Morphological Changes in the Anterior Eye Segment after Long-Term Treatment with Different Receptor Selective Prostaglandin Agonists and a Prostamide

Matrix Metalloproteinases in Glaucoma: An Updated Overview

Matrix metalloproteinases (MMPs) are important regulators of the extracellular matrix (ECM) and are involved in many stages of cellular growth and development. An imbalance of MMP expression is also the basis of many diseases, including eye diseases, such as diabetic retinopathy (DR), glaucoma, dry eye, corneal ulcer, keratoconus. This paper describes the role of MMPs in the glaucoma and their role in the glaucomatous trabecular meshwork (TM), aqueous outflow channel, retina, and optic nerve (ON). This review also summarizes several treatments for glaucoma that target MMPs imbalance and suggests that MMPs may represent a viable therapeutic target for glaucoma.

Proposed Mechanism of Long-Term Intraocular Pressure Lowering With the Bimatoprost Implant

Purpose

The purpose of this study was to evaluate the effects of pharmacologically relevant bimatoprost and bimatoprost free acid (BFA) concentrations on matrix metalloproteinase (MMP) gene expression in cells from human aqueous outflow tissues.

Methods

MMP gene expression by human trabecular meshwork (TM), scleral fibroblast (SF), and ciliary muscle (CM) cells exposed to 10 to 1000 µM bimatoprost or 0.1 to 10 µM BFA (intraocular concentrations after intracameral bimatoprost implant and topical bimatoprost dosing, respectively) was measured by polymerase chain reaction array.

Results

Bimatoprost dose-dependently upregulated MMP1 and MMP14 mRNA in all cell types and MMP10 and MMP11 mRNA in TM and CM cells; in TM cells from normal eyes, mean MMP1 mRNA levels were 62.9-fold control levels at 1000 µM bimatoprost. BFA upregulated MMP1 mRNA only in TM and SF cells, to two- to three-fold control levels. The largest changes in extracellular matrix (ECM)-related gene expression by TM cells derived from normal (n = 6) or primary open-angle glaucoma (n = 3) eyes occurred with 1000 µM bimatoprost (statistically significant, ≥50% change for 9-11 of 84 genes on the array, versus 1 gene with 10 µM BFA).

Conclusions

Bimatoprost and BFA had differential effects on MMP/ECM gene expression. Dramatic upregulation in MMP1 and downregulation of fibronectin, which occurred only with bimatoprost at high concentrations observed in bimatoprost implant-treated eyes, may promote sustained outflow tissue remodeling and long-term intraocular pressure reduction beyond the duration of intraocular drug bioavailability. Variability in bimatoprost-stimulated MMP upregulation among cell strains from different donors may help explain differential long-term responses of patients to bimatoprost implant.

Bimatoprost Implant Biodegradation in the Phase 3, Randomized, 20-Month ARTEMIS Studies

Purpose: To evaluate the time course of biodegradation of an intracameral, biodegradable, sustained-release bimatoprost implant that lowers intraocular pressure without the need for daily eye drops. Methods: In 2 identically designed, randomized, phase 3 clinical trials, adults with open-angle glaucoma or ocular hypertension and open iridocorneal angles inferiorly in the study eye were administered 10- or 15-μg bimatoprost implant (day 1 and weeks 16 and 32) or twice-daily topical timolol 0.5%. Implants were assessed on gonioscopy throughout the studies. Investigators reported whether implants were visible, estimated the size of visible implants relative to their initial size at implantation, and reported the implant location. Data for 10-μg implant placed on day 1 were pooled from both studies for analysis. Results: A total of 372 patients received the 10-μg bimatoprost implant. The degree of implant biodegradation at each follow-up time point was variable among patients. The implant frequently swelled during the initial phase of biodegradation from 6 to 28 weeks. Accelerated biodegradation occurred between 31 and 52 weeks, resulting in 82% of implants absent or ≤25% of initial size by 52 weeks. By month 20, 95% of implants had biodegraded to absent or ≤25% of initial size. The implant was predominantly located inferiorly in the iridocorneal angle. Conclusions: Bimatoprost implant biodegradation in phase 3 studies showed some degree of variability among patients. Clinically significant implant biodegradation was observed in the majority of patients by 12 months. Clinical studies are in progress to further understand implant biodegradation and the ideal timing for implant re-administration. ClinicalTrials.gov NCT02247804; ClinicalTrials.gov NCT02250651.

Emerging drugs for the treatment of glaucoma: a review of phase II & III trials

INTRODUCTION

Glaucoma is a progressive optic neuropathy and the leading cause of irreversible vision loss. By 2040, the number of individuals with glaucoma is expected to nearly double. The only known modifiable risk factor for glaucoma is intraocular pressure. Topical medications are often used as first-line therapies. Although there are numerous available treatments, there continues to be a need for the development of new medical therapies due to variable response, intolerable side-effect profiles in some patients, and elevated intraocular pressure refractory to other treatments.

AREAS COVERED

This review will cover glaucoma medications currently undergoing phase II and III of drug development.

EXPERT OPINION

There are numerous drugs currently in development that have demonstrated significant and clinically relevant reduction of intraocular pressure. Differentiating factors include improved tolerability, novel mechanisms of action, multiple mechanisms of action, or superior IOP reduction. However, the availability of generic prostaglandin analogs may limit adoption of these novel compounds as first-line agents, except for certain subgroups of glaucoma patients. Use as adjuvant or second-line therapy appears more likely for the majority of glaucoma patients.

Comparison of the Effects of Latanoprostene Bunod and Timolol on Retinal Blood Vessel Density: A Randomized Clinical Trial

PURPOSE

To compare the differences in retinal vessel density (VD) between topical administration of latanoprostene bunod (LBN) ophthalmic solution 0.024% and timolol maleate 0.5% in patients with open-angle glaucoma (OAG) or ocular hypertension (OHT) and normal subjects.

DESIGN

Randomized, single center, crossover clinical trial.

METHODS

Eligible subjects were examined during 6 study visits over 12 weeks. All subjects were randomized in a 1:1 ratio to LBN dosed once daily or timolol dosed twice daily in both eyes (OU) for a duration of 4 weeks each, separated by a 2-week washout period. A comprehensive eye examination OU was performed at each visit. Testing was performed with optical coherence tomography and optical coherence tomography angiography (optic nerve and macula), as well as visual field examination, on the study eye at baseline and before and after each treatment.

RESULTS

One eye from each of 50 patients was enrolled (10 healthy patients, 26 patients with OHT, and 14 patients with OAG). After administration of LBN there was significantly increased macular VD (0.76% [0.20%-1.33%], P = 0.009) and a trend in increasing peripapillary VD in patients with OAG and patients with OHT. In contrast, after administration of timolol, there were no differences in macular VD, and a decrease in peripapillary VD only was observed in the nasal inferior sector (-0.56% [-1.08% to -0.03%], P = .04) in patients with OAG and patients with OHT. No change in peripapillary or macular VD was observed in the normal subjects (P > .05 for all).

CONCLUSIONS

Topical administration of LBN enhanced macular VD in patients with OAG or patients with OHT. In contrast, timolol administration did not have any effect on VD.

Comparison of the Drug-Induced Efficacies between Omidenepag Isopropyl, an EP2 Agonist and PGF2α toward TGF-β2-Modulated Human Trabecular Meshwork (HTM) Cells

To compare the drug-induced efficacies between omidenepag (OMD), an EP2 agonist, and prostaglandin F2α (PGF2α) on glaucomatous trabecular meshwork (TM) cells, two- and three-dimensional (2D and 3D) cultures of TGF-β2-modulated human trabecular meshwork (HTM) cells were used. The following analyses were performed: (1) transendothelial electrical resistance (TEER) and FITC-dextran permeability measurements (2D), (2) the size and stiffness of the 3D spheroids, and (3) the expression (both 2D and 3D) by several extracellular matrix (ECM) molecules including collagen (COL) 1, 4 and 6, and fibronectin (FN), and α smooth muscle actin (αSMA), tight junction (TJ)-related molecules, claudin11 (Cldn11) and ZO1, the tissue inhibitor of metalloproteinase (TIMP) 1–4, matrix metalloproteinase (MMP) 2, 9 and 14, connective tissue growth factor (CTGF), and several endoplasmic reticulum (ER) stress-related factors. TGF-β2 significantly increased the TEER values and decreased FITC-dextran permeability, respectively, in the 2D HTM monolayers, and induced the formation of downsized and stiffer 3D HTM spheroids. TGF-β2-induced changes in TEER levels and FITC-dextran permeability were remarkably inhibited by PGF2α. PGF2α induced increases in the sizes and stiffness of the TGF-β2-treated 3D spheroids, but OMD enhanced only spheroid size. Upon exposure to TGF-β2, the expression of most of the molecules that were evaluated were significantly up-regulated, except some of ER stress-related factors were down-regulated. TJ-related molecules or ER stress-related factors were significantly up-regulated (2D) or down-regulated (3D), and down-regulated (2D) by PGF2α and OMD, while both drugs altered the expression of some of the other genes in the 3D spheroids in a different manner. The findings presented herein suggest that PGF2α and OMD differently modulate the permeability of the TGFβ2-modulated 2D monolayers and the physical properties of the 3D HTM spheroids.

