Gene therapy for neovascular age-related macular degeneration by subretinal delivery of RGX-314: a phase 1/2a dose-escalation study.

BACKGROUND: Frequent anti-vascular endothelial growth factor A (VEGF-A) injections reduce the risk of rapid and severe vision loss in patients with neovascular age-related macular degeneration (nAMD); however, due to undertreatment, many patients lose vision over time. New treatments that provide sustained suppression of VEGF-A are needed. RGX-314 (currently known as ABBV-RGX-314) is an adeno-associated virus serotype 8 vector that expresses an anti-VEGF-A antigen-binding fragment, which provides potential for continuous VEGF-A suppression after a single subretinal injection. We report results on the safety and efficacy of subretinal injection of RGX-314 in patients with nAMD. METHODS: For this open-label, multiple-cohort, multicentre, phase 1/2a, dose-escalation study conducted at eight sites in the USA, we enrolled participants with nAMD aged 50-89 years who had previously been treated with anti-VEGF injections into five cohorts (with five different doses of RGX-314). To be eligible, participants had to have macular neovascularisation secondary to nAMD with subretinal or intraretinal fluid in the centre subfield, be pseudophakic (after cataract removal), and have a best-corrected visual acuity (BCVA) in the study eye between 20/63 and 20/400 for the first participant in each cohort and between 20/40 and 20/400 for others. Subretinal injection of RGX-314 was done without a pre-bleb by a wet-laboratory-trained vitreoretinal surgeon. Cohort 1 received 3 × 109 genome copies per eye, cohort 2 received 1 × 1010, and cohort 3 received 6 × 1010. Two additional dose cohorts (cohort 4: 1·6 × 1011; cohort 5: 2·5 × 1011) were added. Participants were seen 1 day and 1 week after administration of RGX-314, and then monthly for 2 years (up to week 106). The primary outcome was safety of RGX-314 delivered by subretinal injection up to week 26. This analysis includes all 42 patients enrolled in the study. This study is registered with ClinicalTrials.gov, NCT03066258. FINDINGS: Between May 12, 2017, and May 21, 2019, we screened 110 patients for eligibility and enrolled 68. 42 participants demonstrated the required anatomic response to intravitreal ranibizumab and then received a single RGX-314 injection (dose range 3 × 109 to 2·5 × 1011 genome copies per eye) and were followed up for 2 years. There were 20 serious adverse events in 13 participants, of which one was possibly related to RGX-314: pigmentary changes in the macula with severe vision reduction 12 months after injection of RGX-314 at a dose of 2·5 × 1011 genome copies per eye. Asymptomatic pigmentary changes were seen in the inferior retinal periphery several months after subretinal injection of RGX-314 most commonly at doses of 6 × 1010 genome copies per eye or higher. There were no clinically determined immune responses or inflammation beyond that expected following routine vitrectomy. Doses of 6 × 1010 genome copies or higher resulted in sustained concentrations of RGX-314 protein in aqueous humour and stable or improved BCVA and central retinal thickness with few or no supplemental anti-VEGF-A injections in most participants. INTERPRETATION: Subretinal delivery of RGX-314 was generally well tolerated with no clinically recognised immune responses. RGX-314 gene therapy provides a novel approach for sustained VEGF-A suppression in patients with nAMD that has potential to control exudation, maintain vision, and reduce treatment burden after a single administration. Results from this study informed the pivotal programme to evaluate RGX-314 in patients with nAMD. FUNDING: RegenxBio.

Archway Randomized Phase 3 Trial of the Port Delivery System with Ranibizumab for Neovascular Age-Related Macular Degeneration.

PURPOSE: To evaluate the safety and efficacy of the Port Delivery System with ranibizumab (PDS) for the treatment of neovascular age-related macular degeneration (nAMD). DESIGN: Phase 3, open-label, randomized, visual acuity assessor-masked noninferiority and equivalence trial. PARTICIPANTS: Patients with nAMD diagnosed within 9 months of screening previously treated with and responsive to anti-vascular endothelial growth factor therapy. METHODS: Patients were randomized 3:2 to treatment with the PDS with ranibizumab 100 mg/ml with fixed 24-week (Q24W) refill-exchanges (PDS Q24W) or intravitreal ranibizumab 0.5-mg injections every 4 weeks (monthly ranibizumab). MAIN OUTCOME MEASURES: Primary end point was change in best-corrected visual acuity (BCVA) Early Treatment Diabetic Retinopathy Study letter (letters) score from baseline averaged over weeks 36 and 40 (noninferiority margin,-4.5 letters; equivalence margin, ±4.5 letters). RESULTS: Archway enrolled 418 patients; 251 were randomized to and 248 received treatment with the PDS Q24W, and 167 were randomized to and received treatment with monthly ranibizumab. Baseline BCVA was 74.4 letters (PDS Q24W arm) and 75.5 letters (monthly ranibizumab arm; Snellen equivalent, 20/32). Adjusted mean change in BCVA score from baseline averaged over weeks 36 and 40 was +0.2 letters (standard error [SE], 0.5 letters) in the PDS Q24W arm and +0.5 letters (SE, 0.6 letters) in the monthly ranibizumab arm (difference, -0.3 letters; 95% confidence interval, -1.7 to 1.1 letters). PDS Q24W was both noninferior and equivalent to monthly ranibizumab. Of 246 PDS-treated patients assessed for supplemental ranibizumab treatment, 242 (98.4%) did not receive supplemental ranibizumab treatment before the first refill-exchange procedure, including 4 patients who discontinued treatment before the first refill-exchange procedure. Prespecified ocular adverse events of special interest were reported in 47 patients (19.0%) in the PDS Q24W arm and 10 patients (6.0%) in the monthly ranibizumab arm, which included, in the former arm, 4 (1.6%) endophthalmitis cases, 2 (0.8%) retinal detachments, 13 (5.2%) vitreous hemorrhages, 6 (2.4%) conjunctival erosions, and 5 (2.0%) conjunctival retractions. Most ocular adverse events in the PDS Q24W arm occurred within 1 month of implantation. CONCLUSIONS: Archway met its primary objective and PDS Q24W demonstrated noninferior and equivalent efficacy to monthly ranibizumab, with 98.4% of PDS-treated patients not receiving supplemental treatment in the first 24-week interval.

