Final Report Summary - STRONG (European Consortium for the Study of a Topical Treatment of iCRVO to prevent Neovascular Glaucoma)
Executive Summary:
The STRONG project is a European consortium for the study of a topical treatment of ischaemic central retinal vein occlusion (iCRVO) to prevent neovascular glaucoma (NVG). Secondary NVG, the major cause of which is iCRVO, is a very aggressive, rare form of glaucoma, responsible for 3.9 % of glaucoma cases, but contributing disproportionately to blindness from all eye diseases. Also, NVG is the second most common cause for enucleations (removal of the eye ball) across all eye diseases, usually for intractable pain.
Glaucoma in general is more than a single disease entity: it is a group of conditions characterized by progressive optic nerve degeneration (detectable by pathological cupping of the optic disc) and loss of visual function, ultimately resulting in total blindness. The lack of oxygen in the specific tissue (hypoxia) associated with retinal vein occlusion is mostly (but not exclusively) responsible for the subsequent release of angiogenic factors (i.e. vascular endothelial growth factor, VEGF). These also cause the growth of a fibrovascular membrane over the trabecular meshwork leading to an obstruction of the trabecular meshwork and/or associated peripheral anterior synechiae leading to an increase of intraocular pressure (IOP).
Today’s therapeutic approaches are insufficient and involve mainly lowering the elevated IOP, laser or cryo-therapy to destroy the affected retina, or off-label intravitreal injection of anti-VEGF compounds, with unsolved issues in determining the correct timing, dosing and place of such interventions. There is, therefore, a need to widen the existing therapeutic options for NVG secondary to iCRVO. Aganirsen is an antisense oligonucleotide which topical administration inhibits the production of VEGF, which plays a major role in the pathogenesis of NVG. The study was designed to test whether aganirsen is able to inhibit the formation of neovascularisations and fibrovascular membranes leading to the development of secondary NVG. This would be the first non-invasive treatment for this disease.
At the same time, STRONG was planned to provide important data on age and sex matched normal values of controls and retinal vein occlusion (RVO) patients and the natural course of iCRVO and NVG in a very large and well-investigated cohort. Analyses of biomarkers for the development and progression of iCRVO and NVG were part of the STRONG project with a high potential to discover new ones. Finally, image analyses tools and biomorphometric methods were developed and refined to better quantify and stage the disease by the evaluation of vessels in images.
Project Context and Objectives:
Glaucoma is more than a single disease entity: it is a group of conditions characterized by progressive optic nerve degeneration (detectable by pathological cupping of the optic disc) and loss of visual function, ultimately resulting in total blindness.
The two most frequent types are primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG). However, there are many forms of rare secondary glaucomas that develop following other eye diseases, including secondary neovascular glaucoma (NVG) most frequently presenting following ischemic central retinal vein occlusion (iCRVO).
NVG, which develops as a result of iCRVO typically after an average period of about 90 days (“90 days-glaucoma”), but may also appear as early as two weeks or alternatively after a much longer period of time. Anti-proliferative laser or cryo treatment of the retina must be performed in iCRVO as soon as neovascularizations are diagnosed: yet, it cannot be implemented before the blood that typically obscures the retina has been absorbed. Thus, the correct timing of Pan Retinal Photocoagulation (PRP) laser therapy is difficult to determine, retinas the bleedings may prohibit timely therapy. But if the angiogenic stimulus continues in that interval NVG develops before anti-proliferative treatment can be begun. An alternative may be cryo-therapy but this cannot be selectively directed to affected areas of the retina and is accompanied by destruction of large areas of the retina. Moreover, even laser treatment does not cure the disease. It only reduces the oxygen demand of the retina, and thus leads to a regression of the neovascularizations. It is clear that, while beneficial in the short term, reducing retinal ischaemia by PRP or even cryo-therapy destroys a relatively large proportion of the retina. There is, therefore, a need to widen the existing therapeutic options for NVG secondary to iCRVO.
At present, management of NVG relies predominantly on lowering the elevated intraocular pressure (IOP), but also needs to address the underlying cause of the disease. Several factors have been identified as potentially causing ocular neovascularization. Recent studies suggest that endogenous VEGF plays a central role in angiogenesis. Once released, the angiogenic factors diffuse into the aqueous and the anterior segment and interact with vascular structures. The resultant growth of new vessels in the anterior chamber angle (neovascularization of the angle [NVA]) and iris surface (neovascularization of the iris [NVI]) lead to the formation of fibrovascular membranes. The fibrovascular membranes, which may be invisible on gonioscopy, progressively obstruct the trabecular meshwork, the place of outflow of aqueous humour from the eye. This causes a rise in IOP and secondary glaucoma. Another mechanism by which NVG can occur relates to breakdown of the aqueous humour/blood barrier leading to inflammation, synechiae between iris and lens and pupillary block glaucoma. Both phenomena are often irreversible.
Currently, reduction of IOP remains the focus of all therapeutic approaches for all forms of glaucoma. Elevated IOP is a major risk factor in the pathogenesis of optic nerve damage and visual field loss. The higher the IOP, the greater the likelihood of visual field loss together with optic nerve damage. There are relatively effective treatment options for the most frequent form of glaucoma, namely POAG (primary open angle glaucoma). In NVG however, IOP lowering medications are moderately helpful since outflow is obstructed. Furthermore, the accompanying inflammation and proliferative stimulus lead to a very poor success-rate of fistulating glaucoma surgery. Thus, there is often a limitation to anti-proliferative and cyclodestructive surgery. Anti-proliferative treatment aims at destroying parts of the retina that are assumed to produce VEGF but is accompanied by irreversible loss of the retinal function, which, clearly, is a problematic approach. Furthermore, even if these treatment approaches are used consequently, still many eyes are lost.
Because of the pivotal role of angiogenesis in the initiation and progression of NVG, several studies propose the use of anti-angiogenic agents such as anti-VEGF combined with traditional treatments such as PRP, with or without additional surgery, and vary in the timing and combination. All present therapeutics require an injection into the eye. Standardized guidelines of NVG treatment with anti-VEGFs (dose and place of injection [intracameral or intravitreal, or both simultaneously]) have, however, not yet been established, since no prospective trials have been performed, and the use of existing anti-angiogenic agents is off-label.
The application of a topically active anti-angiogenic agent (aganirsen) would be a non-invasive, easy to titrate, and easy to use treatment option to anticipate the formation of fibrovascular membranes and to treat secondary NVG. Aganirsen is a 25mer antisense oligonucleotide of 8’035 Daltons developed by Gene Signal (oligonucleotides are short strands of DNA designed to prevent translation of messenger RNA into unwanted proteins). Aganirsen is a promising candidate to prevent the development of NVG: it inhibits the expression of Insulin Receptor Substrate (IRS-1) in pathological pro-angiogenic conditions. Aganirsen was granted orphan designation for NVG from the EC in April 2004 (EU/3/03/161; EMEA/COMP/1421/03). Its efficacy when applied topically in corneal neovascularization has already been demonstrated. Phase I-III trials in the cornea have also shown a positive safety profile, while non-human primate studies have proven the capability of the topical preparation to reach not only the anterior chamber but even the retina. The hypothesis of the STRONG study is that aganirsen could be well tolerated, effective and safe to inhibit the development of NVG following iCRVO.