Phase 3, Randomized, 20-Month Study of the Efficacy and Safety of Bimatoprost Implant in Patients with Open-Angle Glaucoma and Ocular Hypertension (ARTEMIS 2)

Objective

To evaluate the intraocular pressure (IOP)-lowering efficacy and safety of 10 and 15 µg bimatoprost implant in patients with open-angle glaucoma (OAG) or ocular hypertension (OHT).

Methods

This randomized, 20-month, multicenter, masked, parallel-group, phase 3 trial enrolled 528 patients with OAG or OHT and an open iridocorneal angle inferiorly in the study eye. Study eyes were administered 10 or 15 µg bimatoprost implant on day 1, week 16, and week 32, or twice-daily topical timolol maleate 0.5%. Primary endpoints were IOP and IOP change from baseline through week 12. Safety measures included treatment-emergent adverse events (TEAEs) and corneal endothelial cell density (CECD).

Results

Both 10 and 15 µg bimatoprost implant met the primary endpoint of noninferiority to timolol in IOP lowering through 12 weeks. Mean IOP reductions from baseline ranged from 6.2–7.4, 6.5–7.8, and 6.1–6.7 mmHg through week 12 in the 10 µg implant, 15 µg implant, and timolol groups, respectively. IOP lowering was similar after the second and third implant administrations. Probabilities of requiring no IOP-lowering treatment for 1 year after the third administration were 77.5% (10 µg implant) and 79.0% (15 µg implant). The most common TEAE was conjunctival hyperemia, typically temporally associated with the administration procedure. Corneal TEAEs of interest (primarily corneal endothelial cell loss, corneal edema, and corneal touch) were more frequent with the 15 than the 10 µg implant and generally were reported after repeated administrations. Loss in mean CECD from baseline to month 20 was ~ 5% in 10 µg implant-treated eyes and ~ 1% in topical timolol-treated eyes. Visual field progression (change in the mean deviation from baseline) was reduced in the 10 µg implant group compared with the timolol group.

Conclusions

The results corroborated the previous phase 3 study of the bimatoprost implant. The bimatoprost implant met the primary endpoint and effectively lowered IOP. The majority of patients required no additional treatment for 12 months after the third administration. The benefit-risk assessment favored the 10 over the 15 µg implant. Studies evaluating other administration regimens with reduced risk of corneal events are ongoing. The bimatoprost implant has the potential to improve adherence and reduce treatment burden in glaucoma.

Clinicaltrials.gov Identifier

NCT02250651.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40265-021-01624-9.

Morphological changes in the trabecular meshwork and Schlemm's canal after treatment with topical intraocular pressure-lowering agents

Glaucoma treatment is usually initiated with topical medication that lowers the intraocular pressure (IOP) by reducing the aqueous production, enhancing the aqueous outflow, or both. However, the effect of topical IOP-lowering medications on the microstructures of the aqueous outflow pathway are relatively unknown. In this retrospective, observational study, 56 treatment-naïve patients with primary open-angle glaucoma were enrolled. Images of the nasal and temporal corneoscleral limbus were obtained using anterior segment optical coherence tomography (AS-OCT). The conjunctival vessels and iris anatomy were used as landmarks to select the same limbal area scan, and the trabecular meshwork (TM) width, TM thickness, and Schlemm’s canal (SC) area were measured before and after using the IOP-lowering agents for 3 months. Among the 56 patients enrolled, 33 patients used prostaglandin (PG) analogues, and 23 patients used dorzolamide/timolol fixed combination (DTFC). After 3 months of DTFC usage, the TM width, TM thickness, and SC area did not show significant changes in either the nasal or temporal sectors. Conversely, after prostaglandin analog usage, the TM thickness significantly increased, and the SC area significantly decreased (all P < 0.01). These findings warrant a deeper investigation into their relationship to aqueous outflow through the conventional and unconventional outflow pathways after treatment with PG analogues.

Effects of selective EP2 receptor agonist, omidenepag, on trabecular meshwork cells, Schlemm's canal endothelial cells and ciliary muscle contraction

This study investigated the effects of omidenepag (OMD), a novel selective EP2 receptor agonist, on human trabecular meshwork (HTM) cells, monkey Schlemm’s canal endothelial (SCE) cells, and porcine ciliary muscle (CM) to clarify the mechanism of intraocular pressure (IOP) reduction involving conventional outflow pathway. In HTM and SCE cells, the effects of OMD on transforming growth factor-β2 (TGF-β2)-induced changes were examined. The expression of actin cytoskeleton and extracellular matrix (ECM) proteins, myosin light chain (MLC) phosphorylation in HTM cells were evaluated using real-time quantitative PCR, immunocytochemistry, and western blotting. The expression of barrier-related proteins, ZO-1 and β-catenin, and permeability of SCE cells were evaluated using immunocytochemistry and transendothelial electrical resistance. The CM contraction was determined by contractibility assay. OMD significantly inhibited expression of TGF-β2 induced mRNA, protein, and MLC-phosphorylation on cytoskeletal and ECM remodeling in the HTM dose dependently. In SCE cells, OMD suppressed TGF-β2-induced expression of the barrier-related proteins and decreased SCE monolayer permeability. OMD at 3 µM significantly inhibited CM contraction, however, the effect was not significant at lower concentrations. IOP lowering effect of OMD through conventional outflow pathway is exerted by increasing outflow facilities with the modulation of TM cell fibrosis and SCE cell permeability.

Clinical Trial: Diurnal IOP Fluctuations in Glaucoma Using Latanoprost and Timolol with Self-Tonometry

SIGNIFICANCE

Assessment of treatment efficacy via comparison with a target IOP is fundamental in monitoring patients with open-angle glaucoma and ocular hypertension. This article highlights that diurnal IOP fluctuations obtained using self-tonometry may more accurately reflect IOP responses to therapy.

PURPOSE

This study aimed to investigate fluctuations in diurnal IOP measurements in patients with open-angle glaucoma and ocular hypertension treated with latanoprost 0.005% and timolol 0.25%.

METHODS

In this crossover treatment trial, 14 participants performed self-tonometry with iCare HOME 4 times daily for (1) 1 week using latanoprost, (2) 4 weeks using no medications, and (3) 2 weeks using timolol. Daily peak IOPs, IOP fluctuations, and mean IOPs from different treatments were compared on an individual basis. Treatment efficacy between medications was assessed by comparing mean percentage IOP reductions with latanoprost and timolol across participants. In addition, effects of age, years since commencing latanoprost, sex, and diagnosis were investigated, and peak IOP times were compared with assess impacts on diurnal profiles.

RESULTS

Between individuals, IOP responses ranged from reductions in peak IOPs, IOP fluctuations, and mean IOPs on both medications to no change in any parameter and medication. IOP fluctuations showed greater mean percentage reductions than did peak and mean IOPs (χ2 = 16.51, P = .002). There were significant associations between years since commencing latanoprost and peak and mean IOP responses on timolol (r = 0.69, P = .007), and sex and relative reductions in IOP fluctuations on both medications (P = .03). There were no differences in peak IOP times between treatment conditions.

CONCLUSIONS

Despite variability in IOP responses to latanoprost and timolol, IOP fluctuation with self-tonometry was more consistent in evaluating target IOP, reflecting its importance in ascertaining true IOP response to topical therapies. These findings may impact clinical decision making based on target IOP criteria in patients on topical therapy.

