Depression and anxiety oral drug patented in Europe by Vistagen

The company made the announcement on April 6 that the European Patent Office (EPO) had granted the company a patent for AV-101, its oral N-methyl-D-aspartate receptor (NMDAR) glycine site antagonist.

The patent is related to the small molecule drug’s synthesis and certain chemical intermediaries, which synthesis yields AV-101 in commercial quantities and has scalability for commercial manufacture.

The new patent is a counterpart to previously granted US patent 11,427,530 and will be in effect until at least 2039.

Based on preclinical observations and findings, AV-101 has the potential to become a new oral treatment alternative for multiple central nervous system (CNS) disorders involving the NMDAR, such as dyskinesia associated with levodopa therapy for Parkinson’s disease, major depressive disorder, and neuropathic pain.

“Expanding our patent portfolio for all of our product candidates is an ongoing priority to support our global development and commercialization strategies across our pipeline,” said Shawn Singh, Chief Executive Officer of Vistagen.

“AV-101’s potential to inhibit the function of the NMDAR, without fully blocking it like other NMDAR antagonists such as ketamine, anchors our interest in developing it as an innovative therapy for millions of patients affected by CNS disorders involving the NMDAR. This new patent covering our improved and streamlined manufacturing process may result in advantages for getting AV-101 to patients, on our own or potentially with a partner.”

AV-101 (4-chlorokynurenine) is an oral prodrug of 7-chloro-kynurenic acid (7-Cl-KYNA), which is a potent and selective full antagonist of the glycine co-agonist site of the N-methyl-D-aspartate receptor that inhibits certain functions of the NMDAR.

Unlike ketamine and many other NMDAR antagonists, 7-Cl-KYNA is not an ion channel blocker.

The company says that preclinical studies demonstrate that AV-101 activity appears to be specific to the GlycineB site, with virtually no off-target activity in a panel of more than 50 receptor targets, including dopamine and opioid receptors, making AV-101 a potentially safer option for patients than current treatments for numerous CNS disorders involving the NMDAR. 

Doses have been administered in multiple clinical studies completed to date and has proven to be well tolerated, has not exhibited dissociative or hallucinogenic psychological side-effects, Vistagen reports.

The company is running an ongoing phase 1b drug-drug interaction clinical study of AV-101 in combination with probenecid. It is intends to facilitate potential future phase 2a clinical development, alone or in combination with probenecid, in one or more CNS disorders involving the NMDAR. 

The FDA has granted Fast Track designation for development of AV-101 as a potential adjunctive treatment for major depressive disorder and as a stand-alone non-opioid treatment for neuropathic pain.