A shortage of efficacy compared to placebo in a phase II study of treating cognitive impairment has put Aptinyx Inc. on the defensive. The company’s oral, small-molecule NMDA receptor modulator, NYX-458, was being studied in 99 patients with mild cognitive impairment or mild dementia associated with Parkinson’s disease or Lewy body dementia. Based on the results, Aptinyx has decided to stop the therapy’s development, along with closing its phase IIb study of another oral, small molecule, NYX-783, for treating post-traumatic stress disorder.