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CompletedNCT04479852Updated Jun 12, 2025Results posted

A Study of the Safety and Efficacy of SP-624 in the Treatment of Adults With Major Depressive Disorder

A Phase 2 interventional study of SP-624 and Placebo in Major Depressive Disorder, sponsored by Sirtsei Pharmaceuticals, Inc.. Completed at 39 sites in United States. Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2025-06-12.

Sponsored by Sirtsei Pharmaceuticals, Inc. · Phase 2, Interventional, and Treatment

Phase
Phase 2
Study type
Interventional
Enrollment
319
Allocation
Randomized
Ages
18 Years to 65 Years
Sex
All
01

Study summary

This is a Phase 2 clinical study evaluating the safety and effectiveness of SP-624 as compared to placebo in the treatment of adults with Major Depressive Disorder.

02

Conditions studied

  • Major Depressive Disorder
03

In context

Depressive Disorder

4,845 studies on the registry are indexed under Depressive Disorder; 514 are open to participants now.

This study's enrollment of 319 is above the median of 80 across 3,999 interventional studies indexed under Depressive Disorder.

Browse Depressive Disorder studies →

Lead sponsor

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.

04

Who can participate

Ages eligible
18 Years to 65 Years
Sexes eligible
All
Accepts healthy volunteers
No

Inclusion criteria

  • Willing and able to provide written informed consent to participate in the study
  • Males and females, aged 18 to 65 years
  • In generally good physical health
  • Body mass index (BMI) must be between 18 and 40 kg/m2
  • Females of reproductive potential and males with partners of reproductive potential must agree to remain abstinent or use adequate and reliable contraception throughout the study and for at least 30 days after the last dose of study drug
  • Subjects must meet criteria for moderate to severe Major Depressive Disorder, as confirmed by the Mini International Neuropsychiatric Interview (MINI)
  • Willing and able to comply with the study design schedule and other requirements

Exclusion criteria

Exclusion Criteria:

  • Female who is pregnant, breastfeeding, or less than six months postpartum at Screening
  • History or presence of any clinically significant medical condition, disease, or surgical history that could jeopardize the safety of the subject or validity of the study data, or interfere with the absorption, distribution, metabolism, or excretion of the study drug
  • Failure to discontinue all psychoactive medications or psychoactive supplements including antidepressants and mood stabilizers, within a time period prior to Baseline corresponding to at least five half-lives of the medication in question
  • Presence of a clinically significant abnormality on physical examination or electrocardiogram (ECG), including a corrected QT interval using Fridericia's formula (QTcF) >450 msec for males and >470 msec for females
  • Presence of uncontrolled hypertension, defined as consistent systolic blood pressure (SBP) >160 mmHg or consistent diastolic blood pressure (DBP) >95 mmHg despite present therapy
  • Screening laboratory value(s) outside the laboratory reference range that are considered to be clinically significant by the Investigator (clinical chemistry, hematology, coagulation, and urinalysis)
  • Screening liver function tests (ALT, AST, Alkaline phosphatase) > 2x the upper limit of normal
  • Subjects who, in the opinion of the Investigator, are not suitable candidates for the study
05

Study design

Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment
319 participants (actual)

Study arms

  • Experimental
    SP-624

    Daily oral capsule, 20 mg/day

    Drug: SP-624

  • Placebo comparator
    Placebo

    Daily oral capsule

    Drug: Placebo

Interventions

  • DrugSP-624

    Oral capsule

  • DrugPlacebo

    Oral capsule

06

What researchers measure

Primary outcomes

  1. Change From Baseline to Week 4 in Montgomery Asberg Depression Rating Scale (MADRS) Total Score

    The Montgomery Asberg Depression rating scale is a 10-item scale used to assess the severity of depression. Individual items are scored on a 7-point scale (0 to 6). The total 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

Secondary outcomes

  1. Change From Baseline to Week 4 in Clinical Global Impression - Severity (CGI-S) Total 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 Week 4

  2. Change From Baseline to Week 4 in the 17-item Hamilton Depression Rating Scale (HAM D-17) Total Score

    The 17-item Hamilton Depression rating scale 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 Week 4

  3. Change From Baseline to Week 4 in the Sheehan Disability Scale (SDS)

    The Sheehan Disability Scale 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". Each item (work, social, and family life) can have a score of 0-10. 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, where a higher score represents a worse outcome, i.e., more disruption on work, social, and family life. 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 "unproductive". The results of these questions have a range from 0 to 7 and are not included in the overall scale total.

