Addex Therapeutics Ltd. announced the initiation of a Phase 2a clinical study with dipraglurant as a potential treatment for blepharospasm, a type of dystonia characterized by involuntary contractions or spasms of the eyelid muscles resulting in sustained eyelid closure, which can result in substantial visual disturbance or functional blindness. Dipraglurant selectively targets the metabotropic glutamate receptor subtype 5 (mGlu5) to downregulate neurotransmission through allosteric modulation. This double-blind, randomized Phase 2a feasibility study will enroll 15 patients with blepharospasm. It is designed to assess the safety and tolerability of dipraglurant (50 and 100mg) as well as explore its effects on the severity and frequency of blepharospasm signs and symptoms using objective measures, clinical ratings and patient reported outcomes. Data from the study are expected in first quarter of 2022. Blepharospasm is a form of dystonia characterized by involuntary contractions or spasms. It currently affects around 50,000 people in the US, with approximately 2,000 new cases diagnosed each year. The cause of blepharospasm is thought to involve overstimulation of the blink reflex resulting from excessive glutamate stimulation. Botulinum toxin injections are the only approved drug treatment.