Screening of the Drug-Induced Effects of Prostaglandin EP2 and FP Agonists on 3D Cultures of Dexamethasone-Treated Human Trabecular Meshwork Cells

The objective of the current study was to perform a screening of the drug-induced effects of the prostaglandin F2α (PGF2α) and EP2 agonist, omidenepag (OMD), using two- and three-dimensional (2D and 3D) cultures of dexamethasone (DEX)-treated human trabecular meshwork (HTM) cells. The drug-induced effects on 2D monolayers were characterized by measuring the transendothelial electrical resistance (TEER) and fluorescein isothiocyanate (FITC)–dextran permeability, the physical properties of 3D spheroids, and the gene expression of extracellular matrix (ECM) molecules, including collagen (COL) 1, 4 and 6, and fibronectin (FN), α smooth muscle actin (αSMA), a tissue inhibitor of metalloproteinase (TIMP) 1–4, matrix metalloproteinase (MMP) 2, 9 and 14 and endoplasmic reticulum (ER) stress-related factors. DEX induced a significant increase in TEER values and a decrease in FITC–dextran permeability, respectively, in the 2D HTM monolayers, and these effects were substantially inhibited by PGF2α and OMD. Similarly, DEX also caused decreased sizes and an increased stiffness in the 3D HTM spheroids, but PGF2α or OMD had no effects on the stiffness of the spheroids. Upon exposure to DEX, the following changes were observed: the upregulation of COL4 (2D), αSMA (2D), and TIMP4 (2D and 3D) and the downregulation of TIMP1 and 2 (3D), MMP2 and 14 (3D), inositol-requiring enzyme 1 (IRE1), activating transcription factor 6 (ATF6) (2D), and glucose regulator protein (GRP)78 (3D). In the presence of PGF2α or OMD, the downregulation of COL4 (2D), FN (3D), αSMA (2D), TIMP3 (3D), MMP9 (3D) and the CCAAT/enhancer-binding protein homologous protein (CHOP) (2D), and the upregulation of TIMP4 (2D and 3D), MMP2, 9 and 14 (2D), respectively, were observed. The findings presented herein suggest that 2D and 3D cell cultures can be useful in screening for the drug-induced effects of PGF2α and OMD toward DEX-treated HTM cells.

Medical anti-glaucoma therapy: Beyond the drop

Barriers to effective medical therapy are numerous and include difficulties with effective and sustained control of intraocular pressure (IOP) and adherence to prescribed anti-glaucoma drop regimens. In an effort to circumvent these challenges, a number of new anti-glaucoma therapies with sustained effects have emerged. Methods for sustained delivery of prostaglandin analogs are being intensely investigated and many are in human clinical trials. Intracameral devices include the following: Allergan's Durysta^™ Bimatoprost SR, Envisia Therapeutics' ENV515 travoprost implant, Glaukos' iDose^™ , Ocular Therapeutix's OTX-TIC travoprost implant, and Santen's polycaprolactone implant with PGE2-derivative DE-117. Other prostaglandin-based technologies include Allergan's bimatoprost ring (placed in the conjunctival fornix), Ocular Therapeutics' OTX-TP intracanalicular travoprost implant, subconjunctival latanoprost in a liposomal formulation, and the PGE2 derivative PGN 9856-isopropyl ester that is applied to the periorbital skin. Exciting breakthroughs in gene therapy include using viral vectors to correct defective genes such as MYOC or to modulate gonioimplant fibrosis, CRISPR technology to edit MYOC or to alter aquaporin to reduce aqueous humor production, and siRNA technology to silence specific genes. Stem cell technology can repopulate depleted tissues or, in the case of Neurotech's Renexus® NT-501 intravitreal implant, serve as a living drug delivery device that continuously secretes neurotrophic factors. Other unique approaches involve nanotechnology, nasal sprays that deliver drug directly to the optic nerve and noninvasive alternating current stimulation of surviving cells in the optic nerve. Over time these modalities are likely to challenge the preeminent role that drops currently play in the medical treatment of glaucoma in animals.

24-Month Phase I/II Clinical Trial of Bimatoprost Sustained-Release Implant (Bimatoprost SR) in Glaucoma Patients

Objective

The objective of this study was to evaluate the safety and intraocular pressure (IOP)-lowering effects over 24 months of biodegradable bimatoprost sustained-release implant (Bimatoprost SR) administration versus topical bimatoprost 0.03% in patients with open-angle glaucoma (OAG).

Methods

This was a phase I/II, prospective, 24-month, dose-ranging, paired-eye controlled clinical trial. At baseline following washout, adult patients with OAG (N = 75) received Bimatoprost SR (6, 10, 15, or 20 µg) intracamerally in the study eye; the fellow eye received topical bimatoprost 0.03% once daily. Rescue topical IOP-lowering medication or single repeat administration with implant was permitted. The primary endpoint was IOP change from baseline. Safety measures included adverse events (AEs).

Results

At month 24, mean IOP reduction from baseline was 7.5, 7.3, 7.3, and 8.9 mmHg in eyes treated with Bimatoprost SR 6, 10, 15, and 20 µg, respectively, versus 8.2 mmHg in pooled fellow eyes; 68, 40, and 28% of pooled study eyes had not been rescued/retreated at months 6, 12, and 24, respectively. AEs in study eyes that occurred ≤ 2 days post-procedure typically were transient. After 2 days post-procedure, overall AE incidence was similar between study and fellow eyes, with some events typically associated with topical prostaglandin analogs having lower incidence in study eyes.

Conclusions

Bimatoprost SR showed favorable efficacy and safety profiles up to 24 months, with all evaluated dose strengths demonstrating overall IOP-reducing effects comparable to those of topical bimatoprost. Targeted and sustained delivery of bimatoprost resulted in protracted IOP lowering, suggesting that Bimatoprost SR may represent a transformational new approach to glaucoma therapy. Clinicaltrials.gov identifier: NCT01157364

Electronic supplementary material

The online version of this article (10.1007/s40265-019-01248-0) contains supplementary material, which is available to authorized users.

Phase 3, Randomized, 20-Month Study of Bimatoprost Implant in Open-Angle Glaucoma and Ocular Hypertension (ARTEMIS 1)

PURPOSE

To evaluate the intraocular pressure (IOP)-lowering efficacy and safety of 10- and 15-μg bimatoprost implant in subjects with open-angle glaucoma (OAG) and ocular hypertension (OHT) after initial and repeated administrations.

DESIGN

Randomized, 20-month, multicenter, subject- and efficacy evaluator-masked, parallel-group, phase 3 clinical study.

PARTICIPANTS

Adults with OAG or OHT in each eye, open iridocorneal angle inferiorly in the study eye, and study eye baseline IOP (hour 0; 8 am) of 22-32 mmHg after washout.

METHODS

Study eyes received bimatoprost implant 10 μg (n = 198) or 15 μg (n = 198) on day 1 with readministration at weeks 16 and 32, or twice-daily topical timolol maleate 0.5% (n = 198). Intraocular pressure was measured at hours 0 and 2 at each visit.

MAIN OUTCOME MEASURES

Primary end points were IOP and change from baseline IOP through week 12. Safety measures included treatment-emergent adverse events (TEAEs) and corneal endothelial cell density (CECD).

RESULTS

Both dose strengths of bimatoprost implant were noninferior to timolol in IOP lowering after each administration. Mean diurnal IOP was 24.0, 24.2, and 23.9 mmHg at baseline and from 16.5-17.2, 16.5-17.0, and 17.1-17.5 mmHg through week 12 in the 10-μg implant, 15-μg implant, and timolol groups, respectively. The incidence of corneal and inflammatory TEAEs of interest (e.g., corneal endothelial cell loss, iritis) was higher with bimatoprost implant than timolol and highest with the 15-μg dose strength. Incidence of corneal TEAEs increased after repeated treatment; with 3 administrations at fixed 16-week intervals, incidence of ≥20% CECD loss was 10.2% (10-μg implant) and 21.8% (15-μg implant). Mean best-corrected visual acuity (BCVA) was stable; 3 implant-treated subjects with corneal TEAEs had >2-line BCVA loss at their last visit.

CONCLUSIONS

Both dose strengths of bimatoprost implant met the primary end point of noninferiority to timolol through week 12. One year after 3 administrations, IOP was controlled in most subjects without additional treatment. The risk-benefit assessment favored the 10-μg implant over the 15-μg implant. Ongoing studies are evaluating other administration regimens to reduce the potential for CECD loss. The bimatoprost implant has potential to improve adherence and reduce treatment burden in glaucoma.