    Time frame: Baseline to Week 4

  4. Change From Baseline to Week 4 in the Quick Inventory of Depressive Symptomology - Self Report (QIDS-SR)

    The Quick Inventory of Depressive Symptomology - Self Report (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 such that the highest score in a group of questions is entered once. For example, there are 4 questions related to sleep and the highest score on any of the 4 sleep items is entered once. The total score ranges from 0 to 27 where a higher score indicates more depression.

    Time frame: Baseline to Week 4

  5. Change From Baseline to Week 4 in the Quality of Life Enjoyment and Satisfaction Questionnaire - Short Form (Q-LES-Q-SF)

    The Quality of Life Enjoyment and Satisfaction Questionnaire - Short Form (Q-LES-Q-SF) is a 16 item satisfaction scale where each item has a 5-point scale. A score of 1 represents "very poor satisfaction", while a score of 5 represents "very good satisfaction". Only the first 14 items are summed for a total score that ranges from 14 to 70, where a lower score represents a worse outcome.

    Time frame: Baseline to Week 4

07

Results

Posted Jun 12, 2025

Participant flow

Participant flow — Overall Study
MilestoneSP-624Placebo
Started163156
Safety population161156
Completed133130
Not completed3026

Outcome measures

PrimaryChange From Baseline to Week 4 in Montgomery Asberg Depression Rating Scale (MADRS) Total Score

The Montgomery Asberg Depression rating scale is a 10-item scale used to assess the severity of depression. Individual items are scored on a 7-point scale (0 to 6). The total 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
Reported as:
Least squares mean · Score on a scale
Change From Baseline to Week 4 in Montgomery Asberg Depression Rating Scale (MADRS) Total Score
Score on a scaleSP-624Placebo
Change From Baseline to Week 4 in Montgomery Asberg Depression Rating Scale (MADRS) Total Score-12.6 ± 0.83-10.8 ± 0.84
Statistical analysis
  • SP-624 vs Placebo · Mixed Models Analysis · p = 0.133 · Mean difference (final values): -1.8 · 95% CI -4.1 to 0.5A negative difference favors the SP-624 treatment group, i.e., a greater reduction in MADRS score from baseline.
SecondaryChange From Baseline to Week 4 in Clinical Global Impression - Severity (CGI-S) Total 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 Week 4
Reported as:
Least squares mean · Score on a scale
Change From Baseline to Week 4 in Clinical Global Impression - Severity (CGI-S) Total Score
Score on a scaleSP-624Placebo
Change From Baseline to Week 4 in Clinical Global Impression - Severity (CGI-S) Total Score-1.2 ± 0.10-0.9 ± 0.10
Statistical analysis
  • SP-624 vs Placebo · Mixed Models Analysis · p = 0.059 · Mean difference (final values): -0.3 · 95% CI -0.5 to 0.0A negative difference favors the SP-624 treatment group, i.e., a greater reduction in CGI-S score from baseline.
SecondaryChange From Baseline to Week 4 in the 17-item Hamilton Depression Rating Scale (HAM D-17) Total Score

The 17-item Hamilton Depression rating scale 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 Week 4
Reported as:
Least squares mean · Score on a scale
Change From Baseline to Week 4 in the 17-item Hamilton Depression Rating Scale (HAM D-17) Total Score
Score on a scaleSP-624Placebo
Change From Baseline to Week 4 in the 17-item Hamilton Depression Rating Scale (HAM D-17) Total Score-8.3 ± 0.56-7.1 ± 0.57
Statistical analysis
  • SP-624 vs Placebo · Mixed Models Analysis · p = 0.159 · Mean difference (final values): -1.1 · 95% CI -2.7 to 0.4A negative difference favors the SP-624 treatment group, i.e., a greater reduction in HAM-D score from baseline.
SecondaryChange From Baseline to Week 4 in the Sheehan Disability Scale (SDS)

The Sheehan Disability Scale 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". Each item (work, social, and family life) can have a score of 0-10. 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, where a higher score represents a worse outcome, i.e., more disruption on work, social, and family life. 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 "unproductive". The results of these questions have a range from 0 to 7 and are not included in the overall scale total.

