Chronic Pruritus of Unknown OriginPhase 2NCT07833306
Efficacy and Safety of ATTO-1310 in the Treatment of Participants With Chronic Pruritus of Unknown Origin
A Phase 2 study testing ATTO-1310 in people with Chronic Pruritus of Unknown Origin, run by Attovia Therapeutics Inc.
Trial summary
The goal of this clinical trial is to assess the efficacy and safety of ATTO-1310 in patients with chronic pruritus/itch of unknown origin. The main questions it aims to answer are: Does ATTO-1310 treatment alleviate symptoms of itch in participants with chronic pruritus/itch? What medical problems do participants… Read more about this study
- Who is it for?
- Ages 18 to 90 years
- Conditions the study is for
- Chronic Pruritus of Unknown Origin
- What is being tested?
- ATTO-1310
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 300 participants
- Where
- No sites listed yet
- Study dates
- 21 Dec 2026to 30 Oct 2028
- Phase
- Phase 2
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 to 90 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Aged 18 to 90 years with a body weight of 50 to 125 kg and body mass index (BMI) between 18.5 and 40 kg/m^2.
- History of chronic pruritus for at least 6 months that is considered of unknown origin (without a clear association to another condition or medication) as assessed by the Investigator.
- Chronic pruritus must affect at least 2 of the following body areas: legs, arms, or trunk.
- History of inadequate control of pruritus with at least 1 antihistamine within 6 months of Screening.
- Patient Global Impression of Severity (PGI-S) of pruritus of "severe" at Screening.
- Use of a stable dose of topical bland emollient twice daily for at least 2 weeks immediately before Day 1
- Weekly mean of daily WI-NRS ≥7 at Day 1
- Negative pregnancy test
Who cannot join
- Known condition, other than dry skin, that is considered by the Investigator to be the primary cause of chronic pruritus, including: Presence of a primary dermatologic condition associated with pruritic skin lesions, regional neuropathic pruritus with the exception of peripheral small fiber neuropathy, severe renal failure, hepatobiliary disease, recent infectious dermatoses, suspected somatoform pruritus, ongoing drug-induced pruritus, malignancy or hemopathy, uncontrolled endocrine disease,
- Liver function tests (bilirubin, AST, ALT, alkaline phosphatase) >2.5 times above the upper limit of normal
- Estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m²
- History of malignancy within 5 years of Screening
- History of severe or uncontrolled asthma
- History of known primary immunodeficiency, is considered immunocompromised, or has been treated for a parasitic infection in the past 6 months.
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- History of attempted suicide within the past 2 years.
- History of hypersensitivity (including anaphylaxis) to a biologic medication, vaccine, an immunoglobulin product (plasma-derived or recombinant, eg, monoclonal antibody), or to any of the IP excipients
- Active hepatitis B virus (HBV) or hepatitis C virus (HCV) or is positive for HIV.
- Active or untreated latent tuberculosis (TB) infection.
- Any infection requiring treatment with oral or parenteral antibiotics, antivirals, antiparasitics, or antifungals within 2 weeks before Day 1.
- History of drug or alcohol abuse within 1 year of Screening
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: A Phase 2, Multicenter, Randomized, Double-Blind, Placebo-Controlled Study to Assess the Efficacy and Safety of ATTO-1310 for the Treatment of Participants With Chronic Pruritus of Unknown Origin
The goal of this clinical trial is to assess the efficacy and safety of ATTO-1310 in patients with chronic pruritus/itch of unknown origin.
The main questions it aims to answer are:
Does ATTO-1310 treatment alleviate symptoms of itch in participants with chronic pruritus/itch? What medical problems do participants have when taking ATTO-1310 for 24 weeks? Researchers will compare ATTO-1310 to a placebo (a look-alike substance that contains no drug). Participants will be dosed with ATTO-1310 or a placebo, visit the clinic for checkups and tests, and keep a diary of their symptoms.
Read the detailed description
This is a Phase 2, multicenter, randomized, double-blind, placebo-controlled, dose-ranging study to evaluate the efficacy and safety of ATTO-1310 in adults with chronic pruritus/itch of unknown origin (CPUO). Participants with CPUO will receive one of three induction treatments (low dose ATTO-1310, high dose ATTO-1310, or placebo) for 12 weeks. Following induction, participants will be assessed for response to treatment. Response to the 12 week induction treatment will determine their treatment progression for the maintenance period. Responders will be re-randomized to one of 4 ATTO-1310 active treatment regimens (high or low dose combined with frequent or infrequent dosing). Non-responders and participants who received placebo during the induction period will be assigned to receive a high dose high frequency ATTO-1310 regimen for the maintenance period through 28 weeks. Participants will be followed for safety through week 36.
