A Phase 2 interventional study of Doxycycline Hyclate and Placebo in Hereditary Hemorrhagic Telangiectasia (HHT), sponsored by Unity Health Toronto. Completed at 1 site in Canada. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-04-01.
Sponsored by Unity Health Toronto · Phase 2, Interventional, and Treatment
This study will investigate the effectiveness of oral doxycycline for the treatment of recurrent nasal hemorrhage in Hereditary Hemorrhagic Telangiectasia (HHT) subjects. The primary outcome for the trials will be the reduction of epistaxis severity (minutes of bleeding per week). The biological outcomes of interest are the regression of vascular malformations as well as tissue and circulation biomarkers of the relevant mechanistic pathways. A Phase II, randomized double-blind placebo-controlled crossover trial. Approximately 30 subjects with HHT, with moderate-severe recurrent epistaxis will participate in the randomized double-blind placebo-controlled cross over trial. Subject will be treated with a 6-month course of doxycycline 100mg twice daily or placebo twice daily.
The aim is to study is to evaluate doxycycline as a treatment for HHT with the proposed "HHT Clinical Trial Protocol". Rare disease presents a number of challenges in clinical trial design, including recruitment challenges, related power limitations and less knowledge about outcomes measurement. Considering these limitations, as well as the large variability in epistaxis measures across HHT patients, a crossover-trial design, with each subject receiving the study drug and placebo, and therefore serving as their own control, has been selected, including randomization and blinding, to limit bias in measuring this subjective outcome.
This study will investigate doxycycline, given its demonstrated anti-angiogenic and anti-inflammatory properties, as well as compelling effects in arteriovenous malformation (AVM) models. Doxycycline also has the advantages of a proven safety track record for long-term use, oral administration and low cost. Doxycycline suppresses vascular endothelial growth factor (VEGF)-induced cerebral matric metalloproteinase-9 (MMP-9) activity in vivo in the mouse model, and has anti-inflammatory effects as well, via inhibition of pro-inflammatory cytokines. In human brain vascular malformation tissue, there is evidence of increased expression of MMP-9 and VEGF and another tetracycline, minocycline, has attenuated brain hemorrhage in the mouse. Recently, a small retrospective case series reported sustained reduction in nasal hemorrhage in seven HHT patients treated with oral doxycycline. We hypothesize that oral doxycycline will reduce nasal hemorrhage in HHT subjects, through anti-angiogenic and/or anti-inflammatory mechanisms, both of which have been implicated in HHT.
This is a double-blind randomized placebo-controlled trial (N=30) of oral doxycycline (100mg twice daily, 6-month course) in HHT subjects with moderate-severe recurrent nasal hemorrhage. Drug dosing and safety monitoring will be tailored specifically to the agent studied. The primary outcome will be reduction of bleeding minutes per week. In addition, vascular malformation tissue (cutaneous) will be obtained pre and post-treatment, and stained for inflammatory, angiogenic and bone morphogenetic protein-9 (BMP9)-activin A receptor like type1(ALK1)-endoglin- Smad1/5/9 pathway markers. In addition, pre-excision, vascular malformations will be imaged with speckle variance optical coherence tomography (SVOCT), in vivo non-invasive micro-angiography to measure lesion structure, vessel volume and vessel density, as previously described. If the drugs studied are effective at reducing nasal hemorrhage, this will have important clinical implications for HHT patients, and the tissue and imaging may provide important insights into mechanisms.
At least two skin telangiectases
Ability to give written informed consent
Exclusion Criteria:
subjects will be treated with a 6-month course of doxycycline oral capsule at a dose of 100mg twice daily
Drug: Doxycycline Hyclate
subjects will be given a placebo oral capsule twice daily for 6-months
Drug: Placebo
Doxycycline will be given for 6 months, followed by a washout period for 6 months (pre or post a crossover intervention)
Also known as: capsule
Placebo will be given for 6 months, followed by a washout period for 6 months (pre or post a crossover intervention)
Also known as: capsule
The reduction in epistaxis (nose bleeding) severity over 96 weeks
Participants will be asked to maintain a daily diary for the duration of the study (96 weeks). Participants will record all epistaxis events daily, noting the duration in minutes and whether or not there was gushing during each nosebleed. The change in epistaxis severity will be measured from a sum of duration of all bleeding events each week, as measured from the participant daily diary.
Time frame: daily for 96 weeks
Change in epistaxis severity score (ESS)
The epistaxis severity score is a six item questionnaire used to calculate a severity of HHT related nose bleeding. Each question is pertaining to the subject's typical symptoms within the last 3 months period. The first three questions are related to frequency, duration and intensity. The forth question whether or not medical attention was sought for nose bleeding. The remaining two questions are related to the presence of anemia and the need for blood transfusion due to nose bleeding. The resulting epistaxis severity score vary between; none 0-1, mild bleeding \>1-4, moderate bleeding \>4-7 and \>7-10 for severe bleeding.
Time frame: baseline, week 12, week 24, week 36, week 48, week 60, week 72, week 84, week 96
Measures related to chronic bleeding by a change from baseline
Blood samples will be taken to measure change in chronic bleeding by looking at the hemoglobin, ferritin and iron saturation level. Samples will be taken prior to investigational product for a baseline value. This will be followed by measurements every six weeks during the periods of investigational product for comparative analysis.
Time frame: Baseline, week 12, week 18, week 24, week 30, week 36, week 42, week 48, week 60, week 66, week 72, week 78, week 84, week 96
Regression of vascular malformations using Micro-imaging measures
Telangiectases will be micro-imaged using an established medical imaging technique speckle variance optical coherence tomography (SVOCT). The micro-imaging will be used for vasculature measurements. The SVOCT will measure the telangiectasia lesion area, volume, and density, lesion flow velocity and volume flow rate. Structural images will be generated. Imaging will be performed at four time points throughout the duration of the study.
Time frame: week 12 (day 0), week 36, week 60, week 84
Elucidate the mechanisms of action of doxycycline using tissue sample
A punch biopsy of one cutaneous telangiectasia will be performed at two time points during the study. The biopsy tissue sample will be taken at the end of each 6 month active comparator (drug) or placebo treatment. The tissue will be analyze for lesion vessel density, distribution of vessel types (capillary, venule, arteriole) and for insights into mechanisms. Further investigation will include staining for inflammatory, angiogenesis and BMP9-ALK1-endoglin-Smad1/5/9 pathway markers (VEGF, MMP-9, cyclooxygenase-2 (COX-2), Endoglin, ALK1).
Time frame: week 36, week 84
The measurement of a change in biomarkers
Serum, plasma levels will be measured for inflammatory, angiogenic, and BMP9-ALK1-endoglin-Smad1/5/9 pathway (VEGF, MMP-9, Thrombospondin-2, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), endothelin). Biomarker samples will be collected every 3-months. This will allow each subject to also provide their own controls for each treated case. The change in biomarkers will be analyzed.
Time frame: week 12 (day 0), week 24, week 36, week 48, week 60, week 72, week 84, week 96
Plan to share: No
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