Long-term experience with intranasal bevacizumab therapy

Evaluation of AAV Capsids and Delivery Approaches for Hereditary Hemorrhagic Telangiectasia Gene Therapy

Nosebleeds and intracranial hemorrhage from brain arteriovenous malformations (bAVMs) are among the most devastating symptoms of patients with hereditary hemorrhagic telangiectasis (HHT). All available managements have limitations. We showed that intravenous (i.v.) delivery of soluble Feline McDonough Sarcoma (FMS)-related tyrosine kinase 1 using an adeno-associated viral vector (AAV9-sFLT1) reduced bAVM severity of endoglin deficient mice. However, minor liver inflammation and growth arrest in young mice were observed. To identify AAV variants and delivery methods that can best transduce brain and nasal tissue with an optimal transduction profile, we compared 3 engineered AAV capsids (AAV.cc47, AAV.cc84, and AAV1RX) with AAV9. A single-stranded CBA promoter driven tdTomato transgene was packaged in these capsids and delivered i.v. or intranasally (i.n.) to wild-type mice. A CMV promoter driven Alk1 transgene was packaged into AAV.cc84 and delivered to PdgfbiCre;Alk1f/f mice through i.v. followed by bAVM induction. Transduced cells in organs, vessel density, abnormal vessels in the bAVMs, and liver inflammation were analyzed histologically. Liver and kidney function were measured enzymatically. Compared to other viral vectors, AAV.cc84, after i.v. delivery, transduced a high percentage of brain endothelial cells (ECs) and few hepatocytes; whereas after i.n. delivery, AAV.cc84 transduced ECs and perivascular cells in the brain, and ECs, epithelial cells, and muscles in the nose with minimum hepatocyte transduction. No changes to liver or kidney function were detected. The delivery of AAV.cc84-Alk1 through i.v. to PdgfbiCre;Alk1f/f mice reduced bAVM severity. In summary, we propose that AAV.cc84-Alk1 is a promising candidate for developing gene therapy in HHT patients.

Efficacy of bevacizumab in hereditary hemorrhagic telangiectasia: a systematic review and network meta-analysis

BACKGROUND

Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal multi-systemic vascular dysplasia caused by gene mutations that lead to recurrent epistaxis and other serious complications including mucocutaneous telangiectasias, gastrointestinal bleeding, and arteriovenous malformations. Treatment is limited to symptomatic relief with no approved standard therapy. Bevacizumab is a monoclonal antibody used primarily in treating metastatic malignancies and ophthalmology. Several studies have shown that bevacizumab is effective in the treatment of HHT-related epistaxis with a high safety profile.

PURPOSE

This systematic review and network meta-analysis aims to explore the efficacy and safety of bevacizumab in the treatment of HHT epistaxis.

METHODS

A comprehensive literature search was done in many databases, including PubMed, Web of Science, Scopus, and the Cochrane Library. We conducted our network meta-analysis using R version 4.2.2 and R Studio version 2022.07.2. Dichotomous data was analyzed as risk ratio and 95% confidence interval and continuous data as mean difference and 95% confidence interval.

RESULTS

We included four randomized clinical trials in our network meta-analysis. Different doses of bevacizumab failed to yield any statistically significant difference in reducing the epistaxis severity score, the number of epistaxis episodes, the duration of epistaxis, or improving hemoglobin levels compared to placebo or other comparators. The pooled effect sizes for all outcomes were homogenous.

CONCLUSION

Bevacizumab failed to show any significant difference compared to tranexamic acid, estriol, or placebo. These findings underscore the challenges in addressing HHT-related symptoms and highlight the ongoing need for innovative and more effective interventions.

