Addex Therapeutics, a clinical-stage biopharmaceutical company developing small-molecule allosteric modulators for neurological disorders, announced that its spin-out company, Neurosterix, has completed Phase 1 clinical studies of NTX-253 and plans to advance the candidate into Phase 2 clinical development for schizophrenia. Addex holds a 20 percent equity interest in Neurosterix.

NTX-253 is an oral Positive Allosteric Modulator (PAM) of the muscarinic M4 receptor. The Phase 1 programme was designed to characterise the candidate’s clinical profile and generate safety and pharmacokinetic data to support further development.

The multi-part study included Single Ascending Dose (SAD) and Multiple Ascending Dose (MAD) components. It also incorporated food-effect and Cerebrospinal Fluid (CSF) assessments. Both healthy volunteers and stable patients with schizophrenia participated in the studies.

“Completing Phase 1 and the decision by Neurosterix to progress NTX-253 into Phase 2 studies in schizophrenia patients is a significant achievement,” said Tim Dyer, CEO of Addex Therapeutics. He added that the study design, which included healthy volunteers and patients with schizophrenia, had generated important safety and pharmacokinetic data.

The muscarinic M4 receptor is being investigated as a target for schizophrenia and related disorders through its role in modulating dopamine signalling. NTX-253 is designed to modulate M4 receptor activity and has the potential to address psychosis symptoms while avoiding certain movement-related and metabolic complications associated with traditional dopamine antagonists. According to the company, preclinical studies have demonstrated antipsychotic-like activity and a favourable safety profile.

Neurosterix was spun out of Addex in April 2024 and secured $65 million in Series A financing led by funds affiliated with Perceptive Advisors. Addex retains a 20 percent equity stake in the company.

The planned Phase 2 programme will advance the clinical evaluation of NTX-253 in patients with schizophrenia.