- Conditions
- Chronic Pruritus of Unknown Origin
- Being tested
- ATTO-1310, Placebo
- Keywords
- pruritus, CPUO, itch, itchy
- Medical subject headings
- Pruritus
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ATTO-1310Drug
ATTO-1310
PlaceboDrug
Placebo preparation to match ATTO-1310 dose
| Study group | Role | What they receive |
|---|---|---|
| ATTO-1310 Dose A | Experimental | ATTO-1310 high dose induction Receives: Drug: ATTO-1310 |
| ATTO-1310 Dose B | Experimental | ATTO-1310 low dose induction Receives: Drug: ATTO-1310 |
| Placebo | Experimental | Placebo induction Receives: Drug: Placebo |
| ATTO-1310 Dose C | Experimental | ATTO-1310 high dose high frequency maintenance Receives: Drug: ATTO-1310 |
| ATTO-1310 Dose D | Experimental | ATTO-1310 high dose low frequency maintenance Receives: Drug: ATTO-1310 |
| ATTO-1310 Dose E | Experimental | ATTO-1310 low dose high frequency maintenance Receives: Drug: ATTO-1310 |
| ATTO-1310 dose F | Experimental | ATTO-1310 low dose low frequency maintenance Receives: Drug: ATTO-1310 |
What is being measured
The primary outcome is the main question the study is designed to answer.
≥4-point improvement from baseline in Worst Itch Numerical Rating Scale (WI-NRS) at Week 12 (WI-NRS4 response)
Participants achieved a response if their WI-NRS improved 4 or more points from baseline on a scale ranging from zero (no itch) to 10 (worst possible itch). The baseline is calculated as the average in the final week prior to Day 1. The WI-NRS4 response endpoint at Week 12 is calculated as the average of the daily WI-NRS during Week 12 visit relative to the baseline average WI-NRS.
Measured: Baseline and Week 12
Secondary outcomes (19)
WI-NRS4 response at Week 4
Participants achieved a response if they had an improvement of at least 4 points on a scale ranging from 0 (no itch) to 10 (worst possible itch).
Measured: Baseline and Week 4
≥5-point improvement from baseline in WI-NRS (WI-NRS5 response) at Week 4
Participants achieved a response if they scored a 5 or more point improvement from baseline on a scale ranging from 0 (no itch) to 10 (worst possible itch).
Measured: Baseline and Week 4
≥5-point improvement from baseline in WI-NRS (WI-NRS5 response) at Week 12
Participants achieved a response if they scored a 5 or more point improvement from baseline on a scale ranging from 0 (no itch) to 10 (worst possible itch).
Measured: Baseline and Week 12
WI-NRS <2 (WI-NRS<2 response) at Week 4
Participants achieved a response if their WI-NRS score was less than 2 at Week 4
Measured: Week 4
WI-NRS <2 (WI-NRS<2 response) at Week 12
Participants achieved a response if their WI-NRS score was less than 2 at Week 4
Measured: Week 12
Patient Global Impression of Severity (PGI-S) of pruritus of "none" or "mild" at Week 4
Participant's impression of severity of itching over the past 7 days on a 4-point Likert scale with the options of: none, mild, moderate, or severe.
Measured: Week 4
Patient Global Impression of Severity (PGI-S) of pruritus of "none" or "mild" at Week 12
Participant's impression of severity of itching over the past 7 days on a 4-point Likert scale with the options of: none, mild, moderate, or severe.
Measured: Week 12
Absolute change from baseline in weekly average WI-NRS at Week 4
WI-NRS score of zero is equivalent to "no itch" and 10 is equivalent to "worst possible itch". Positive change from baseline will indicate worsening of itch. Negative change from baseline will indicate improvement. No change from baseline will indicate no improvement.
Measured: Baseline, Week 4
Absolute change from baseline in weekly average WI-NRS at Week 12
WI-NRS score of zero is equivalent to "no itch" and 10 is equivalent to "worst possible itch". Positive change from baseline will indicate worsening of itch. Negative change from baseline will indicate improvement. No change from baseline will indicate no improvement.