Hereditary haemorrhagic telangiectasia

Hereditary haemorrhagic telangiectasia (HHT) is a vascular dysplasia inherited as an autosomal dominant trait and caused by loss-of-function pathogenic variants in genes encoding proteins of the BMP signalling pathway. Up to 90% of disease-causal variants are observed in ENG and ACVRL1, with SMAD4 and GDF2 less frequently responsible for HHT. In adults, the most frequent HHT manifestations relate to iron deficiency and anaemia owing to recurrent epistaxis (nosebleeds) or bleeding from gastrointestinal telangiectases. Arteriovenous malformations (AVMs) in the lungs, liver and the central nervous system cause additional major complications and often complex symptoms, primarily due to vascular shunting, which is right-to-left through pulmonary AVMs (causing ischaemic stroke or cerebral abscess) and left-to-right through systemic AVMs (causing high cardiac output). Children usually experience isolated epistaxis; in rare cases, childhood complications occur from large AVMs in the lungs or central nervous system. Management goals encompass control of epistaxis and intestinal bleeding from telangiectases, screening for and treatment of iron deficiency (with or without anaemia) and AVMs, genetic counselling and evaluation of at-risk family members. Novel therapeutics, such as systemic antiangiogenic therapies, are actively being investigated. Although HHT is associated with increased morbidity, the appropriate screening and treatment of visceral AVMs, and the effective management of bleeding and anaemia, improves quality of life and overall survival.

Evaluation of Aav Capsids and Delivery Approaches for Hereditary Hemorrhagic Telangiectasia Gene Therapy

Nosebleeds and intracranial hemorrhage from brain arteriovenous malformations (bAVMs) are among the most devastating symptoms of patients with hereditary hemorrhagic telangiectasis (HHT). All available managements have limitations. We showed that intravenous delivery of soluble FMS-related tyrosine kinase 1 using an adeno-associated viral vector (AAV9-sFLT1) reduced bAVM severity of endoglin deficient mice. However, minor liver inflammation and growth arrest in young mice were observed. To identify AAV variants and delivery methods that can best transduce brain and nasal tissue with an optimal transduction profile, we compared 3 engineered AAV capsids (AAV.cc47, AAV.cc84 and AAV1RX) with AAV9. A single-stranded CBA promoter driven tdTomato transgene was packaged in these capsids and delivered intravenously (i.v.) or intranasally (i.n.) to wild-type mice. A CMV promoter driven Alk1 transgene was packaged into AAV.cc84 and delivered to PdgfbiCre;Alk1 f/f mice through i.v. injection followed by brain AVM induction. Transduced cells in different organs, vessel density and abnormal vessels in the bAVMs, and liver inflammation were analyzed histologically. Liver and kidney function were measured enzymatically. Compared to other viral vectors, AAV.cc84, after i.v. delivery, transduced a high percentage of brain ECs and few hepatocytes; whereas after i.n. delivery, AAV.cc84 transduced ECs and perivascular cells in the brain, and ECs, epithelial cells, and skeletal muscles in the nose with minimum hepatocyte transduction. No changes to liver or kidney function were detected. Delivery of AAV.cc84-Alk1 through i.v. to PdgfbiCre;Alk1 f/f mice reduced bAVM severity. In summary, we propose that AAV.cc84-Alk1 is a promising candidate for developing gene therapy in HHT patients.

Hereditary hemorrhagic telangiectasia: from signaling insights to therapeutic advances

Hereditary hemorrhagic telangiectsia (HHT) is an inherited vascular disorder with highly variable expressivity, affecting up to 1 in 5,000 individuals. This disease is characterized by small arteriovenous malformations (AVMs) in mucocutaneous areas (telangiectases) and larger visceral AVMs in the lungs, liver, and brain. HHT is caused by loss-of-function mutations in the BMP9-10/ENG/ALK1/SMAD4 signaling pathway. This Review presents up-to-date insights on this mutated signaling pathway and its crosstalk with proangiogenic pathways, in particular the VEGF pathway, that has allowed the repurposing of new drugs for HHT treatment. However, despite the substantial benefits of these new treatments in terms of alleviating symptom severity, this not-so-uncommon bleeding disorder still currently lacks any FDA- or European Medicines Agency-approved (EMA-approved) therapies.

