MedicalResearch.com Interview with:
Robert Lutjens, PhD
Head of Discovery at Addex Therapeutics
MedicalResearch.com: What is the background for this study? What are the main findings?
Metabotropic glutamate receptors represent an attractive therapeutic target for various neurologic conditions. In particular, the metabotropic glutamate receptor subtype 2 (mGlu2) can affect excitatory synaptic transmission by decreasing glutamate release. As excess gluatamate is observed in epilepsy, targeting mGlu2 could lead to new avenues of therapy. Positive allosteric modulators (PAMs) of mGlu2 could be valuable candidate drugs as they do not directly activate receptors. Therefore, they may avoid tachyphylaxis and side effects emerging from direct receptor agonism.
The publication summarizes the effects obtained when the mGlu2 receptor is activated using an agonist or PAM, such as ADX71149, in the 6Hz psychomotor seizure test, considered to be the most relevant model of pharmacoresistant limbic seizures. The data show that while seizures are reduced when mGlu2-acting compounds are administered alone, their combination with the antiseizure drug levetiracetam
(LEV) result in a potent reduction of doses required to produce full efficacy, which is important because higher doses of LEV are associated with dose-limiting side effects, such as aggression, nervousness/anxiety, somnolence and fatigue. In this study, a fixed dose of ADX71149 was seen to increase the potency of LEV, leading to an approximate 35-fold increase in its potency. Conversely, using a fixed dose of LEV with varying doses of ADX71149 resulted in an approximate 14-fold increase in ADX71149 potency.