Aflibercept for choroidal neovascularizations secondary to pseudoxanthoma elasticum: a prospective study

Pseudoxanthoma elasticum - Genetics, Pathophysiology, and Clinical Presentation

Pseudoxanthoma elasticum (PXE) is an autosomal-recessively inherited multisystem disease. Mutations in the ABCC6-gene are causative, coding for a transmembrane transporter mainly expressed in hepatocytes, which promotes the efflux of adenosine triphosphate (ATP). This results in low levels of plasma inorganic pyrophosphate (PPi), a critical anti-mineralization factor. The clinical phenotype of PXE is characterized by the effects of elastic fiber calcification in the skin, the cardiovascular system, and the eyes. In the eyes, calcification of Bruch's membrane results in clinically visible lesions, including peau d'orange, angioid streaks, and comet tail lesions. Frequently, patients must be treated for secondary macular neovascularization. No effective treatment is available for treating the cause of PXE, but several promising approaches are emerging. Finding appropriate outcome measures remains a significant challenge for clinical trials in this slowly progressive disease. This review article provides an in-depth summary of the current understanding of PXE and its multi-systemic manifestations. The article offers a detailed overview of the ocular manifestations, including their morphological and functional consequences, as well as potential complications. Lastly, previous and future clinical trials of causative treatments for PXE are discussed.

The role of multimodal imaging in characterization and monitoring of choroidal neovascularization secondary to angioid streaks

BACKGROUND

To characterize and monitor choroidal neovascularisation (CNV) secondary to angioid streaks (AS) using multimodal imaging and to compare the results with conventional fluorescein angiography (FA).

METHODS

A total of 11 eyes with CNV secondary to AS were included in this retrospective study. Multimodal morphological and functional assessment, including spectral-domain optical coherence tomography (SD-OCT), spectral-domain optical coherence tomography angiography (SD-OCTA), and fundus autofluorescence (FAF), were used to assess for evidence of CNV activity and compared with conventional FA. Morphological features of CNV were analyzed and treatment was continuously monitored using SD-OCT and SD-OCTA.

RESULTS

Our results showed that SD-OCTA provided reliable results for the detection of secondary CNV in AS that were comparable to conventional FA. With SD-OCTA, a total of 13 CNVs were detected in 11 eyes and analyzed by means of outer retinal choriocapillaris depth (ORCC) segmentation and the corresponding B-scans. Twelve of the 13 CNVs were classified as active and therefore required treatment. For treatment monitoring during intravitreal therapy (IVT), SD-OCTA was found to be a valuable diagnostic tool over a mean follow-up of 76 weeks.

CONCLUSIONS

Our study demonstrates that SD-OCTA can be routinely used to identify ill-defined CNV without dye-based angiography, especially in cases of CNV secondary to AS, where Bruch's membrane (BM) defects limit the diagnostic value of FA. Our results showed that non-invasive multimodal imaging facilitates sufficient CNV monitoring and treatment guidance. Further studies are warranted to provide more evidence in this rare retinal disease.

Anti-VEGF Treatment for Secondary Neovascularization in Pseudoxanthoma Elasticum - Age of Onset, Treatment Frequency, and Visual Outcome

PURPOSE

To assess the onset, treatment frequency, and visual outcome of anti-vascular endothelial growth factor (anti-VEGF) treatment due to secondary choroidal neovascularization (CNV) in patients with pseudoxanthoma elasticum (PXE).

DESIGN

Retrospective cohort study METHODS: One-hundred six eyes of 53 patients with PXE were analyzed. The assessment of CNV activity relied on hemorrhage visible on funduscopy and intra- / subretinal fluid on optical coherence tomography (OCT), individually defining a shortening or extension of treatment interval. Best-corrected visual acuity (BCVA) at baseline, age at anti-VEGF therapy initiation, and BCVA-drop events at exudation onset (worsening of BCVA of 2 or more lines) were documented. Further, we assessed the number of injections during the first year and the total number of injections, the time to treatment initiation of the fellow eye, and BCVA over time.

