Addex Therapeutics’ attempt to expand use of dipraglurant into muscle spasms has stumbled at the first hurdle. A phase 2a clinical trial of the mGluR5 negative allosteric modulator has delivered “inconclusive” data in an eyelid disorder, raising doubts about a broader push beyond Parkinson’s disease.
The primary use case for dipraglurant is in levodopa-induced dyskinesia in Parkinson’s, an indication Addex is evaluating in a phase 3 clinical trial that is due to report data in the first half of next year. While working to seize the Parkinson’s opportunity, Addex identified the potential to use dipraglurant to treat muscle spasms, starting with an eyelid condition, blepharospasm, that can cause functional blindness.
To test the spasm hypothesis, Addex randomized 15 blepharospasm patients to receive placebo or one of two doses of dipraglurant. While mainly designed to evaluate the safety and tolerability of the 50-mg and 100-mg doses, the study also gathered data on changes in blinking and spasms across a range of other endpoints. Safety was fine. Efficacy? Not so much.
As Addex put it, the study was “inconclusive and did not meet all of its objectives.” Despite that setback, Roger Mills, M.D., chief medical officer at Addex, still found some positives to take from the clinical trial.
“While not showing conclusive effects of dipraglurant in this first study of an mGlu5 NAM in blepharospasm patients, it has provided us with a number of important insights related to the patient population. These include clinical rating scales and novel objective measuring devices that will help to inform us for future development,” Mills said in a statement.
The findings dent Addex’s prospects of establishing dipraglurant as an alternative to surgery and Botox in the treatment of blepharospasm. Shares in the Geneva-based biotech fell around 5% in Switzerland after the release of the data, dipping below 0.60 Swiss francs ($0.63). The blow leaves Addex, which expects its cash runway to extend into the first half of next year, looking to its Parkinson’s results and a fourth-quarter midphase readout on its Johnson & Johnson-partnered epilepsy drug for a boost.