What is a clinical trial, and where does it sit?
A trial is a planned study in people, run to answer one question. It is research first and care second. It sits in the middle of a long process, not at the end of it. Evidence Evidence Evidence
How to use this step
- Reasonably supported
FDA splits drug work into five stages. They are discovery, lab research, trials in people, FDA review, and watching the product once it is sold. Early stages ask about safety in small groups. Later stages test a treatment against a comparison. One psoriasis trial of injected methotrexate enrolled 120 adults at 16 sites in four countries, and ran for 52 weeks.
Check before moving on
- Depends on you
What that means for you is that a study is a question being asked, not an answer already found. A trial can end without a benefit. One design does not describe every psoriasis study.
Questions for your dermatologist or the study team
Which stage is this study in, and what is it trying to find out?
Saving keeps this on your device and needs JavaScript, which is off in this browser.Is joining research a reasonable step for my psoriasis right now?
Saving keeps this on your device and needs JavaScript, which is off in this browser.
Where a trial sits in the FDA process
Discovery
The first of the five stages FDA describes, and it comes long before any study in people.
Lab research
Work in the laboratory, still before anyone has been given the treatment.
Trials in people
The stage a trial sits in, where early studies ask about safety and later ones test against a comparison.
FDA review
Regulators read what the studies found, after the trials have ended.
Watching after sale
FDA watches the product once it is sold, so the record keeps moving after your last visit.
FDA, Learn About Drug and Device Approvals.
Where are psoriasis trials listed?
On ClinicalTrials.gov, the United States government registry. Search by condition, then filter to studies that are recruiting near you. Read the study record itself rather than a summary of it. Evidence
How to use this step
- Reasonably supported
ClinicalTrials.gov is run by the National Library of Medicine. Sponsors submit the study records it holds. A record can carry the study status, the eligibility criteria, the locations and a contact.
Check before moving on
- Depends on you
What that means for you is that a listing is a starting point. It is not government approval, and it is not proof of benefit. Every word in a record was written by that study sponsor.
Questions for your dermatologist or the study team
Do you know of a psoriasis study running at this practice or nearby?
Saving keeps this on your device and needs JavaScript, which is off in this browser.Would you look at this study record with me before I contact the site?
Saving keeps this on your device and needs JavaScript, which is off in this browser.
What decides whether you can join?
Each study writes its own entry rules, and the record lists them. For psoriasis they usually turn on two things: how much skin is involved, and what you have already taken. Evidence Evidence Evidence Evidence
How to use this step
- Reasonably supported
The Psoriasis Area and Severity Index was first set out in 1978, and a study can name a score and a bar to clear. The International Psoriasis Council uses psoriasis on 10 per cent or more of the body surface, psoriasis on a high-impact site, or failure of topical therapy. It defines that failure as not reaching clear or almost-clear skin after two four-week courses in a row. Prior treatment can rule you out as well as in. One psoriasis trial enrolled only adults who had never taken methotrexate.
Check before moving on
- Depends on you
What that means for you is that a number on a page decides a lot of this. What each score measures is set out on how severe is yours. Council criteria describe candidacy for treatment, not entry to a study. Only the study team can confirm that you qualify.
Questions for your dermatologist or the study team
What is my current severity score, and where does it sit against this study?
Saving keeps this on your device and needs JavaScript, which is off in this browser.Do the treatments I have already taken rule me out of it?
Saving keeps this on your device and needs JavaScript, which is off in this browser.
What are placebo and an open-label extension?
A placebo is a dummy treatment that looks like the real one. It is how a study separates the drug from everything else. An open-label extension is a later period in which everyone knows what they are getting. Evidence Evidence Evidence
How to use this step
- Reasonably supported
In one psoriasis trial, 91 adults received injected methotrexate and 29 received a placebo. Neither side knew which. At week 16, 41 per cent on the drug and 10 per cent on placebo reached a 75 per cent fall in their score. In cream studies the comparison is a dummy cream. Zoryve (roflumilast) reached clear or almost-clear skin in 42.4 per cent, against 6.1 per cent. CONSORT 2025 asks a report to state the design, the treatments and how people moved through the study.
Check before moving on
- Depends on you
What that means for you is that a dummy arm is real. You may spend part of the study on it. Those percentages describe groups at a stated week, not one person. Whether a study runs a later open period is set out in its own record.
Questions for your dermatologist or the study team
What are my chances of being put in the dummy group?
Saving keeps this on your device and needs JavaScript, which is off in this browser.If this study has a later open period, would I be offered a place in it?
Saving keeps this on your device and needs JavaScript, which is off in this browser.
What does consent cover, and can you leave?
