DOI: 10.60645/bdc-8g0r-uv68
title: Pomalidomide for the Treatment of Bleeding in HHT (PATH-HHT)

description: 
**Data Access NOTE**: Please refer to the "Authorized Access" section below for information about how access to the data from this accession differs from many other dbGaP accessions.

**Objectives**: To determine efficacy (reduction in severity of epistaxis), tolerability, and improvement in quality of life of pomalidomide compared to placebo after 24 weeks of treatment.<br>

**Background**: This study addresses the efficacy of pomalidomide in the treatment of epistaxis in patients with Hereditary Hemorrhagic Telangiectasia (HHT) who have anemia and/or require blood transfusion or iron infusion for treatment of bleeding-induced anemia and iron deficiency. HHT (also known as Osler-Weber-Rendu disease) is an inherited bleeding disorder. Over 95% of patients develop recurrent epistaxis, which may be severe and result in chronic anemia, need for iron infusions and blood transfusions, substantial psychiatric comorbidity (including depression and post-traumatic stress disorder) and reduction in health-related quality of life (HRQoL). HHT is clinically diagnosed using the Curacao criteria, which consists of 1) spontaneous and recurrent epistaxis, 2) telangiectasias at characteristic sites, 3) visceral arteriovenous malformations (AVMs) or telangiectasias, and 4) a first degree relative with HHT (inheritance is usually autosomal dominant). Patients with three criteria are considered to have definite HHT, and those with 2 criteria probable HHT. HHT affects approximately 1 in 3,800 individuals. Significant manifestations of HHT often do not appear until the third or fourth decades, sometimes later.

**Participants**: 144 patients from 11 clinical centers were enrolled.<br>

**Design**: This is a multi-center, double blind, randomized placebo-controlled trial that investigated the efficacy and safety of pomalidomide in patients with HHT and chronic epistaxis leading to iron-deficiency anemia or requiring intravenous iron infusions or blood transfusion.

Screening evaluation included the Epistaxis Severity Score (ESS) with three-month recall, which reflected the patient's history of epistaxis and bleeding over the prior three months, as well as detailed review of iron infusion and red cell transfusion over the preceding six months. Eligible patients were provided a diary to record the duration of each epistaxis event that occurred during the 4 weeks prior to the baseline visit, and then returned for the baseline randomization visit, at which time patients underwent genetic testing, if this had not been previously performed, and completed an ESS with 4-week recall and quality of life assessments. <br>

Patients were randomized 2:1, stratified by study site, to either pomalidomide 4 mg/day or matching placebo during each of six 28 day cycles (24 weeks). Patients were seen every four weeks during treatment, and at a 4-week post-treatment follow-up visit to measure the ESS (with 4-week recall), laboratory assessments including iron stores and need for iron infusion, CBC, and metabolic profile. Patients were assessed for adverse events (AE) throughout the study. Treatment dosage could be reduced, or temporarily or permanently discontinued following AE-specific guidelines related to fatigue, cytopenias or other toxicities.<br>Quality of life assessments were completed at baseline, and the 12- and 24-week visits, and the 4-week post-treatment follow-up visit using validated NIH instruments of 1) Neuro-QOL satisfaction with social roles and activities, 2) PROMIS emotional distress &#8211; depression, and 3) PROMIS fatigue, and the HHT-specific quality of life instrument developed specifically for this study. The effect of pomalidomide on duration of epistaxis was assessed via diary between weeks 8-12, 20-24 and the 4-week post-treatment period.<br>

**Conclusions**:** **Among patients with HHT, pomalidomide treatment resulted in a significant, clinically relevant reduction in epistaxis severity. No unexpected safety signals were identified (Al-Samkari et al., 2024; PMID: [39292928](https://pubmed.ncbi.nlm.nih.gov/39292928/))<br>