Proteosomal degradation impairs transcytosis of AAV vectors from suprachoroidal space to retina.

Suprachoroidal injection provides a new route of delivery for AAV vectors to retinal pigmented epithelial cells and photoreceptors that can be done in an outpatient setting and is less invasive and potentially safer than subretinal injection, the most common route of delivery for ocular gene therapy. After suprachoroidal injection of AAV8 or AAV9 vectors, there is strong transduction of photoreceptors, but it is unclear how vector traverses the retinal pigmented epithelium. In this study, we found that transduction of photoreceptors was significantly increased after suprachoroidal injection of AAV2tYF-CBA-GFP versus AAV2-CBA-GFP vector. Compared with AAV2, AAV2tYF is more resistant to proteosomal degradation. Treatment with protease inhibitors significantly increased photoreceptor transduction after suprachoroidal injection of AAV5-GRK1-GFP. These data suggest that after suprachoroidal injection, AAV vectors access photoreceptors by transcytosis through retinal pigmented epithelial cells during which they are subject to proteosomal degradation, which if suppressed can enhance transduction of photoreceptors.

Retinal vascular occlusions.

Acute retinal vascular occlusions are common causes of visual impairment. Although both retinal artery occlusions and retinal vein occlusions are associated with increased age and cardiovascular risk factors, their pathophysiology, systemic implications, and management differ substantially. Acute management of retinal artery occlusions involves a multidisciplinary approach including neurologists with stroke expertise, whereas treatment of retinal vein occlusions is provided by ophthalmologists. Optimisation of systemic risk factors by patients' primary care providers is an important component of the management of these two disorders.

Fibulin-7 C-terminal fragment and its active synthetic peptide suppress choroidal and retinal neovascularization.

Wet age-related macular degeneration (AMD) and diabetic retinopathy are the leading causes of blindness through increased angiogenesis. Although VEGF-neutralizing proteins provide benefit, inconsistent responses indicate a need for new therapies. We previously identified the Fibulin-7 C-terminal fragment (Fbln7-C) as an angiogenesis inhibitor in vitro. Here we show that Fbln7-C inhibits neovascularization in vivo, in both a model of wet AMD involving choroidal neovascularization (CNV) and diabetic retinopathy involving oxygen-induced ischemic retinopathy. Furthermore, a short peptide sequence from Fbln7-C is responsible for the anti-angiogenic properties of Fbln7-C. Our work suggests Fbln7-C as a therapeutic candidate for wet AMD and ischemic retinopathy.

Suppression of Ocular Vascular Inflammation through Peptide-Mediated Activation of Angiopoietin-Tie2 Signaling.

Persistent inflammation is a complication associated with many ocular diseases. Changes in ocular vessels can amplify disease responses and contribute to vision loss by influencing the delivery of leukocytes to the eye, vascular leakage, and perfusion. Here, we report the anti-inflammatory activity for AXT107, a non-RGD, 20-mer αvß3 and α5ß1 integrin-binding peptide that blocks vascular endothelial growth factor (VEGF)-signaling and activates tyrosine kinase with immunoglobulin and EGF-like domains 2 (Tie2) using the normally inhibitory ligand angiopoietin 2 (Ang2). Tumor necrosis factor α (TNFα), a central inflammation mediator, induces Ang2 release from endothelial cells to enhance its stimulation of inflammation and vascular leakage. AXT107 resolves TNFα-induced vascular inflammation in endothelial cells by converting the endogenously released Ang2 into an agonist of Tie2 signaling, thereby disrupting both the synergism between TNFα and Ang2 while also preventing inhibitor of nuclear factor-κB α (IκBα) degradation directly through Tie2 signaling. This recovery of IκBα prevents nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) nuclear localization, thereby blocking NF-κB-induced inflammatory responses, including the production of VCAM-1 and ICAM-1, leukostasis, and vascular leakage in cell and mouse models. AXT107 also decreased the levels of pro-inflammatory TNF receptor 1 (TNFR1) without affecting levels of the more protective TNFR2. These data suggest that AXT107 may provide multiple benefits in the treatment of retinal/choroidal and other vascular diseases by suppressing inflammation and promoting vascular stabilization.

Metipranolol promotes structure and function of retinal photoreceptors in the rd10 mouse model of human retinitis pigmentosa.

