FDA Names Anavex2-73, Potential Fragile X Therapy, an Orphan Drug

Anavex Life Sciences planning for possibly pivotal Phase 2/3 trial in patients

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by Vanda Pinto, PhD |

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Anavex2-73 (blarcamesine), an experimental small molecule being developed by Anavex Life Sciences, has been designated an orphan drug by the U.S. Food and Drug Administration (FDA) as a potential treatment of fragile X syndrome.

This designation is given to investigational treatments for people with rare diseases, defined as those affecting fewer than 200,000 in the U.S. Orphan drug status is meant to speed the therapy’s development by providing regulatory support and financial incentives, including tax credits on clinical testing, waivers of certain fees, and a guarantee of seven years of marketing exclusivity if the therapy is approved.

“The Orphan Drug Designation highlights the potential to expand the therapeutic profile of ANAVEX2-73 into the largest portion of autism spectrum disorder, Fragile X syndrome,” Christopher U. Missling, PhD, president and CEO of Anavex, said in a press release.

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Anavex2-73 aims to ease patients’ behavioral, cognitive symptoms

Fragile X is caused by mutations in the FMR1 gene, which encodes the FMRP protein. FMRP regulates the production of other proteins at synapses, the sites where neurons communicate.

As the most common cause of inherited intellectual disability and most frequent genetic cause of autism spectrum disorders (ASDs), fragile X often is marked by behavioral issues that include anxiety, irritability, and repetitive behavior. A parent survey conducted by the U.S. Centers for Disease Control reported that 46% of males and 16% of females with the syndrome have been diagnosed with or treated for ASD, the release stated.

Anavex2-73 is an agonist (activator) of the protein sigma-1 receptor (S1R), a protein that helps regulate the activity of synapses. Blocking S1R is expected to restore synapse health in fragile X and in other neurological diseases. As such, the therapy was designed to ease behavioral and cognitive symptoms characteristic of autism spectrum disorder.

In preclinical studies, Anavex2-73 was found to ease hyperactivity as well as other behavioral symptoms in a mouse model of fragile X. The company announced plans to initiate a placebo-controlled Phase 2/3 study in patients last year, and these plans were included in an August report on biomarker testing of the treatment in a mouse model.

Anavex2-73 has completed a Phase 2a clinical trial of the therapy for Alzheimer’s disease, a Phase 2 proof-of-concept treatment study in Parkinson’s disease dementia, and both a Phase 2 and a Phase 3 study in adult patients with Rett syndrome.

“We look forward to working with the Fragile X syndrome community to rapidly advance ANAVEX2-73 as a potential treatment for Fragile X syndrome while we continue to expand late-stage clinical investigation of ANAVEX2-73 … for both neurodevelopmental and neurodegenerative indications,” Missling said.