Matrix Metalloproteinases and Glaucoma Treatment

Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that degrade extracellular matrix (ECM) components such as collagen and have important roles in multiple biological processes, including development and tissue remodeling, both in health and disease. The activity of MMPs is influenced by the expression of MMPs and tissue inhibitors of metalloproteinase (TIMPs). In the eye, MMP-mediated ECM turnover in the juxtacanalicular region of the trabecular meshwork (TM) reduces outflow resistance in the conventional outflow pathway and helps maintain intraocular pressure (IOP) homeostasis. An imbalance in the MMP/TIMP ratio may be involved in the elevated IOP often associated with glaucoma. The prostaglandin analog/prostamide (PGA) class of topical ocular hypotensive medications used in glaucoma treatment reduces IOP by increasing outflow through both conventional and unconventional (uveoscleral) outflow pathways. Evidence from in vivo and in vitro studies using animal models and anterior segment explant and cell cultures indicates that the mechanism of IOP lowering by PGAs involves increased MMP expression in the TM and ciliary body, leading to tissue remodeling that enhances conventional and unconventional outflow. PGA effects on MMP expression are dependent on the identity and concentration of the PGA. An intracameral sustained-release PGA implant (Bimatoprost SR) in development for glaucoma treatment can reduce IOP for many months after expected intraocular drug bioavailability. We hypothesize that the higher concentrations of bimatoprost achieved in ocular outflow tissues with the implant produce greater MMP upregulation and more extensive, sustained MMP-mediated target tissue remodeling, providing an extended duration of effect.

Nonclinical Pharmacokinetic and Pharmacodynamic Assessment of Bimatoprost Following a Single Intracameral Injection of Sustained-Release Implants

Purpose

To assess the pharmacokinetic (PK)/pharmacodynamic (PD) relationship following intracameral Bimatoprost sustained-release (SR) implants (8, 15, 30, and 60 µg) in dogs to determine the optimal investigative dose in humans.

Methods

Forty-four male normotensive beagle dogs were assigned to 1 of 8 groups receiving 8-, 15-, 30-, and 60-µg implants (PD assessment [n = 8/group, 4 groups]; PK assessment [n = 3/group, 4 groups]). Intraocular pressure (IOP) in PD animals and aqueous humor/blood concentrations of bimatoprost and its acid in PK animals were assessed. PK/PD correlation analysis was performed using steady-state data. Residual implants were recovered to assess polymer degradation.

Results

Dose-dependent IOP lowering was observed for all dose groups for at least 3 months postdose. Blood concentrations of bimatoprost and bimatoprost acid were below the limit of quantification (<0.25 ng/mL), whereas dose-dependent concentration-time profiles were observed in the aqueous humor. At steady state, observed and predicted correlation between aqueous humor drug concentration and IOP lowering was similar and translatable to findings in humans following topical bimatoprost eyedrop administration. Implants at all doses were well tolerated and polymer degradation was apparent.

Conclusions

Dose-dependent IOP lowering with Bimatoprost SR was maintained for at least 3 months in dogs, and the implants were well tolerated. The established PK/PD relationship appears to translate to humans. Doses between 8 and 15 µg appear to provide the best benefit/risk profile for clinical development of the implants.

Translational Relevance

The close PK/PD relationship between dog and human helps inform which bimatoprost dose should be investigated in clinical studies.

Effect of 6-week washout period on intraocular pressure following chronic prostaglandin analogue treatment: a randomized controlled trial

OBJECTIVE

To evaluate the effect of a 6-week washout period on intraocular pressure (IOP) following long-term monotherapy prostaglandin use.

DESIGN

Prospective, randomized, controlled, single-centre, single-blinded, parallel-group clinical study.

PARTICIPANTS

Subjects aged >18 years diagnosed with open-angle glaucoma or open-angle glaucoma suspects based on elevated IOP in one or both eyes, using monotherapy topical latanoprost, bimatoprost, or travoprost once daily.

METHODS

Subjects were prospectively randomized to continue prostaglandin analogue (PGA) monotherapy (control group) or discontinue PGA monotherapy (washout group) for 42 days. IOP was measured at day 0 (day of randomization), 7, 21, and 42.

MAIN OUTCOME MEASURE

Mean IOP (mm Hg) ± standard deviation.

RESULTS

154 eyes (87 participants) completed the study, with 69 eyes (39 participants) in the control group and 85 eyes (48 participants) in the washout group. In the control group, day 0 IOP (14.64 ± 2.68 mm Hg) did not significantly differ from IOP at days 7 (14.25 ± 3.01 mm Hg), 21 (14.57 ± 2.61 mm Hg), and 42 (14.78 ± 2.30 mm Hg) (all p > 0.30). In the washout group, mean IOP values at days 7 (16.19 ± 3.80 mm Hg), 21 (17.28 ± 3.55 mm Hg), and 42 (17.84 ± 3.31 mm Hg) were significantly greater than those at day 0 (14.48 ± 1.94 mm Hg) and day-matched control group values (all p < 0.002). In the washout group, 24.7% of eyes had a day 42 IOP ≥21 mm Hg. No eyes in the control group had a day 42 IOP ≥21 mm Hg.

CONCLUSIONS

Six weeks of PGA washout after long-term monotherapy resulted in a small but statistically significant IOP increase. Majority of washout group participants maintained an IOP lower than 21 mm Hg after the 6-week washout duration. (https://clinicaltrials.gov/ identifier, NCT03534882).

Latanoprostene Bunod 0.024% in Subjects With Open-angle Glaucoma or Ocular Hypertension: Pooled Phase 3 Study Findings

PURPOSE

To compare the diurnal intraocular pressure (IOP)-lowering effect of latanoprostene bunod (LBN) 0.024% with timolol maleate 0.5% in subjects with open-angle glaucoma (OAG) or ocular hypertension (OHT).

PATIENTS AND METHODS

Pooled analysis of two phase 3, randomized, multicenter, double-masked, parallel-group, noninferiority trials (APOLLO and LUNAR), each with open-label safety extension phases. Adults with OAG or OHT were randomized 2:1 to double-masked treatment with LBN once daily (qd) or timolol twice daily (bid) for 3 months followed by open-label LBN treatment for 3 (LUNAR) or 9 (APOLLO) months. IOP was measured at 8 AM, 12 PM, and 4 PM at week 2, week 6, and months 3, 6, 9, and 12.

RESULTS

Of the 840 subjects randomized, 774 (LBN, n=523; timolol crossover to LBN, n=251) completed the efficacy phase, and 738 completed the safety extension phase. Mean IOP was significantly lower with LBN versus timolol at all 9 evaluation timepoints during the efficacy phase (P<0.001). A significantly greater proportion of LBN-treated subjects attained a mean IOP ≤18 mm Hg and IOP reduction ≥25% from baseline versus timolol-treated subjects (P<0.001). The IOP reduction with LBN was sustained through the safety phase; subjects crossed over from timolol to LBN experienced additional significant IOP lowering (P≤0.009). Both treatments were well tolerated, and there were no safety concerns with long-term LBN treatment.

CONCLUSIONS

In this pooled analysis of subjects with OAG and OHT, LBN 0.024% qd provided greater IOP-lowering compared with timolol 0.5% bid and maintained lowered IOP through 12 months. LBN demonstrated a safety profile comparable to that of prostaglandin analogs.

Antiglaucoma EP2 Agonists: A Long Road That Led Somewhere

For >2 decades, EP₂ agonists have been the subject of antiglaucoma research and development by scientists in industry and academia around the world. The road has led to the recent approval of the first drug of this class. This article reviews the development of EP₂ agonists from conception to clinical approval, discussing pharmacology, structure, biodistribution, therapeutics, and drug delivery. An extensive list of source references is provided for the reader's benefit.

Effect of topical ophthalmic administration of 0.005% latanoprost solution on aqueous humor flow rate and intraocular pressure in ophthalmologically normal adult Beagles

OBJECTIVE

To determine the effect of topical ophthalmic administration of 0.005% latanoprost solution on aqueous humor flow rate (AHFR) and intraocular pressure (IOP) in ophthalmologically normal dogs.

ANIMALS

12 adult Beagles.

PROCEDURES

In a masked crossover design involving two 10-day experimental periods separated by a 7-day washout period, dogs were randomly assigned to first receive latanoprost or artificial tears (control) solution and then the opposite treatment in the later experimental period. Each experimental period was divided into a baseline phase (days 1 to 3), baseline fluorophotometry assessment (day 4), treatment phase (1 drop of latanoprost or artificial tears solution administered twice daily in each eye on days 5 to 9 and once on day 10), and posttreatment fluorophotometry assessment (day 10). Measured fluorescein concentrations were used to calculate baseline and posttreatment AHFRs. The IOP was measured 5 times/d in each eye during baseline and treatment (days 5 to 9) phases.