The primary objective of the treatment with aganirsen within the STRONG trial was to avert or minimize the rise in IOP in patients with iCRVO by averting abnormal neovessels formation and further obstruction of the trabecular meshwork by the treatment with aganirsen. The STRONG trial was also designed to evaluate the efficacy of two aganirsen doses, to assess aganirsen efficacy relative to placebo on time to and intensity of additional interventions such as PRP or cryotherapy, to compare aganirsen and placebo on health outcome and quality of life (QoL) and to confirm a positive safety profile of aganirsen.
The overarching goal of the phase II/III randomized, double- masked, 3 armed, placebo-controlled STRONG trial was therefore:
• To assess whether at 24 weeks, topical aganirsen treatment can reduce the rate of anterior iris- and chamber-angle and posterior segment neovascularisation and NVG development after iCRVO, in a study with up to 333 patients in over 30 different sites.
• To assess the natural course of iCRVO and NVG in the placebo-arm.
• To evaluate known or suspected risk factors and biomarkers for RVO and NVG and to identify new ones for the development of NVG.
• To improve the early diagnosis of NVG in iCRVO patients by image analysis and biomorphometric analysis.
To achieve the above-mentioned goals the overall objectives for the trial were:
• To finalize the trial design.
• To enlist sufficient trial centres to ensure recruitment of the statistically appropriate number of patients.
• To manufacture sufficient trial supplies of aganirsen and its placebo in compliance with the Good Manufacturing Practices (GMP).
• To provide central reading services to the STRONG trial for both established and novel methods for assessing NVG.
• To perform the STRONG trial, recruiting up to 333 patients while adhering to the highest GCP standards and protecting patient safety.
• To analyse the collected trial data for NVG treatment, reducing if possible the trial sample size below 333 patients while meeting all requirements to file for conditional market authorisation.
• To disseminate the test results to affected communities in Europe and beyond.
Project Results:
The STRONG project includes four major scientific topics in which results and foregrounds have been generated:
1) The finalization of the clinical investigational plan following protocol assistance from the European Medicines Agency (EMA)
2) Development of a stable ophthalmic emulsion (composition and manufacturing steps)
3) Prototype methods (software) to quantify iris vessels dilation and degree of pathological iris neovascularization
4) Analyses of biomarkers and normal values for RVO patients and healthy subjects.
The finalization of the clinical investigational plan following protocol assistance from the European Medicines Agency (EMA):
The STRONG trial was designed to fulfil requirements for clinical trials to be used for a future marketing authorization. Therefore, protocol assistance was sought from the EMA at the beginning of the project to ensure that the protocol is compliant with the European regulation with Orphan Drug Designation (ODD) of aganirsen for the treatment of NVG and satisfies the needs of European regulatory bodies. After extensive protocol assistance, the sponsor received the positive opinion for the orphan drug designation for the “treatment of CRVO” in April 2014.
The completion of the trial protocol following to the closed protocol assistance with the EMA allowed the submission to the regulatory authorities. Regulatory approval by the Ethics Committees and the Competent Authorities were sought in all participating countries and trial sites. Ethics approvals were obtained in Germany and France; regulatory approval in Italy. The submission in further countries has been set on hold until all questions from the regulatory authorities could be answered. This requires the finalized production of the study drug.
The basis for a successful trial performance is prepared by the above mentioned final trial protocol including all connected documents and Ethics / regulatory submission and approvals. The trial design has been published in an open-access journal. The design and programming of the trial-specific forms and Case Report Forms was performed within the STRONG FP7 project. The Electronic Data Capture (EDC) system is developed and only needs final approval. Training material was prepared for on-line EDC training for all monitors, project managers and site representatives. The EDC including eCRF and Reading Center submission platform is integrated in the project website. The website (www.strong-nvg.com) also contains all necessary trial documents, Standard Operating Procedures (SOPs) and training manuals for download for trial staff:
SOPs:
• Swinging-flashlight test
• Refraction and visual acuity measurement
• Goldman perimetry/semiautomatic kinetic perimetry
• Gonioscopy
• Blood pressure and heart rate measurement
• Blood sample collection, separation, labelling, storage and transportion for risk factor and biomarker sub-study
• Standard 12 lead ECG recording
Available training manuals:
• Overall manual of study procedures & outcome measures (aganirsen and project protocol, trial indication, biomarker and risk factor sub-studies, safety management and Good Clinical Practice, data management, EDC/eCRF)
• Instructions for iris and chamber angle photographs
• Digital colour fundus photography, fluorescein angiography and OCT imaging instructions
• Gonioscopic images
In total 27 trial sites have been evaluated for participation. All sites are qualified for performing the clinical trial with specific trial staff and equipment to ensure a high quality STRONG trial.
Development of a stable ophthalmic emulsion (composition and manufacturing steps):
The development of a stable ophthalmic emulstion was one major aim of the STRONG project. Initial issues in the development of a stable formulation have been overcome successfully. The manufacturing process of the study drug (an emulsion) faced unexpected handling issues at the start of the project: several attempts of the manufacturing partner proved unsuccessful with regards to the trial objectives. Gene Signal, in line with a first amendment to the Grant Agreement, took over the responsibility of the development of an adequately stable formulation and its manufacturing process. Following a lengthy redesign process, a stable formulation was demonstrated on the basis of laboratory tests in mid-2017. Gene Signal therefore significantly improved the emulsion formulation which led to patents applied for in 2017 and 2018 and a manufacturing process.
Title: STERILE FORMULATION COMPRISING A STABLE PHOSPHOROTHIOATE OLIGONUCLEOTIDE
Country Application Publication Status
USA 15/423964 (2017-02-03) Confidential Pending
Europe 17154670 (2017-02-03) Confidential Pending
World PCT/EP2018/052663 (2018-02-03) Confidential Pending
The resulting viscous solution can now be packaged within a sterile environment, using state-of-the art dosing/filling machines available in Europe, the blister-based technology allowing indeed for the effective aseptic filling of the emulsion. The emulsion is thus protected against external effects such as light or oxygen, as well as evaporation, and can keep its stability properties for period of time compatible with the targeted therapeutic end uses. An optional spout offers added versatility when it comes to the dose administration options.
A drug manufacturer was found to implement the proper manufacturing steps for the emulsion and its packaging. Yet, it requires investing into a specific equipment to be implemented in the sterile GMP manufacturing site in view of confirming the stability properties found at laboratory scale. The fixed project deadlines (march 2018) imposed by the EC were not enough to reach a process ready to manufacture the stable emulsion quantity needed for the trial.
Prototype methods (software) to quantify iris vessels dilation and degree of pathological iris neovascularization:
The CORIC reading centre was responsible for the blinded evaluation of chamber angle and iris slit-lamp pictures qualitatively for presence or absence of pathological neovascularisations to facilitate an objective diagnosis of NVG. Scientific evaluation of the correlation between the degree of IOP and patterns of iris and chamber angle neovascularisations will help to better understand the disease mechanism of NVG.