An in vitro study on the effect of bevacizumab on endothelial cell proliferation and VEGF concentration level in patients with hereditary hemorrhagic telangiectasia

Previous studies have demonstrated that vascular endothelial growth factor (VEGF) is upregulated in patients with hereditary hemorrhagic telangiectasia (HHT). The use of Bevacizumab as an anti-angiogenic treatment agent seems promising. The purpose of the present in vitro study was to determine the efficacy and potential toxicity levels of bevacizumab on cell proliferation and VEGF concentrations in endothelial cells of HHT patients. In this in vitro study, endothelial cells from patients with HHT and HUVECs (control) were incubated with different concentration levels of bevacizumab (2, 4, 6, 8 or 10 mg/ml). After 24, 48 or 72 h, the cell proliferation was assessed by Alamar Blue^® Assay and the VEGF levels in the cell culture supernatants were measured by VEGF-ELISA. All endothelial cells incubated with bevacizumab showed an initial decrease in cell proliferation. Cell proliferation recovered within 72 h in cell cultures incubated with concentration levels of up to 4 mg/ml bevacizumab, whereas those incubated with higher concentration levels showed a continuous decline in cell proliferation. VEGF expression decreased after 24 h in cell cultures incubated with bevacizumab concentration levels of 2 and 4 mg/ml but increased again after 48 h. Cell cultures incubated with bevacizumab concentration levels of 10 mg/ml showed a constant decline in VEGF expression without any tendency for recovery. Translating these results into daily clinical practice, the present study suggests that the intranasal submucosal injection of bevacizumab in HHT patients should not exceed a concentration level of 4 mg/ml. Overall, higher bevacizumab concentration levels not only reduce VEGF expression but pose a higher risk of toxic effects on endothelial cells as they jeopardize cell proliferation.

Randomized controlled double-blinded clinical trial of the effect of bevacizumab injection in the management of epistaxis in HHT patients undergoing surgical cauterization

INTRODUCTION

Given its role in the disease pathophysiology, inhibition of VEGF-mediated angiogenesis has received attention as a potential strategy to reduce epistaxis associated with hereditary hemorrhagic telangiectasia (HHT). This study evaluates the efficacy of a submucosal injection of bevacizumab, a VEGF-inhibitor, in reducing the severity of epistaxis and improving quality of life when given at the time of operative electrocautery.

METHODS

This randomized, double-blinded placebo-controlled trial was conducted at a single institution from 2014 to 2019. Patients scheduled to undergo operative bipolar electrocautery of nasal telangiectasias were randomized to receive a submucosal injection of saline or bevacizumab at time of surgery. Surveys to assess epistaxis severity and quality-of-life (QOL), including the Epistaxis Severity Score (ESS) and Short Form 12 (SF-12), were administered preoperatively and at 1, 2, 4, and 6 months postoperatively. The minimal clinically important difference (MCID) of the ESS instrument is reported to be 0.71.

RESULTS

Of 39 patients enrolled, 37 (94.9%) completed the study. The saline group demonstrated reduced ESS versus baseline at 1 (-1.2, p = 0.01) and 4 (-1.2, p = 0.05) months post-procedure. The bevacizumab group demonstrated reduced ESS versus baseline at 1 (-2.3, p<0.001), 2 (-2.3, p<0.001), 4 (-2.0, p = 0.003), and 6 (-1.3, p = 0.05) months post-procedure. The additive benefit of bevacizumab over saline exceeded the MCID at 1, 2, and 4 months but the difference was not statistically significant.

CONCLUSION

The addition of a single treatment of submucosal bevacizumab may be associated with additional clinically meaningful benefit for up to 4 months when compared to electrocautery alone. This article is protected by copyright. All rights reserved.

A comparative study of two grading systems for epistaxis in hereditary haemorrhagic telangiectasia

BACKGROUND

Different institutions use different grading systems for hereditary haemorrhagic telangiectasia (HHT)-associated epistaxis. It is important to have a universal, standardized grading system to compare and evaluate the effectiveness of different treatment options. We introduced the "Intensity, Frequency and need for Blood Transfusion" (IFT) grading system for HHT-associated epistaxis in 2008. Hoag et al. proposed the "Epistaxis Severity Score" (ESS) for the International HHT foundation in 2010. This study aimed to evaluate the potential correlation between the ESS and IFT grading systems.

