Hereditary Hemorrhagic Telangiectasia (HHT)Phase 1/2NCT07601425
Harmony-HHT: ATV-1601 in Participants With Hereditary Hemorrhagic Telangiectasia (HHT)
A Phase 1/2 study testing ATV-1601 in people with Hereditary Hemorrhagic Telangiectasia (HHT) and Osler Weber Rendu Disease, run by Atavistik Bio, Inc at 6 sites in United States.
Trial summary
This is a 2-part study evaluating ATV-1601 in participants with moderate to severe HHT. Part 1 is a randomized, double-blind, placebo-controlled study evaluating 3 dosing regimens of ATV-1601. Patients completing Part 1 may participate in the Part 2 open-label extension to receive ATV-1601. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Hereditary Hemorrhagic Telangiectasia (HHT), Osler Weber Rendu Disease
- What is being tested?
- ATV-1601
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 100 participants
- Where
- 6 sitesUnited States
- Study dates
- 27 Jul 2026to Mar 2030
- Phase
- Phase 1/2
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 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Ability to provide informed consent prior to any study-specific procedures
- Confirmed diagnosis of hereditary hemorrhagic telangiectasia (HHT) based on Curaçao criteria
- Moderate to severe HHT with an ESS ≥ 4
- Anemia at Screening and/or requirement for at least 1 red-cell unit (RUE) in the previous 6 months
- Adequate hematologic, renal, and hepatic function per protocol-defined laboratory criteria
- Use highly effective contraception during the study and for a protocol-defined period after last dose
Who cannot join
- Clinically significant abnormalities of glucose metabolism including diagnosed Type 1 or uncontrolled Type 2 diabetes
- Chronic cardiac disease, or cardiac rhythm abnormalities
- History of significant cardiovascular, hepatic, renal, or hematologic disease not related to HHT that may confound study results
- Use of prohibited concomitant medications within a protocol-defined washout period prior to first dose (including strong CYP modulators and certain herbal supplements)
- Recent (within 6 weeks) major surgery or local ablative procedures, or procedures on nasal telangiectasias
- Prior AKT inhibitor
Show all 9Show fewer
- Pregnant or breastfeeding women
- Additional Criteria for Open-Label Extension:
- Participants must complete the double-blind treatment period (Part 1)
Trial locations and contacts
6 sites in 1 country. Contact the study team or a site near you to ask about taking part.
6 sites in 1 country
United States6 sites, 6 recruiting
- Recruiting
Augusta University Medical Center
Augusta, Georgia, 30912
Study Director Atavistik, 857-285-5400, studydirector@atavistikbio.com
- Recruiting
Massachusetts General Hospital
Boston, Massachusetts, 02114
Study Director Atavistik, 857-285-5400, studydirector@atavistikbio.com
- Recruiting
Innovative Hematology
Indianapolis, Indiana, 46260
Study Director Atavistik, 857-285-5400, studydirector@atavistikbio.com
- Recruiting
Arizona Pulmonary Specialists
Phoenix, Arizona, 85013
Study Director Atavistik, 857-285-5400, studydirector@atavistikbio.com
- Recruiting
Mayo Clinic
Rochester, Minnesota, 55905
Study Director Atavistik, 857-285-5400, studydirector@atavistikbio.com
- Recruiting
University of Utah Health Sciences Center
Salt Lake City, Utah, 84132
Study Director Atavistik, 857-285-5400, studydirector@atavistikbio.com
About this study
Official title: A Randomized, Placebo-Controlled, Double-Blind, Proof-of-Concept Study of ATV-1601 in Participants With Hereditary Hemorrhagic Telangiectasia (HHT)
This is a 2-part study evaluating ATV-1601 in participants with moderate to severe HHT. Part 1 is a randomized, double-blind, placebo-controlled study evaluating 3 dosing regimens of ATV-1601. Patients completing Part 1 may participate in the Part 2 open-label extension to receive ATV-1601.
Read the detailed description
Part 1: This is a Phase 1/2 proof-of-concept, double-blind, multicenter, placebo-controlled study to evaluate the safety, pharmacokinetics and efficacy of 3 oral dosing regimens of ATV-1601. Participants who meet eligibility requirements will be randomized in a double-blind manner to one of 3 doses of ATV-1601 or placebo. Participants will receive double-blind study treatment for a 16-week period.
Part 2: Eligible participants who complete Part 1 may enroll in an open-label extension study to receive up to 2 years of additional treatment. All participants in the open-label extension will receive ATV-1601. Once the recommended Phase 2 dose (RP2D) is determined based on Part 1, all participants in Part 2 will have the option to switch to the RP2D.