To perform the evaluation of neovascularizations, CORIC developed a semiautomatic method (software) to quantify iris vessel dilation and degree of iris neovascularisation. The aim of this project was to realize a network analysis of complex vascularization patterns found in the inflamed cornea or neovascularised iris by a digital skeletonization tool. Gray scale images of murine vascularized corneal flat mounts were used to establish this method. The performance criteria are false negative rate (FNR) in case of vessels loss and false positive rate (FPR) in case of fake vessels reconstruction. These criteria should be estimated after the whole analysis comparing the original image with the reconstructed skeleton. For the vessel structure identification two filtering-based methods were tested: hysteresis thresholding algorithm and adaptive contrast enhancement (ACE) algorithm, where the ACE-method was found to be more robust for fine vessels identification than the hysteresis based algorithm. However, the hysteresis algorithm is faster. For large images with relatively homogeneous background the hysteresis algorithm can be used to accelerate the analysis process without the quality loss during binarisation. The analysis chain is combined in one tool and implemented in a Graphical User Interface (GUI) in Matlab. The graphical user interface was called BranchTool and handles with all image processing steps. Images can be resized, contrast be changed, a noise filter applied or an image format converted from and into TIF, JPG, BMP, GIF, EPS and PNG.
Vessels determination procedure is often restricted by pixel classification, i.e. by making decision whether a pixel belongs to a vessel or to the background.
Enhancement of the small vessel identification, mathematical morphology tools and calculation speed should be optimized. The most time consuming process is the ACE binarisation. The mean computing time of this step depends on the computing machine power and in the worst case can take about 10 minutes working with the original images.
In a second step of software development the aim was to extract vessel like structures from iris images of patients with NVG. The main issue with these images is the massive background generated by the iris pigmentation ranging between brown, hazel, green, gray, or blue as well as by structural features of the iris like the crypts of Fuchs or folds of Schwalbe. In the grey scale analysis performed to detect and analyse the vessels these structures interfere with the grey scale threshold of the blood vessels. Therefore a method had to be established to eliminate this background structures. Depending on the iris colour the image is split into the cyan, magenta and yellow (CMY) channels. In mainly blue, green and gray irides cyan mainly represents the iris pigmentation whereby in brown (hazel) irides the iris is represented mainly by the yellow channel. Magenta mainly represents the blood vessels.
Based on these findings the following algorithm was established: 1) To outbalance the inhomogenous illumination due to the anatomical curvature of the iris first shading correction is performed. An equally illuminated and therefore plane appearing iris is resulting. This image afterwards is divided into the above explained three channels. In the cyan channel the blood vessels are mainly disappeared whereas in the magenta channel these vessels are significantly pronounced. Anyway, also bright iris crinkles are still visible and interfere with the gray scale range of the blood vessels. Therefore the cyan image is substracted from the magenta image resulting in an almost background free vessel image. 2) To further extract the vessels from the background a so called DCE filter is used. This filter (Differential Contrast Enhancement) increases only the weak contrast differences. Thereby image structures get visible which could not be discriminated before. The resulting image can now be analysed by the branching analysis tool.
By subtracting the magenta channel from the cyan channel the background signal from the crypts of Fuchs or folds of Schwalbe could be significantly reduced. Thereby the vessels and bleedings can be identified more precise. When quantifying the elongation and the roundness of the detected particles it is now even possible to discriminate between vessels and bleedings on the level of area quantification. Thereby also leakage of the pathologic iris vessels can be monitored.
A cutting edge, in vivo method to analyze iris vessels in the mouse model was used afterwards. The method was transferred to Optical Coherence Tomography (OCT) - a non-invasive optical imaging method using infrared light to produce depth-resolved cross-sectional images of tissue. A volume can be created by combining numerous depth-scans.
In normal OCT images, blood vessels are not directly visible. However, intensity fluctuations due to the altered position of blood cells can be observed when vessels are present. A further processing of the data thus can reveal vessels by flow analysis. OCT-Angiography (OCT-A) is non-invasive like OCT. However, it is very sensitive to motion of the subject. Small movements of the subject, e.g. caused by breathing, lead to artifacts. The intensity of those spurious lines often superimposes the actual vessel signal, which was shown by a lead off experiment.
Consequently, the quality of an OCT angiography depends on how calm the animal was, or how fast the data could be acquired, respectively. Images with only moderate artifacts can be evaluated in 3D by further processing steps using the MeVisLab-environment. Here by we not only can analyze the area covered by vessels, but also the total volume, length, branches, end points as well as tortuosity of the iris vessels in three dimensions (3D). These three-dimensional parameters will give far more information on the vessel network and are independent of iris pigmentation. By this technique changes in the iris vasculature in the context of neovascular glaucoma will be detectable more precisely.
Analyses of biomarkers in RVO patients and healthy subjects:
One common cause of NVG is ischaemic retinal vein occlusion (iCRVO), but also CRVO as well as BRVO can lead to NVG. Within the first examination of the participants in the Gutenberg Health Study (GHS) we were able to find 59 participants suffering from RVO. Therefore the GHS provides the unique opportunity to evaluate potential associations of RVO and subsequent glaucoma development in a population-based setting. The GHS is a population-based, single-center, prospective, cohort study at the University Medical Center of the Johannes Gutenberg University Mainz in Germany. The population sample was randomly drawn via local residents’ registration offices and equally stratified by sex for each decade of age. The baseline examination included 15,010 participants aged 35 to 74 years and was conducted from 2007 to 2012. The examination consisted of an ophthalmological examination, general and cardiovascular examinations, biomaterial sampling, and questionnaires and interviews. A Visucam PRO NM nonmydriatic fundus camera (Carl Zeiss AG, Jena, Germany) was used to take digital fundus pictures through a nonpharmacologically dilated pupil. The participants were positioned in a darkened room to allow for natural pupil dilation. The grading of the baseline fundus photographs for the detection of RVO was carried out by a trained grader at the Moorfields Eye Hospital Reading Center, London, UK, and was adjudicated by an experienced clinician grader. We identified n=59 participants with RVO (n=12 for central RVO and n=47 for branch RVO).
The aim is to determine which participants possible could be of higher risk of developing glaucoma after suffering from a RVO. For this we will evaluate the association of autoantibody (AAB) levels with RVO in GHS participants and age- and sex-matched controls (1:4) and also will measure autoantibodies previously described to be associated with ischaemic and degenerative eye diseases. The results hopefully will contribute to elucidate the role of autoantibodies in the development of RVO and furthermore show relevant factors important for the development of subsequent glaucoma. The corresponding antigenes have been purchased and spotted onto special nitrocellulose coated slides by a non-contact microarray spotter (sciFLEXARRAYER S3, Scienion, Germany). This specialized non-contact spotting process allows spotting of antigens and antibodies with a very low spot to spot variability, thus increasing the data reproducibility. The customized microarrays will be incubated with RVO and control sera. In order to compare spot signals and to detect antibodies (biomarkers), we will use a combination of different algorithms for data normalization (e.g. Z-score algorithm) and a set of diverse statistical techniques, such as artificial neural networks and tree algorithms.
