atai Life Sciences announced results from Perception Neuroscience?s Phase 1 intravenous-to-subcutaneous bridging study of PCN-101 (R-ketamine). The Phase 1 open-label, 4-period crossover study assessed the safety, tolerability, and pharmacokinetic profile of 60mg, 90mg and 120mg of PCN-101 delivered subcutaneously (?SQ?) as compared to 60mg of PCN-101 delivered intravenously. The study enrolled 16 healthy volunteers, each into one of four sequences of administration.

The study was designed to inform dosing regimens of the new subcutaneous formulation that may optimize the therapeutic index?the balance of safety, tolerability, and efficacy?of PCN-101 in future studies, thereby supporting further exploration of the potential of R-ketamine as a rapid acting anti-depressant for at-home use. Pharmacokinetic (PK) analysis indicates that 120mg of PCN-101 delivered SQ resulted in an approximate doubling of drug exposure (AUC) while maintaining approximately the same maximum concentration (Cmax) as the 60mg IV dose. Further, PCN-101 was generally well-tolerated with no serious adverse events reported.

At the 60mg IV dose, rates of sedation and dissociation were consistent with prior studies of PCN-101 at this dose-level. Encouragingly, at the higher SQ dose of 120mg, rates of sedation (defined as MOAA/S score <5) and dissociation (defined as CADSS total score >4 and change from baseline >0) were each 14%. While recognizing the limitations of this small bridging study and cross-trial comparisons, this safety and tolerability profile compares favorably to that of Spravato, for which rates of sedation and dissociation have been reported to be in the ranges of 50%-61% and 61%-69%, respectively, in prior studies.

In addition, rates of sedation and dissociation were similar to those seen in the placebo arms of both the prior Phase 2 study of PCN-101 and the Spravato clinical trials in depression. Collectively, they believe these data support the concept of at-home use of PCN-101 in future studies. atai continues to work with Perception Neuroscience to explore strategic partnership options.