Time frame:
Baseline to Week 4
Reported as:
Least squares mean · Score on a scale
Change From Baseline to Week 4 in the Sheehan Disability Scale (SDS)
Score on a scaleSP-624Placebo
Change From Baseline to Week 4 in the Sheehan Disability Scale (SDS)-5.6 ± 0.52-4.6 ± 0.54
Statistical analysis
  • SP-624 vs Placebo · Mixed Models Analysis · p = 0.188 · Mean difference (final values): -1.0 · 95% CI -2.5 to 0.5A negative difference favors the SP-624 treatment group, i.e., a greater reduction in SDS score from baseline.
SecondaryChange From Baseline to Week 4 in the Quick Inventory of Depressive Symptomology - Self Report (QIDS-SR)

The Quick Inventory of Depressive Symptomology - Self Report (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 such that the highest score in a group of questions is entered once. For example, there are 4 questions related to sleep and the highest score on any of the 4 sleep items is entered once. The total score ranges from 0 to 27 where a higher score indicates more depression.

Time frame:
Baseline to Week 4
Reported as:
Least squares mean · Score on a scale
Change From Baseline to Week 4 in the Quick Inventory of Depressive Symptomology - Self Report (QIDS-SR)
Score on a scaleSP-624Placebo
Change From Baseline to Week 4 in the Quick Inventory of Depressive Symptomology - Self Report (QIDS-SR)-5.0 ± 0.39-4.1 ± 0.40
Statistical analysis
  • SP-624 vs Placebo · Mixed Models Analysis · p = 0.091 · Mean difference (final values): -0.9 · 95% CI -2.0 to 0.2A negative difference favors the SP-624 treatment group, i.e., a greater reduction in QIDS score from baseline.
SecondaryChange From Baseline to Week 4 in the Quality of Life Enjoyment and Satisfaction Questionnaire - Short Form (Q-LES-Q-SF)

The Quality of Life Enjoyment and Satisfaction Questionnaire - Short Form (Q-LES-Q-SF) is a 16 item satisfaction scale where each item has a 5-point scale. A score of 1 represents "very poor satisfaction", while a score of 5 represents "very good satisfaction". Only the first 14 items are summed for a total score that ranges from 14 to 70, where a lower score represents a worse outcome.

Time frame:
Baseline to Week 4
Reported as:
Least squares mean · Score on a scale
Change From Baseline to Week 4 in the Quality of Life Enjoyment and Satisfaction Questionnaire - Short Form (Q-LES-Q-SF)
Score on a scaleSP-624Placebo
Change From Baseline to Week 4 in the Quality of Life Enjoyment and Satisfaction Questionnaire - Short Form (Q-LES-Q-SF)9.5 ± 1.037.8 ± 1.06
Statistical analysis
  • SP-624 vs Placebo · Mixed Models Analysis · p = 0.243 · Mean difference (final values): 1.7 · 95% CI -1.2 to 4.6A positive difference favors the SP-624 treatment group, i.e., a greater increase in Q-LES-Q score from baseline.
Post-hocFemale Subjects Change From Baseline Montgomery Asberg Depression Rating Scale Score at Week 4