Frequency of prevalent and cumulative 5-year incident glaucoma and associated factors in RVO patients from the population based from the Gutenberg Health Study:
The sample-size and the phenotyping of RVO are described above. As we would like to determine the subsequent development of glaucoma over a time course, analysis of the follow-up visit after 5 years were performed. For the grading of glaucoma, the optic nerve head images of all RVO cases and of 236 age- and sex-matched healthy controls from baseline and from the 5-year-follow-up have been measured. We used EVICR (European Vision Institute Clinical Research Network) standards and the ISGEO (International Society Geographical & Epidemiological Ophthalmology) classification. The ISGEO classification is based on vertical cup-to-disc ratio (vCDR) and rim width-to-disc-ratio (RWDR) controlled for optic disc size, refraction and keratometry, visual field testing, IOP, and ophthalmic history. The grading have been performed independently by two trained graders. Regular recalibration and masked intra-rater-reliability (10% of analyzed images) has been performed. After ongoing quality and plausibility checks, we will calculate the prevalence and the cumulative 5-year-incidence of glaucoma among RVO participants, crude and weighted to the population of the region. In addition, we will evaluate factors potentially associated with prevalence and incidence using regression models.
The availability of population-based prevalence and incidence data will contribute to the understanding of the connection between RVO and glaucoma.
Potential Impact:
Glaucoma is more than a single disease entity: it is a group of conditions characterized by progressive optic nerve degeneration (detectable by pathological cupping of the optic disc) and loss of visual function, ultimately resulting in total blindness. The two most frequent types are primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG). However, there are many forms of rare secondary glaucomas that develop following other eye diseases, including secondary neovascular glaucoma (NVG). NVG is a rare, very aggressive form of secondary glaucoma. While the overall prevalence of glaucoma is about 1% in the general population, NVG makes up for approximately 3.9% of all glaucoma cases. NVG as a rare disease contributes disproportionately to blindness from glaucoma, and even to the loss of eyes from its painful end-stages: NVG is the second most frequent cause for enucleations (removal of the eye ball) not only from glaucoma but from any eye disease and, thus, accounts for a disproportionate large amount of individual suffering as well as high socio-economic costs from medical care, absence from work and the necessary benefits for visually handicapped and blind patients. This emphasizes the need for new efficient and more pathogenetically oriented treatment options for NVG, an orphan indication.
Today’s still inadequate treatment options for NVG can leave the patient exposed to blindness, and in so much pain that enucleation (removal of the eyeball) is required. Blindness inflicts very significant individual suffering and leads to economic and social costs. For the healthy population the threat of blindness has been shown to be one of the most feared health threats, second only to death from long-standing cancer disease. The loss of visual function is “valued” by patients inflicted by disease in a way similar to a severe stroke, indicating the severe loss of quality of life that is experienced.
Moreover, the socio-economic burden to societies is high. Taking the example of Germany to provide an order of magnitude for a population of nearly 82 million people, about one million of the population are disabled due to low vision, 164 000 people are blind, 132 000 people get a monthly financial allocation from public funds (approx. 10% of those entitled to these social benefits do not ask for the allocation even though they could apply for): this monthly allocation ranges from 170 € to 525 € depending on age and region. The rate of growth for blindness up to 2030 is expected to be 30%, because of the demographic changes with eye diseases increasing more than other diseases with aging: in 2000, a first estimate for the direct and indirect costs for blindness reached about one billion €, in 2006, a similar evaluation covering also the cost of lost incomes and the costs for the services to the blind reached 9 Billion € (or roughly 12 600 € per year per affected person (low vision and blind) over a total population of about 730 000. Furthermore blindness is associated with a tremendous loss of quality of life and with individual suffering.
There are several impacts expected from the STRONG project and the clinical trial. The project focuses on the development of preventive, diagnostic and therapeutic interventions. As described above, the current therapeutic interventions are inadequate. Gene Signal developed an ophthalmic emulsion for the topical treatment of iCRVO to prevent NVG. The project aimed at validating anti-angiogenic eye drops, thus impacting 1) the general community by management of impending NVG and/or attenuation of NVG, quality of life in affected individuals applying a non-invasive route and prevention of painful NVG end stages, and the reduction of economic burden related to NVG and blindness.
The development and manufacturing of an ophthalmic emulsion is a new area. The knowledge generated within the project about the development of emulsions has a great scientific impact for the future development of new drugs. The project may initiate research on new topical anti-angiogenic candidates to address other eye diseases as well. The topical formulation developed under the management of Gene Signal SAS is able to reach the back of the eye, with appropriate stability properties. This formulation has therefore more applications than the treatment of iCRVO to prevent NVG. Investigations are going on to address arresting wet AMD development.
Today’s standard of care for wet AMD uses anti-VEGFs: they have to be injected every 1-3 months. This causes significant anguish to patients, and consumes time and money. Moreover, while vision loss is effectively averted, only 30 % - 40 % of AMD patients gain three lines in visual acuity at 2 years, and roughly every sixth patient continues losing visual acuity and progresses to legal blindness. The novel aganirsen ophthalmic formulation can be used for targeting the back of the eye, which, in turn, would provide patients with a less invasive alternative and reduce the total cost of performing anti-VEGF injections.
Beside the development of the new ophthalmic emulsion, scientific research has been performed in two other major topics: 1) Imaging Analysis of neovascularizations and 2) Biomarker analysis. Results of the biomarker sub-studies may have the potential for new concepts in the treatment of ischaemic CRVO and for novel strategies targeting ischaemic retinal diseases for the prevention of NVG.
The results generated within the whole project may have an impact on different stakeholders. Through several dissemination activities as listed in table 2 and planned activities after the project, the scientific community with communications in international meetings and publications in peer-reviewed journals has been reached and informed about an innovative treatment for the prevention of NVG, new imaging methods to detect neovascularizations and the identification of biomarkers to both describe more precisely the risk for the development of disease and disease severity, as well as to predict the benefit of treatment and the natural course of ischaemic CRVO.
Health care systems may also be impacted: the burden of NVG, due to its devastating nature, is appropriately addressed at the European level. Reaching the goals of the STRONG study will make a significant impact towards reducing blindness; a major socio-economic challenge facing the European Union, especially since the loss of function from glaucoma is going to increase dramatically within Europe’s aging societies. Other main impacts on health care systems are expected: a) Reduction of NVG incidence, thus alleviating the economic burden related to this disease and blindness, b) potential biomarker allowing for the cost-effective treatment of patients most likely to respond to aganirsen, c) the opening of a new non-invasive and effective route for the administration of anti-angiogenic agents for ocular disease treatment.
A positive and compelling outcome of this clinical phase II/III study will allow discussions with the European Medicines Agency (EMA) thus leading to either Market Authorization (MA) or Conditional Market Authorization (CMA) for aganirsen in CRVO and/or the commercialization of a new drug developed in the EU with potential for global drug development. For an effective consultation, Gene Signal successfully requested protocol assistance from the EMA.
The involvement of a patient advocacy group in Germany for glaucoma patients right from the start of the project, guaranteed and will ensure in the future quick dissemination of new results of the study and the impacts on the quality of life of patients.
To disseminate the trial results to a general public and in great parts to the scientific community, different dissemination activities have been performed. As described right before, a patient advocacy group is a beneficiary of the STRONG project. With member magazines and public meetings of glaucoma patients and ophthalmologists, a wider public was informed about the STRONG project and its progress. To reach the scientific community, oral presentations were held on yearly ophthalmologists meetings in Europe and the EVICR.net members meetings (see table 2).
It is planned to publish the results of the ongoing projects in an open access journal as well to further inform the scientic community about developments around the topic of iCRVO and NVG.