RESULTS

During a median observation period of 77 months (IQR 49; 126) patients received a median number of 28.0 anti-VEGF-injections (IQR 9.8; 43.5). Eight patients received no injection (median age at baseline 38.1 years), 11 patients underwent anti-VEGF treatment in one eye (median age 47.2 years) and 34 patients in both eyes (median age 51.8 years). The median age at the first anti-VEGF treatment was 52.80 years (IQR 47.2-57.6). Applying Cox regression models, the median "survival" time of fellow eye until treatment initiation was 16.8 months. In the group of bilateral treated patients, the median time difference was 9.6 months (IQR 2.1- 32.4, range 0-122) The median number of injections was 5.5 per eye in the first year of treatment (IQR 3-7) and was associated with the total number of injections in the observation period (2.33, CI 1.22-3.44, P < .001). A better BCVA at the last follow-up visit was associated with a better baseline BCVA (P < .001, R2 = 0.318) and with the absence of a BCVA drop at the onset of exudation (P = 0.035, R2 = 0.339).

CONCLUSIONS

The results of this study indicate that anti-VEGF treatment is required for most PXE patients at a relatively young age. Once treatment in one eye is initiated, the time to fellow eye treatment is relatively short. A BCVA drop before treatment initiation is a risk factor for worse visual outcomes, suggesting that treatment is prudent before exudation affects the central retina. Given the young age of onset and intensive treatment needs, patients with PXE might particularly benefit from longer-acting anti-VEGF therapeutics.

Macular neovascularization in inherited retinal diseases: A review

Inherited retinal diseases (IRDs) are the most common cause of blindness in working-age adults. Macular neovascularization (MNV) may be a presenting feature or occurs as a late-stage complication in several IRDs. We performed an extensive literature review on MNV associated with IRDs. MNV is a well-known complication of Sorsby fundus dystrophy and pseudoxanthoma elasticum. Those with late-onset Stargardt disease may masquerade as exudative age-related macular degeneration (AMD) when MNV is the presenting feature. Peripherinopathies may develop MNV that responds well to a short course of anti-vascular endothelial growth factor (anti-VEGF) therapy, while bestrophinopathies tend to develop MNV in the early stages of the disease without vision loss. Enhanced S-cone syndrome manifests type 3 MNV that typically regresses into a subfoveal fibrotic nodule. MNV is only a rare complication in choroideraemia and rod-cone dystrophies. Most IRD-related MNVs exhibit a favorable visual prognosis requiring less intensive regimens of anti-vascular endothelial growth factor therapy compared to age-related macular degeneration. We discuss the role of key imaging modalities in the diagnosis of MNV across a wide spectrum of IRDs and highlight the gaps in our knowledge with respect to the natural history and prognosis to pave the way for future directions of research.

HYPERREFLECTIVE FOCI PRECEDE MACULAR NEOVASCULARIZATION FORMATION IN ANGIOID STREAKS

PURPOSE

To describe the steps leading to the development and progression of macular neovascularization (MNV) in angioid streaks.

METHODS

The study was designed as retrospective, longitudinal case series. Patients with angioid streaks were investigated by means of multimodal imaging, including fundus autofluorescence and structural optical coherence tomography. Main outcome measures were hyperreflective foci and MNV progression steps.

RESULTS

Overall, 40 eyes (20 patients) affected by angioid streaks were evaluated. Over the follow-up, five eyes of five patients developed MNV. The mean follow-up was of 1.6 years. The mean number of anti-vascular endothelial growth factor injections was 4.35 ± 1.4. Mean best-corrected visual acuity was 0.53 ± 0.38 LogMAR at the MNV onset, improving to 0.42 ± 0.40 LogMAR at the end of the follow-up ( P > 0.05). Intraretinal hyperreflective foci onset and coalescence represented the first alterations occurring before the onset of the MNV. Anti-vascular endothelial growth factor treatment was associated with exudation relapsing and remitting, with still present intraretinal hyperreflective foci and pigment accumulation. The longitudinal analysis of our cohort of eyes outlined the event timeline: 1.2 months to find concentrated hyperreflective foci, 4.5 months to observe pigment organization through the outer nuclear layer, and 1.5 years to detect MNV.

CONCLUSION

Hyperreflective foci formation, concentration, and migration represent early alterations occurring before the onset of the MNV in angioid streaks.

Inner retinal degeneration associated with optic nerve head drusen in pseudoxanthoma elasticum

BACKGROUND/AIMS

To determine the association of age, presence of optic nerve head drusen (ONHD) and number of previous intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections with inner retinal layer thicknesses in patients with pseudoxanthoma elasticum (PXE).

METHODS

In this retrospective case-control study, longitudinal spectral-domain optical coherence tomography imaging data from patients with PXE were compared with controls. A custom deep-learning-based segmentation algorithm was trained and validated to quantify the retinal nerve fibre layer (RNFL) and ganglion cell layer (GCL). The association of age, number of anti-VEGF injections and ONHD with the RNFL and GCL thickness in the outer ETDRS subfields as dependent variables was investigated using mixed model regression.

