Cure HHT has led the development of the first international consensus on how to define, measure, and track bleeding in Hereditary Hemorrhagic Telangiectasia (HHT), published July 15 in the American Journal of Hematology. This global report introduces standardized tools and criteria—such as the Hematologic Support Score and Hematologic Impact Score—to improve the consistency and effectiveness of clinical trials. With no FDA-approved therapies for HHT to date, these new standards remove a critical barrier to drug development and pave the way for future treatments. The effort reflects one of the most significant collaborations in HHT research and underscores Cure HHT's leadership in advancing care and cures for the HHT community.
MONKTON, Md., July 18, 2025 /PRNewswire-PRWeb/ -- A newly published international consensus report—developed under the leadership of Cure HHT, the only nonprofit organization in the world dedicated to funding global research, awareness, and education for Hereditary Hemorrhagic Telangiectasia (HHT)—marks a major step forward in standardizing how bleeding is assessed in HHT. Published July 15 in the American Journal of Hematology, the report, "Standardization of Terminology, Definitions, and Outcome Criteria for Bleeding in Hereditary Hemorrhagic Telangiectasia," establishes the first unified global framework for evaluating bleeding in clinical studies of HHT — a critical advancement poised to transform clinical research, accelerate therapeutic development, and ultimately improve patient care.
HHT, also known as Osler-Weber-Rendu syndrome, is a rare genetic disorder that affects blood vessels and is the second most common inherited bleeding disorder, impacting approximately 1 in 5,000 people worldwide. People with HHT often experience frequent and spontaneous nosebleeds, chronic gastrointestinal bleeding, and anemia due to blood loss. The disease can also lead to serious complications from arteriovenous malformations (AVMs) — abnormal connections between arteries and veins — which may occur in major organs such as the lungs, liver, and brain. These AVMs can cause life-threatening issues including stroke, brain abscess, heart failure, and internal hemorrhage. Despite its prevalence and severity, the lack of consistent language and standardized criteria for measuring comprehensive bleeding has been a major barrier to developing effective therapies for HHT.
To address this critical gap, Cure HHT convened its Global Research and Medical Advisory Board (known as GRMAB) — an international panel of the world's leading HHT clinical, scientific, and research experts. Working in collaboration, Cure HHT and GRMAB spearheaded the development of this report to provide the first global consensus on how bleeding in HHT should be measured, categorized, and tracked in clinical research and care. The resulting framework defines clear criteria for classifying bleeding severity, introduces standardized goals for treatment, and provides validated methodologies for assessing outcomes such as epistaxis (nosebleeds) frequency, gastrointestinal blood loss, anemia, and health-related quality of life.
The report also introduces two important tools — the Hematologic Support Score (HSS) and Hematologic Impact Score (HIS) — composite measures that track a patient's need for iron and blood transfusions over time. These scores address a longstanding gap in HHT research: traditional measures like hemoglobin levels often don't reflect the full impact of chronic bleeding. By offering a more complete and consistent view of a patient's condition, HSS and HIS make it easier to evaluate how well treatments are working and to compare outcomes across clinical trials. The report also sets clear definitions for treatment response and non-response, providing researchers and regulators with essential benchmarks to assess therapies and guide future drug development.
"This is a watershed moment for the global HHT community," said Marianne Clancy, MPA, Chief Executive Officer of Cure HHT and co-author of the report. "By establishing these long-overdue standards, we are giving researchers, clinicians, pharmaceutical partners, and regulatory agencies such as FDA and EMA the tools and framework they need to accelerate the development of life-changing therapies for a patient population that has been overlooked for far too long."
"This consensus fills a decades-long void in the HHT field," added Dr. Hanny Al-Samkari, MD, Chairperson of the 23-member HHT International Consensus Report Working Group and lead author of the report, who serves as the Peggy S. Blitz Endowed Chair in Hematology/Oncology at the Massachusetts General Hospital, an Associate Professor of Medicine at Harvard Medical School, and Co-Director of the HHT Center of Excellence at Massachusetts General Hospital. "We now have a clear and practical roadmap to assess bleeding severity, design more rigorous clinical trials, and ultimately guide therapies more quickly and effectively through regulatory approval. Researchers around the world can now speak the same 'language' of research in HHT for the first time. It cannot be overstated: This is a foundational step forward for HHT research, drug development, and patient care. This is a tremendous achievement by all involved."
Driven by Cure HHT's leadership, this publication marks one of the most impactful collaborations and unification efforts in HHT care and research to date — laying the groundwork for standardized clinical trials and a globally aligned approach to treating bleeding in HHT. As interest in the disease grows among researchers and drug developers, clear, consistent standards are essential to help move promising therapies forward more efficiently. While no FDA-approved treatments for HHT currently exist, several clinical trials are underway — with more on the horizon — that will directly benefit from the standardized definitions and outcome measures established in this report.
For over 30 years, Cure HHT has been the only organization in the world focused solely on finding a cure for HHT and improving the well-being of those affected. Through advocacy, strategic research funding, and global collaboration, Cure HHT has played a pivotal role in every major advancement in the field. The release of this international consensus report marks another defining achievement in Cure HHT's mission to transform research and care.
For more information, visit www.curehht.org.
About Cure HHT
Cure HHT is the only organization in the world solely dedicated to finding a cure for HHT and improving the lives of those affected by the disease. For over 30 years, Cure HHT has led the charge in advancing research, building clinical infrastructure, advocating for federal funding, and connecting patients with expert care. The organization has established a global network of HHT Centers of Excellence, secured millions in NIH research investment, and catalyzed the first large-scale clinical trials for HHT treatments. Through patient advocacy, professional education, and groundbreaking initiatives, Cure HHT continues to drive innovation and hope for the HHT community.
Media Contact
Riley Blevins, Cure HHT, 1 410-357-9932, [email protected], curehht.org
SOURCE Cure HHT
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