Hidradenitis Suppurativa (HS)Phase 2CitylightsNCT06993233
A Study With CIT-013 in HS Patients
A Phase 2 study testing CIT-013 high dose and CIT-013 medium dose in people with Hidradenitis Suppurativa (HS), run by Citryll BV at 28 sites in 6 countries.
Trial summary
The goal of this clinical trial is to learn if CIT-013 works to treat Hidradenitis Suppurativa in adults. It will also learn about the safety of CIT-013. The main questions it aims to answer are: Does CIT-013 lower the disease activity of HS patients? What medical problems do participants have when receiving CIT-013?… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Hidradenitis Suppurativa (HS)
- What is being tested?
- CIT-013 high dose and CIT-013 medium dose
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 108 participants
- Where
- 28 sitesin 6 countries
- Study dates
- 31 Oct 2025to Jul 2027
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Male or female participants with HS of more than 6 months duration,
- 18 years of age at screening visit,
- Hidradenitis suppurativa lesions present in ≥ 2 distinct anatomic areas, one of which is Hurley Stage II or III (according to Hurley classification system),
- A total abscess and inflammatory nodule (AN) count of ≥ 5 at screening and Day 1 prior to enrollment/randomization,
- Participant must have had an inadequate response to oral antibiotics OR exhibited recurrence after discontinuation to, OR demonstrated intolerance to, OR have a contraindication to oral antibiotics for treatment of their HS,
- Total draining tunnel count less than 20
Who cannot join
- Participants for whom an approved therapy with demonstrated clinical benefit is indicated, available and expected to be tolerated, OR choose to proceed with standard of care treatment options over the IP (after being appropriately informed of the treatment options, risks, and benefits).
- Any current and/or recurrent clinically significant skin condition in the treatment area other than HS,
- Prior treatment with a recombinant therapeutic protein during the 6 weeks before baseline
- Prior treatment with any of the following medications before baseline:
- Any other systemic therapy for HS (28 days before baseline)
- Any IV anti-infective therapy (14 days before baseline)
- History of malignancy with exception of non-melanoma skin cancer that has been excised and cured,
Trial locations and contacts
28 sites in 6 countries.
28 sites in 6 countries
Poland8 sites
PL-06
Bialystok
PL-08
Gdansk
PL-03
Katowice
PL-02
Lodz
PL-10
Lodz
PL-09
Poznan
PL-01
Rzeszów
PL-05
Wroclaw
Germany6 sites
DE-06
Bad Bentheim
DE-01
Bochum
DE-04
Dresden
DE-02
Frankfurt
DE-08
Kiel
DE-03
Oldenburg
Canada5 sites
CA-01
Barrie
CA-05
Calgary
CA-02
London
CA-04
Newmarket
CA-03
Winnipeg
Spain5 sites
ES-05
Barcelona
ES-04
Madrid
ES-02
Santiago de Compostela
ES-03
Seville
ES-01
Valencia
About this study
Official title: A Phase 2a Double Blind, Randomized, Parallel Arm, Placebo-controlled Trial to Investigate the Effects of Two Dose Levels of CIT-013 on Disease Activity in Patients With Hidradenitis Suppurativa
The goal of this clinical trial is to learn if CIT-013 works to treat Hidradenitis Suppurativa in adults. It will also learn about the safety of CIT-013. The main questions it aims to answer are:
Does CIT-013 lower the disease activity of HS patients? What medical problems do participants have when receiving CIT-013? Researchers will compare CIT-013 to a placebo (a look-alike substance that contains no drug) to see if CIT-013 works to treat the symptoms of HS.