Metipranolol is a ß-adrenergic receptor antagonist that is given orally for the treatment of hypertension and also applied topically to the cornea for treating glaucoma. It also inhibits nitrosative stress which has previously been shown to be the cause of cone photoreceptor death in retinitis pigmentosa. In this study, we tested the hypothesis that metipranolol protects photoreceptor structure and function in the mouse model rd10. At P35, compared with vehicle-treated rd10 mice in which rod degeneration was nearly complete, rd10 mice given daily subcutaneous injections of 40 mg/kg of metipranolol had reduction in markers of nitrosative stress, fewer TUNEL-positive cells, increased outer nuclear layer thickness, and substantially more staining for rhodopsin. This was accompanied by significantly higher mean scotopic and photopic electroretinogram b-wave amplitudes indicating improved photoreceptor function. At P50, metipranolol-treated rd10 mice had decreased 3-nitrotyrosine staining in the retina, increased immunostaining for cone arrestin, a marker for cone photoreceptors, and significantly higher scotopic and photopic b-wave amplitudes at the highest stimulus intensity compared with vehicle-treated mice. At P65, cone density was significantly higher in metipranolol-treated versus vehicle-injected rd10 mice. Metipranolol applied as eye drops promoted cone photoreceptor function in retinas of rd10 mice greater than subcutaneously injected metipranolol. The reduced nitrosative damage and rescue of functional loss of photoreceptors in rd10 mice suggests that metipranolol, a drug with established ocular safety and tolerability, may have potential for treating patients with retinitis pigmentosa.

Different Factors Associated with 2-Year Outcomes in Patients with Branch versus Central Retinal Vein Occlusion Treated with Ranibizumab.

PURPOSE: To investigate characteristics associated with visual and anatomic outcomes in branch and central retinal vein occlusion (BRVO and CRVO) patients treated with ranibizumab. DESIGN: Post hoc analysis of patients with BRVO and CRVO from 2 multicenter clinical trials who completed month 12 of the HORIZON extension trial. PARTICIPANTS: 205 patients with BRVO and 181 patients with CRVO who completed month 12 of the extension trial. METHODS: With the use of logistic regression, covariates with a P value < 0.20 from univariate analysis were included in multivariate models to identify independent factors associated with a given outcome (at P < 0.05), with preset variables of disease duration and original treatment assignment. MAIN OUTCOME MEASURES: Best-corrected visual acuity (BCVA) ≥20/40 (≥70 letters), gain ≥15 letters, and central subfield thickness (CST) ≤250 µm at HORIZON month 12. RESULTS: In patients with BRVO, good baseline BCVA (odds ratio [OR], 1.53; 95% confidence interval [CI], 1.30-1.79), male sex (OR, 2.48; 95% CI, 1.20-5.13), and normal hematocrit (low vs. normal, OR, 0.26; 95% CI, 0.12-0.59) predicted BCVA ≥20/40; high central foveal thickness (OR, 1.03; 95% CI, 1.01-1.04) and normal hematocrit (low vs. normal, OR, 0.31; 95% CI, 0.15-0.66) predicted BCVA improvement ≥15 letters; and extensive baseline subretinal fluid modestly predicted CST ≤250 µm (OR, 1.08; 95% CI, 1.00-1.16). In patients with CRVO, good baseline BCVA (OR, 1.59; 95% CI, 1.35-1.89), never smoking (OR, 2.80; 95% CI, 1.27-6.17), and young age (OR, 0.58; 95% CI, 0.41-0.82) predicted BCVA ≥20/40; never smoking (OR, 2.13; 95% CI, 1.03-4.39), young age (OR, 0.41; 95% CI, 0.28-0.59), poor baseline BCVA (OR, 0.82; 95% CI, 0.73-0.93), hypertension (OR, 4.47; 95% CI, 1.70-11.75), and low diastolic ocular perfusion pressure (OPP) throughout the study (OR, 0.39; 95% CI, 0.21-0.72) predicted BCVA improvement ≥15 letters; and young age (OR, 0.65; 95% CI, 0.47-0.90), lower mean hematocrit (low vs. normal, OR, 2.81; 95% CI, 1.06-7.49), high systolic OPP throughout the study (OR, 1.61; 95% CI, 1.14-2.27), large areas of central hemorrhage (OR, 1.44; 95% CI, 1.04-2.00), and no subretinal fluid (OR, 2.15; 95% CI, 1.06-4.40) predicted CST ≤250 µm. CONCLUSIONS: There are substantial differences in good outcome factors in CRVO versus BRVO, suggesting differences in pathophysiology. Young age, never smoking, hemodilution, and hypertension/high systolic perfusion pressure are more beneficial in CRVO, suggesting that avoidance of sluggish blood flow and maintenance of perfusion may be particularly important in CRVO.

The Port Delivery System with Ranibizumab for Neovascular Age-Related Macular Degeneration: Results from the Randomized Phase 2 Ladder Clinical Trial.