Consent is a conversation and a signed form, not a formality. Ask the study team to walk you through it. Ask what leaving would mean before you sign, so the answer is not a surprise later. Evidence Evidence
How to use this step
- Reasonably supported
A registry listing does not determine that you qualify. The record names a study contact, so the terms of taking part come from that team and its review board.
Check before moving on
- Depends on you
What that means for you is that the consent form is the document that binds, so read it slowly. You can take it home, and you can bring someone with you.
Questions for your dermatologist or the study team
What happens to my care if I stop taking part partway through?
Saving keeps this on your device and needs JavaScript, which is off in this browser.Who do I contact if a question comes up after I take the form home but before I sign?
Saving keeps this on your device and needs JavaScript, which is off in this browser.
What does taking part cost you?
Time is usually the larger cost. Visits, tests, travel and time away from work add up across months. Money can move both ways, so ask about both directions in one go. Evidence Evidence
How to use this step
- Reasonably supported
One psoriasis trial ran for 52 weeks across 16 sites. A registry record lists the open locations, so the travel a study asks for can be read before anyone is contacted.
Check before moving on
- Depends on you
What that means for you is that the visit schedule is the number to get first. Payment for time, mileage and parking varies between studies. So does the handling of what a study does not cover.
Questions for your dermatologist or the study team
How many visits would this study need, and how long is each one?
Saving keeps this on your device and needs JavaScript, which is off in this browser.Which costs would be covered, and would my mileage or parking be reimbursed?
Saving keeps this on your device and needs JavaScript, which is off in this browser.
Three more questions, answered: your current treatment during a trial, whether people like you were studied, and what happens after the last visit
What happens to the treatment you are on now?
That is a prescriber conversation, and it should happen before you enrol. Some studies ask you to stop a treatment first, and to leave a gap before the first visit. That gap is called a washout. Evidence Evidence
How to use this step
- Reasonably supported
What you have already taken can decide entry. One psoriasis trial enrolled only adults who had never taken methotrexate. The council failure definition works the same way, as a written rule about earlier treatment. So a study question and a current plan belong in one conversation.
Check before moving on
- Depends on you
What that means for you is that a pause has consequences worth naming out loud. Staying on a treatment or switching is set out on reviewing your plan. What a pause tends to do is set out on will it clear or flare.
Questions for your dermatologist or the study team
Would this study ask me to stop my current treatment, and for how long?
Saving keeps this on your device and needs JavaScript, which is off in this browser.If my skin worsens during that gap, what would we do?
Saving keeps this on your device and needs JavaScript, which is off in this browser.
Were people like you in the earlier studies?
Worth checking before you read any result the team shows you. Enrollment in psoriasis research is often narrow, and a missing group is common enough to look for first. Evidence Evidence
How to use this step
- Reasonably supported
FDA guidance asks study sponsors to plan who gets enrolled, and to set goals in writing for groups left out in the past. One review of narrowband UVB covered about 1,334 people with Fitzpatrick type III through V skin, most of them from Asia. It reports no results for Fitzpatrick I and II skin. Redness can be harder to see in some skin of colour patients, so side effects may be under-reported.
Check before moving on
- Depends on you
What that means for you is that a gap limits the reading rather than settling it. A group left out is a group the earlier work cannot speak for, either way. Who was studied goes deeper into this check across the site.
Questions for your dermatologist or the study team
Has this treatment been studied in people with my skin tone?
Saving keeps this on your device and needs JavaScript, which is off in this browser.Would under-reported redness change how the team watches me for side effects?
Saving keeps this on your device and needs JavaScript, which is off in this browser.
What happens after the last visit?
Two things are worth settling early. Whether you can keep the treatment if it helped, and when the results will be published. Your own dated record is the part you keep either way. Evidence Evidence Evidence
How to use this step
- Reasonably supported
CONSORT 2025 asks a trial report to state its design, participants, treatments, outcomes, harms, analysis and participant flow. FDA watches a product once it is sold, so the record keeps moving after the last visit. The National Psoriasis Foundation backs bringing a symptom tracker to a visit, kept on paper or on a phone.
Check before moving on
- Depends on you
What that means for you is that a study ends before its story does. CONSORT is a reporting guide, not a promise that a result gets published. Dated photographs and notes are set out on tracking flares and photos. Reading the published paper afterwards is set out on the research page.
Questions for your dermatologist or the study team
If the treatment helps me, could I keep taking it after the study ends?
Saving keeps this on your device and needs JavaScript, which is off in this browser.When and where would the results of this study be published?
Saving keeps this on your device and needs JavaScript, which is off in this browser.
Evidence behind this page
Sources
Each evidence badge opens the source and its limits. The full list stays available here.
