FDA grants orphan drug status to Fabry gene therapy EXG110

The U.S. Food and Drug Administration (FDA) has granted orphan drug designation to EXG110, an experimental gene therapy aimed at treating Fabry disease, developed by Exegenesis Bio and currently undergoing clinical trials. This designation underscores the pressing need for innovative solutions for Fabry disease, a severe condition impacting thousands globally, according to Exegenesis’ CEO, Zhenhua Wu, PhD.

Orphan drug status provided by the FDA offers economic incentives to companies developing treatments for rare diseases, those affecting fewer than 200,000 people in the U.S. This status ensures benefits such as seven years of market exclusivity upon approval, helping companies recover investments and gain profits despite the limited market size. Wu regards this recognition as a testament to Exegenesis’ robust scientific efforts, innovative culture, and dedication to patients with rare diseases. He views it as a significant step towards becoming a global leader in gene therapy.

Fabry disease arises from mutations in the GLA gene, which encodes the enzyme alpha-galactosidase A (alpha-Gal A). This enzyme’s normal function is to break down specific fatty molecules. In Fabry disease patients, the lack of functional alpha-Gal A leads to the accumulation of these fatty molecules within cells, causing organ damage and related symptoms. EXG110 is designed as a single-dose gene therapy to introduce a healthy copy of the GLA gene to liver and heart cells, enabling the production of the functional enzyme to eliminate the toxic fatty molecules. The liver is targeted as it can produce and distribute the enzyme to other organs, while the heart is directly affected by this disease.

The delivery mechanism for EXG110 involves a modified adeno-associated virus (AAV). This virus is engineered to carry the therapeutic gene without causing harmful infections, making it a popular choice for gene therapies. AAV is favored in laboratory settings due to its ease of manipulation and its typically non-pathogenic nature in humans.

Exegenesis is conducting a clinical trial for EXG110 in Fabry disease patients in China, with the first participant already dosed. Plans for a similar trial in the U.S. are also in the pipeline, though specific dates have not been disclosed.

Besides Fabry disease, Exegenesis is also developing gene therapies for other conditions, such as wet age-related macular degeneration and spinal muscular atrophy. Wu congratulated Exegenesis’ global team for their rapid progress across all pipeline programs and platform technologies, emphasizing their urgency to bring essential treatments to patients worldwide.