Safety, Tolerability, PK and Efficacy of Single Doses of NV-5138 in Healthy Volunteers and Subjects With Treatment-Resistant Depression

This is a randomized, two-part, double-blind, placebo-controlled study of single ascending dosage levels of NV-5138 in healthy volunteers and a single dose of NV-5138 in subjects with TRD. The study includes an up to 28-day screening period, an in-house period during which NV-5138 or placebo will be administered, and a 3- to 7-day follow-up period after discharge. In Part A of the study (single-ascending-dose \[SAD\] portion in healthy volunteers), up to approximately 48 healthy volunteers will be randomly assigned to double-blind treatment. Eight (8) subjects will be randomized in each of six dosage-level cohorts (150, 300, 600, 1000, 1600, or 2400 mg NV-5138, or placebo, administered as an oral solution). Within each cohort, six subjects will be randomized to receive NV-5138 and two subjects will be randomized to receive placebo. Each subject will receive only one dose of either NV-5138 or placebo on Day 1. Within each cohort, initially one subject will receive NV-5138 and one subject will receive placebo. Provided no clinically significant safety issues are noted in the 24 hours after dosing the initial two subjects in the cohort, the six subjects remaining in the cohort may be dosed. In Part B of the study (single-dose portion in subjects with TRD), up to approximately 40 subjects will be randomly assigned to double-blind treatment in one cohort. The dosage level for this cohort will be determined based on the safety, tolerability, and pharmacokinetic data from Part A of the study. However, in no case will the dose in Part B of the study exceed the highest dose administered in Part A of the study. Within this cohort, after potential eligibility has been confirmed by a site-independent review process, twenty (20) subjects will be randomized to receive NV-5138 and twenty (20) subjects will be randomized to receive placebo.