- U.S. National Library of MedicineRegulatory · Regulatory / guideline, tier 1Independent source
- Published
- SteadySkin last checked
What this source can and cannot tell you
What this source supports
Supports that ClinicalTrials.gov is a U.S. government database whose sponsor-submitted study records can include status, eligibility, locations and contacts.
What it does not support
A listing is not government approval, scientific validation, proof of benefit, a completeness guarantee or a determination that a reader qualifies.
Claim-specific review for this source is still in progress. Only the source-level evidence and limits are shown here.
- The BMJ (Hopewell S, et al.)Guideline · Regulatory / guideline, tier 1Independent source
- Published
- SteadySkin last checked
What this source can and cannot tell you
What this source supports
Supports transparent reporting of randomized-trial design, participants, interventions, outcomes, harms, analysis and participant flow so applicability and missing information can be assessed.
What it does not support
It is a reporting guideline, not a quality score, proof that a report is complete or evidence that a Vitiligo intervention works.
Claim-specific review for this source is still in progress. Only the source-level evidence and limits are shown here.
- U.S. Food and Drug AdministrationRegulatory · Regulatory / guideline, tier 1Independent source
- Published
- SteadySkin last checked
What this source can and cannot tell you
What this source supports
Supports the importance of planning enrollment for populations historically underrepresented in clinical studies and making enrollment goals explicit.
What it does not support
It is draft, nonbinding guidance restored with a federal-site notice; it does not describe representation in any particular Vitiligo trial or prove applicability to an unstudied group.
Claim-specific review for this source is still in progress. Only the source-level evidence and limits are shown here.
- U.S. Food and Drug AdministrationRegulatory · Regulatory / guideline, tier 1Independent source
- Published
- SteadySkin last checked
What this source can and cannot tell you
What this source supports
Supports the distinction between discovery, preclinical research, clinical research, FDA review and post-market monitoring in U.S. product development.
What it does not support
It is a high-level process overview, not a verdict on a specific emerging therapy, a statement that every research stage succeeds or a substitute for the current product label.
Claim-specific review for this source is still in progress. Only the source-level evidence and limits are shown here.
- International Psoriasis CouncilGuideline · Clinical research, tier 2Relevant relationship disclosed
- Published
- SteadySkin last checked
What this source can and cannot tell you
Why the independence label says this: The International Psoriasis Council names its corporate members on its own site (psoriasiscouncil.org/about/corporate-members/, checked 2026-09-11). The top tier names AbbVie, Johnson & Johnson, Eli Lilly, Novartis and Takeda. LEO Pharma, UCB, Almirall, Sun Pharma, Amgen, Alumis, Arcutis and Oruka sit below them. Those firms make the drugs this severity rule opens the door to. A wider rule on who qualifies is a wider market for them. The page says nothing about how that money relates to IPC independence.
What this source supports
Supports that IPC dropped the mild, moderate and severe scale. In its place a person is a candidate for topical therapy, or a candidate for systemic therapy. Supports that any one of three criteria is enough to be a candidate for systemic therapy. The first is psoriasis on 10% or more of the body surface. The second is psoriasis on a high-impact site. IPC names those sites as the face, palms, soles, genitalia, scalp and nails. The third is failure of topical therapy. Supports that IPC defines that failure in writing. It is not reaching clear or almost-clear skin after two four-week courses in a row. IPC gives clear or almost-clear as 1% or less body surface, with a physician global assessment of 0 or 1. Supports the source paper. It is Strober B, Ryan C, van de Kerkhof P, et al. Recategorization of psoriasis severity: Delphi consensus from the International Psoriasis Council. J Am Acad Dermatol 2020 Jan;82(1):117-122. Supports that IPC's own June 2025 teaching deck lists payers among the groups it set out to move. That deck also names refusal to pay as a result of the older scale.
What it does not support
Does not set any health plan's coverage rule. This is a professional-society consensus. It is not a regulation and not a plan document. Does not say which systemic treatment follows once a person meets a criterion. It sets no dose, no frequency and no schedule. Does not give the number of experts who voted, the response rate, or their conflict-of-interest disclosures. IPC's own June 2025 deck states the body-surface threshold two ways. Its criteria summary says 10% or more. The slide expanding that criterion says above 10%. Does not establish that a given reader meets a criterion. It predicts nothing about what a plan will decide.
Claim-specific review for this source is still in progress. Only the source-level evidence and limits are shown here.
- National Psoriasis FoundationPatient education · Patient education, tier 5Independent source
- Published
- SteadySkin last checked
What this source can and cannot tell you
What this source supports
Supports bringing a symptom tracker, kept on paper or on a phone, to share with a doctor at an appointment. Supports clearly describing symptoms and noting changes in severity and affected areas as part of preparing for a visit.