PURPOSE: To evaluate the safety and efficacy of the Port Delivery System with ranibizumab (PDS) for neovascular age-related macular degeneration (nAMD) treatment. DESIGN: Phase 2, multicenter, randomized, active treatment-controlled clinical trial. PARTICIPANTS: Patients diagnosed with nAMD within 9 months who had received 2 or more prior anti-vascular endothelial growth factor intravitreal injections and were responsive to treatment. METHODS: Patients were randomized 3:3:3:2 to receive the PDS filled with ranibizumab 10 mg/ml, 40 mg/ml, 100 mg/ml, or monthly intravitreal ranibizumab 0.5-mg injections. MAIN OUTCOME MEASURES: Time to first implant refill assessed when the last enrolled patient completed the month 9 visit (primary efficacy end point), improvement in best-corrected visual acuity (BCVA) and central foveal thickness (CFT), and safety. RESULTS: The primary analysis population was 220 patients, with 58, 62, 59, and 41 patients in the PDS 10-mg/ml, PDS 40-mg/ml, PDS 100-mg/ml, and monthly intravitreal ranibizumab 0.5-mg arms, respectively. Median time to first implant refill was 8.7, 13.0, and 15.0 months in the PDS 10-mg/ml, PDS 40-mg/ml, and PDS 100-mg/ml arms, respectively. At month 9, the adjusted mean BCVA change from baseline was ‒3.2 Early Treatment Diabetic Retinopathy Study (ETDRS) letters, ‒0.5 ETDRS letters, +5.0 ETDRS letters, and +3.9 ETDRS letters in the PDS 10-mg/ml, PDS 40-mg/ml, PDS 100-mg/ml, and monthly intravitreal ranibizumab 0.5-mg arms, respectively. At month 9, the adjusted mean CFT change from baseline was similar in the PDS 100-mg/ml and monthly intravitreal ranibizumab 0.5-mg arms. The optimized PDS implant insertion and refill procedures were generally well tolerated. After surgical procedure optimization, postoperative vitreous hemorrhage rate was 4.5% (7/157; 1 event classified as serious). There was no evidence of implant clogging. CONCLUSIONS: In the phase 2 Ladder trial, the PDS was generally well tolerated and demonstrated a dose response across multiple end points in patients with nAMD. The PDS 100-mg/ml arm showed visual and anatomic outcomes comparable with monthly intravitreal ranibizumab 0.5-mg injections but with a reduced total number of ranibizumab treatments. The PDS has the potential to reduce treatment burden in nAMD while maintaining vision.

AAV8-antiVEGFfab Ocular Gene Transfer for Neovascular Age-Related Macular Degeneration.

Sustained suppression of VEGF is needed in many patients with neovascular age-related macular degeneration (NVAMD), and gene transfer of a VEGF-neutralizing protein is a promising approach to achieve it. Initial clinical trials testing this approach have shown encouraging signals, but evidence of robust transgene expression and consistent antiangiogenic and antipermeability activity has been lacking. In this study, we demonstrate expression of an anti-human VEGF antibody fragment (antiVEGFfab) after subretinal injection of AAV8-antiVEGFfab. In transgenic mice expressing human VEGF in retina (rho/VEGF mice), a model of type 3 choroidal neovascularization (NV), eyes injected with ≥1 × 107 gene copies (GC) of AAV8-antiVEGFfab had significantly less mean area of NV than null vector-injected eyes. A dose-dependent response was observed with modest reduction of NV with ≤3 × 107, >50% reduction with ≥1 × 108 GC and almost complete elimination of NV with 3 × 109 or 1 × 1010 GC. In Tet/opsin/VEGF mice, in which doxycycline-induced high expression of VEGF leads to severe vascular leakage and exudative retinal detachment (RD), reduction of total RD by 70%-80% occurred with 3 × 109 or 1 × 1010 GC of AAV8-antiVEGFfab, an effect that was sustained for at least a month. These data strongly support initiating clinical trials testing subretinal injection of AAV8-antiVEGFfab in patients with NVAMD.

Intravitreous injection of AAV2-sFLT01 in patients with advanced neovascular age-related macular degeneration: a phase 1, open-label trial.

BACKGROUND: Long-term intraocular injections of vascular endothelial growth factor (VEGF)-neutralising proteins can preserve central vision in many patients with neovascular age-related macular degeneration. We tested the safety and tolerability of a single intravitreous injection of an AAV2 vector expressing the VEGF-neutralising protein sFLT01 in patients with advanced neovascular age-related macular degeneration. METHODS: This was a phase 1, open-label, dose-escalating study done at four outpatient retina clinics in the USA. Patients were assigned to each cohort in order of enrolment, with the first three patients being assigned to and completing the first cohort before filling positions in the following treatment groups. Patients aged 50 years or older with neovascular age-related macular degeneration and a baseline best-corrected visual acuity score of 20/100 or less in the study eye were enrolled in four dose-ranging cohorts (cohort 1, 2 × 108 vector genomes (vg); cohort 2, 2 × 109 vg; cohort 3, 6 × 109 vg; and cohort 4, 2 × 1010 vg, n=3 per cohort) and one maximum tolerated dose cohort (cohort 5, 2 × 1010 vg, n=7) and followed up for 52 weeks. The primary objective of the study was to assess the safety and tolerability of a single intravitreous injection of AAV2-sFLT01, through the measurement of eye-related adverse events. This trial is registered with ClinicalTrials.gov, number NCT01024998. FINDINGS: 19 patients with advanced neovascular age-related macular degeneration were enrolled in the study between May 18, 2010, and July 14, 2014. All patients completed the 52-week trial period. Two patients in cohort 4 (2 × 1010 vg) experienced adverse events that were possibly study-drug related: pyrexia and intraocular inflammation that resolved with a topical steroid. Five of ten patients who received 2 × 1010 vg had aqueous humour concentrations of sFLT01 that peaked at 32·7-112·0 ng/mL (mean 73·7 ng/mL, SD 30·5) by week 26 with a slight decrease to a mean of 53·2 ng/mL at week 52 (SD 17·1). At baseline, four of these five patients were negative for anti-AAV2 serum antibodies and the fifth had a very low titre (1:100) of anti-AAV2 antibodies, whereas four of the five non-expressers of sFLT01 had titres of 1:400 or greater. In 11 of 19 patients with intraretinal or subretinal fluid at baseline judged to be reversible, six showed substantial fluid reduction and improvement in vision, whereas five showed no fluid reduction. One patient in cohort 5 showed a large decrease in vision between weeks 26 and 52 that was not thought to be vector-related. INTERPRETATION: Intravitreous injection of AAV2-sFLT01 seemed to be safe and well tolerated at all doses. Additional studies are needed to identify sources of variability in expression and anti-permeability activity, including the potential effect of baseline anti-AAV2 serum antibodies. FUNDING: Sanofi Genzyme, Framingham, MA, USA.

