A Phase 2 interventional study of SP-624 and Placebo in Major Depressive Disorder, sponsored by Sirtsei Pharmaceuticals, Inc.. Completed at 50 sites in United States. Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-08-18.
Sponsored by Sirtsei Pharmaceuticals, Inc. · Phase 2, Interventional, and Treatment
This is a Phase 2B clinical study evaluating the effectiveness and safety of SP-624 as compared to placebo in the treatment of adults with Major Depressive Disorder.
2,741 studies on the registry are indexed under Depressive Disorder, Major; 559 are open to participants now.
This study's enrollment of 497 is above the median of 80 across 2,283 interventional studies indexed under Depressive Disorder, Major.
Browse Depressive Disorder, Major studies →Sirtsei Pharmaceuticals, Inc. is the lead sponsor of 4 studies on the registry; none are open to participants now.
Counted across the registry records on this site, refreshed daily.
Key Inclusion Criteria:
Key Exclusion Criteria:
Participants to receive two 10 mg capsules of SP-624 once daily for a total daily dose of 20 mg
Drug: SP-624
Participant to receive 2 matching placebo capsules once daily
Drug: Placebo
Once daily oral administration of two capsules totaling 20 mg/day
Once daily oral administration of two matching placebo capsules
Change from Baseline in the Montgomery-Asberg Depression Rating Scale (MADRS) total score.
The MADRS is a 10-item depression rating scale used to assess the severity of depression. Individual items are scored on a 7-point scale (0 to 6). The toal score is the sum of individual items, ranging from 0 to 60; where a higher score indicates more depression.
Time frame: Baseline to Week 4
Change from Baseline in the Clinical Global Impression - Severity (CGI-S) score.
The CGI-S is a 7-point scale to rate the severity of the participant's illness at the time of assessment, relative to the clinician's past experience with participants who have the same diagnosis. A score of 1 represents "normal" and 7 represents "most extremely ill".
Time frame: Baseline to Weeks 1-4 and 1- and 2- Week Follow-up
Change from Baseline in Quick Inventory of Depressive Symptomology-Self-Report (QIDS-SR) total score.
The QIDS-SR is a 16-item self-reported scale where each item has a 4-point scale where 0 represents least impact scores while 3 represents greatest impact scores. Some questions are linked. The total score ranges from 0 to 27 where a higher score indicates more depression.
Time frame: Baseline to Weeks 1-4 and 1- and 2- Week Follow-up
Change from Baseline in the Montgomery-Asberg Depression Rating Scale (MADRS) total score.
The MADRS is a 10-item depression rating scale used to assess the severity of depression. Individual items are scored on a 7-point scale (0 to 6). The toal score is the sum of individual items, ranging from 0 to 60; where a higher score indicates more depression.
Time frame: Baseline to Weeks 1-3 and 1- and 2- Week Follow-up
Change from Baseline in 17-item-Hamilton Depression Rating Scale (HAM-D-17) total score.
The 17-item HAM-D is used to assess the severity of depression. Individual items are scored on either a 3-point (0 to 2) or a 5-point scale (0 to 4), with 0=No difficulty/absent and 4=most severe. The total score is the sum of individual items, ranging from 0 to 52; where a higher score indicates more depression.
Time frame: Baseline to Weeks 2 and 4
Change from Baseline in Sheehan Disability Scale (SDS) total score.
The SDS is a 3-part scale that measures the degree of disruption on work, social and family life using an 11-point scale where 0 represents "no disruption" and 10 represents "extreme disruption". In addition to the 11-point scale, participants are asked to indicate the number of days in the past week that were "lost" and numbers of days that were "underproductive". The results of these questions have a range from 0 to 7. A total global functioning impairment score can be utilized by summing the scores from work, social and family life scales for a value range from 0 to 30.
Time frame: Baseline to Weeks 2 and 4
Change from Baseline in Symbol Digit Modalities Test (SDMT) score.
The SDMT is an assessment of complex scanning and visual tracking requiring elements of attention, visuoperceptual processing, working memory, and cognitive/psychomotor speed. The SDMT measures the time to pair abstract symbols with specific numbers. The number of correct substitutions within 90 seconds is recorded and the total score is derived from the total number of correct responses with a minimum possible score of 0 and maximum of 110 where high scores indicate better outcome.
Time frame: Baseline to Weeks 2 and 4
Incidence rates of treatment emergent adverse events (TEAEs), serious adverse events (SAEs), and TEAEs leading to withdrawal from study.
Time frame: Baseline to Weeks 1-4 and 1- and 2- Week Follow up
Plan to share: No
This study is completed, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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Sirtsei Pharmaceuticals, Inc.