Systemic safety of anti-VEGF drugs: a commentary

Spectral-domain optical coherence tomography combined with electroretinography in the assessment of conbercept for neovascular age-related macular degeneration: a preliminary study

Objective

To observe the effect of three consecutive intravitreal injections of conbercept in the treatment of neovascular age-related macular degeneration (nAMD), to investigate the correlation between retinal anatomy and retinal function by spectral-domain optical coherence tomography (SD-OCT) and electroretinography (ERG), to evaluate the short-term clinical efficacy of conbercept in the treatment of nAMD, and to explore the value of ERG as a predictor of treatment efficacy.

Method

A retrospective investigation was conducted on 36 patients (36 eyes) treated with intravitreal injections of conbercept at 0.5 mg a month for three consecutive courses. Data collected included the best corrected visual acuity (BCVA), central retinal thickness (CRT), retinal pigment epithelium (RPE) elevation volume in 1 mm-diameter (1RV), 3 mm-diameter (3RV), and 6 mm-diameter circles around the fovea (6RV), amplitude density and latency of the P1 wave in the multifocal electroretinography (mf-ERG) R1 ring and amplitude and latency in full-field electroretinography (ff-ERG) at baseline and monthly. The paired t test was used to compare the difference between pre- and posttreatment. Pearson correlation analysis was used to analyze the correlation between macular retinal structure and function. The difference was significant when p < 0.05.

Results

At 12 weeks, the BCVA, CRT, 1RV, 3RV, 6RV, the P1 wave amplitude density of the mf-ERG R1 ring and the ff-ERG amplitude parameters were all significantly improved (p < 0.001). The BCVA in logMAR was positively correlated with CRT; 1RV, 3RV, and 6RV were negatively correlated with the amplitude density and latency of the mf-ERG R1 ring P1 wave. There were no severe ocular or systemic complications during the follow-up period.

Conclusion

Conbercept is useful for the short-term treatment of nAMD. It can safely improve the visual acuity of affected eyes and restore the structure and function of the retina. ERG could serve as an objective indicator of function for evaluating the efficacy of and determining the need for retreatment during nAMD treatment.

Exosomes Derived From Hypoxia-Conditioned Stem Cells of Human Deciduous Exfoliated Teeth Enhance Angiogenesis via the Transfer of let-7f-5p and miR-210-3p

Physiological root resorption of deciduous teeth is a normal phenomenon. How the angiogenesis process is regulated to provide adequate levels of oxygen and nutrients in hypoxic conditions when the dental pulp tissue is reduced at the stage of root resorption is not fully understood. In this study, we designed hypoxic preconditioning (2%) to mimic the physiological conditions. We isolated exosomes from hypoxic-preconditioned SHED (Hypo-exos) cells and from normally cultured SHED cells (Norm-exos). We found that treatment with Hypo-exos significantly enhanced the growth, migration and tube formation of endothelial cells in vitro compared with Norm-exos. We also performed matrigel plug assays in vivo and higher expression of VEGF and higher number of lumenal structures that stained positive for CD31 were found in the Hypo-exos treated group. To understand the potential molecular mechanism responsible for the positive effects of Hypo-exos, we performed exosomal miRNA sequencing and validated that Hypo-exos transferred both let-7f-5p and miR-210-3p to promote the tube formation of endothelial cells. Further study revealed that those two miRNAs regulate angiogenesis via the let-7f-5p/AGO1/VEGF and/or miR-210-3p/ephrinA3 signal pathways. Finally, we found that the increased release of exosomes regulated by hypoxia treatment may be related to Rab27a. Taking these data together, the present study demonstrates that exosomes derived from hypoxic-preconditioned SHED cells promote angiogenesis by transferring let-7f-5p and miR-210-3p, which suggests that they can potentially be developed as a novel therapeutic approach for pro-angiogenic therapy in tissue regeneration engineering.

Intravitreal anti-VEGF therapy is not associated with a higher risk of all-cause mortality in patients with macular oedema caused by posterior segment vascular diseases

PURPOSE

To examine whether real-world clinical patients with macular oedema (MO) receiving intravitreal antivascular endothelial growth factor (VEGF) therapy have a higher mortality compared with a matched reference population.

