Study of OSU6162 Added to SSRISNRI Treatment in Adults 25 to 65 with Treatment-Resistant Depression

What this Trial Is About

Researchers are evaluating OSU6162 as an add-on treatment for adults aged 25 to 65 with major depressive disorder who have not improved after at least 6 weeks of treatment with an SSRI or SNRI. This phase 2, randomized, double-blind, placebo-controlled trial aims to assess the efficacy and safety of OSU6162 compared to placebo in patients resistant to SSRISNRI treatment. The study also explores biomarkers in serum and brain activity changes related to reward processing using fMRI and the Probabilistic Reward Task in optional substudy components. Participants will be randomly assigned to receive either OSU6162 tablets or placebo tablets alongside their ongoing SSRISNRI treatment for 6 weeks. OSU6162 is given at flexible doses starting at 15 mg three times daily, with a maximum of 45 mg three times daily. During the treatment period, participants attend seven study visits and have four telephone contacts. Those who respond to treatment based on symptom improvement and a reduction in depression rating scales may continue treatment for an additional 4-week extension phase with three visits and three telephone interviews. Throughout the study, participants undergo various assessments including depression rating scales such as the Bech 6-item subscale of the Hamilton Depression Rating Scale HDRS at 42 days, Montgomery sberg Depression Rating Scale MADRS, Clinical Global Impression scales, fatigue and pleasure scales, and serum biomarker measurements. Safety monitoring includes adverse event tracking and laboratory tests. Optional brain imaging with fMRI is performed in substudy participants to assess changes in brain activity. The total participation may last up to 10 weeks for those continuing in the extension phase.

OSU6162 as add-on in SSRI/SNRI-resistant Depression