Aptinyx, reeling from series of setbacks, dumps dementia drug, stops PTSD trial after phase 2 flop

Serial clinical trial train wreck Aptinyx is at it again. After seeing a pain prospect flunk three clinical trials, the biotech has added Parkinson's disease and dementia to its list of failed indications—prompting it to stop work on its two clinical candidates, cut costs and seek strategic alternatives.

Last year, the third midphase failure of NYX-2925 prompted Aptinyx to drop the pain program and switch its attention to a pair of other NMDA receptor positive allosteric modulators, NYX-458 and NYX-783. The delivery of data from a phase 2 clinical trial of NYX-458 has prompted the company to rethink its plans once again and sent its stock down 54% to 27 cents in premarket trading.

The midphase study randomized 99 patients with mild cognitive impairment or mild dementia caused by Parkinson’s or Lewy body dementia to receive NYX-458 or placebo for 12 weeks. Aptinyx began the trial on the basis of evidence that the molecule boosts cognition by addressing glutamatergic dysregulation. 

Across a slate of efficacy endpoints, NYX-458 failed to deliver on the preclinical promise. Aptinyx is yet to share data from the trial but revealed the absence of clinically meaningful improvements. The efficacy endpoints included two evaluations of the patients’ everyday functions and a battery of computerized neurocognitive tests designed to assess cognition.

The comprehensive failure led Aptinyx to drop plans for further development of NYX-458. The fallout has hit the rest of the business, with the biotech terminating an ongoing study of NYX-783 in post-traumatic stress disorder (PTSD) early. Aptinyx had expected to report phase 2b data in PTSD in the second half of the year.

Now, the biotech will review the data generated on NYX-783 to date to inform the next steps while trying to conserve its cash and identify a way out of its current predicament. Aptinyx is yet to publicly disclose layoffs but said it will “undertake cost-cutting measures.” The biotech ended September with $67 million to its name.