- Being tested
- ATV-1601, Placebo
- Keywords
- Arteriovenous malformations, ATV-1601, HarmonyHHT, Harmony-HHT, HarmonyHHTStudy, Vascular Diseases, Bleeding disorders, Hematologic disorders, Disorders, Telangiectasias, Hereditary hemorrhagic, Hemorrhagic disorders, Cardiovascular diseases, Vascular malformations, HHT
- Medical subject headings
- Telangiectasia, Hereditary Hemorrhagic, Arteriovenous Malformations, Vascular Diseases, Hemostatic Disorders, Hematologic Diseases, Disease, Telangiectasis, Hemorrhagic Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ATV-1601Drug
Also called Active drug, capsule
Administered orally, daily
PlaceboDrug
Also called Inactive, Placebo
Administered orally, daily
| Study group | Role | What they receive |
|---|---|---|
| Part 1: 60 mg QD | Experimental | Active drug, once daily Receives: Drug: ATV-1601 |
| Part 1: 100 mg QD | Experimental | Active drug, once daily Receives: Drug: ATV-1601 |
| Part 1: 60 BID | Experimental | Active drug, twice daily Receives: Drug: ATV-1601 |
| Part 1: Placebo | Experimental | Control Arm Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Part 1: Safety and tolerability
Number and severity of treatment-emergent adverse events (TEAEs) and study drug-related TEAEs
Measured: 16 weeks
Part 2: Safety and tolerability
Type, incidence, severity, timing, seriousness and relatedness of AEs and laboratory abnormalities
Measured: 24 months
Secondary outcomes (21)
Part 1: Change in Epistaxis duration
28-day total duration compared to baseline
Measured: 16 weeks
Part 1: Epistaxis frequency
28-day frequency of nosebleeds compared to baseline
Measured: 16 weeks
Part 1: Epistaxis intensity
28-day average epistaxis intensity (6-point scale) of nosebleeds compared to baseline
Measured: 16 weeks
Part 1: Intensity-weighted epistaxis duration
28-day intensity-weighted duration of nosebleeds
Measured: 16 weeks
Part 1: Epistaxis Severity Score (ESS)
The Epistaxis Severity Score (ESS) is a validated 6-question instrument with scores ranging from 0 to 10, where higher scores indicate more severe epistaxis symptoms.
Measured: 16 weeks
Part 1: Change in Hemoglobin
Hemoglobin levels compared to baseline
Measured: 16 weeks
Part 1: Change in Parenteral iron use
Amount of parenteral iron administered compared to 16-weeks prior to treatment initiation
Measured: 16 weeks
Part 1: Change in Blood transfusion requirements
Amount of packed red blood cell (PRBC) transfusions and rate of transfusion independence compared to 16-weeks prior to treatment initiation
Measured: 16 Weeks
Part 1: Pharmacokinetics - Maximum observed concentration (Cmax)
Maximum plasma concentration
Measured: 16 Weeks
Part 1: Pharmacokinetics - Area under the concentration-time curve over the dosing interval (AUCtau)
Systemic exposure of ATV-1601 over the dosing interval
Measured: 16 Weeks
Part 1: Pharmacokinetics - Area under the concentration-time curve extrapolated to infinity (AUCinf)
Total systemic exposure of ATV-1601 extrapolated to infinite time
Measured: 16 Weeks
Part 1: Pharmacokinetics - Time to maximum concentration (Tmax)
Time to reach maximum plasma concentration
Measured: 16 Weeks
Part 1: Pharmacokinetics - minimum concentration (Cmin)
Pre-dose trough plasma concentration
Measured: 16 Weeks
Part 1: Pharmacokinetics - Half-life (t½)
Time required for plasma concentration to decrease by half
Measured: 16 Weeks
Part 2: Epistaxis duration
28-day total duration every 4 weeks
Measured: Up to 2 years
Part 2: Epistaxis frequency
Total number of nosebleeds every 4 weeks
Measured: Up to 2 years
Part 2: Epistaxis Severity Score (ESS)
Severity of nosebleeds using a score of 0-10 automatically calculated based on responses to 6 questions.
Measured: At 12 weeks and every 12 weeks thereafter up to study completion
Part 2: Change in Hemoglobin
Hemoglobin levels compared to baseline
Measured: Monthly during Part 2
Part 2: Parenteral iron use
Total amount of parenteral iron infused (mg) compared to baseline (12 weeks prior to treatment initiation
Measured: At 12 weeks and every 12 weeks thereafter up to study completion
Part 2: Blood transfusion requirements
Total number of packed red blood cell (PRBC) transfusions (units) compared to baseline
Measured: At 12 weeks and every 12 weeks thereafter during part 2
Part 2: Transfusion independence
Proportion of participants who do not require PRBC transfusions
Measured: At 12 weeks and every 12 weeks thereafter during part 2
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 May 2026
- Study start27 Jul 2026
- Primary completionDec 2027 (estimated)
- Study completionMar 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Hereditary Hemorrhagic Telangiectasia (HHT)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 1/2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants will be randomized to one of 3 doses of ATV-1601 or placebo
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Atavistik Bio, Inc
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07601425
- Sponsor's protocol ID
- ATV-1601-102
- Other IDs
- Harmony-HHT
- Status last verified
- Aug 2026
- First submitted
- 12 May 2026
- Last updated
- 5 Oct 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No