RESULTS

Mean baseline and posttreatment AHFR values did not differ significantly in either experimental period (latanoprost or control). In the latanoprost period, mean IOP was significantly lower during treatment than at baseline; there was no difference in corresponding IOP values during the control period. In the latanoprost period, mean IOP was significantly higher on the first day of treatment than on subsequent treatment days.

CONCLUSIONS AND CLINICAL RELEVANCE

In ophthalmologically normal dogs, topical ophthalmic administration of 0.005% latanoprost solution significantly decreased IOP but did not affect AHFR. Thus, the ocular hypotensive effect of latanoprost did not appear to have been caused by a reduction in aqueous humor production. (Am J Vet Res 2019;80:498-504).

[Efficacy and safety of travoprost in patients with primary open-angle glaucoma]

PURPOSE

To study the hypotensive efficacy and safety of Travapress (0.004% travoprost) in patients with primary open-angle glaucoma (POAG).

MATERIAL AND METHODS

The study included 50 patients (91 eyes) aged 45 to 74 years. The first group consisted of 23 patients (41 eyes) who received monotherapy with Travaprost. Patients of the second group (27 patients, 50 eyes) Travaprost was added to therapy with timolol 0.5% (17 patients, 32 eyes) or dorzolamide 2% (10 patients, 18 eyes). Travaprost was given for a period of 6 months. IOP was determined in 2 weeks, 1, 3 and 6 months from the beginning of treatment and daily IOP measurement was at 10.00, 12.00, 14.00 and 16.00. Subjective symptoms were evaluated in points by special scales.

RESULTS

The study was completed by 42 patients (84%, 79 eyes). Two patients (4.7%) has stopped to use Travapress due to the side effects. Local side effects were observed in 9 patients (21.4%) with mild hyperemia being the most common and seen in 5 patients (11.9%). In the first group, the maximum IOP decrease was recorded for 3 months of the study and amounted to 7.3±1.2 mm Hg (27.5%) compared to baseline. By 6 months, IOP decreased by 6.8±1.5 mm Hg on average (25.6%). In the second group in the subgroup with timolol 0,5% IOP decreased by 4,9±1.7 mm Hg (20%) compared to baseline, in the subgroup with dorzolamid 2% - by 4,3±1,3 mm Hg (16,9%) compared to baseline. Evening use the drug was accompanied by significantly lower levels of daily IOP fluctuations compared with morning intake (3.0±1.2 and 3.8±1.7 mm Hg, respectively, p = 0,002).

CONCLUSION

Travapress was established as highly efficient and safe. It can be recommended for wide use in the treatment of patients with POAG.

Latanoprost could exacerbate the progression of presbyopia

Purpose

Prostaglandin analogues (PG) reduce intra-ocular pressure by enhancing uveoscleral flow at the ciliary body, which controls accommodation via the ciliary muscle. We investigated the effect of PG on accommodation and presbyopia progression in glaucoma patients.

Methods

We conducted a clinic-based, retrospective, cross-sectional study. Inclusion criteria were bilateral phakic patients aged 40–69 years with best corrected visual acuity better than 20/30. Exclusion criteria were any disease affecting vision other than glaucoma and history of ocular surgery. Subjects with no prescription or vision-affecting disease served as controls (n = 260). The glaucoma patients were prescribed eye drops containing 0.005% latanoprost for more than six months (n = 23). We measured the binocular near add power at a distance of 30 cm in both groups and compared the results using Kaplan-Meier analysis.

Results

The mean age (± SD) of the control subjects was 51.5 ± 5.2 years and 39% were male. Similarly, the glaucoma patients had a mean age of 51.0 ± 7.2 years and 39% were male. There were no significant differences in age, gender, intra-ocular pressure, spherical equivalent, astigmatism, or anisometropia between groups. Survival analysis indicated that the glaucoma patients in this study reached the endpoint (near add power of +3.00 D) significantly earlier than control patients (P = 0.0001; generalized Wilcoxon test).

Conclusions

Exacerbation of presbyopia progression in glaucoma patients is a potential side effect of latanoprost eyedrops.

Dose-Response of Intracameral Bimatoprost Sustained-Release Implant and Topical Bimatoprost in Lowering Intraocular Pressure

Purpose: To compare the dose–response profiles of bimatoprost sustained-release implant (Bimatoprost SR) and topical bimatoprost in lowering intraocular pressure (IOP) in normotensive beagle dogs.

Methods: In 1 study, topical bimatoprost 0.001%, 0.01%, or 0.1% was administered twice daily in the study eye for 5 days. IOP was measured at baseline and up to hour 6 each day. Other studies evaluated the IOP response to a single administration of Bimatoprost SR at dose strengths ranging from 8 to 120 μg. IOP was measured before implant administration and during 3 months of follow-up; IOP in response to topical bimatoprost 0.03% was measured prestudy as an internal control.

Results: Mean percentage decrease in IOP from baseline at hour 6 (peak effect) across study days was 15.7%, 36.1%, and 24.8% (2.8, 7.0, and 4.0 mmHg) in animals treated with topical bimatoprost 0.001%, 0.01%, and 0.1%, respectively. After Bimatoprost SR administration, mean percentage decrease in IOP from baseline across 3 months consistently increased with increasing dose strength and was 38.7% (7.2 mmHg) with Bimatoprost SR 120 μg. Mean percentage IOP decrease with topical bimatoprost 0.03% was 27.6% (5.9 mmHg).

Conclusions: Topical bimatoprost demonstrated a U-shaped dose–response curve; increasing the bimatoprost concentration to 0.1% resulted in reduced IOP-lowering efficacy. In contrast, the dose–response curve for Bimatoprost SR showed consistently greater IOP lowering as the dose strength increased, with the dose strength producing maximum IOP lowering not yet determined. At 60- and 120-μg dose strengths, Bimatoprost SR produced greater IOP reductions than were achieved with topical dosing.

Intracameral Sustained-Release Bimatoprost Implant Delivers Bimatoprost to Target Tissues with Reduced Drug Exposure to Off-Target Tissues

Purpose: To explore the ocular distribution of bimatoprost after intracameral administration of a biodegradable sustained-release bimatoprost implant (Bimatoprost SR) versus repeated topical administration of bimatoprost 0.03% ophthalmic solution in dogs. Bimatoprost SR and topical bimatoprost 0.03% previously were shown to have similar intraocular pressure-lowering effects in humans in a phase 1/2 clinical trial.

Methods: Twenty-four beagle dogs received either once-daily topical bimatoprost 0.03% for 7 days or a bilateral intracameral administration of Bimatoprost SR (15 μg). At predetermined time points, ocular tissues were collected and concentrations of bimatoprost and bimatoprost acid were quantified using liquid chromatography–tandem mass spectrometry.

Results: Bimatoprost SR administration enhanced delivery of study drug to a site of action [iris–ciliary body (ICB)] compared with topical bimatoprost (C_max [bimatoprost+bimatoprost acid] = 18,200 and 4.13 ng/g, respectively). However, distribution of drug to tissues associated with prostaglandin analog (PGA)-related side effects (i.e., bulbar conjunctiva, eyelid margins, and periorbital fat) was limited following Bimatoprost SR administration (C_max [bimatoprost+bimatoprost acid] = BLQ [beneath the limit of quantitation] to 0.354 ng/g) compared with topical dosing (C_max [bimatoprost+bimatoprost acid] = 36.6–2,110 ng/g).

Conclusions: Bimatoprost SR administration in dogs selectively delivered drug to the ICB with low or undetectable drug levels in ocular surface and extraocular tissues. Use of Bimatoprost SR for glaucoma treatment may reduce the incidence of adverse events typically associated with topical PGAs by targeting bimatoprost delivery to the key site of action of the PGA class and reducing exposure to off-target tissues.

The Effect of Prostaglandin Analogues on the Ciliary Zonular Fibers of the Rabbit Crystalline Lens

PURPOSE

To evaluate the influence of prostaglandin (PG) analogues on the ciliary zonular fibers of the crystalline lens using scanning electron microscopy (SEM) of rabbit eyes, and to measure the matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) levels of the aqueous humor and crystalline lens treated with topical PG analogues Methods: Fifty eyes from 25 New Zealand white rabbits were divided into five groups of five rabbits each. In the control group, balanced salt solution was administered via the topical route once a day to the eyes. The benzalkonium chloride (BAC) group was treated with 0.02% BAC, the Latanoprost group with 0.005% latanoprost, the Travoprost group with 0.004% Travoprost, and the Bimatoprost group with 0.03% Bimatoprost for 10 months. We examined the ciliary zonular fibers using SEM. We also measured the MMP and TIMP levels of the aqueous humor and crystalline lens.