The Montgomery Asberg Depression rating scale is a 10-item scale used to assess the severity of depression. Individual items are scored on a 7-point scale (0 to 6). The total 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
Reported as:
Least squares mean · Score on a scale
Female Subjects Change From Baseline Montgomery Asberg Depression Rating Scale Score at Week 4
Score on a scaleSP-624Placebo
Female Subjects Change From Baseline Montgomery Asberg Depression Rating Scale Score at Week 4-13.4 ± 1.05-9.4 ± 1.02
Statistical analysis
  • SP-624 vs Placebo · Mixed Models Analysis · p = .008 · Mean difference (final values): -3.9 · 95% CI -6.8 to -1.0A negative difference favors the SP-624 treatment group, i.e., a greater reduction in MADRS score from baseline.
Post-hocFemale Change From Baseline to Week 4 in Clinical Global Impression - Severity (CGI-S) Total 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 Week 4
Reported as:
Least squares mean · Score on a scale
Female Change From Baseline to Week 4 in Clinical Global Impression - Severity (CGI-S) Total Score
Score on a scaleSP-624Placebo
Female Change From Baseline to Week 4 in Clinical Global Impression - Severity (CGI-S) Total Score-1.2 ± 0.12-0.8 ± 0.11
Statistical analysis
  • SP-624 vs Placebo · Mixed Models Analysis · p = 0.006 · Mean difference (final values): -0.5 · 95% CI -0.8 to -0.1A negative difference favors the SP-624 treatment group, i.e., a greater reduction in CGI-S score from baseline.
Post-hocMale Subjects Change From Baseline Montgomery Asberg Depression Rating Scale Score at Week 4

The Montgomery Asberg Depression rating scale is a 10-item scale used to assess the severity of depression. Individual items are scored on a 7-point scale (0 to 6). The total 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
Reported as:
Least squares mean · Score on a scale
Male Subjects Change From Baseline Montgomery Asberg Depression Rating Scale Score at Week 4
Score on a scaleSP-624Placebo
Male Subjects Change From Baseline Montgomery Asberg Depression Rating Scale Score at Week 4-11.3 ± 1.21-14.0 ± 1.35
Statistical analysis
  • SP-624 vs Placebo · Mixed Models Analysis · p = 0.134 · Mean difference (final values): 2.7 · 95% CI -0.8 to 6.3A negative difference favors the SP-624 treatment group, i.e., a greater reduction in MADRS score from baseline.
Post-hocMale Change From Baseline to Week 4 in Clinical Global Impression - Severity (CGI-S) Total 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 Week 4
Reported as:
Least squares mean · Score on a scale
Male Change From Baseline to Week 4 in Clinical Global Impression - Severity (CGI-S) Total Score
Score on a scaleSP-624Placebo
Male Change From Baseline to Week 4 in Clinical Global Impression - Severity (CGI-S) Total Score-1.0 ± 0.15-1.2 ± 0.16
Statistical analysis
  • SP-624 vs Placebo · Mixed Models Analysis · p = 0.437 · Mean difference (final values): 0.2 · 95% CI -0.3 to 0.6A negative difference favors the SP-624 treatment group, i.e., a greater reduction in CGI-S score from baseline.

Adverse events

Collected over Consent through 2 week follow up, up to 10 weeks (up to 28 day screening period, 4 week treatment period, and 2 week follow up period). Non-serious events are listed at a 2% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
SP-6240/161 (0%)0/161 (0%)35/161 (21.7%)
Placebo0/156 (0%)2/156 (1.3%)36/156 (23.1%)
Most frequent serious events
Most frequent serious events
EventSP-624Placebo
Accidental OverdoseInjury, poisoning and procedural complications0/1611/156
Gastrointestinal hemorrhageGastrointestinal disorders0/1611/156
Most frequent other events
Most frequent other events
EventSP-624Placebo
HeadacheNervous system disorders13/16118/156
NauseaGastrointestinal disorders9/16113/156
DizzinessNervous system disorders4/1619/156
DiarrheaGastrointestinal disorders9/1617/156
AnxietyPsychiatric disorders4/1611/156
SomnolenceNervous system disorders4/1612/156

Baseline characteristics

Safety population - all subjects who took at least one dose of study drug

Age, Categorical
Age, Categorical(Participants)SP-624PlaceboTotal
<=18 years213
Between 18 and 65 years156154310
>=65 years314
Sex: Female, Male
Sex: Female, Male(Participants)SP-624PlaceboTotal
Female101110211
Male6046106
Ethnicity (NIH/OMB)
Ethnicity (NIH/OMB)(Participants)SP-624PlaceboTotal
Hispanic or Latino162137
Not Hispanic or Latino142135277
Unknown or Not Reported303
Race (NIH/OMB)
Race (NIH/OMB)(Participants)SP-624PlaceboTotal
American Indian or Alaska Native213
Asian61016
Native Hawaiian or Other Pacific Islander112
Black or African American393271
White108107215
More than one race5510
Unknown or Not Reported000
Region of Enrollment
Region of Enrollment(Participants)SP-624PlaceboTotal
United States161156317
08