METHODS

A population-based, retrospective cohort study of 26 386 patients from Finland, from January 1, 2001, to December 31, 2017. Index patients were identified through the Caring Epidemiology Project database, receiving at least one intravitreal anti-VEGF injection for wet age-related macular degeneration (AMD, n = 2243, 48.61%), diabetic MO (n = 744, 16.12%), MO due to retinal vascular occlusion (n = 589, 12.77%), or other MO (n = 1038, 22.5%). For each individual treated with intravitreal injection (n = 4614), five age- , sex- , calendar year- and hospital district- matched control individuals (n = 21 772) were chosen. Baseline data of chronic conditions were available. All-cause and cause-specific mortality was analysed using Cox´s proportional hazards model.

RESULTS

In general, the anti-VEGF treated patients had a higher prevalence of systemic conditions, including diabetes (60.1% vs. 46.8%, p < 0.001), chronic hypertension (38.4% vs. 34.6%, p < 0.001), in hospital-treated ischaemic heart disease (23.1% vs. 21.5%, p = 0.014), and glaucoma (11.1% vs. 6.3%, p < 0.001) than controls. There was no difference in all-cause mortality between the anti-VEGF treated patients and matched controls (p = 0.62). In unadjusted Kaplan-Meier analysis of wet AMD subgroup, all-cause mortality was lower in anti-VEGF treated patients than matched controls (p = 0.015), but adjusted Cox´s proportional hazards model showed no difference in the risk of all-cause mortality (HR 0.85, 95% CI 0.66-1.09).

CONCLUSIONS

Intravitreal anti-VEGF therapy was not associated with an increase in the risk of mortality in patients with MO compared with age- and sex-matched controls.

Development of lipid-like materials for RNA delivery based on intracellular environment-responsive membrane destabilization and spontaneous collapse

Messenger RNA and small interfering RNA are attractive modalities for curing diseases by complementation or knock-down of proteins. For success of these RNAs, a drug delivery system (DDS) is required to control a pharmacokinetics, to enhance cellular uptake, to overcome biological membranes, and to release the cargo into the cytoplasm. Based on past research, developing nanoparticles that are neutrally charged have been the mainstream of their development. Also, the materials are further mounted with pH- and/or reducing environment-responsive units. In this review, we summarize progress made in the molecular design of these materials. We also focus on the importance of the hydrophobic scaffold for tissue/cell targeting, intracellular trafficking, and immune responses. As a practical example, the design concept of the SS-cleavable and pH-activated lipid-like material (ssPalm) and subsequent molecular modification tailored to the RNA-based medical application is discussed.

A Pilot Clinical Study of Intravitreal Injection of Artesunate for Ocular Neovascularization

Purpose: To evaluate the efficacy and primary safety of treatment with artesunate in reducing ocular neovascularization in humans. Methods: Five patients with corneal, iris, and retinal neovascularization and no light perception were treated with intravitreal injections of artesunate 80 μg. Visual acuity, anterior segment photography, fundus fluorescein angiography, and optical coherence tomography were used to evaluate efficacy, while intraocular pressure (IOP) and lens opacity degree were employed to evaluate safety. The primary endpoint was attenuation of neovascularization as determined at 24 weeks, with the last posttreatment follow-up at 52 weeks. Results: Corneal and iris neovascularization, which were secondary to fundus ischemic diseases and retinal neovascularization in all 5 patients, were attenuated after 1 or 2 injections by the 52-week follow-up. Retinal neovascularization was also attenuated, and papilledema was alleviated. The average IOP fell from 25.5 mmHg to 17.66 mmHg. Conclusions: This pilot study determined that intravitreal artesunate injection is efficacious for reducing corneal, iris, and retinal neovascularization. These results indicate that this drug may be a novel alternative to the currently popular antivascular endothelial growth factor drugs used to suppress ocular neovascularization and improve visual function.