List of Websites:
www.strong-nvg.com
STRONG Coordinator:
Prof. Dr. med. Norbert Pfeiffer
Langenbeckstr. 1
55131 Mainz
Germany
Tel. +49-6131-17-7085
eMail: Norbert.pfeiffer@unimedizin-mainz.de
The STRONG project is a European consortium for the study of a topical treatment of ischaemic central retinal vein occlusion (iCRVO) to prevent neovascular glaucoma (NVG). Secondary NVG, the major cause of which is iCRVO, is a very aggressive, rare form of glaucoma, responsible for 3.9 % of glaucoma cases, but contributing disproportionately to blindness from all eye diseases. Also, NVG is the second most common cause for enucleations (removal of the eye ball) across all eye diseases, usually for intractable pain.
Glaucoma in general is more than a single disease entity: it is a group of conditions characterized by progressive optic nerve degeneration (detectable by pathological cupping of the optic disc) and loss of visual function, ultimately resulting in total blindness. The lack of oxygen in the specific tissue (hypoxia) associated with retinal vein occlusion is mostly (but not exclusively) responsible for the subsequent release of angiogenic factors (i.e. vascular endothelial growth factor, VEGF). These also cause the growth of a fibrovascular membrane over the trabecular meshwork leading to an obstruction of the trabecular meshwork and/or associated peripheral anterior synechiae leading to an increase of intraocular pressure (IOP).
Today’s therapeutic approaches are insufficient and involve mainly lowering the elevated IOP, laser or cryo-therapy to destroy the affected retina, or off-label intravitreal injection of anti-VEGF compounds, with unsolved issues in determining the correct timing, dosing and place of such interventions. There is, therefore, a need to widen the existing therapeutic options for NVG secondary to iCRVO. Aganirsen is an antisense oligonucleotide which topical administration inhibits the production of VEGF, which plays a major role in the pathogenesis of NVG. The study was designed to test whether aganirsen is able to inhibit the formation of neovascularisations and fibrovascular membranes leading to the development of secondary NVG. This would be the first non-invasive treatment for this disease.
At the same time, STRONG was planned to provide important data on age and sex matched normal values of controls and retinal vein occlusion (RVO) patients and the natural course of iCRVO and NVG in a very large and well-investigated cohort. Analyses of biomarkers for the development and progression of iCRVO and NVG were part of the STRONG project with a high potential to discover new ones. Finally, image analyses tools and biomorphometric methods were developed and refined to better quantify and stage the disease by the evaluation of vessels in images.
Project Context and Objectives:
Glaucoma is more than a single disease entity: it is a group of conditions characterized by progressive optic nerve degeneration (detectable by pathological cupping of the optic disc) and loss of visual function, ultimately resulting in total blindness.
The two most frequent types are primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG). However, there are many forms of rare secondary glaucomas that develop following other eye diseases, including secondary neovascular glaucoma (NVG) most frequently presenting following ischemic central retinal vein occlusion (iCRVO).
NVG, which develops as a result of iCRVO typically after an average period of about 90 days (“90 days-glaucoma”), but may also appear as early as two weeks or alternatively after a much longer period of time. Anti-proliferative laser or cryo treatment of the retina must be performed in iCRVO as soon as neovascularizations are diagnosed: yet, it cannot be implemented before the blood that typically obscures the retina has been absorbed. Thus, the correct timing of Pan Retinal Photocoagulation (PRP) laser therapy is difficult to determine, retinas the bleedings may prohibit timely therapy. But if the angiogenic stimulus continues in that interval NVG develops before anti-proliferative treatment can be begun. An alternative may be cryo-therapy but this cannot be selectively directed to affected areas of the retina and is accompanied by destruction of large areas of the retina. Moreover, even laser treatment does not cure the disease. It only reduces the oxygen demand of the retina, and thus leads to a regression of the neovascularizations. It is clear that, while beneficial in the short term, reducing retinal ischaemia by PRP or even cryo-therapy destroys a relatively large proportion of the retina. There is, therefore, a need to widen the existing therapeutic options for NVG secondary to iCRVO.
At present, management of NVG relies predominantly on lowering the elevated intraocular pressure (IOP), but also needs to address the underlying cause of the disease. Several factors have been identified as potentially causing ocular neovascularization. Recent studies suggest that endogenous VEGF plays a central role in angiogenesis. Once released, the angiogenic factors diffuse into the aqueous and the anterior segment and interact with vascular structures. The resultant growth of new vessels in the anterior chamber angle (neovascularization of the angle [NVA]) and iris surface (neovascularization of the iris [NVI]) lead to the formation of fibrovascular membranes. The fibrovascular membranes, which may be invisible on gonioscopy, progressively obstruct the trabecular meshwork, the place of outflow of aqueous humour from the eye. This causes a rise in IOP and secondary glaucoma. Another mechanism by which NVG can occur relates to breakdown of the aqueous humour/blood barrier leading to inflammation, synechiae between iris and lens and pupillary block glaucoma. Both phenomena are often irreversible.
Currently, reduction of IOP remains the focus of all therapeutic approaches for all forms of glaucoma. Elevated IOP is a major risk factor in the pathogenesis of optic nerve damage and visual field loss. The higher the IOP, the greater the likelihood of visual field loss together with optic nerve damage. There are relatively effective treatment options for the most frequent form of glaucoma, namely POAG (primary open angle glaucoma). In NVG however, IOP lowering medications are moderately helpful since outflow is obstructed. Furthermore, the accompanying inflammation and proliferative stimulus lead to a very poor success-rate of fistulating glaucoma surgery. Thus, there is often a limitation to anti-proliferative and cyclodestructive surgery. Anti-proliferative treatment aims at destroying parts of the retina that are assumed to produce VEGF but is accompanied by irreversible loss of the retinal function, which, clearly, is a problematic approach. Furthermore, even if these treatment approaches are used consequently, still many eyes are lost.
Because of the pivotal role of angiogenesis in the initiation and progression of NVG, several studies propose the use of anti-angiogenic agents such as anti-VEGF combined with traditional treatments such as PRP, with or without additional surgery, and vary in the timing and combination. All present therapeutics require an injection into the eye. Standardized guidelines of NVG treatment with anti-VEGFs (dose and place of injection [intracameral or intravitreal, or both simultaneously]) have, however, not yet been established, since no prospective trials have been performed, and the use of existing anti-angiogenic agents is off-label.
The application of a topically active anti-angiogenic agent (aganirsen) would be a non-invasive, easy to titrate, and easy to use treatment option to anticipate the formation of fibrovascular membranes and to treat secondary NVG. Aganirsen is a 25mer antisense oligonucleotide of 8’035 Daltons developed by Gene Signal (oligonucleotides are short strands of DNA designed to prevent translation of messenger RNA into unwanted proteins). Aganirsen is a promising candidate to prevent the development of NVG: it inhibits the expression of Insulin Receptor Substrate (IRS-1) in pathological pro-angiogenic conditions. Aganirsen was granted orphan designation for NVG from the EC in April 2004 (EU/3/03/161; EMEA/COMP/1421/03). Its efficacy when applied topically in corneal neovascularization has already been demonstrated. Phase I-III trials in the cornea have also shown a positive safety profile, while non-human primate studies have proven the capability of the topical preparation to reach not only the anterior chamber but even the retina. The hypothesis of the STRONG study is that aganirsen could be well tolerated, effective and safe to inhibit the development of NVG following iCRVO.