Study locations

39 sites
  • Alea Research
    Phoenix, Arizona 85012, United States
  • Woodland International Research Group
    Little Rock, Arkansas 72211, United States
  • Woodland Research Northwest
    Rogers, Arkansas 72758, United States
  • Collaborative Neuroscience Research
    Garden Grove, California 92845, United States
  • Pacific Research Partners
    Oakland, California 94607, United States
  • Artemis Institute for Clinical Research
    San Diego, California 92103, United States
  • Collaborative Neuroscience Research
    Torrance, California 90502, United States
  • MCB Clinical Research Centers
    Colorado Springs, Colorado 80910, United States
  • Sarkis Clinical Trials
    Gainesville, Florida 32607, United States
  • Clinical Neuroscience Solutions, Inc.
    Jacksonville, Florida 32256, United States
  • Innovative Clinical Research
    Lauderhill, Florida 33319, United States
  • Clinical Neuroscience Solutions, Inc.
    Orlando, Florida 32801, United States
  • Institute for Advanced Medical Research
    Alpharetta, Georgia 30022, United States
  • Atlanta Center for Medical Research
    Atlanta, Georgia 30331, United States
  • iResearch Atlanta
    Decatur, Georgia 30030, United States
  • American Medical Research
    Chicago, Illinois 60612, United States
  • Capstone Clinical Research
    Libertyville, Illinois 60048, United States
  • CBH Health
    Gaithersburg, Maryland 20877, United States
  • Midwest Research Group
    Saint Charles, Missouri 63304, United States
  • Altea Research Institute
    Las Vegas, Nevada 89102, United States
  • Hassman Research Institute
    Berlin, New Jersey 08009, United States
  • Center for Emotional Fitness
    Cherry Hill, New Jersey 08002, United States
  • Hassman Research Institute
    Marlton, New Jersey 08053, United States
  • SPRI Clinical Trials
    Brooklyn, New York 11235, United States
  • Manhattan Behavioral Medicine
    New York, New York 10036, United States
  • Richmond Behavioral Associates
    Staten Island, New York 10312, United States
  • New Hope Clinical Research
    Charlotte, North Carolina 28211, United States
  • Clinical Trials of America
    Hickory, North Carolina 28601, United States
  • Midwest Clinical Research Center
    Dayton, Ohio 45417, United States
  • Cutting Edge Research Group
    Oklahoma City, Oklahoma 73116, United States
  • Oregon Center for Clinical Investigations
    Portland, Oregon 97214, United States
  • Oregon Center for Clinical Investigations
    Salem, Oregon 97301, United States
  • Lehigh Center for Clinical Research
    Allentown, Pennsylvania 18104, United States
  • Clinical Neuroscience Solutions, Inc.
    Memphis, Tennessee 38119, United States
  • Donald J. Garcia, Jr., MD, PA
    Austin, Texas 78737, United States
  • Future Search Trials of Dallas
    Dallas, Texas 75231, United States
  • Red Oak Psychiatry Associates
    Houston, Texas 77090, United States
  • Grayline Research Center
    Wichita Falls, Texas 76309, United States
  • Core Clinical Research
    Everett, Washington 98201, United States
09

References and documents

Study documents

  • Study protocol · May 26, 2021
  • Statistical analysis plan · Aug 26, 2022

Documents are hosted by the registry — open the source record to download them.

10

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jun 12, 2025, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
11

Registry details

Key details

Study ID
NCT04479852
Lead sponsor
Sirtsei Pharmaceuticals, Inc.
Responsible party
Sponsor
First posted
Jul 21, 2020
Start date
Sep 30, 2020
Primary completion
Jun 27, 2022
Completion
Aug 9, 2022
Results posted
Jun 12, 2025
Last update
Jun 12, 2025

Study contacts

Greg Rigdon, PhD
study director · Sirtsei Pharmaceuticals, Inc.

Oversight

Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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