RESULTS

SEM revealed some splitting of zonular fibers in eyes treated with topical PG analogues when compared with the control and BAC groups. The MMP-1 and TIMP-1 levels after treatment with the PG analogues did not differ significantly from the control and BAC groups (P > 0.05). There was no significant difference in MMP-1, MMP-3, TIMP-1, and MMP-1/TIMP-1 levels in the lens among all five groups.

CONCLUSIONS

PG analogues may induce zonular change in rabbits microscopically. There was no association between zonular changes and the levels of certain types of MMP or TIMP in the aqueous humor or crystalline lens after topical treatment with PG analogues.

Biomechanical, ultrastructural, and electrophysiological characterization of the non-human primate experimental glaucoma model

Laser-induced experimental glaucoma (ExGl) in non-human primates (NHPs) is a common animal model for ocular drug development. While many features of human hypertensive glaucoma are replicated in this model, structural and functional changes in the unlasered portions of trabecular meshwork (TM) of laser-treated primate eyes are understudied. We studied NHPs with ExGl of several years duration. As expected, ExGl eyes exhibited selective reductions of the retinal nerve fiber layer that correlate with electrophysiologic measures documenting a link between morphologic and elctrophysiologic endpoints. Softening of unlasered TM in ExGl eyes compared to untreated controls was observed. The degree of TM softening was consistent, regardless of pre-mortem clinical findings including severity of IOP elevation, retinal nerve fiber layer thinning, or electrodiagnostic findings. Importantly, this softening is contrary to TM stiffening reported in glaucomatous human eyes. Furthermore, microscopic analysis of unlasered TM from eyes with ExGl demonstrated TM thinning with collapse of Schlemm's canal; and proteomic analysis confirmed downregulation of metabolic and structural proteins. These data demonstrate unexpected and compensatory changes involving the TM in the NHP model of ExGl. The data suggest that compensatory mechanisms exist in normal animals and respond to elevated IOP through softening of the meshwork to increase outflow.

Open-angle glaucoma: therapeutically targeting the extracellular matrix of the conventional outflow pathway

INTRODUCTION

Ocular hypertension in open-angle glaucoma is caused by a reduced rate of removal of aqueous humour (AH) from the eye, with the majority of AH draining from the anterior chamber through the conventional outflow pathway, comprising the trabecular meshwork (TM) and Schlemm's Canal. Resistance to outflow is generated, in part, by the extracellular matrix (ECM) of the outflow tissues. Current pressure-lowering topical medications largely suppress AH production, or enhance its clearance through the unconventional pathway. However, therapies targeting the ECM of the conventional pathway in order to decrease intraocular pressure have become a recent focus of attention. Areas covered: We discuss the role of ECM of the TM in outflow homeostasis and its relevance as a target for glaucoma therapy, including progress in development of topical eye formulations, together with gene therapy approaches based on inducible, virally-mediated expression of matrix metalloproteinases to enhance aqueous outflow. Expert opinion: There remains a need for improved glaucoma medications that more specifically act upon sites causative to glaucoma pathogenesis. Emerging strategies targeting the ECM of the conventional outflow pathway, or associated components of the cytoskeleton of TM cells, involving new pharmacological formulations or genetically-based therapies, are promising avenues of future glaucoma treatment.

Efficacy and safety of bimatoprost in glaucoma and ocular hypertension in non-responder patients

AIM

To establish the efficacy and safety of bimatoprost 0.03% monotherapy in glaucoma and ocular hypertension (OHT) patients with inadequate intraocular pressure (IOP)on current therapy.

METHODS

Pre- and post-switch IOPs were analyzed for 59 consecutive patients who were switched from current therapy to bimatoprost monotherapy between 2011-2015. Demographic information, diagnosis, and any adverse events were recorded. Change in IOP post-pre switch was analyzed using a 2-sided Student's paired t-test at the 5% significance level.

RESULTS

There was a statistically significant mean reduction in IOP at the first follow up visit, which was maintained at subsequent follow up visits for patients regardless of diagnosis, or pre-switch treatment (P<0.001). Subgroup analysis also demonstrated a statistically significant mean reduction in IOP when looking at OHT patients only, as well as patients with any diagnosis switched from latanoprost monotherapy to bimatoprost monotherapy (P<0.001).

CONCLUSION

This is the largest independent data set which supports switching glaucoma patients with poor response to current treatment onto bimatoprost monotherapy before considering other adjuvant medical or more invasive therapy.

Stanniocalcin-1 Is an Ocular Hypotensive Agent and a Downstream Effector Molecule That Is Necessary for the Intraocular Pressure-Lowering Effects of Latanoprost

Purpose

To identify downstream signaling molecules through which intraocular pressure (IOP) is lowered following treatment with the prostaglandin analog latanoprost.

Methods

Total RNA and protein isolated from primary human Schlemm's canal cells (n = 3) treated with latanoprost (free acid; 100 nM) were processed for quantitative PCR and Western blot analysis. IOP was evaluated in stanniocalcin-1 (STC-1^−/−) and wild-type mice following treatment with latanoprost or Rho kinase inhibitor Y27632. Human anterior segment pairs (n = 8) were treated with recombinant STC-1 (5, 50, or 500 ng/mL) and pressure was recorded using custom-designed software. The effect of recombinant STC-1 (0.5 mg/mL) on IOP was evaluated in wild-type mice. Tissue morphology was evaluated by light and transmission electron microscopy.

Results

Increased STC-1 mRNA (4.0- to 25.2-fold) and protein expression (1.9- to 5.1-fold) was observed within 12 hours following latanoprost treatment. Latanoprost reduced IOP in wild-type mice (22.0% ± 1.9%), but had no effect on STC-1^−/− mice (0.5% ± 0.7%). In contrast, Y27632 reduced IOP in both wild-type (12.5% ± 1.2%) and in STC-1^−/− mice (13.1% ± 2.8%). Human anterior segments treated with STC-1 (500 ng/mL) showed an increase in outflow facility (0.15 ± 0.03 to 0.27 ± 0.09 μL/min/mm Hg) while no change was observed in paired vehicle-treated controls. Recombinant STC-1 reduced IOP in wild-type mice by 15.2% ± 3.0%. No observable morphologic changes were identified between treatment groups when evaluated by microscopy.

Conclusions

Latanoprost-induced reduction of IOP is mediated through the downstream signaling molecule STC-1. When used by itself, STC-1 exhibits ocular hypotensive properties.

Prostaglandin analogues: past, present, and future

This literature review is focused on the prostaglandin topical analogues and describes peculiarities of their structure, pharmacokinetics and pharmacodynamics, results of clinical trials and meta-analyzes, as well as modern trends in the topical IOP-lowering glaucoma therapy evolution.

Intraocular Pressure-Lowering Effect of Latanoprost Is Hampered by Defective Cervical Lymphatic Drainage

Purpose

To evaluate whether defects in cervical lymphatic drainage influence the intraocular pressure (IOP)-lowering effect of latanoprost in patients with primary open-angle glaucoma (POAG) who have undergone unilateral radical neck dissection (uRND).

Methods

We enrolled (1) bilateral POAG patients who had started (bilateral) latanoprost (0.005%) monotherapy prior to their uRND and (2) treatment-naïve, bilateral glaucoma suspects (GSs) who had undergone the same surgery. We compared the eyes ipsilateral to the uRND with their fellow eyes in terms of the changes in IOP between the baseline (prior to the uRND) and the follow-up visits (1, 3, and 6 months after the uRND).

Results

The study involved 22 eyes of 11 POAG patients and 14 eyes of 7 GSs. In the POAG patients, IOP had increased significantly after surgery in the eyes ipsilateral to the uRND (from 14.7±1.4mmHg to 17.1±2.2mmHg; P = 0.007). Interestingly, in the eyes contralateral to the uRND, IOP had not changed significantly after surgery (from 14.2±1.8mmHg to 14.4±2.0mmHg; P = 0.826). In GSs, the eyes ipsilateral to the uRND did not differ significantly from their fellow eyes in terms of post-operative IOP change (ipsilateral value: 0.3±0.5mmHg, fellow eyes: -0.1±0.7mmHg; P = 0.242).