Long-term Effects of Intravitreal 0.19 mg Fluocinolone Acetonide Implant on Progression and Regression of Diabetic Retinopathy.

OBJECTIVE: To investigate the effects of fluocinolone acetonide (FAc) on the progression to proliferative diabetic retinopathy (PDR) and the impact of FAc on changes in Early Treatment Diabetic Retinopathy Study (ETDRS) diabetic retinopathy (DR) severity scale (DRSS) grade during the Fluocinolone Acetonide in Diabetic Macular Edema (FAME) A and B Phase III clinical trials. DESIGN: Post hoc analysis of data from the 36-month prospective, randomized, FAME A and B trials. PARTICIPANTS: Patients with diabetic macular edema (DME) who received sham control or FAc 0.2 or 0.5 µg/day. METHODS: A masked reading center (University of Wisconsin-Madison) determined DRSS grade and retinal perfusion status using standard 7-field stereo fundus photography and fluorescein angiography, respectively. Retinopathy changes over time were determined by DRSS step differences from baseline to month 36. Pairwise comparisons between the 3 treatment groups were performed using a log-rank test without adjustment for covariates, with the primary comparison between sham control and 0.2 µg/day FAc. MAIN OUTCOME MEASURES: Study eye progression to PDR based on a composite clinical outcome of (1) progression from nonproliferative diabetic retinopathy (NPDR) to PDR based on graded fundus photographs, (2) panretinal photocoagulation (PRP), or (3) pars plana vitrectomy (PPV) for PDR; and study eye changes on the DRSS. RESULTS: In the integrated FAME data set, compared with sham control-treated subjects, time to first PDR event was significantly delayed in subjects treated with FAc (P < 0.001), and this effect was confirmed in subgroups with more severe DR and chronic DME at baseline. In addition, subjects with retinal nonperfusion at baseline showed greater reduction in progression to PDR with FAc treatment. Both FAc dosages demonstrated statistically significant improvements in mean DR severity compared with sham treatment at months 6, 12, and 18. Numerically more subjects who received FAc experienced 2-or-more- or 3-or-more-step improvements in DR severity compared with subjects who received sham; conversely, fewer subjects treated with FAc experienced 2-or-more- or 3-or-more-step worsening in DR severity. The 3-or-more-step improvement with 0.5 µg/day FAc was statistically significantly different from sham control. CONCLUSIONS: In subjects with DME, sustained intraocular delivery of FAc slows development of PDR and slows progression of diabetic retinopathy.

Anti-Vascular Endothelial Growth Factor Agents in the Treatment of Retinal Disease: From Bench to Bedside.

The association of retinal hypoxia with retinal neovascularization has been recognized for decades, causing Michaelson to postulate in 1948 that a factor secreted by hypoxic retina was involved. The isolation of vascular endothelial growth factor (VEGF), characterization of its angiogenic activity, and demonstration that its expression was increased in hypoxic tissue made it a prime candidate. Intraocular levels of VEGF are elevated in patients with retinal or iris neovascularization, and VEGF-specific antagonists markedly suppress retinal neovascularization in mice and primates with ischemic retinopathy. Vascular endothelial growth factor antagonists also suppress choroidal neovascularization, and transgenic expression of VEGF in the retina of mice causes subretinal neovascularization. Clinical trials using a VEGF antagonist that blocks all isoforms of VEGF-A in patients with neovascular age-related macular degeneration (nAMD) demonstrated dramatic benefit. Similar results have been obtained with 2 other VEGF antagonists. Retinal hypoxia also contributes to diabetic macular edema (DME), and because of the absence of good animal models, small clinical trials were used to test the role of VEGF. The results clearly implicated VEGF as a major contributor to DME and have been confirmed by several large multicenter trials. A similar strategy demonstrated that VEGF is a major contributor to macular edema resulting from retinal vein occlusion, also confirmed in multicenter trials. Secondary outcomes in these large clinical trials have shown that VEGF inhibition improves retinal hemorrhages, retinal vessel closure, and progression of nonproliferative diabetic retinopathy. Anti-VEGF agents also provide therapeutic benefits in proliferative diabetic retinopathy. Thus, the development of VEGF antagonists has revolutionized the treatment of nAMD, diabetic retinopathy, and other ischemic retinopathies, but in many patients, the upregulation of VEGF is prolonged. Although the molecular signaling by which hypoxia and some other insults lead to upregulation of VEGF has been elucidated, it has not yet led to a treatment that reliably reduces the production of VEGF, necessitating continued neutralization by repeated intraocular injections of VEGF antagonists in many patients. The next horizon in the evolution of anti-VEGF therapy is the development of longer-acting agents or delivery platforms that provide sustained neutralization with fewer injections.