RESULTS

Fourty-eight eyes of 30 patients with PXE were compared with 100 healthy eyes. The mean age was 52.5±12.9 years (range 21.3-68.2) for patients and 54.2±18.7 years (range 18.0-84.5) for controls. In patients, ONHD were visible in 15 eyes from 13 patients and 31 eyes had received anti-VEGF injections. In the multivariable analysis, age (-0.10 µm/year, p<0.001), the diagnosis of PXE (-2.03 µm, p=0.005) and an interaction term between age and the presence of ONHD (-0.20 µm/year, p=0.001) were significantly associated with the GCL thickness. Including the number of intravitreal injections did not improve the model fit. The RNFL thickness was not significantly associated with any of these parameters.

CONCLUSIONS

This study demonstrates a significant association of ageing and ONHD with GCL thinning in patients with PXE, but not with the number of anti-VEGF injections. Given the severity of inner retinal degeneration in PXE, a clinical trial investigating neuroprotective therapy warrants consideration.

A customized regimen of intravitreal aflibercept for the treatment of choroidal neovascularization secondary to different chorioretinal diseases

BACKGROUND

To assess the response of CNV secondary to chorioretinal diseases to IVA and to explore the adequate dosing regimen and the long-term results.

METHODS

A retrospective study including patients with treatment-naïve active CNV secondary to chorioretinal diseases. All patients received an initial IVA injection followed by a PRN regimen. The main outcome measures were improvement of BCVA, improvement of anatomical morphology and vascularity of the CNV on SS-OCT, and SS-OCTA, respectively, and ocular or systemic complications attributed to IVA.

RESULTS

The study included 17 eyes of 15 patients. Nine patients (60%) were females. The median age was 20 years. The main primary chorioretinal disease was vitelliform macular dystrophy (29%). The mean baseline BCVA was 0.16. The mean follow-up period was 15 months. Final BCVA improved by a mean of 6 lines. The CNV regressed or became inactive in all eyes. The median number of IVA injections was 2. There were no ocular or systemic complications attributed to IVA.

CONCLUSION

The customized IVA regimen is effective in inducing long-term regression of secondary CNV and in improving BCVA. Multimodal imaging is fundamental in establishing the diagnosis of CNV, and in monitoring its response to IVA.

Long-Term Effect of Anti-Vascular Endothelial Growth Factor (Anti-VEGF) Injections in Choroidal Neovascularization Secondary to Angioid Streaks

Purpose

This study aimed to evaluate the long-term effectiveness of intravitreal anti-vascular endothelial growth factor (VEGF) injections in the treatment of choroidal neovascularization (CNV) associated with angioid streaks.

Methods

Multicenter retrospective cohort study, including eyes with CNV secondary to angioid streaks treated with anti-VEGF injections, were performed. Best-corrected visual acuity (BCVA) in ETDRS letters; qualitative and quantitative (foveal thickness) OCT parameters; anti-VEGF type; and number of injections were collected at baseline and at 3, 6, 12, 24, 36, 48, 60, and 72 months.

Results

Thirty-nine eyes from 29 patients, 17 (58.6%) females, were included. The mean follow-up time was 69.4 ± 34.5 months. BCVA was 59.3 ± 23.3 letters at baseline and 63.7 ± 21.9 letters at 48 months. At 3 months, BCVA improved 6.9 ± 11.7 letters (P=0.003). Then, BCVA remained stable. The mean foveal thickness decreased from 343.3 ± 120.2 μm at baseline to 268.3 ± 65.4 at 48 months (P=0.021). The mean number of injections was 4.6 ± 2.1 at 12 months, decreasing to 1.7 ± 2.4 injections between 36 and 48 months (P=0.093).

Conclusion

This real-world study suggests that the functional and morphologic response to anti-VEGF therapy for CNV related to angioid streaks is generally satisfactory and maintained in the long term.

The identification of activity of choroidal neovascularization complicating angioid streaks

OBJECTIVES

To inspect the inter-reader agreement of different diagnostic modalities in identifying choroidal neovascularization (CNV) activity secondary to angioid streaks (AS) and to analyze the prevalence of subretinal hyper-reflective material (SHRM) in active CNV.

METHODS

Retrospective study of patients with AS with active CNV; optical coherence tomography (OCT), OCT angiography (OCTA), fundus fluorescein angiography (FFA), and indocyanine green angiography (ICGA) from each patient were collected. Agreement between two readers using different diagnostic modalities is presented as free-marginal kappa (k) and 95% confidence interval (CI).