What it does not support
Does not mention photographing skin changes specifically. The page shows no visible byline or update date. The site copyright year, 2026, is used here.
Claim-specific review for this source is still in progress. Only the source-level evidence and limits are shown here.
- Dermatologica 1978;157(4):238-244 (Fredriksson T, Pettersson U)Observational study · Supporting research, tier 3Independence not established
- Published
- SteadySkin last checked
What this source can and cannot tell you
Why the independence label says this: This 1978 paper is the first description of the Psoriasis Area and Severity Index. It is not open access. Any funding or competing-interest statement could not be read, and the study itself tested a drug.
What this source supports
Supports that the Psoriasis Area and Severity Index was first described here. Supports that the index scores three features of the skin: redness, thickness and scale. Supports that each of the three is graded on a scale of 0 to 4. Supports that the amount of skin involved is graded separately, on a scale of 0 to 6. Supports that the body is divided into four regions: the head, the upper limbs, the trunk and the lower limbs. Supports that each region carries its own weight, because each holds a different share of the skin. Supports that the four region scores are added, and that the total runs from 0 to 72.
What it does not support
Does not report how closely two clinicians scoring the same skin agree. Does not say how the redness grade behaves on brown or black skin. Does not set a score at which a person qualifies for any treatment. Does not say which health plans ask for the score. Does not diagnose a reader or predict what one person will score.
Claim-specific review for this source is still in progress. Only the source-level evidence and limits are shown here.
- Canadian Agency for Drugs and Technologies in Health (CADTH)Systematic review · Clinical research, tier 2Independent source
- Published
- SteadySkin last checked
What this source can and cannot tell you
What this source supports
Supports the DERMIS-1 and DERMIS-2 phase 3 trial results at week 8: IGA success (clear or almost clear) in 42.4% (108 of 286) of the roflumilast group versus 6.1% (8 of 153) on vehicle in DERMIS-1, and 37.5% (99 of 290) versus 6.9% (9 of 152) in DERMIS-2. Supports PASI 75 (at least 75% clearer) in 41.6% versus 7.6% in DERMIS-1, and 39.0% versus 5.3% in DERMIS-2, both statistically significant.
What it does not support
This is a Canadian government health-technology-assessment review of the same pivotal trials the FDA reviewed, not a US regulatory document. It does not report results for any group narrower than the trial population as a whole (ages 12 and older), and it does not predict an individual result.
Claim-specific review for this source is still in progress. Only the source-level evidence and limits are shown here.
- PMC (National Library of Medicine)Systematic review · Clinical research, tier 2Independent source
- Published
- SteadySkin last checked
What this source can and cannot tell you
What this source supports
Supports a pooled PASI75 response rate of 70.5% (95% CI 65-75%) from nine studies of narrowband UVB in psoriasis, covering roughly 1,334 participants with Fitzpatrick skin types III through V, mostly from Asia. Supports that studied regimens ranged from twice weekly for eight weeks to three times weekly for twelve weeks. Supports that one included study reached 93.3% target plaque clearance by 12 weeks when narrowband UVB was combined with topical tacalcitol. Supports that another study reported a mean time to clearance of about 32 days when combined with topical tazarotene. Supports post-treatment hyperpigmentation as a reported consideration in darker skin tones, and notes that reduced visibility of erythema in some skin of color patients may lead to underreporting of side effects.
What it does not support
Does not report data on skin cancer risk or long-term safety monitoring, and does not report outcomes for Fitzpatrick I-II skin. Its pooled response rate should not be read as a prediction for every skin tone or population.
Claim-specific review for this source is still in progress. Only the source-level evidence and limits are shown here.
- The Lancet (Warren RB, et al.)Randomized trial · Clinical research, tier 2Independent source
- Published
- SteadySkin last checked
What this source can and cannot tell you
What this source supports
Supports a randomised, double-blind, placebo-controlled phase 3 trial of subcutaneous (injected) methotrexate in 120 methotrexate-naive adults with moderate-to-severe plaque psoriasis. It ran at 16 sites in Germany, France, the Netherlands, and the UK, with 91 participants on methotrexate and 29 on placebo. Supports a PASI75 response in 37 of 91 (41%) methotrexate participants versus 3 of 29 (10%) placebo participants at week 16. Supports that subcutaneous methotrexate was generally well tolerated over the full 52-week treatment period, with no deaths, serious infections, malignancies, or major adverse cardiovascular events. Supports serious adverse events in 3% of methotrexate participants.
What it does not support
This trial studied the injected form, not the oral tablet form, and is one study population, not a guarantee of a given response for an individual reader. Does not report outcomes for methotrexate combined with another treatment.
Claim-specific review for this source is still in progress. Only the source-level evidence and limits are shown here.