The primary objective of the treatment with aganirsen within the STRONG trial was to avert or minimize the rise in IOP in patients with iCRVO by averting abnormal neovessels formation and further obstruction of the trabecular meshwork by the treatment with aganirsen. The STRONG trial was also designed to evaluate the efficacy of two aganirsen doses, to assess aganirsen efficacy relative to placebo on time to and intensity of additional interventions such as PRP or cryotherapy, to compare aganirsen and placebo on health outcome and quality of life (QoL) and to confirm a positive safety profile of aganirsen.
The overarching goal of the phase II/III randomized, double- masked, 3 armed, placebo-controlled STRONG trial was therefore:
• To assess whether at 24 weeks, topical aganirsen treatment can reduce the rate of anterior iris- and chamber-angle and posterior segment neovascularisation and NVG development after iCRVO, in a study with up to 333 patients in over 30 different sites.
• To assess the natural course of iCRVO and NVG in the placebo-arm.
• To evaluate known or suspected risk factors and biomarkers for RVO and NVG and to identify new ones for the development of NVG.
• To improve the early diagnosis of NVG in iCRVO patients by image analysis and biomorphometric analysis.
To achieve the above-mentioned goals the overall objectives for the trial were:
• To finalize the trial design.
• To enlist sufficient trial centres to ensure recruitment of the statistically appropriate number of patients.
• To manufacture sufficient trial supplies of aganirsen and its placebo in compliance with the Good Manufacturing Practices (GMP).
• To provide central reading services to the STRONG trial for both established and novel methods for assessing NVG.
• To perform the STRONG trial, recruiting up to 333 patients while adhering to the highest GCP standards and protecting patient safety.
• To analyse the collected trial data for NVG treatment, reducing if possible the trial sample size below 333 patients while meeting all requirements to file for conditional market authorisation.
• To disseminate the test results to affected communities in Europe and beyond.
Project Results:
The STRONG project includes four major scientific topics in which results and foregrounds have been generated:
1) The finalization of the clinical investigational plan following protocol assistance from the European Medicines Agency (EMA)
2) Development of a stable ophthalmic emulsion (composition and manufacturing steps)
3) Prototype methods (software) to quantify iris vessels dilation and degree of pathological iris neovascularization
4) Analyses of biomarkers and normal values for RVO patients and healthy subjects.
The finalization of the clinical investigational plan following protocol assistance from the European Medicines Agency (EMA):
The STRONG trial was designed to fulfil requirements for clinical trials to be used for a future marketing authorization. Therefore, protocol assistance was sought from the EMA at the beginning of the project to ensure that the protocol is compliant with the European regulation with Orphan Drug Designation (ODD) of aganirsen for the treatment of NVG and satisfies the needs of European regulatory bodies. After extensive protocol assistance, the sponsor received the positive opinion for the orphan drug designation for the “treatment of CRVO” in April 2014.
The completion of the trial protocol following to the closed protocol assistance with the EMA allowed the submission to the regulatory authorities. Regulatory approval by the Ethics Committees and the Competent Authorities were sought in all participating countries and trial sites. Ethics approvals were obtained in Germany and France; regulatory approval in Italy. The submission in further countries has been set on hold until all questions from the regulatory authorities could be answered. This requires the finalized production of the study drug.
The basis for a successful trial performance is prepared by the above mentioned final trial protocol including all connected documents and Ethics / regulatory submission and approvals. The trial design has been published in an open-access journal. The design and programming of the trial-specific forms and Case Report Forms was performed within the STRONG FP7 project. The Electronic Data Capture (EDC) system is developed and only needs final approval. Training material was prepared for on-line EDC training for all monitors, project managers and site representatives. The EDC including eCRF and Reading Center submission platform is integrated in the project website. The website (www.strong-nvg.com) also contains all necessary trial documents, Standard Operating Procedures (SOPs) and training manuals for download for trial staff:
SOPs:
• Swinging-flashlight test
• Refraction and visual acuity measurement
• Goldman perimetry/semiautomatic kinetic perimetry
• Gonioscopy
• Blood pressure and heart rate measurement
• Blood sample collection, separation, labelling, storage and transportion for risk factor and biomarker sub-study
• Standard 12 lead ECG recording
Available training manuals:
• Overall manual of study procedures & outcome measures (aganirsen and project protocol, trial indication, biomarker and risk factor sub-studies, safety management and Good Clinical Practice, data management, EDC/eCRF)
• Instructions for iris and chamber angle photographs
• Digital colour fundus photography, fluorescein angiography and OCT imaging instructions
• Gonioscopic images
In total 27 trial sites have been evaluated for participation. All sites are qualified for performing the clinical trial with specific trial staff and equipment to ensure a high quality STRONG trial.
Development of a stable ophthalmic emulsion (composition and manufacturing steps):
The development of a stable ophthalmic emulstion was one major aim of the STRONG project. Initial issues in the development of a stable formulation have been overcome successfully. The manufacturing process of the study drug (an emulsion) faced unexpected handling issues at the start of the project: several attempts of the manufacturing partner proved unsuccessful with regards to the trial objectives. Gene Signal, in line with a first amendment to the Grant Agreement, took over the responsibility of the development of an adequately stable formulation and its manufacturing process. Following a lengthy redesign process, a stable formulation was demonstrated on the basis of laboratory tests in mid-2017. Gene Signal therefore significantly improved the emulsion formulation which led to patents applied for in 2017 and 2018 and a manufacturing process.
Title: STERILE FORMULATION COMPRISING A STABLE PHOSPHOROTHIOATE OLIGONUCLEOTIDE
Country Application Publication Status
USA 15/423964 (2017-02-03) Confidential Pending
Europe 17154670 (2017-02-03) Confidential Pending
World PCT/EP2018/052663 (2018-02-03) Confidential Pending
The resulting viscous solution can now be packaged within a sterile environment, using state-of-the art dosing/filling machines available in Europe, the blister-based technology allowing indeed for the effective aseptic filling of the emulsion. The emulsion is thus protected against external effects such as light or oxygen, as well as evaporation, and can keep its stability properties for period of time compatible with the targeted therapeutic end uses. An optional spout offers added versatility when it comes to the dose administration options.
A drug manufacturer was found to implement the proper manufacturing steps for the emulsion and its packaging. Yet, it requires investing into a specific equipment to be implemented in the sterile GMP manufacturing site in view of confirming the stability properties found at laboratory scale. The fixed project deadlines (march 2018) imposed by the EC were not enough to reach a process ready to manufacture the stable emulsion quantity needed for the trial.
Prototype methods (software) to quantify iris vessels dilation and degree of pathological iris neovascularization:
The CORIC reading centre was responsible for the blinded evaluation of chamber angle and iris slit-lamp pictures qualitatively for presence or absence of pathological neovascularisations to facilitate an objective diagnosis of NVG. Scientific evaluation of the correlation between the degree of IOP and patterns of iris and chamber angle neovascularisations will help to better understand the disease mechanism of NVG.