Epithelial Membrane Protein-2 (EMP2) Antibody Blockade Reduces Corneal Neovascularization in an In Vivo Model

Purpose

Pathologic corneal neovascularization is a major cause of blindness worldwide, and treatment options are currently limited. VEGF is one of the critical mediators of corneal neovascularization but current anti-VEGF therapies have produced limited results in the cornea. Thus, additional therapeutic agents are needed to enhance the antiangiogenic arsenal. Our group previously demonstrated epithelial membrane protein-2 (EMP2) involvement in pathologic angiogenesis in multiple cancer models including breast cancer and glioblastoma. In this paper, we investigate the efficacy of anti-EMP2 immunotherapy in the prevention of corneal neovascularization.

Methods

An in vivo murine cornea alkali burn model was used to study pathologic neovascularization. A unilateral corneal burn was induced using NaOH, and subconjunctival injection of either anti-EMP2 antibody, control antibody, or sterile saline was performed after corneal burn. Neovascularization was clinically scored at 7 days postalkali burn, and eyes were enucleated for histologic analysis and immunostaining including VEGF, CD31, and CD34 expression.

Results

Anti-EMP2 antibody, compared to control antibody or vehicle, significantly reduced neovascularization as measured by clinical score and central cornea thickness, as well as by histologic reduction of neovascularization, decreased CD34 staining, and decreased CD31 staining. Incubation of corneal limbal cells in vitro with anti-EMP2 blocking antibody significantly decreased EMP2 expression, VEGF expression and secretion, and cell migration.

Conclusions

This work demonstrates the effectiveness of EMP2 as a novel target in pathologic corneal neovascularization in an animal model and supports additional investigation into EMP2 antibody blockade as a potential new therapeutic option.

Real-World Safety of Intravitreal Bevacizumab and Ranibizumab Treatments for Retinal Diseases in Thailand: A Prospective Observational Study

BACKGROUND

There is very limited evidence examining serious systemic adverse events (SSAEs) and post-injection endophthalmitis of intravitreal bevacizumab (IVB) and intravitreal ranibizumab (IVR) treatments in Thailand and low- and middle-income countries. Moreover, findings from the existing trials might have limited generalizability to certain populations and rare SSAEs.

OBJECTIVES

This prospective observational study aimed to assess and compare the safety profiles of IVB and IVR in patients with retinal diseases in Thailand.

METHODS

Between 2013 and 2015, 6354 patients eligible for IVB or IVR were recruited from eight hospitals. Main outcomes measures were prevalence and risk of SSAEs, mortality, and endophthalmitis during the 6-month follow-up period.

RESULTS

In the IVB and IVR groups, 94 and 6% of patients participated, respectively. The rates of outcomes in the IVB group were slightly greater than in the IVR group. All-cause mortality rates in the IVB and IVR groups were 1.10 and 0.53%, respectively. Prevalence rates of endophthalmitis and non-fatal strokes in the IVB group were 0.04% of 16,421 injections and 0.27% of 5975 patients, respectively, whereas none of these events were identified in the IVR group. There were no differences between the two groups in the risks of mortality, arteriothrombotic events (ATE), and non-fatal heart failure (HF). Adjustment for potential confounding factors and selection bias using multivariable models for time-to-event outcomes and propensity scores did not alter the results.

CONCLUSIONS

The rates of SAEs in both groups were low. The IVB and IVR treatments were not associated with significant risks of mortality, ATE, and non-fatal HF.

TRIAL REGISTRATION

Thai Clinical Trial Registry identifier TCTR20141002001.

Intravitreal Bevacizumab and Cardiovascular Risk in Patients with Age-Related Macular Degeneration: Systematic Review and Meta-Analysis of Randomized Controlled Trials and Observational Studies

INTRODUCTION

Intravitreal bevacizumab (IVTB) is used to treat age-related macular degeneration (ARMD), although its use is off-label and its cardiovascular safety has not been unequivocally established.

OBJECTIVES

Our objective was to assess the cardiovascular safety of IVTB in patients with ARMD.

METHODS

We conducted a systematic review and meta-analysis of published randomized controlled trials (RCTs) and observational studies.