Participants will:
Take receive 50 or 100 mg CIT-013 or placebo every other week for 12 weeks Visit the clinic once every 2 weeks for checkups and tests Keep monitor their symptoms during this period
- Conditions
- Hidradenitis Suppurativa (HS)
- Being tested
- CIT-013 high dose, CIT-013 medium dose, Placebo
- Medical subject headings
- Hidradenitis Suppurativa
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CIT-013 high doseDrug
subcutaneous injection
CIT-013 medium doseDrug
subcutaneous injection
PlaceboDrug
subcutaneous injection
| Study group | Role | What they receive |
|---|---|---|
| CIT-013 high dose | Experimental | 6 SC injections with CIT-013 high dose Receives: Drug: CIT-013 high dose |
| CIT-013 medium dose | Experimental | 6 SC injections with CIT-013 medium dose Receives: Drug: CIT-013 medium dose |
| Placebo | Placebo comparator | 6 SC injections with placebo Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Proportion of participants with HiSCR75 on CIT 013 versus placebo
Measured: week 12
Secondary outcomes (2)
Incidence of TEAEs as assessed by CTCAE
Measured: week 12
Maximum Plasma Concentration of CIT-013 before doses
Measured: 4, 6, 10 and 12 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 May 2025
- Study start31 Oct 2025
- Primary completionApr 2027 (estimated)
- Study completionJul 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Hidradenitis Suppurativa (HS)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 108 participants (actual)
Sponsor and investigators
- Lead sponsor
- Citryll BV
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Maarten Kraan, Study director, Citryll BV
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06993233
- Sponsor's protocol ID
- CITRYLL003
- Acronym
- Citylights
- Status last verified
- Nov 2025
- First submitted
- 19 May 2025
- Last updated
- 19 Oct 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 19 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 2a Double Blind, Randomized, Parallel Arm, Placebo-controlled Trial to Investigate the Effects of Two Dose Levels of CIT-013 on Disease Activity in Patients With Hidradenitis Suppurativa
- ClinicalTrials.gov ID
- NCT06993233
- Acronym / sponsor ID
- Citylights / CITRYLL003
- Conditions
- Hidradenitis Suppurativa (HS)
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 108 participants (actual)
- Lead sponsor
- Citryll BVIndustry (pharma, biotech, devices)
- Study start
- 31 Oct 2025 (actual)
- Primary completion
- Apr 2027 (estimated)
- Study completion
- Jul 2027 (estimated)
- First posted
- 28 May 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this clinical trial is to learn if CIT-013 works to treat Hidradenitis Suppurativa in adults. It will also learn about the safety of CIT-013. The main questions it aims to answer are:
Does CIT-013 lower the disease activity of HS patients? What medical problems do participants have when receiving CIT-013? Researchers will compare CIT-013 to a placebo (a look-alike substance that contains no drug) to see if CIT-013 works to treat the symptoms of HS.
Participants will:
Take receive 50 or 100 mg CIT-013 or placebo every other week for 12 weeks Visit the clinic once every 2 weeks for checkups and tests Keep monitor their symptoms during this period
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| CIT-013 high dose | Experimental | Drug: CIT-013 high dose6 SC injections with CIT-013 high dose |
| CIT-013 medium dose | Experimental | Drug: CIT-013 medium dose6 SC injections with CIT-013 medium dose |
| Placebo | Placebo comparator | Drug: Placebo6 SC injections with placebo |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Male or female participants with HS of more than 6 months duration,
- 18 years of age at screening visit,
- Hidradenitis suppurativa lesions present in ≥ 2 distinct anatomic areas, one of which is Hurley Stage II or III (according to Hurley classification system),
- A total abscess and inflammatory nodule (AN) count of ≥ 5 at screening and Day 1 prior to enrollment/randomization,
- Participant must have had an inadequate response to oral antibiotics OR exhibited recurrence after discontinuation to, OR demonstrated intolerance to, OR have a contraindication to oral antibiotics for treatment of their HS,
Key exclusion criteria (7 listed)
- Participants for whom an approved therapy with demonstrated clinical benefit is indicated, available and expected to be tolerated, OR choose to proceed with standard of care treatment options over the IP (after being appropriately informed of the treatment options, risks, and benefits).
- Any current and/or recurrent clinically significant skin condition in the treatment area other than HS,
- Prior treatment with a recombinant therapeutic protein during the 6 weeks before baseline
- Prior treatment with any of the following medications before baseline:
- History of malignancy with exception of non-melanoma skin cancer that has been excised and cured,
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| CIT-013 high dosesubcutaneous injection | Drug | CIT-013 high dose |
| CIT-013 medium dosesubcutaneous injection | Drug | CIT-013 medium dose |
| Placebosubcutaneous injection | Drug | Placebo |
Primary outcome
Proportion of participants with HiSCR75 on CIT 013 versus placebo
Time frame: week 12
2 secondary outcomes
Incidence of TEAEs as assessed by CTCAE
Time frame: week 12
Maximum Plasma Concentration of CIT-013 before doses
Time frame: 4, 6, 10 and 12 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 19 Oct 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Maarten Kraan study director
Citryll BV
28 sites in 6 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing CIT-013 high dose and CIT-013 medium dose in people with Hidradenitis Suppurativa (HS), run by Citryll BV at 28 sites in 6 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 19 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 28 sites in Poland, Germany, Canada, Spain, United Kingdom and 1 more country. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Proportion of participants with HiSCR75 on CIT 013 versus placebo (time frame: week 12). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 19 Oct 2026.