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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 10 sites in 2 countries.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
Search all trials

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
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
10 sitesin 2 countries
Study dates
27 Jul 2026to Mar 2030
Phase
Phase 1/2
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
  • 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

10 sites in 2 countries. Contact the study team or a site near you to ask about taking part.

10 sites in 2 countries

United States9 sites, 9 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

  • University of North Carolina

    Chapel Hill, North Carolina, 27599

    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

    Recruiting

  • University of California, San Diego

    San Diego, California, 92161

    Study Director Atavistik, 857-285-5400, studydirector@atavistikbio.com

    Recruiting

  • Washington University in St. Louis

    St Louis, Missouri, 63110

    Study Director Atavistik, 857-285-5400, studydirector@atavistikbio.com

    Recruiting

Other trials in United States

Argentina1 site, 1 recruiting

  • Hospital Italiano de Buenos Aires

    Buenos Aires, C1199ABB

    Study Director Atavistik, 857-285-5400, studydirector@atavistikbio.com

    Recruiting

Other trials in Argentina

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 groups in NCT07601425
Study groupRoleWhat they receive
Part 1: 60 mg QDExperimentalActive drug, once daily
Receives: Drug: ATV-1601
Part 1: 100 mg QDExperimentalActive drug, once daily
Receives: Drug: ATV-1601
Part 1: 60 BIDExperimentalActive drug, twice daily
Receives: Drug: ATV-1601
Part 1: PlaceboExperimentalControl Arm
Receives: Drug: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Part 1: Safety and tolerability

    Number and severity of treatment-emergent adverse events (TEAEs) and study drug-related TEAEs

    Measured: 16 weeks

  2. Part 2: Safety and tolerability

    Type, incidence, severity, timing, seriousness and relatedness of AEs and laboratory abnormalities

    Measured: 24 months

Secondary outcomes (21)

  1. Part 1: Change in Epistaxis duration

    28-day total duration compared to baseline

    Measured: 16 weeks

  2. Part 1: Epistaxis frequency

    28-day frequency of nosebleeds compared to baseline

    Measured: 16 weeks

  3. Part 1: Epistaxis intensity

    28-day average epistaxis intensity (6-point scale) of nosebleeds compared to baseline

    Measured: 16 weeks

  4. Part 1: Intensity-weighted epistaxis duration

    28-day intensity-weighted duration of nosebleeds

    Measured: 16 weeks

  5. 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

  6. Part 1: Change in Hemoglobin

    Hemoglobin levels compared to baseline

    Measured: 16 weeks

  7. Part 1: Change in Parenteral iron use

    Amount of parenteral iron administered compared to 16-weeks prior to treatment initiation

    Measured: 16 weeks

  8. 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

  9. Part 1: Pharmacokinetics - Maximum observed concentration (Cmax)

    Maximum plasma concentration

    Measured: 16 Weeks

  10. 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

  11. 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

  12. Part 1: Pharmacokinetics - Time to maximum concentration (Tmax)

    Time to reach maximum plasma concentration

    Measured: 16 Weeks

  13. Part 1: Pharmacokinetics - minimum concentration (Cmin)

    Pre-dose trough plasma concentration

    Measured: 16 Weeks

  14. Part 1: Pharmacokinetics - Half-life (t½)

    Time required for plasma concentration to decrease by half

    Measured: 16 Weeks

  15. Part 2: Epistaxis duration

    28-day total duration every 4 weeks

    Measured: Up to 2 years

  16. Part 2: Epistaxis frequency

    Total number of nosebleeds every 4 weeks

    Measured: Up to 2 years

  17. 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

  18. Part 2: Change in Hemoglobin

    Hemoglobin levels compared to baseline

    Measured: Monthly during Part 2

  19. 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

  20. 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

  21. 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.

  1. First posted22 May 2026
  2. Study start27 Jul 2026
  3. Primary completionDec 2027 (estimated)
  4. Study completionMar 2030 (estimated)

Resources

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)
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
6 Nov 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

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 10 sites in 2 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 9 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: looking for participants now, as of the sponsor's last update on 6 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 10 sites in United States, Argentina. 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. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this combined phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

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?

Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Part 1: Safety and tolerability (time frame: 16 weeks). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07601425.

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 6 Nov 2026; AzTrials last refreshed its copy on 8 Nov 2026.

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