Conclusion

In the POAG patients, IOP had increased significantly in the eyes ipsilateral to the uRND. However, it had not changed significantly in the eyes contralateral to the surgery or in the eyes of the GSs. These findings suggest that, latanoprost works, at least in part, by enhancing outflow from the aqueous humor via the uveolymphatic pathway.

Long-term Safety and Efficacy of Latanoprostene Bunod 0.024% in Japanese Subjects with Open-Angle Glaucoma or Ocular Hypertension: The JUPITER Study

INTRODUCTION

Latanoprostene bunod (LBN) is a novel nitric oxide (NO)-donating prostaglandin F2α analog. We evaluated the long-term safety and intraocular pressure (IOP)-lowering efficacy of LBN ophthalmic solution 0.024% over 1 year in Japanese subjects with open-angle glaucoma (OAG) or ocular hypertension (OHT).

METHODS

This was a single-arm, multicenter, open-label, clinical study. Subjects aged 20 years and older with a diagnosis of OAG or OHT instilled 1 drop of LBN ophthalmic solution 0.024% in the affected eye(s) once daily in the evening for 52 weeks and were evaluated every 4 weeks. Safety assessments included vital signs, comprehensive ophthalmic exams, and treatment-emergent adverse events (AEs). Absolute and percent reductions from baseline in IOP were also determined.

RESULTS

Of 130 subjects enrolled, 121 (93.1%) completed the study. Mean age was 62.5 years, and mean (standard deviation) baseline IOP was 19.6 (2.9) and 18.7 (2.6) mmHg in study eyes and treated fellow eyes, respectively. Overall, 76/130 (58.5%) and 78/126 (61.9%) subjects experienced ≥1 AEs in study eyes and treated fellow eyes, respectively. In both study eyes and treated fellow eyes, the most common AEs were conjunctival hyperemia, growth of eyelashes, eye irritation, and eye pain. At 52 weeks, 9% of treated eyes had an increase in iris pigmentation compared with baseline based on iris photographs. No safety concerns emerged based on vital signs or other ocular assessments. Mean reductions from baseline in IOP of 22.0% and 19.5% were achieved by week 4 in study and treated fellow eyes, respectively. These reductions were maintained through week 52 (P < 0.001 vs. baseline at all visits).

CONCLUSION

Once daily LBN ophthalmic solution 0.024% was safe and well-tolerated in Japanese subjects with OAG or OHT when used for up to 1 year. Long-term treatment with LBN ophthalmic solution 0.024% provided significant and sustained IOP reduction.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT01895972.

FUNDING

Bausch & Lomb, Inc. a division of Valeant Pharmaceuticals International Inc.

Does the intraocular pressure-lowering effect of prostaglandin analogues continue over the long term?

The purpose of the study is to assess the changes in the long-term effects of prostaglandin analogues (PGAs) on intraocular pressure (IOP) reduction in patients with primary open-angle glaucoma (POAG). Data of POAG patients treated with latanoprost (0.005 %), travoprost (0.004 %), or bimatoprost (0.03 %) as the first line treatment for 5 years or more were retrospectively evaluated. Baseline ophthalmic assessment values were recorded together with the IOP at the 6th month, 1st year, and then annually. The 79 patients included 33 (41.8 %) men and 46 (58.2 %) women. There were 34 (43.0 %) patients using latanoprost (0.005 %), 23 (29.1 %) patients using bimatoprost (0.03 %), and 22 (27.8 %) patients using travoprost (0.004 %). There was no difference between the groups in terms of age, gender, or baseline IOP levels. IOP levels at the 6th month were significantly lower than baseline IOP levels in all groups (p < 0.01, Friedman test). The IOP decrease was maintained after the 6th month in all three group with no statistically significant difference compared to the 6th month IOP value (p > 0.05, Friedman test) and no statistically significant difference between the groups during follow-up (Kruskal-Wallis test, p > 0.05). IOP reductions with PGAs were adequate and stable in the 5-year follow-up period with no decrease in effectiveness over time.

Comparison of Latanoprostene Bunod 0.024% and Timolol Maleate 0.5% in Open-Angle Glaucoma or Ocular Hypertension: The LUNAR Study

PURPOSE

To compare the intraocular pressure (IOP)-lowering effect of latanoprostene bunod (LBN) 0.024% with timolol maleate 0.5% in subjects with open-angle glaucoma (OAG) or ocular hypertension (OHT).

DESIGN

Prospective, randomized, double-masked, parallel-group, noninferiority clinical trial.

METHODS

Adults with OAG or OHT from 46 clinical sites (United States and European Union) were randomized 2:1 to LBN instilled once daily (QD) in the evening and vehicle in the morning or timolol instilled twice a day (BID) for 3 months. IOP was measured at week 2, week 6, and month 3 (8 AM, 12 PM, and 4 PM each visit).

RESULTS

A total of 387 subjects (LBN, n = 259; timolol, n = 128) completed the study. Analysis of covariance showed that mean IOP reduction with LBN was not only noninferior to timolol but significantly greater (P ≤ .025) than timolol at all but the first time point in this study (week 2, 8 AM). Of LBN- and timolol-treated subjects, respectively, 31.0% and 18.5% (P = .007) had their IOP reduced ≥25% from baseline, and 17.7% and 11.1% (P = .084) had their IOP reduced to ≤18 mm Hg over all time points/visits in this study. Ocular treatment-emergent adverse events, while uncommon, appeared more frequently in the LBN group (all mild-moderate except 1 case of severe hyperemia).

CONCLUSIONS

LBN 0.024% QD in the evening was noninferior to timolol 0.5% BID over 3 months of treatment, with significantly greater IOP lowering in subjects with OAG or OHT at all but the earliest time point evaluated, and demonstrated a good safety profile.

Latanoprostene Bunod 0.024% versus Timolol Maleate 0.5% in Subjects with Open-Angle Glaucoma or Ocular Hypertension: The APOLLO Study

PURPOSE

To compare the diurnal intraocular pressure (IOP)-lowering effect of latanoprostene bunod (LBN) ophthalmic solution 0.024% every evening (qpm) with timolol maleate 0.5% twice daily (BID) in subjects with open-angle glaucoma (OAG) or ocular hypertension (OHT).

DESIGN

Phase 3, randomized, controlled, multicenter, double-masked, parallel-group clinical study.

PARTICIPANTS

Subjects aged ≥18 years with a diagnosis of OAG or OHT in 1 or both eyes.

METHODS

Subjects were randomized (2:1) to a 3-month regimen of LBN 0.024% qpm or timolol 0.5% 1 drop BID. Intraocular pressure was measured at 8 am, 12 pm, and 4 pm of each postrandomization visit (week 2, week 6, and month 3). Adverse events were recorded throughout the study.

MAIN OUTCOME MEASURES

The primary efficacy end point was IOP in the study eye measured at each of the 9 assessment time points. Secondary efficacy end points included the proportion of subjects with IOP ≤18 mmHg consistently at all 9 time points and the proportion of subjects with IOP reduction ≥25% consistently at all 9 time points.

RESULTS

Of 420 subjects randomized, 387 completed the study (LBN 0.024%, n = 264; timolol 0.5%, n = 123). At all 9 time points, the mean IOP in the study eye was significantly lower in the LBN 0.024% group than in the timolol 0.5% group (P ≤ 0.002). At all 9 time points, the percentage of subjects with mean IOP ≤18 mmHg and the percentage with IOP reduction ≥25% were significantly higher in the LBN 0.024% group versus the timolol 0.5% group (mean IOP ≤18 mmHg: 22.9% vs. 11.3%, P = 0.005; IOP reduction ≥25%: 34.9% vs. 19.5%, P = 0.001). Adverse events were similar in both treatment groups.

CONCLUSIONS

In this phase 3 study, LBN 0.024% qpm demonstrated significantly greater IOP lowering than timolol 0.5% BID throughout the day over 3 months of treatment. Latanoprostene bunod 0.024% was effective and safe in these adults with OAG or OHT.

Evaluation of the Effect of Latanoprostene Bunod Ophthalmic Solution, 0.024% in Lowering Intraocular Pressure over 24 h in Healthy Japanese Subjects

Introduction

Latanoprostene bunod is a novel nitric oxide (NO)-donating prostaglandin F2α receptor agonist in clinical development for the reduction of intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension. We evaluated the effect of latanoprostene bunod 0.024% instilled once daily (QD) on lowering IOP over a 24-h period in healthy Japanese subjects following 14 days of treatment.