To perform the evaluation of neovascularizations, CORIC developed a semiautomatic method (software) to quantify iris vessel dilation and degree of iris neovascularisation. The aim of this project was to realize a network analysis of complex vascularization patterns found in the inflamed cornea or neovascularised iris by a digital skeletonization tool. Gray scale images of murine vascularized corneal flat mounts were used to establish this method. The performance criteria are false negative rate (FNR) in case of vessels loss and false positive rate (FPR) in case of fake vessels reconstruction. These criteria should be estimated after the whole analysis comparing the original image with the reconstructed skeleton. For the vessel structure identification two filtering-based methods were tested: hysteresis thresholding algorithm and adaptive contrast enhancement (ACE) algorithm, where the ACE-method was found to be more robust for fine vessels identification than the hysteresis based algorithm. However, the hysteresis algorithm is faster. For large images with relatively homogeneous background the hysteresis algorithm can be used to accelerate the analysis process without the quality loss during binarisation. The analysis chain is combined in one tool and implemented in a Graphical User Interface (GUI) in Matlab. The graphical user interface was called BranchTool and handles with all image processing steps. Images can be resized, contrast be changed, a noise filter applied or an image format converted from and into TIF, JPG, BMP, GIF, EPS and PNG.
Vessels determination procedure is often restricted by pixel classification, i.e. by making decision whether a pixel belongs to a vessel or to the background.
Enhancement of the small vessel identification, mathematical morphology tools and calculation speed should be optimized. The most time consuming process is the ACE binarisation. The mean computing time of this step depends on the computing machine power and in the worst case can take about 10 minutes working with the original images.
In a second step of software development the aim was to extract vessel like structures from iris images of patients with NVG. The main issue with these images is the massive background generated by the iris pigmentation ranging between brown, hazel, green, gray, or blue as well as by structural features of the iris like the crypts of Fuchs or folds of Schwalbe. In the grey scale analysis performed to detect and analyse the vessels these structures interfere with the grey scale threshold of the blood vessels. Therefore a method had to be established to eliminate this background structures. Depending on the iris colour the image is split into the cyan, magenta and yellow (CMY) channels. In mainly blue, green and gray irides cyan mainly represents the iris pigmentation whereby in brown (hazel) irides the iris is represented mainly by the yellow channel. Magenta mainly represents the blood vessels.
Based on these findings the following algorithm was established: 1) To outbalance the inhomogenous illumination due to the anatomical curvature of the iris first shading correction is performed. An equally illuminated and therefore plane appearing iris is resulting. This image afterwards is divided into the above explained three channels. In the cyan channel the blood vessels are mainly disappeared whereas in the magenta channel these vessels are significantly pronounced. Anyway, also bright iris crinkles are still visible and interfere with the gray scale range of the blood vessels. Therefore the cyan image is substracted from the magenta image resulting in an almost background free vessel image. 2) To further extract the vessels from the background a so called DCE filter is used. This filter (Differential Contrast Enhancement) increases only the weak contrast differences. Thereby image structures get visible which could not be discriminated before. The resulting image can now be analysed by the branching analysis tool.
By subtracting the magenta channel from the cyan channel the background signal from the crypts of Fuchs or folds of Schwalbe could be significantly reduced. Thereby the vessels and bleedings can be identified more precise. When quantifying the elongation and the roundness of the detected particles it is now even possible to discriminate between vessels and bleedings on the level of area quantification. Thereby also leakage of the pathologic iris vessels can be monitored.
A cutting edge, in vivo method to analyze iris vessels in the mouse model was used afterwards. The method was transferred to Optical Coherence Tomography (OCT) - a non-invasive optical imaging method using infrared light to produce depth-resolved cross-sectional images of tissue. A volume can be created by combining numerous depth-scans.
In normal OCT images, blood vessels are not directly visible. However, intensity fluctuations due to the altered position of blood cells can be observed when vessels are present. A further processing of the data thus can reveal vessels by flow analysis. OCT-Angiography (OCT-A) is non-invasive like OCT. However, it is very sensitive to motion of the subject. Small movements of the subject, e.g. caused by breathing, lead to artifacts. The intensity of those spurious lines often superimposes the actual vessel signal, which was shown by a lead off experiment.
Consequently, the quality of an OCT angiography depends on how calm the animal was, or how fast the data could be acquired, respectively. Images with only moderate artifacts can be evaluated in 3D by further processing steps using the MeVisLab-environment. Here by we not only can analyze the area covered by vessels, but also the total volume, length, branches, end points as well as tortuosity of the iris vessels in three dimensions (3D). These three-dimensional parameters will give far more information on the vessel network and are independent of iris pigmentation. By this technique changes in the iris vasculature in the context of neovascular glaucoma will be detectable more precisely.
Analyses of biomarkers in RVO patients and healthy subjects:
One common cause of NVG is ischaemic retinal vein occlusion (iCRVO), but also CRVO as well as BRVO can lead to NVG. Within the first examination of the participants in the Gutenberg Health Study (GHS) we were able to find 59 participants suffering from RVO. Therefore the GHS provides the unique opportunity to evaluate potential associations of RVO and subsequent glaucoma development in a population-based setting. The GHS is a population-based, single-center, prospective, cohort study at the University Medical Center of the Johannes Gutenberg University Mainz in Germany. The population sample was randomly drawn via local residents’ registration offices and equally stratified by sex for each decade of age. The baseline examination included 15,010 participants aged 35 to 74 years and was conducted from 2007 to 2012. The examination consisted of an ophthalmological examination, general and cardiovascular examinations, biomaterial sampling, and questionnaires and interviews. A Visucam PRO NM nonmydriatic fundus camera (Carl Zeiss AG, Jena, Germany) was used to take digital fundus pictures through a nonpharmacologically dilated pupil. The participants were positioned in a darkened room to allow for natural pupil dilation. The grading of the baseline fundus photographs for the detection of RVO was carried out by a trained grader at the Moorfields Eye Hospital Reading Center, London, UK, and was adjudicated by an experienced clinician grader. We identified n=59 participants with RVO (n=12 for central RVO and n=47 for branch RVO).
The aim is to determine which participants possible could be of higher risk of developing glaucoma after suffering from a RVO. For this we will evaluate the association of autoantibody (AAB) levels with RVO in GHS participants and age- and sex-matched controls (1:4) and also will measure autoantibodies previously described to be associated with ischaemic and degenerative eye diseases. The results hopefully will contribute to elucidate the role of autoantibodies in the development of RVO and furthermore show relevant factors important for the development of subsequent glaucoma. The corresponding antigenes have been purchased and spotted onto special nitrocellulose coated slides by a non-contact microarray spotter (sciFLEXARRAYER S3, Scienion, Germany). This specialized non-contact spotting process allows spotting of antigens and antibodies with a very low spot to spot variability, thus increasing the data reproducibility. The customized microarrays will be incubated with RVO and control sera. In order to compare spot signals and to detect antibodies (biomarkers), we will use a combination of different algorithms for data normalization (e.g. Z-score algorithm) and a set of diverse statistical techniques, such as artificial neural networks and tree algorithms.
Frequency of prevalent and cumulative 5-year incident glaucoma and associated factors in RVO patients from the population based from the Gutenberg Health Study:
The sample-size and the phenotyping of RVO are described above. As we would like to determine the subsequent development of glaucoma over a time course, analysis of the follow-up visit after 5 years were performed. For the grading of glaucoma, the optic nerve head images of all RVO cases and of 236 age- and sex-matched healthy controls from baseline and from the 5-year-follow-up have been measured. We used EVICR (European Vision Institute Clinical Research Network) standards and the ISGEO (International Society Geographical & Epidemiological Ophthalmology) classification. The ISGEO classification is based on vertical cup-to-disc ratio (vCDR) and rim width-to-disc-ratio (RWDR) controlled for optic disc size, refraction and keratometry, visual field testing, IOP, and ophthalmic history. The grading have been performed independently by two trained graders. Regular recalibration and masked intra-rater-reliability (10% of analyzed images) has been performed. After ongoing quality and plausibility checks, we will calculate the prevalence and the cumulative 5-year-incidence of glaucoma among RVO participants, crude and weighted to the population of the region. In addition, we will evaluate factors potentially associated with prevalence and incidence using regression models.