Enhanced Benefit in Diabetic Macular Edema from AKB-9778 Tie2 Activation Combined with Vascular Endothelial Growth Factor Suppression.

PURPOSE: To assess the effect of AKB-9778 alone or in combination with ranibizumab in subjects with diabetic macular edema (DME). DESIGN: A phase IIa, randomized, placebo- and sham injection-controlled, double-masked clinical trial. PARTICIPANTS: Subjects (n = 144) with decreased vision from DME and central subfield thickness (CST) ≥325 µm measured by spectral-domain optical coherence tomography (SD OCT) enrolled at 36 sites. METHODS: Subjects were randomized to (1) AKB-9778 monotherapy: subcutaneous AKB-9778 15 mg twice per day (BID) + monthly sham intraocular injections; (2) combination therapy: subcutaneous AKB-9778 15 mg BID + monthly 0.3 mg ranibizumab; or (3) ranibizumab monotherapy: subcutaneous placebo injections BID + monthly 0.3 mg ranibizumab. Best-corrected visual acuity (BCVA) and CST were measured at baseline and every 4 weeks. MAIN OUTCOME MEASURES: Primary outcome measure was mean change from baseline CST at week 12. Other outcomes included BCVA, safety assessments, and Diabetic Retinopathy Severity Score (DRSS). RESULTS: At week 12, mean change from baseline CST was significantly greater in the combination group (-164.4±24.2 µm) compared with the ranibizumab monotherapy group (-110.4±17.2 µm; P = 0.008) and was 6.2±13.0 µm in the AKB-9778 monotherapy group. Mean CST at week 12 and percentage of eyes with resolved edema was 340.0±11.2 µm and 29.2%, respectively, in the combination group versus 392.1±17.1 µm and 17.0%, respectively, in the ranibizumab monotherapy group. Mean change from baseline BCVA (letters) was 6.3±1.3 in the combination group, 5.7±1.2 in the ranibizumab monotherapy group, and 1.5±1.2 in the AKB-9778 monotherapy group. The percentage of study eyes that gained ≥10 or ≥15 letters was 8.7% and 4.3%, respectively, in the AKB-9778 monotherapy group, 29.8% and 17.0%, respectively, in the ranibizumab monotherapy group, and 35.4% and 20.8%, respectively, in the combination group. Improvements in DRSS in study eyes were similar across groups, and the percentage of qualified fellow eyes with a ≥2-step change was 11.4% in all AKB-9778-treated subjects compared with 4.2% in the ranibizumab monotherapy group. AKB-9778 was well tolerated, with no clear by-treatment differences in adverse events. CONCLUSIONS: Activation of Tie2 by subcutaneous injections of AKB-9778 combined with suppression of vascular endothelial growth factor (VEGF) causes a significantly greater reduction in DME than that seen with suppression of VEGF alone.

Intravitreal Aflibercept for Macular Edema Following Branch Retinal Vein Occlusion: 52-Week Results of the VIBRANT Study.

PURPOSE: To determine week 52 efficacy and safety outcomes in eyes with macular edema after branch retinal vein occlusion (BRVO) treated with 2 mg intravitreal aflibercept injection (IAI) compared with grid laser. DESIGN: VIBRANT was a double-masked, randomized, phase 3 trial. PARTICIPANTS: Eyes randomized and treated in VIBRANT were followed to week 52. METHODS: In the IAI group, eyes received IAI every 4 weeks through week 24 and IAI every 8 weeks through week 48 with rescue grid laser if needed at week 36. In the grid laser group, all eyes received grid laser at baseline and, if prespecified rescue criteria were met, 1 additional laser from week 12 to 20 and IAI every 8 weeks after 3 monthly doses from week 24 onward (the laser/IAI group). MAIN OUTCOME MEASURES: The primary outcome measure was percentage of eyes with improvement from baseline best-corrected visual acuity (BCVA) letter score ≥15 at week 24. All outcome measures at week 52 were exploratory, and P values are considered nominal. RESULTS: The percentage of eyes with improvement from baseline letter score ≥15 in the IAI and laser/IAI groups was 52.7% versus 26.7% (P = 0.0003) at week 24 and 57.1% versus 41.1% (P = 0.0296) at week 52. The corresponding mean change from baseline BCVA letter score was 17.0 versus 6.9 (P < 0.0001) at week 24 and 17.1 versus 12.2 (P = 0.0035) at week 52. The mean reduction from baseline central retinal thickness was 280.5 µm versus 128.0 µm (P < 0.0001) at week 24 and 283.9 µm versus 249.3 µm (P = 0.0218) at week 52. In the IAI group, 10.6% of eyes received rescue laser at week 36, and in the laser/IAI group, 80.7% received rescue IAI from week 24 to week 48. Traumatic cataract in 1 eye (1.1%) in the IAI group was the only ocular serious adverse event. CONCLUSIONS: After 6 monthly IAI, injections every 8 weeks maintained control of macular edema and visual benefits through week 52. In the laser group, rescue IAI given from week 24 onward resulted in substantial visual improvements at week 52.