RESULTS

This study included 19 eyes of 12 patients with active CNV (5 naive and 14 previously treated). Agreement among readers on CNV activity was excellent for OCT (k =0.88; 95% CI 0.71-1.00), good for FFA (k = 0.70; 95% CI 0.46-0.94) and ICGA (k = 0.58; 95% CI 0.31-0.84), and poor using OCTA (k = 0.39; 95% CI 0.11-0.68). SHRM was the most common OCT finding associated with active CNV (100%); fuzzy borders were present in 53% of SHRM cases at baseline.

CONCLUSIONS

Identification of CNV activity in AS is challenging; OCT was the best modality to inspect active CNV. The identification of SHRM contributed to recognizing active CNV. Further studies are needed to assess the role of SHRM in anticipating prognosis and guiding treatment of CNV secondary to AS.

Therapy of Pseudoxanthoma Elasticum: Current Knowledge and Future Perspectives

Pseudoxanthoma elasticum (PXE) is a rare, genetic, metabolic disease with an estimated prevalence of between 1 per 25,000 and 56,000. Its main hallmarks are characteristic skin lesions, development of choroidal neovascularization, and early-onset arterial calcification accompanied by a severe reduction in quality-of-life. Underlying the pathology are recessively transmitted pathogenic variants of the ABCC6 gene, which results in a deficiency of ABCC6 protein. This results in reduced levels of peripheral pyrophosphate, a strong inhibitor of peripheral calcification, but also dysregulation of blood lipids. Although various treatment options have emerged during the last 20 years, many are either already outdated or not yet ready to be applied generally. Clinical physicians often are left stranded while patients suffer from the consequences of outdated therapies, or feel unrecognized by their attending doctors who may feel uncertain about using new therapeutic approaches or not even know about them. In this review, we summarize the broad spectrum of treatment options for PXE, focusing on currently available clinical options, the latest research and development, and future perspectives.

A case report: pseudoxanthoma elasticum diagnosed based on ocular angioid streaks and the curative effect of Conbercept treatment

Background

This article is a case report of pseudoxanthoma elasticum (PXE) which was diagnosed based on significant angioid streaks (AS) with choroidal neovascularization (CNV) and regain normal visual function by intravitreal injection with Conbercept.

Case presentation

A 51-year-old woman was referred to the Ophthalmology Department of Qingdao Municipal Hospital (Qingdao, China) on September 14, 2020 for metamorphopsia and loss of vision in the left eye in the preceding three days. Past history: high myopia for more than 30 years, best corrected visual acuity (BCVA) of both eyes was 1.0 (5 m Standard Logarithm Visual Acuity chart in decimal notations), hypertension for six years, and cerebral infarction two years ago, no history of ocular trauma or surgeries or similar patients in family was documented. We used methods for observation, including fundus examination, optical coherence tomography (OCT), fluorescein angiography combined with indocyanine green angiography (FFA + ICGA). Due to her symptoms and manifestations, along with the appearance of her neck skin, which resembled ‘chicken skin’, we speculated that she should be further examined at the Department of Dermatology by tissue paraffin section and molecular pathology analyses, and the diagnosis of PXE was then confirmed. After intravitreal injection with Conbercept (10 mg/ml, 0.2 ml, Chengdu Kanghong Biotechnologies Co., Ltd.; Chengdu, Sichuan, China) she regained her BCVA.

Conclusions

This patient regained her best corrected visual acuity through intravitreal injection with Conbercept. To the best of our knowledge, no publications are available on cases in which a vision loss and the normal visual function can be reverted by intravitreal injection with Conbercept. Although PXE is a disease with low incidence and thus no effective cure established, targeted symptomatic treatment can effectively retard the disease progression and improve visual function, such as intravitreal injection with Conbercept.

