Addex Therapeutics announced that its gamma-aminobutyric acid B (GABA-B) receptor positive allosteric modulator, ADX71441, caused dose dependent changes in growth hormone (GH) plasma concentrations compared to vehicle control in a rodent preclinical model. These data are consistent with published scientific literature demonstrating that GABA, the endogenous neurotransmitter for GABA-B receptors, plays both a stimulatory and inhibitory role in modulating the neuro-endocrine regulation of GH secretion in both animals and humans. GH plasma concentration changes occurred at doses and plasma concentrations of ADX71441 which have been demonstrated to induce pharmacological and efficacious effects in preclinical models of CMT1A, anxiety, pain, overactive bladder and alcohol addiction. The study was performed on samples from single oral treatment studies where ADX71441 was given at doses of 5, 20 and 80 mg/kg. Assessment of GH and ADX71441 plasma concentrations were performed at 4 and 24 hours post-treatment. The results demonstrate a direct relationship between plasma concentrations of ADX71441 and effect on GH levels. GH changes occur at doses (< 10 mg/kg) and plasma concentrations (between 300 and 600 ng/mL) that have been shown to induce pharmacological and efficacious effects in several preclinical models, including CMT1A, anxiety, pain, overactive bladder and alcohol addiction.

Addex Therapeutics Ltd. announced that Tim Dyer, Co-Founder and Chief Financial Officer, will transition to an external consulting role on June 1, 2013 and no longer serve as CFO.

Addex Therapeutics announced that the regulatory authorities in the Netherlands have approved the clinical trial application (CTA) to initiate a Phase 1 study of ADX71441, a GABA-B receptor positive allosteric modulator (PAM). The Company plans to initiate clinical testing at the Centre of Human Drug Research in Leiden, in the first half of 2013 and expects to deliver top-line safety, pharmacokinetic and biomarker data by year end. Addex previously announced achievement of positive Proof of Concept for ADX71441 in a validated pre-clinical model of Charcot-Marie-Tooth 1A (CMT1A) neuropathy as well as a number of other disease indications. The Company plans to move quickly to Phase 2a testing of ADX71441 for the treatment of CMT1A, an orphan disease, in 2014. The CTA was submitted to the authorities in March 2013. ADX71441 is a potent, selective, orally available small molecule that is brain penetrant and shows good pharmacokinetic properties for once-daily dosing. Activation of gamma-aminobutyric acid subtype B (GABA-B) receptor, a Family C class of GPCR, is clinically and commercially validated in several indications including spasticity, overactive bladder (OAB), spinal cord injuries and gastroesophageal reflux disease. However, generic GABA-B receptor agonists are not commonly used in certain disorders due to compliance-limiting drug side effects, receptor sensitization, rebound effect and rapid clearance. An oral once-daily small molecule activator of GABA-B receptor without the issues associated with the current GABA-BR agonists could dramatically change the treatment paradigm for a number of diseases. Allosteric modulation is ideally suited to overcome such limitations of an agonist. ADX71441 has shown efficacy in multiple preclinical models including: CMT1A, OAB, pain, obsessive-compulsive disorder, alcohol binge drinking and anxiety. The United States Patent and Trademark Office recently granted Addex a composition of matter patent covering ADX71441 and other GABA-B receptor PAMs. The claims of the issued patent also cover pharmaceutical composition and method of treatment using such GABA-BR PAMs.