Clinical Trial Details
— Status: Active, not recruiting
Administrative data
NCT number |
NCT04646356 |
Other study ID # |
170518448 |
Secondary ID |
|
Status |
Active, not recruiting |
Phase |
Phase 2
|
First received |
|
Last updated |
|
Start date |
October 20, 2020 |
Est. completion date |
December 2024 |
Study information
Verified date |
April 2024 |
Source |
Unity Health Toronto |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
This study will investigate the effectiveness of oral low-dose tacrolimus for the treatment
of recurrent nasal hemorrhage in 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. In this Phase II open label trial, we
estimate a sample size of 30 subjects with HHT, with moderate-severe recurrent epistaxis will
be required. Subject will be treated with a 6-month course of tacrolimus twice daily.
Description:
The aim is to study is to evaluate low-dose tacrolimus as a treatment for HHT. 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
trial design, with each subject receiving the study drug for six months and for one year an
epistaxis daily dairy documentation, providing valuable information about seasonal
variation.in epistaxis.
This study will investigate tacrolimus, given its demonstrated anti-angiogenic and
anti-inflammatory properties, as well as compelling effects in arteriovenous malformation
(AVM) models. Specifically, tacrolimus has been shown to oppose the gene expression
upregulation of the identified pro-angiogenic markers, thus resulting in anti-angiogenic
effects. There are two mechanisms to this. Firstly, recent evidence has shown tacrolimus to
be a potent ALK1 signaling mimetic at the transcriptional level. This is particularly
significant given that the ALK1 pathway signaling is lost in HHT via the hallmark ACVRL1 and
ENG genes. Independent of its effect on the ALK1 pathway, tacrolimus has been shown to be a
potent inhibitor of VGEF signaling.
As mentioned previously, the BMP9-ALK1-endoglin-Smad1/5/9 pathway in HHT, is a novel avenue
of interest for treating hemorrhage in HHT and also regressing vascular malformations. Given
the upstream inactivation of the ALK1 pathway, therapeutic potential via this pathway is
dependent on Smad1/5/8 activation and signaling irrespective of the functional status of the
corresponding ALK1 receptors. To this end, tacrolimus has been shown to activate Smad1/5/8
signaling in HHT patient-derived cells, thus confirming its therapeutic potential in HHT.
Tacrolimus also has anti-inflammatory effects, via inhibition of pro-inflammatory cytokines,
specifically IL2, which is associated with cytotoxic T cell proliferation and activation.
Finally, recent evidence also demonstrated a reduction of vascular pathology in mouse models
via tacrolimus administration. Tacrolimus also has the advantages of a proven safety track
record for long-term use, given its long history in transplant medicine, and can be orally
administered, making it more acceptable to patients. In addition to promising effects in
laboratory-based studies, Canadian case study reported the regression of angiodysplasia and
reduction of mucosal hemorrhage in a probable HHT patient who underwent liver transplantation
following high-output cardiac failure and hepatic AVM development. A recent case report of
treatment with oral low-dose -dose tacrolimus in an individual with HHT, found that
tacrolimus dramatically improved epistaxis. Based on the evidence to date, the investigators
hypothesize that oral low-dose tacrolimus will reduce nasal hemorrhage in HHT subjects,
through anti-angiogenic and/or anti-inflammatory mechanisms, both of which have been
implicated in HHT.
This clinical trial of oral low-dose tacrolimus (0.025mg/kg/day and adjusted to maintain
blood levels of 2-5ng/ml 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-investigational
product from some subject, and stained for inflammatory, angiogenic and BMP9-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. Tissue and imaging may provide important insights into physiological
mechanisms that explain clinical changes. If the drugs studied are effective at reducing
nasal hemorrhage, this will have important clinical implications for HHT patients.