Measured: Baseline, Week 12
Percent change from baseline in weekly average WI-NRS at Week 4
WI-NRS score of zero is equivalent to "no itch" and 10 is equivalent to "worst possible itch". Positive percent change from baseline will indicate worsening of itch. Negative Percent change from baseline will indicate improvement. No change from baseline will indicate no improvement.
Measured: Baseline, Week 4
Percent change from baseline in weekly average WI-NRS at Week 12
WI-NRS score of zero is equivalent to "no itch" and 10 is equivalent to "worst possible itch". Positive percent change from baseline will indicate worsening of itch. Negative Percent change from baseline will indicate improvement. No change from baseline will indicate no improvement.
Measured: Baseline, Week1 12
Absolute change from baseline in weekly average itch-related sleep disruption NRS (iSD-NRS) at Week 4
iSD-NRS score of 0 is equivalent to "itching did not disrupt my sleep" and 10 indicates "complete disruption, I was unable to sleep because of itching." Positive change from baseline will indicate worsening of sleep disruption due to itch. Negative change from baseline will indicate improvement. No change from baseline will indicate no improvement.
Measured: Baseline, Week 4
Absolute change from baseline in weekly average itch-related sleep disruption NRS (iSD-NRS) at Week 12
iSD-NRS score of 0 is equivalent to "itching did not disrupt my sleep" and 10 indicates "complete disruption, I was unable to sleep because of itching." Positive change from baseline will indicate worsening of sleep disruption due to itch. Negative change from baseline will indicate improvement. No change from baseline will indicate no improvement.
Measured: Baseline, Week 12
Percent change from baseline in weekly average iSD-NRS at Week 4
iSD-NRS score of 0 is equivalent to "itching did not disrupt my sleep" and 10 indicates "complete disruption, I was unable to sleep because of itching." Positive percent change from baseline will indicate worsening of itch. Negative percent change from baseline will indicate improvement. No change from baseline will indicate no improvement.
Measured: Baseline, Week 4
Percent change from baseline in weekly average iSD-NRS at Week 12
iSD-NRS score of 0 is equivalent to "itching did not disrupt my sleep" and 10 indicates "complete disruption, I was unable to sleep because of itching." Positive percent change from baseline will indicate worsening of itch. Negative percent change from baseline will indicate improvement. No change from baseline will indicate no improvement.
Measured: Baseline, Week 12
WI-NRS4 response through Week 28
Participants achieved a response if they had a 4 or more point improvement in WI-NRS on a scale where zero is "no itch" and 10 is equivalent to "worst possible itch".
Measured: Weekly through Week 28
Absolute change from baseline in weekly average WI-NRS through Week 28
WI-NRS score of zero is equivalent to "no itch" and 10 is equivalent to "worst possible itch". Positive change from baseline will indicate worsening of itch. Negative change from baseline will indicate improvement. No change from baseline will indicate no improvement.
Measured: Baseline and weekly through week 28
Percent change from baseline in weekly average WI-NRS through Week 28
WI-NRS score of zero is equivalent to "no itch" and 10 is equivalent to "worst possible itch". Positive percent change from baseline will indicate worsening of itch. Negative Percent change from baseline will indicate improvement. No change from baseline will indicate no improvement.
Measured: Baseline and weekly through Week 28
Incidence and severity of treatment-emergent adverse events (TEAEs) or serious adverse events (SAEs) from baseline through end of study (EOS)
The analysis will describe the incidence of AEs and laboratory abnormalities from baseline through end of study. AEs will be coded according to system organ class and preferred term using the Medical Dictionary for Regulatory Activities (MedDRA). Their severity will be graded using the NCI CTCAE V6.0 or current version.
Measured: Baseline through Day 253 (EOS)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Sep 2026
- Study start21 Dec 2026 (estimated)
- Primary completion30 Aug 2028 (estimated)
- Study completion30 Oct 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Chronic Pruritus of Unknown OriginStudies 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
- Model description
- Randomized, Double-Blind, Placebo-Controlled; Randomization to 12 week Induction treatment regimen followed by re-randomization to Maintenance treatment regimen
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 300 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Attovia Therapeutics Inc
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Hubert Chen, MD, Study director, Attovia Therapeutics Inc
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07833306
- Sponsor's protocol ID
- ATTO-1310-201
- Other IDs
- 2026-527672-93
- Status last verified
- Sep 2026
- First submitted
- 16 Sep 2026
- Last updated
- 22 Sep 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Undecided