Changes in Retinal Nonperfusion Associated with Suppression of Vascular Endothelial Growth Factor in Retinal Vein Occlusion.

PURPOSE: To assess changes in retinal nonperfusion (RNP) in patients with retinal vein occlusion (RVO) treated with ranibizumab. DESIGN: Secondary outcome measure in randomized double-masked controlled clinical trial. PARTICIPANTS: Thirty-nine patients with central RVO (CRVO) and 42 with branch RVO (BRVO). METHODS: Subjects were randomized to 0.5 or 2.0 mg ranibizumab every month for 6 months and then were re-randomized to pro re nata (PRN) groups receiving either ranibizumab plus scatter laser photocoagulation or ranibizumab alone for an additional 30 months. MAIN OUTCOME MEASURES: Comparison of percentage of patients with increased or decreased area of RNP in patients with RVO treated with 0.5 versus 2.0 mg ranibizumab, during monthly injections versus ranibizumab PRN, and in patients treated with ranibizumab PRN versus ranibizumab PRN plus laser. RESULTS: In RVO patients given monthly injections of 0.5 or 2.0 mg ranibizumab for 6 months, there was no significant difference in the percentage who showed reduction or increase in the area of RNP. However, regardless of dose, during the 6-month period of monthly injections, a higher percentage of patients showed a reduction in area of RNP and a lower percentage showed an increase in area of RNP compared with subsequent periods of ranibizumab PRN treatment. After the 6-month period of monthly injections, BRVO patients, but not CRVO patients, randomized to ranibizumab PRN plus laser showed significantly less progression of RNP compared with patients treated with ranibizumab PRN. CONCLUSIONS: Regardless of dose (0.5 or 2.0 mg), monthly ranibizumab injections promote improvement and reduce progression of RNP compared with PRN injections. The addition of scatter photocoagulation to ranibizumab PRN may reduce progression of RNP in patients with BRVO, but a statistically significant reduction was not seen in patients with CRVO.

Twenty-four-Month Outcomes of the Ranibizumab for Edema of the Macula in Diabetes - Protocol 3 with High Dose (READ-3) Study.

PURPOSE: To compare 2.0 mg ranibizumab (RBZ) injections with 0.5 mg RBZ for eyes with center-involved diabetic macular edema (DME). DESIGN: Randomized, controlled, double-masked (to the dose), interventional, multicenter clinical trial. PARTICIPANTS: A total of 152 patients (152 eyes) with DME. METHODS: Eligible eyes were randomized in a 1:1 ratio to 0.5 mg (n = 77) or 2.0 mg (n = 75) RBZ. Study eyes received 6 monthly mandatory injections followed by as-needed injections until month 24. MAIN OUTCOME MEASURES: The primary efficacy end point of the study was mean change in best-corrected visual acuity (BCVA) and central foveal thickness (CFT) at month 6. Secondary outcomes included the mean change in BCVA and CFT at month 24, and incidence and severity of systemic and ocular adverse events through month 24. RESULTS: A total of 152 eyes were randomized in the study. At month 24, the mean improvement from baseline BCVA was +11.06 letters in the 0.5 mg RBZ group (n = 59) and +6.78 letters in the 2.0 mg RBZ group (n = 54) (P = 0.02). The mean numbers of RBZ injections through month 24 were 18.4 and 17.3 in the 0.5 mg and 2.0 mg RBZ groups, respectively (P = 0.08). The mean change in CFT was -192.53 µm in the 0.5 mg RBZ group and -170.64 µm in the 2.0 mg RBZ group (P = 0.41). By month 24, 3 deaths had occurred in the 0.5 mg RBZ group and 3 deaths had occurred in the 2.0 mg RBZ group; 5 of these 6 deaths occurred secondary to cardiovascular causes, and 1 death occurred as the result of severe pneumonia. All 5 patients with a cardiovascular cause of death had a history of coronary heart disease. CONCLUSIONS: At month 24, there were significant visual and anatomic improvements in both groups, with subjects in the 0.5 mg RBZ group gaining more vision. Visual and anatomic gains achieved at month 6 were largely maintained through month 24. No new safety events were identified. In this study population, 2.0 mg RBZ does not appear to provide additional benefit over 0.5 mg RBZ.

Targeting Tie2 for Treatment of Diabetic Retinopathy and Diabetic Macular Edema.