METHODS

The study included 354 simultaneous reports using the IFT and ESS from 106 patients. The correlation between the ESS, IFT and haemoglobin levels was measured using Pearson's correlation coefficient. The ESS and IFT were scored simultaneously by the patient and doctor in 48 cases to evaluate if there was a discrepancy in the scoring applied by either set of responders.

RESULTS

The measured correlation between the two grading systems was good (0.75). The grade of epistaxis reported by patients and doctors respectively showed no significant difference. Both the IFT and ESS grading systems correlate significantly to the haemoglobin level.

CONCLUSIONS

Both the IFT and ESS scores correlate to each other, and their results are comparable. Whether the IFT or ESS scoring was performed by the patient or doctor had no significant impact.

Long-term efficacy assessment of current treatment options for epistaxis in HHT

Purpose

Hereditary hemorrhagic telangiectasia (HHT) is a vascular disorder that presents with recurrent, intractable epistaxis. The aim of this study was to retrospectively analyze the efficacy of various treatment options for epistaxis in patients with HHT, over a period of 18 years, and to correlate these findings with available evidence in the literature.

Methods

Records of patients with HHT, treated for epistaxis between 2000 and 2018 were analyzed. Treatment procedures carried out and their efficacy were extracted and analyzed.

Results

Forty-three records were evaluated. All patients were given nasal humidifying ointments, 93% required acute treatment with bipolar electrocautery, and 60% underwent atraumatic nasal packing. Recurrent cases were treated medically with tranexamic acid (26%), oestrogen (19%), and bevacizumab (2%). Laser photocoagulation was done in selected cases (40%) and if unsuccessful, septal dermoplasty was performed (2.3%). Endovascular embolization was reserved for life-threatening emergencies (7%).

Conclusion

Epistaxis in HHT is not curable, but can be managed by employing a comprehensive stepwise approach. An algorithm for effective and comprehensive management has been presented.

[Diagnostic Criteria and Treatment of Hereditary Hemorrhagic Telangiectasia]

Hereditary hemorrhagic telangiectasia (HHT; Osler-Weber-Rendu syndrome; Morbus Osler) represents a syndrome affecting capillary vessels, leading to arteriovenous shunting. With an average worldwide prevalence of 1:5.000-8.000 HHT is considered an orphan disease. Arteriovenous shunts involve predominantly the nasal mucosa, the intestine, lung, liver and central nervous system. Epistaxis is the primary and most bothersome complaint of patients with HHT. A multistage therapeutic concept includes nasal ointment, laser therapy under local anesthesia and surgery under general anesthesia, as well as drug therapies. In addition, screening to determine affection of internal organs is carried out. Lesions that require therapy should be treated in an interdisciplinary setting. Treatment of lesions of the skin, oral and gastrointestinal mucosa and liver is carried out in regard to patients' symptoms, whereas vascular malformations of the lung and brain might need treatment without being symptomatic, due to possible life-threatening complications.

Thalidomide for the Management of Bleeding Episodes in Patients with Hereditary Hemorrhagic Telangiectasia: Effects on Epistaxis Severity Score and Quality of Life

Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominantly inherited disorder characterized by bleeding episodes. These episodes tend to happen spontaneously and reduce the quality of life. Patients are often unresponsive to local measures. With the pathophysiological role of angiogenesis in HHT, antiangiogenic drugs including thalidomide are used to control bleeding episodes. In our study, we evaluated 6 patients with HHT, calculating their Epistaxis Severity Score (ESS) and performing a quality of life assessment with the 36-Item Short Form Health Survey Questionnaire (SF-36), and we studied the alterations of these evaluations with thalidomide treatment. Three patients were male and three were female. Mean age was 60.50 years. No side effects were observed during the treatment period. Improvements of certain SF-36 dimensions including physical functioning, physical component summary, and mental component summary and of the ESS were observed after treatment. Thalidomide may be effective to control bleeding episodes with a reasonable tolerance profile in patients with HHT.