Methods

This was a single-arm, single-center, open-label clinical study of 24 healthy Japanese male volunteers. A baseline IOP profile was established in both eyes in the sitting position at 8 PM, 10 PM, 12 AM, 2 AM, 4 AM, 8 AM, 10 AM, 12 PM, and 4 PM using a Goldmann applanation tonometer. Subjects subsequently instilled latanoprostene bunod 0.024% QD at 8 PM for 14 days in both eyes. The absolute and change from baseline in sitting IOP was assessed on day 14.

Results

The mean (SD) age of the subjects was 26.8 (6.3) years, and mean (SD) baseline IOP was 13.6 (1.3) mmHg in the study eye. Latanoprostene bunod 0.024% instilled QD for 14 days reduced IOP at all the evaluated time points (P < 0.001) with a mean (SD) 24-h reduction of 3.6 (0.8) mmHg or 27% from the baseline in the study eye. Peak and trough IOP lowering occurred at 8 AM and 8 PM (12 and 24 h following instillation) with a mean reduction of 4.2 (1.8) mmHg, or 30%, and 2.8 (2.2) mmHg, or 20%, respectively. Punctate keratitis and ocular hyperemia, both mild in severity, were the most common adverse events.

Conclusion

Latanoprostene bunod ophthalmic solution 0.024%, dosed QD for 14 days, significantly lowered mean IOP in healthy Japanese subjects during the entire 24-h period. Studies of latanoprostene bunod in patients diagnosed with normal tension glaucoma are warranted.

Trial Registration

Clinicaltrials.gov identifier NCT01895985.

Funding

Bausch & Lomb, Inc.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-015-0260-y) contains supplementary material, which is available to authorized users.

Lymphatic drainage from the eye: A new target for therapy

Lowering intraocular pressure (IOP) has been central to glaucoma care for over a century. In order to prevent sight loss from disease, there has been considerable focus on medical and surgical methods to improve fluid drainage from the eye. In spite of this, our understanding of exactly how aqueous humor leaves the eye is not complete. Recently, lymphatic vessels have been discovered in the human uvea, with studies showing lymphatic fluid outflow in several models, in addition to evidence for their pharmacological enhancement. The presence of a lymphatic outflow system points to an exciting, expanded understanding of how fluid and particulate materials such as proteins move out of the eye, and how IOP may be regulated. We coin the term "uveolymphatic pathway"-to reflect a comprehensive and compelling new target for glaucoma and an exciting opportunity for future investigations to better understand the eye in health and disease.

In vitro Effects of Prostaglandin Analogs on Cultured Astrocytes Obtained from the Lamina Cribrosa

PURPOSE

To evaluate the effects of prostaglandin analogs (PGAs) on cell viability and apoptosis in cultured astrocytes obtained from the lamina cribrosa (LC) of the human optic nerve head (ONH).

METHODS

Astrocytes were cultured from LC samples obtained from human donor ONH and treated with three kinds of acid form of PGAs: latanoprost (LAT-A), tafluprost (TAF-A), and bimatoprost (BIM-A) (0.1, 1, 10, 50 and 100 ug/mL). Cell viability was assessed using the WST-1 assay. Cell apoptosis was measured using the deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labeling (TUNEL) assay. Apoptotic protein expression was evaluated using western blot analysis.

RESULTS

ONH astrocytes expressed FP receptor in western blot analysis. In the presence of 0.1 ug/mL of LAT-A, BIM-A, and TAF-A, the cell viability was 85%, 85% and 82%, respectively. WST-1 assay revealed about 50% of cell viability following treatment with 50 ug/mL of all PGAs. After exposing astrocytes to 10 ug/mL of each PGA for 24 hours, apoptotic cells were stained in TUNEL assay. Western blot analysis revealed that the PGAs up-regulated Bax (pro-apoptotic protein) and down-regulated Bcl-xL (anti-apoptotic protein) in the astrocytes.

CONCLUSIONS

PGAs affected cell viability in cultured astrocytes obtained from human ONH LC. PGA treatment may induce apoptosis in ONH astrocytes.

Safety and efficacy of travoprost solution for the treatment of elevated intraocular pressure

Travoprost is a prostaglandin analogue widely used for reducing intraocular pressure (IOP) in patients affected with glaucoma and ocular hypertension. It exerts its ocular hypotensive effect through the prostaglandin FP receptors, located in the ciliary muscle and the trabecular meshwork. Several studies have shown that topical administration of travoprost induces a mean IOP reduction ranging from 25% to 32%, and sustained throughout the 24-hour cycle. When compared with timolol, travoprost is more effective at reducing IOP, while generally no difference has been found in the head-to-head comparison with other prostaglandin analogues. The fixed combination of travoprost and timolol has demonstrated a hypotensive efficacy comparable to the concomitant administration of the two drugs. Recently, a new preservative-free formulation of travoprost 0.004% has been marketed for reducing tolerability-related problems in subjects affected with ocular surface disease. Low rates of topical and systemic adverse reactions, strong ocular hypotensive efficacy, and once-a-day dosing make travoprost a first-line treatment for patients affected with elevated IOP.

Pharmacology of topical prostaglandin F2 α analogs and their place in the treatment of glaucoma in small animals

A distinguishing feature of the most common types of glaucoma is an increased intra-ocular pressure (IOP), which has a damaging effect on optic nerve axons, leading to the progressive loss of retinal ganglion cells. Therefore, IOP-lowering medications are the mainstay of glaucoma therapy. Topical prostaglandin F2 α analogs (PGAs) are a relatively new class of ocular hypotensive drugs, which have made a huge impact on the treatment of glaucoma in dogs. This study summarizes the current state of knowledge on the mechanism of action of these agents and their effect on IOP in dogs and cats. It also discusses potential harmful side effects of PGAs and presents contemporary opinions about their role and place in the medical management of glaucoma in small animals.

Prospects for lentiviral vector mediated prostaglandin F synthase gene delivery in monkey eyes in vivo

Currently, the most effective outflow drugs approved for clinical use are prostaglandin F2α analogues, but these require daily topical self-dosing and have various intraocular, ocular surface and extraocular side effects. Lentiviral vector-mediated delivery of the prostaglandin F synthase (PGFS) gene, resulting in long-term reduction of intraocular pressure (IOP), may eliminate off-target tissue effects and the need for daily topical PGF2α self-administration. Lentiviral vector-mediated delivery of the PGFS gene to the anterior segment has been achieved in cats and non-human primates. Although these results are encouraging, our studies have identified a number of challenges that need to be overcome for prostaglandin gene therapy to be translated into the clinic. Using examples from our work in non-human primates, where we were able to achieve a significant reduction in IOP (2 mm Hg) for 5 months after delivery of the cDNA for bovine PGF synthase, we identify and discuss these issues and consider several possible solutions.

Endogenous Bioactive Lipids and the Regulation of Conventional Outflow Facility

Perturbation of paracrine signaling within the human conventional outflow pathway influences tissue homeostasis and outflow function. For example, exogenous introduction of the bioactive lipids, sphingosine-1-phosphate, anandamide or prostaglandin F(2α), to conventional outflow tissues alters the rate of drainage of aqueous humor through the trabecular meshwork, and into Schlemm's canal. This review summarizes recent data that characterizes endogenous bioactive lipids, their receptors and associated signaling partners in the conventional outflow tract. We also discuss the potential of targeting such signaling pathways as a strategy for the development of therapeutics to treat ocular hypertension and glaucoma.

Effects of prostaglandin analogues on aqueous humor outflow pathways

Elevated intraocular pressure (IOP) is the most prevalent risk factor for glaucoma. All treatments, whether surgical or pharmaceutical, are aimed at lowering IOP. Prostaglandin analogues are a first line therapy for glaucoma due to their ability to reduce IOP, once-daily dosing, efficacy, and minimal side-effect profile. Whereas prostaglandin analogues have been known to alter aqueous humor outflow through the unconventional (uveoscleral) pathway, more recent evidence suggests their action also occurs through the conventional (trabecular) pathway. Understanding how prostaglandin analogues successfully lower IOP is important, as this information may lead to the discovery of new molecular targets for future therapeutic intervention. This review explores the current understanding of prostaglandin analogue biology as it pertains to IOP reduction and improved aqueous humor outflow facility.