RESULTS

Of the 2028 non-duplicate records, five RCTs versus ranibizumab (N = 3038, 12/24 months), four RCTs comparing different regimens (N = 809, 12/23 months), one RCT versus pegaptanib, photodynamic therapy (PDT), or sham (N = 131, 12 months), and three observational studies versus PDT, ranibizumab, or pegaptanib (~150,000 or 1666 patients/12 months and 317 patients/1-2 years, respectively) had a low risk of bias/high quality and ≥20 patients per arm with ≥6 months and ≥3 injections of treatment. RCT-based comparisons with PDT or pegaptanib are negligible. Observational data have not demonstrated differences [all-cause mortality, myocardial infarction (MI), stroke], but the level of evidence is "very low" (imprecise, indirect). RCT-based comparisons with ranibizumab did not demonstrate differences regarding some outcomes, although certain point estimates were at the level of a relevant harm/benefit [all-cause mortality odds ratio (OR) 1.103, 95 % confidence interval (CI) 0.641-1.898; vascular mortality OR 1.380, 95 % CI 0.476-3.997; MI OR 0.551, 95 % CI 0.265-1.146; stroke OR 0.657, 95 % CI 0.260-1.660; transitory ischemic attack OR 1.536, 95 % CI 0.444-5.313; atherothrombotic events (ATEs) OR 1.007, 95 % CI 0.641-1.593; venous thromboembolism OR 2.325, 95 % CI 0.963-5.612] or suggested a higher risk with bevacizumab (hypertension OR 7.512, 95 % CI 1.056-52.3), but estimates were based on sparse data, were extremely imprecise, and commonly exhibited considerable heterogeneity/inconsistency. The level of evidence per outcome was "low" or "very low". Observational data did not demonstrate difference (all-cause mortality, MI, stroke), or suggested a higher risk with bevacizumab (ATE), but were imprecise and indirect (level of evidence "very low"). RCT-based comparisons of different IVTB regimens suffered from the same limitations.

CONCLUSION

Published data on IVTB in AMRD provide only a low level of evidence on its cardiovascular safety and do not support any finite conclusions.

Age-related macular degeneration and mortality: the Melbourne Collaborative Cohort Study

AimsTo assess associations between features of age-related macular degeneration (AMD) and mortality.MethodsA total of 21 129 participants from the Melbourne Collaborative Cohort Study aged 47-85 years (60% female) were assessed for AMD (2003-2007). Mortality data to December 31, 2012 were obtained through linkage with the National Death Index. Associations were assessed using Cox regression, adjusting for age, sex, smoking, region of birth, education, physical activity, diet and alcohol.ResultsLate AMD was identified in 122 (0.6%) participants, including those with choroidal neovascularisation (n=55, 0.3%), geographic atrophy (n=87, 0.4%) and reticular pseudodrusen (n=87, 0.4%). After a median follow-up period of 8.1 years, 1669 (8%) participants had died, including those from cardiovascular diseases (386), tobacco-related cancers (179), and neurodegenerative disease (157). There was evidence of an increased rate of all-cause mortality for those with choroidal neovascularisation (Hazard Ratio (HR) 1.71 95% CI 1.06-2.76) and geographic atrophy (HR 1.46 95% CI 0.99-2.16). Choroidal neovascularisation was also associated with an increased rate of cardiovascular mortality (HR 3.16 95% CI 1.62-6.15) and geographic atrophy was associated with an increased rate of death from tobacco-related cancer (HR 2.86 95% CI 1.15-7.09). Weak evidence was also present for an association between choroidal neovascularisation and death from neurodegenerative disease (HR 2.49 95% CI 0.79-7.85). Neither reticular pseudodrusen nor the earlier stages of AMD were associated with mortality.ConclusionsLate AMD is associated with an increased rate of all-cause mortality. Choroidal neovascularisation and geographic atrophy were associated with death from cardiovascular disease and tobacco-related cancer, respectively.

Gene Therapy in Neovascular Age-related Macular Degeneration: Three-Year Follow-up of a Phase 1 Randomized Dose Escalation Trial

PURPOSE

To assess the safety of rAAV.sFlt-1 subretinal injection in neovascular age-related macular degeneration (wet AMD) over 36 months.

DESIGN

Phase 1 dose escalation trial.

