 atai Life Sciences NASDAQ:ATAI shares tumbled more than 40 in pre-market trading on Friday after the company reported disappointing results from its subsidiary Perception Neurosciences Phase 2a clinical trial of PCN-101 R-ketamine, a stereoisomer of ketamine, for treatment-resistant depression. The biopharmaceutical company said in a statement that while PCN-101 demonstrated signs of efficacy across all time points out to two weeks, the trial did not meet its primary endpoint of a statistically significant change from baseline in participants Montgomery-Åsberg Depression Rating Scale MADRS score at 24 hours compared to placebo. 