Tie2 is a tyrosine kinase receptor located predominantly on vascular endothelial cells that plays a central role in vascular stability. Angiopoietin-1 (Angpt1), produced by perivascular cells, binds, clusters, and activates Tie2, leading to Tie2 autophosphorylation and downstream signaling. Activated Tie2 increases endothelial cell survival, adhesion, and cell junction integrity, thereby stabilizing the vasculature. Angiopoietin-2 (Angpt2) and vascular endothelial-protein tyrosine phosphatase (VE-PTP) are negative regulators increased by hypoxia; they inactivate Tie2, destabilizing the vasculature and increasing responsiveness to vascular endothelial growth factor (VEGF) and other inflammatory cytokines that stimulate vascular leakage and neovascularization. AKB-9778 is a small-molecule antagonist of VE-PTP which increases phosphorylation of Tie2 even in the presence of high Angpt2 levels. In preclinical studies, AKB-9778 reduced VEGF-induced leakage and ocular neovascularization (NV) and showed additive benefit when combined with VEGF suppression. In two clinical trials in diabetic macular edema (DME) patients, subcutaneous injections of AKB-9778 were safe and provided added benefit to VEGF suppression. Preliminary data suggest that AKB-9778 monotherapy improves diabetic retinopathy. These data suggest that Tie2 activation may be a valuable strategy to treat or prevent diabetic retinopathy.

Predictors of Functional and Anatomic Outcomes in Patients with Diabetic Macular Edema Treated with Ranibizumab.

OBJECTIVE: To investigate baseline predictors of month 24 best-corrected visual acuity (BCVA) and central foveal thickness (CFT) in patients with diabetic macular edema (DME) treated monthly with ranibizumab or sham. DESIGN: Post hoc analysis of DME patients in 2 identical phase 3 studies. PARTICIPANTS: Patients randomized to ranibizumab (n = 502) or sham (n = 257). METHODS: Multivariate regression on predictors with P < 0.20 in univariate logistic regression using backward selection to retain predictors with P < 0.05. MAIN OUTCOME MEASURES: Patient characteristics correlating with month 24 BCVA in Early Treatment Diabetic Retinopathy Study letter score ≥70 (20/40) or ≤50 (20/100), gain or loss from baseline BCVA of ≥15, or CFT ≤250 µm. RESULTS: Baseline predictors of BCVA ≥20/40 in ranibizumab-treated patients were good BCVA, submacular fluid, no cardiovascular disease, no scatter photocoagulation, and male gender, whereas in sham-treated patients, they were mild increase in CFT, presence of hard exudates in center subfield, and absence of renal disease. Predictors of improvement in BCVA letter score ≥15 in ranibizumab-treated patients were poor BCVA, submacular fluid, young age, and short diabetes duration, and those in sham-treated patients were poor BCVA, young age, and mild increase in CFT. Predictors of resolution of edema (CFT ≤250 µm) in ranibizumab-treated patients were mild foveal thickening and prominent subfoveal fluid, and those in sham-treated patients were poor BCVA, mild foveal thickening, and statin usage. Month 24 BCVA ≤20/100 was predicted by poor baseline BCVA in ranibizumab-treated patients, and by poor baseline BCVA, large intraretinal cystoid spaces, renal disease, and absence of hypercholesterolemia in sham-treated patients. Loss of BCVA ≥15 letters was predicted in sham-treated patients by submacular fluid, intraretinal cystoid spaces, and renal disease. CONCLUSIONS: Patients with DME and submacular fluid, intraretinal cysts, severe thickening, or renal disease respond poorly when untreated and respond well to ranibizumab treatment. Elimination of submacular fluid, intraretinal cysts, and severe thickening are important goals of DME treatment, and in patients with renal disease, treatment should be very aggressive, with a goal of eliminating all macular fluid.

Treatment of diabetic macular edema with an inhibitor of vascular endothelial-protein tyrosine phosphatase that activates Tie2.

PURPOSE: AKB-9778 is a small-molecule competitive inhibitor of vascular endothelial-protein tyrosine phosphatase (VE-PTP) that promotes Tie2 activation and reduces vascular leakage and neovascularization in mouse models. The purpose of this study was to test the safety, tolerability, pharmacokinetics, and biological activity of AKB-9778 in patients with diabetic macular edema (DME). DESIGN: Open-label, dose-escalation clinical trial. PARTICIPANTS: Four dose cohorts of 6 patients with DME self-administered subcutaneous injections of 5 mg, 15 mg, 22.5 mg, or 30 mg AKB-9778 twice daily for 4 weeks. METHODS: Patients were seen weekly during a 4-week treatment period for safety assessments, best-corrected visual acuity (BCVA) assessment by Early Treatment Diabetic Retinopathy Study protocol, and measurement of central subfield thickness (CST) by spectral-domain optical coherence tomography. Additional safety assessments were performed at 6, 8, and 12 weeks. MAIN OUTCOME MEASURES: Safety assessments, change from baseline BCVA, and change from baseline CST. RESULTS: All doses were well tolerated. A modest, transient reduction in blood pressure and adverse events consistent with vasodilatory activity of AKB-9778 emerged at doses of 22.5 mg or more twice daily. At the week 4 primary end point, BCVA improved 5 letters or more from baseline in 13 of the 18 patients receiving 15 mg or more twice daily; 1 patient improved by 10 to 15 letters, and 2 patients improved by more than 15 letters. Among 18 patients receiving 15 mg or more twice daily, CST decreased by more than 100 µm in 5 patients and by 50 to 100 µm in 2 patients. There was a significant correlation between reduction in CST and improvement in BCVA. CONCLUSIONS: No safety concerns were identified after systemic administration of AKB-9778 for 4 weeks in patients with DME, and doses of 15 mg or more twice daily reduced macular edema and improved vision in some patients. This is a preliminary demonstration of clinical safety and efficacy of a VE-PTP inhibitor and Tie2 activator.