METHODS

Eight subjects with advanced, treatment-experienced wet AMD were randomly assigned (3:1) to treatment and non-gene therapy control groups. Eligible subjects were ≥65 years, had wet AMD, and had best-corrected visual acuity (BCVA) 10/200 to 20/80 in the study eye and 20/200 or better in the other eye. Three of the treatment group subjects received low-dose (1 × 10¹⁰ vector genomes) and 3 high-dose (1 × 10¹¹ vector genomes) rAAV.sFLT-1 via subretinal injection. Study monitoring was monthly to the primary endpoint at month 12 and then protocol-driven follow-up study visits were conducted at months 18 and 36. All subjects received intravitreal ranibizumab at baseline and at week 4, and retreatment injections at subsequent visits based on prespecified criteria for active wet AMD. The primary endpoint was ocular and systemic safety, but exploratory data including BCVA, retinal center point thickness, and the number of ranibizumab retreatments at and between study visits were also analyzed.

RESULTS

Six of the 8 subjects completed the 36-month study. Subretinal injection with pars plana vitrectomy was well tolerated in this cohort. No ocular or systemic safety signals were observed during the long-term follow-up period. Exploratory data analysis suggests stability of wet AMD over the 36-month period.

CONCLUSIONS

Subretinal delivery of rAAV.sFLT-1 was well tolerated and demonstrated a favourable safety profile through month 36. Thus, rAAV.sFLT-1 could be safely considered for future evaluation in the treatment of wet AMD.

Endocrine vasculatures are preferable targets of an antitumor ineffective low dose of anti-VEGF therapy

Anti-VEGF-based antiangiogenic drugs are designed to block tumor angiogenesis for treatment of cancer patients. However, anti-VEGF drugs produce off-tumor target effects on multiple tissues and organs and cause broad adverse effects. Here, we show that vasculatures in endocrine organs were more sensitive to anti-VEGF treatment than tumor vasculatures. In thyroid, adrenal glands, and pancreatic islets, systemic treatment with low doses of an anti-VEGF neutralizing antibody caused marked vascular regression, whereas tumor vessels remained unaffected. Additionally, a low dose of VEGF blockade significantly inhibited the formation of thyroid vascular fenestrae, leaving tumor vascular structures unchanged. Along with vascular structural changes, the low dose of VEGF blockade inhibited vascular perfusion and permeability in thyroid, but not in tumors. Prolonged treatment with the low-dose VEGF blockade caused hypertension and significantly decreased circulating levels of thyroid hormone free-T3 and -T4, leading to functional impairment of thyroid. These findings show that the fenestrated microvasculatures in endocrine organs are more sensitive than tumor vasculatures in response to systemic anti-VEGF drugs. Thus, our data support the notion that clinically nonbeneficial treatments with anti-VEGF drugs could potentially cause adverse effects.

Safety of monoclonal antibodies and related therapeutic proteins for the treatment of neovascular macular degeneration: addressing outstanding issues

INTRODUCTION

The vascular endothelial growth factor (VEGF) inhibitors most widely used to treat neovascular age-dependent macular degeneration (nAMD) are different proteins with structural features potentially relevant to adverse effects (AEs). Two of these are also established in cancer therapy (with higher dosages and AEs). The importance of ocular AE and extraocular activities is still a subject of controversy and ongoing research.

AREAS COVERED

Potential risks of intraocular VEGF inhibition based on prospective studies, in vitro investigations, pharmacokinetics, and hints from anti-cancer treatment.

EXPERT OPINION

nAMD is a frequently observed chronic clinical condition severely affecting the visual function of elderly persons. Intravitreal injection of VEGF-inactivating proteins is highly effective to prevent loss of vision. Anti-VEGF therapy is well tolerated, and low rates of ocular and systemic AEs in smaller trials suggest a very high benefit/risk ratio. The proteins established in nAMD therapy show similar efficacies. In the controversy over the off-label use of bevacizumab purely on grounds of much lower cost, the small, but potentially relevant differences between the available drugs are easily either dramatized (by pharmaceutical companies) or trivialized (by health insurances) and even political interference is involved. Facing the lack of a convincing body of evidence regarding safety, further long-term study results seem necessary.