The availability of population-based prevalence and incidence data will contribute to the understanding of the connection between RVO and glaucoma.
Potential Impact:
Glaucoma is more than a single disease entity: it is a group of conditions characterized by progressive optic nerve degeneration (detectable by pathological cupping of the optic disc) and loss of visual function, ultimately resulting in total blindness. The two most frequent types are primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG). However, there are many forms of rare secondary glaucomas that develop following other eye diseases, including secondary neovascular glaucoma (NVG). NVG is a rare, very aggressive form of secondary glaucoma. While the overall prevalence of glaucoma is about 1% in the general population, NVG makes up for approximately 3.9% of all glaucoma cases. NVG as a rare disease contributes disproportionately to blindness from glaucoma, and even to the loss of eyes from its painful end-stages: NVG is the second most frequent cause for enucleations (removal of the eye ball) not only from glaucoma but from any eye disease and, thus, accounts for a disproportionate large amount of individual suffering as well as high socio-economic costs from medical care, absence from work and the necessary benefits for visually handicapped and blind patients. This emphasizes the need for new efficient and more pathogenetically oriented treatment options for NVG, an orphan indication.
Today’s still inadequate treatment options for NVG can leave the patient exposed to blindness, and in so much pain that enucleation (removal of the eyeball) is required. Blindness inflicts very significant individual suffering and leads to economic and social costs. For the healthy population the threat of blindness has been shown to be one of the most feared health threats, second only to death from long-standing cancer disease. The loss of visual function is “valued” by patients inflicted by disease in a way similar to a severe stroke, indicating the severe loss of quality of life that is experienced.
Moreover, the socio-economic burden to societies is high. Taking the example of Germany to provide an order of magnitude for a population of nearly 82 million people, about one million of the population are disabled due to low vision, 164 000 people are blind, 132 000 people get a monthly financial allocation from public funds (approx. 10% of those entitled to these social benefits do not ask for the allocation even though they could apply for): this monthly allocation ranges from 170 € to 525 € depending on age and region. The rate of growth for blindness up to 2030 is expected to be 30%, because of the demographic changes with eye diseases increasing more than other diseases with aging: in 2000, a first estimate for the direct and indirect costs for blindness reached about one billion €, in 2006, a similar evaluation covering also the cost of lost incomes and the costs for the services to the blind reached 9 Billion € (or roughly 12 600 € per year per affected person (low vision and blind) over a total population of about 730 000. Furthermore blindness is associated with a tremendous loss of quality of life and with individual suffering.
There are several impacts expected from the STRONG project and the clinical trial. The project focuses on the development of preventive, diagnostic and therapeutic interventions. As described above, the current therapeutic interventions are inadequate. Gene Signal developed an ophthalmic emulsion for the topical treatment of iCRVO to prevent NVG. The project aimed at validating anti-angiogenic eye drops, thus impacting 1) the general community by management of impending NVG and/or attenuation of NVG, quality of life in affected individuals applying a non-invasive route and prevention of painful NVG end stages, and the reduction of economic burden related to NVG and blindness.
The development and manufacturing of an ophthalmic emulsion is a new area. The knowledge generated within the project about the development of emulsions has a great scientific impact for the future development of new drugs. The project may initiate research on new topical anti-angiogenic candidates to address other eye diseases as well. The topical formulation developed under the management of Gene Signal SAS is able to reach the back of the eye, with appropriate stability properties. This formulation has therefore more applications than the treatment of iCRVO to prevent NVG. Investigations are going on to address arresting wet AMD development.
Today’s standard of care for wet AMD uses anti-VEGFs: they have to be injected every 1-3 months. This causes significant anguish to patients, and consumes time and money. Moreover, while vision loss is effectively averted, only 30 % - 40 % of AMD patients gain three lines in visual acuity at 2 years, and roughly every sixth patient continues losing visual acuity and progresses to legal blindness. The novel aganirsen ophthalmic formulation can be used for targeting the back of the eye, which, in turn, would provide patients with a less invasive alternative and reduce the total cost of performing anti-VEGF injections.
Beside the development of the new ophthalmic emulsion, scientific research has been performed in two other major topics: 1) Imaging Analysis of neovascularizations and 2) Biomarker analysis. Results of the biomarker sub-studies may have the potential for new concepts in the treatment of ischaemic CRVO and for novel strategies targeting ischaemic retinal diseases for the prevention of NVG.
The results generated within the whole project may have an impact on different stakeholders. Through several dissemination activities as listed in table 2 and planned activities after the project, the scientific community with communications in international meetings and publications in peer-reviewed journals has been reached and informed about an innovative treatment for the prevention of NVG, new imaging methods to detect neovascularizations and the identification of biomarkers to both describe more precisely the risk for the development of disease and disease severity, as well as to predict the benefit of treatment and the natural course of ischaemic CRVO.
Health care systems may also be impacted: the burden of NVG, due to its devastating nature, is appropriately addressed at the European level. Reaching the goals of the STRONG study will make a significant impact towards reducing blindness; a major socio-economic challenge facing the European Union, especially since the loss of function from glaucoma is going to increase dramatically within Europe’s aging societies. Other main impacts on health care systems are expected: a) Reduction of NVG incidence, thus alleviating the economic burden related to this disease and blindness, b) potential biomarker allowing for the cost-effective treatment of patients most likely to respond to aganirsen, c) the opening of a new non-invasive and effective route for the administration of anti-angiogenic agents for ocular disease treatment.
A positive and compelling outcome of this clinical phase II/III study will allow discussions with the European Medicines Agency (EMA) thus leading to either Market Authorization (MA) or Conditional Market Authorization (CMA) for aganirsen in CRVO and/or the commercialization of a new drug developed in the EU with potential for global drug development. For an effective consultation, Gene Signal successfully requested protocol assistance from the EMA.
The involvement of a patient advocacy group in Germany for glaucoma patients right from the start of the project, guaranteed and will ensure in the future quick dissemination of new results of the study and the impacts on the quality of life of patients.
To disseminate the trial results to a general public and in great parts to the scientific community, different dissemination activities have been performed. As described right before, a patient advocacy group is a beneficiary of the STRONG project. With member magazines and public meetings of glaucoma patients and ophthalmologists, a wider public was informed about the STRONG project and its progress. To reach the scientific community, oral presentations were held on yearly ophthalmologists meetings in Europe and the EVICR.net members meetings (see table 2).
It is planned to publish the results of the ongoing projects in an open access journal as well to further inform the scientic community about developments around the topic of iCRVO and NVG.
List of Websites:
www.strong-nvg.com
STRONG Coordinator:
Prof. Dr. med. Norbert Pfeiffer
Langenbeckstr. 1
55131 Mainz
Germany
Tel. +49-6131-17-7085
eMail: Norbert.pfeiffer@unimedizin-mainz.de