A Phase 2 interventional study of COL-5671-PRO and Placebo in Plaque Psoriasis, sponsored by Coultreon Biopharma. Not yet recruiting at 6 sites in Canada. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-11-03.
Sponsored by Coultreon Biopharma · Phase 2, Interventional, and Treatment
The main purpose of this study is to assess how-well COL-5671-PRO works (clinical efficacy), how safe it is (safety), and how well it is tolerated (tolerability) when compared to placebo (a look-alike substance that contains no drug) in adults with moderate-to-severe plaque psoriasis
Participants will take drug COL-5671 or a placebo every day for 12 weeks.
2,028 studies on the registry are indexed under Psoriasis; 275 are open to participants now.
This study's planned enrollment of 100 is above the median of 75 across 1,565 interventional studies indexed under Psoriasis.
Browse Psoriasis studies →This is the only study on the registry with Coultreon Biopharma as lead sponsor.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Participant meets 1 of the following tuberculosis (TB) criteria at screening:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participant will receive dose A of COL-5671-PRO capsules orally once daily (QD) for 12 weeks.
Drug: COL-5671-PRO
Participant will receive dose B of COL-5671-PRO capsules orally once daily (QD) for 12 weeks.
Drug: COL-5671-PRO
Participant will receive dose C of COL-5671-PRO capsules orally once daily (QD) for 12 weeks.
Drug: COL-5671-PRO
Participant will receive placebo to match COL-5671-PRO capsules orally once daily (QD) for 12 weeks.
Drug: Placebo
COL-5671-PRO oral capsules
Matching placebo to COL-5671-PRO capsules
Reduction of 75% in PASI score relative to baseline (PASI75) at Week 12
The Psoriasis Area and Severity Index (PASI) combines assessments of the extent of body-surface involvement in 4 anatomical regions (head and neck, upper limbs, trunk, lower limbs) and the severity of erythema, induration, and desquamation in each region, yielding an overall score of 0 to 72. A frequency table of participants with a reduction of 75% in PASI score relative to baseline (PASI75) at Week 12 per intervention arm.
Time frame: From enrollment to the end of treatment at 12 weeks
Treatment-emergent adverse events (TEAEs), treatment emergent serious adverse events (SAEs), and TEAEs leading to treatment discontinuation
Number and percentage of participants with events per intervention arm, and total number of events by intervention arm.
Time frame: From enrollment to the end of follow-up at 16 weeks
PASI score and percentage change from baseline in PASI score at Week 12
The Psoriasis Area and Severity Index (PASI) combines assessments of the extent of body-surface involvement in 4 anatomical regions (head and neck, upper limbs, trunk, lower limbs) and the severity of erythema, induration, and desquamation in each region, yielding an overall score of 0 to 72. Descriptive statistics at Week 12 per intervention arm of the actual values and the percent changes from baseline.
Time frame: From enrollment to the end of treatment at 12 weeks
Reduction of 50/90/100% in PASI score relative to baseline at Week 12
The Psoriasis Area and Severity Index (PASI) combines assessments of the extent of body-surface involvement in 4 anatomical regions (head and neck, upper limbs, trunk, lower limbs) and the severity of erythema, induration, and desquamation in each region, yielding an overall score of 0 to 72. A frequency table of participants with a reduction of 50/90/100% in PASI score relative to baseline (PASI50/PASI90/PASI100) at Week 12 per intervention arm.
Time frame: From enrollment till end of treatment at 12 weeks
PASI score ≤1 at Week 12
The Psoriasis Area and Severity Index (PASI) combines assessments of the extent of body-surface involvement in 4 anatomical regions (head and neck, upper limbs, trunk, lower limbs) and the severity of erythema, induration, and desquamation in each region, yielding an overall score of 0 to 72. A frequency table of participants with a PASI score ≤1 at Week 12 per intervention arm.
Time frame: From enrollment till end of treatment at 12 weeks
Percentage change from baseline in affected BSA at Week 12
The percentage of surface area of the body (BSA) involved with plaque psoriasis. The handprint method for assessing BSA will be used, where the surface area of the participant's hand, including the palm and all 5 digits, is used as a guide to estimate 1% BSA. Descriptive statistics at Week 12 per intervention arm of percent changes from baseline.
Time frame: From enrollment till end of treatment at 12 weeks
Change from baseline in sPGA score of plaque psoriasis at Week 12
A global assessment of psoriasis disease activity performed by the physician (sPGA). The sPGA of psoriasis is used to determine the participant's psoriasis lesions overall at a given time point. The participant's psoriasis disease activity will be assessed by a physician for the 3 primary signs of psoriasis (induration, erythema, and scaling), scored as clear (0), almost clear (1), mild (2), moderate (3), and severe (4). Descriptive statistics at Week 12 per intervention arm of changes from baseline.
Time frame: From enrollment till end of treatment at 12 weeks
Change from baseline in PtGA score of plaque psoriasis at Week 12
A global assessment of psoriasis disease activity performed by the participant (PtGA). The PtGA of psoriasis is a single-item, patient-completed assessment that is used to evaluate the overall extent of psoriasis-related cutaneous disease at a particular point in time using an 11-point Numerical Rating Scale (NRS), answering the question "On a scale from 0 to 10, with 0 being 'not at all' and 10 being 'very severe', how would you rate the severity of your PsO at this moment? Descriptive statistics at Week 12 per intervention arm of changes from baseline.
Time frame: From enrollment till end of treatment at 12 weeks
sPGA score of 0 (clear) or 1 (minimal disease) at Week 12
A global assessment of psoriasis disease activity performed by the physician (sPGA). The sPGA of psoriasis is used to determine the participant's psoriasis lesions overall at a given time point. The participant's psoriasis disease activity will be assessed by a physician for the 3 primary signs of psoriasis (induration, erythema, and scaling), scored as clear (0), almost clear (1), mild (2), moderate (3), and severe (4). A frequency table of participants with a sPGA score of 0 or 1 at Week 12 per intervention arm.
Time frame: From enrollment till end of treatment at 12 weeks
sPGA score of 0 (clear) or 1 (minimal disease) and improvement of ≥2 points relative to baseline at Week 12
A global assessment of psoriasis disease activity performed by the physician (sPGA). The sPGA of psoriasis is used to determine the participant's psoriasis lesions overall at a given time point. The participant's psoriasis disease activity will be assessed by a physician for the 3 primary signs of psoriasis (induration, erythema, and scaling), scored as clear (0), almost clear (1), mild (2), moderate (3), and severe (4). A frequency table of participants with a sPGA score of 0 or 1 and an improvement of ≥2 points relative to baseline at Week 12 per intervention arm.
Time frame: From enrollment till end of treatment at 12 weeks
sPGA score of 0 at Week 12
A global assessment of psoriasis disease activity performed by the physician (sPGA). The sPGA of psoriasis is used to determine the participant's psoriasis lesions overall at a given time point. The participant's psoriasis disease activity will be assessed by a physician for the 3 primary signs of psoriasis (induration, erythema, and scaling), scored as clear (0), almost clear (1), mild (2), moderate (3), and severe (4). A frequency table of participants with a sPGA score of 0 at Week 12 per intervention arm.
Time frame: From enrollment till end of treatment at 12 weeks
Plan to share: No
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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