REGENXBIO Inc. announced that initial interim data from a first-in-human single-patient, investigator-initiated trial of RGX-181 for the treatment of late-infantile neuronal ceroid lipofuscinosis type 2 (CLN2) disease, a form of Batten disease, were presented at the Society for the Study of Inborn Errors of Metabolism (SSIEM) Annual Symposium in Jerusalem. Data Summary and Safety Data: A physician investigator from the Hospital de Clinicas in Porto Alegre, Brazil reported initial results from a five-year-old child who received a one-time intracisternal dose of RGX-181. Time of post-administration follow up was six months.

As of June 30, 2023, RGX-181 was well tolerated with no serious adverse events. Key efficacy measures demonstrated sustained levels of TPP1 along with increased intervals between enzyme replacement therapy (ERT) infusions and an 86% reduction in seizure frequency through six months, leading to withdrawal of two anti-epileptic medications. Encouraging improvements in fine motor and expressive language skills were also observed.

RGX-181 is being developed as a novel, one-time treatment for CLN2 disease utilizing the NAV AAV9 vector to deliver the gene encoding for TPP1, the enzyme deficient in children with CLN2 disease. Following administration of a single intracisternal injection, RGX-181 treatment is designed to provide a durable source of TPP1, potentially leading to long-term correction of cells throughout the CNS. In an animal model for CLN2 disease, treatment with RGX-181 has been shown to restore TPP1 activity to levels greater than those in non-affected animals and to improve neurobehavioral function and survival.

The extent of CNS correction observed suggests that RGX-181 has the potential to be an important and suitable one-time therapeutic option for patients with CLN2 disease. Late-infantile neuronal ceroid lipofuscinosis type 2 (CLN2) disease, a form of Batten disease, is a rare, pediatric-onset, autosomal recessive, neurodegenerative lysosomal storage disorder caused by mutations in the TPP1 gene. Deficiency in TPP1 enzymatic activity results in lysosomal accumulation of storage material and degeneration of nerve cells, particularly in the brain and retina.

CLN2 disease is characterized by seizures, rapid deterioration of language and motor functions, cognitive decline, rapid loss of vision and blindness, and premature death by mid-childhood. Onset of symptoms is generally between two to four years of age with initial features of recurrent seizures (epilepsy), language delay and difficulty coordinating movements (ataxia). There is currently no cure for CLN2 disease.

Current treatment options include CNS enzyme replacement therapy, wherein recombinant TPP1 is administered into the lateral ventricles via a permanently implanted device on a biweekly basis, and palliative care. There are currently no approved treatments to treat ocular manifestations of CLN2 disease.