Therapeutics Development for Pseudoxanthoma Elasticum and Related Ectopic Mineralization Disorders: Update 2020

Pseudoxanthoma elasticum (PXE), the prototype of heritable ectopic mineralization disorders, manifests with deposition of calcium hydroxyapatite crystals in the skin, eyes and arterial blood vessels. This autosomal recessive disorder, due to mutations in ABCC6, is usually diagnosed around the second decade of life. In the spectrum of heritable ectopic mineralization disorders are also generalized arterial calcification of infancy (GACI), with extremely severe arterial calcification diagnosed by prenatal ultrasound or perinatally, and arterial calcification due to CD73 deficiency (ACDC) manifesting with arterial and juxta-articular mineralization in the elderly; the latter disorders are caused by mutations in ENPP1 and NT5E, respectively. The unifying pathomechanistic feature in these three conditions is reduced plasma levels of inorganic pyrophosphate (PPi), a powerful endogenous inhibitor of ectopic mineralization. Several on-going attempts to develop treatments for these conditions, either with the goal to normalize PPi plasma levels or by means of preventing calcium hydroxyapatite deposition independent of PPi, are in advanced preclinical levels or in early clinical trials. This overview summarizes the prospects of treatment development for ectopic mineralization disorders, with PXE, GACI and ACDC as the target diseases, from the 2020 vantage point.

Triptolide attenuates laser-induced choroidal neovascularization via M2 macrophage in a mouse model

PURPOSE

To investigate whether triptolide has inhibitory effects on the development of choroidal neovascularization (CNV), together with its underlying anti-angiogenic mechanisms.

METHODS

CNV was induced in C57BL/6 J mice using laser photocoagulation. Triptolide at concentrations of 0.035 and 0.07 mg/kg body weight (BW) or the same volume of phosphate-buffered saline (PBS) was intraperitoneally injected into mice 2 days before laser photocoagulation, which was continued daily till the end of the experiment. CNV areas were measured on day 7. The numbers of M1, M2, and F4/80⁺ macrophages were detected on day 1, 3, and 7 in each group. The levels of vascular endothelial growth factor (VEGF) and inflammatory molecules,including intercellular adhesion molecule (ICAM)-1,tumor necrosis factor (TNF)-α, and interleukin 6 (IL-6) were determined by enzyme-linked immunosorbent assay. Cell proliferation, migration, and tube-formation assays were performed in vitro.

RESULTS

Triptolide at doses of 0.035 mg/kg BW (66,562 ± 39,253 μm², n = 5, P＜0.05) and 0.07 mg/kg BW (37,271 ± 25,182 μm², n = 5, P＜0.001) significantly reduced CNV areas by 54.9 and 74.8 %, respectively, compared with PBS control (147,699 ± 112,900 μm², n = 5) in a dose-dependent manner. Protein levels of VEGF, ICAM-1, TNF-α, and IL-6 in the RPE-choroid-sclera complex were significantly downregulated by triptolide treatment on day 3, which was in accordance with the reduced number of infiltrated F4/80⁺ macrophages and the reduced ratio of M2/F4/80⁺ macrophages. However, no toxic effects of triptolide on the retina or other systemic organs were observed. In addition, triptolide treatment exerted inhibitory effects on cell proliferation, migration, and tube formation in vitro in a concentration-dependent manner.

CONCLUSIONS

Triptolide has therapeutic potential in CNV owing to its anti-angiogenic effect.

Intravitreal aflibercept for management of choroidal neovascularization secondary to angioid streaks : The Italian EYLEA-STRIE study

PURPOSE

To investigate the effect and the safety of intravitreal aflibercept in patients affected by choroidal neovascularization secondary to angioid streaks with a long-term follow-up.

METHODS

Multicentre, open-label, phase IIb study (EYLEA-STRIE, EudraCT Number 2014-000986-30) involving four Italian centres (IRCCS Ospedale San Raffaele (Milano), Fondazione G.B. Bietti (Roma), Policlinico (Milano), Ospedale Luigi Sacco (Milano)). Patients with active choroidal neovascularization secondary to angioid streaks with foveal involvement were prospectively enrolled and followed for 18 months. All the patients received intravitreal 2 mg/0.05 mL aflibercept at the time of enrolment, followed by a pro-re-nata regimen for 48 weeks. Best-corrected visual acuity and central macular thickness were measured monthly. Adverse events were monitored at each visit.

RESULTS

Twenty-three eyes of 20 patients were analysed. Mean number of injections per patient was 4.30 ± 1.2. At week 48, the best-corrected visual acuity was 0.42 ± 0.40 LogMAR (p = 0.6 from baseline) and 18 eyes (81.8%) featured stability within 15 letters. The central macular thickness significantly reduced (p = 0.03). Eleven ocular non-serious adverse events and two serious adverse events were observed (one case of endophthalmitis and one case of acute gastritis were reported).

CONCLUSION

Intravitreal aflibercept represents a valid option for the management of choroidal neovascularization complicating angioid streaks. Further studies with longer follow-up and different therapeutic regimens are warranted to ascertain the best control of the disease.