive dosing of AAV, thus extending durability of expression."

Selecta and AskBio expect to report initial results from this clinical trial in the fourth quarter of 2021.

About Selecta Biosciences, Inc.
Selecta Biosciences Inc. (NASDAQ: SELB) is leveraging its clinically validated 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. The company's first program aimed at addressing immunogenicity to AAV gene therapies is expected to enter clinical trials in early 2021 in partnership with AskBio for the treatment of methylmalonic acidemia (MMA), a rare metabolic disorder. A wholly-owned program focused on addressing IgA nephropathy driven by ImmTOR and a therapeutic enzyme is also in development among additional product candidates. Selecta recently licensed its Phase 3 clinical product candidate, SEL-212, in chronic refractory gout to Sobi. For more information, please visit

About AskBio
Asklepios BioPharmaceutical, Inc. (AskBio), a wholly owned and independently operated subsidiary of Bayer AG acquired in 2020, is a fully integrated AAV gene therapy company dedicated to developing life-saving medicines that cure genetic diseases. The company maintains a portfolio of clinical programs across a range of neuromuscular, central nervous system, cardiovascular and metabolic disease indications with a clinical-stage pipeline that includes therapeutics for Pompe disease, Parkinson's disease and congestive heart failure, as well as out-licensed clinical indications for hemophilia and Duchenne muscular dystrophy. AskBio's gene therapy platform includes Pro10™, an industry-leading proprietary cell line manufacturing process, and an extensive AAV capsid and promoter library. With global headquarters in Research Triangle Park, North Carolina, and European headquarters in Edinburgh, UK, the company has generated hundreds of proprietary third-generation AAV capsids and promoters, several of which have entered clinical testing. Founded in 2001 and an early innovator in the gene therapy field, the company holds more than 500 patents in areas such as AAV production and chimeric and self-complementary capsids. Learn more at or follow us on LinkedIn.

About Bayer
Bayer is a global enterprise with core competencies in the life science fields of health care and nutrition. Its products and services are designed to benefit people by supporting efforts to overcome the major challenges presented by a growing and aging global population. At the same time, the Group aims to increase its earning power and create value through innovation and growth. Bayer is committed to the principles of sustainable development, and the Bayer brand stands for trust, reliability and quality throughout the world. In fiscal 2019, the Group employed around 104,000 people and had sales of 43.5 billion euros. Capital expenditures amounted to 2.9 billion euros, R&D expenses to 5.3 billion euros. For more information, visit

SOURCE: Asklepios Biopharmaceuticals

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