A comparative clinical study of latanoprost and isopropyl unoprostone in Japanese patients with primary open-angle glaucoma and ocular hypertension

Effect of prostaglandin analogs: Latanoprost, bimatoprost, and unoprostone on matrix metalloproteinases and their inhibitors in human trabecular meshwork endothelial cells

Bimatoprost, latanoprost, and unoprostone are prostaglandin F_2α analogs (PGAs) and are used to lower intraocular pressure. We investigated the free acid effects of these three prostaglandin analogs: bimatoprost, latanoprost, and unoprostone on human matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMP) in the trabecular meshwork (TM) cells. Immunoblot results show that all three PGAs generally increased MMPs-1,9 and TIMPs-4. Additionally, bimatoprost and latanoprost both increased MMP-3 and TIMP-2, while unoprostone had an indeterminate effect on both. Zymography results show that all three PGAs except unoprostone increased intermediate MMP-1 activity while bimatoprost and latanoprost increased MMP-9 activity. Together, these data suggest that the balance between MMPs and TIMPs correlate to the relative intraocular pressure lowering effectiveness observed in clinical studies of these PGAs.

Preperimetric Glaucoma Prospective Observational Study (PPGPS): Design, baseline characteristics, and therapeutic effect of tafluprost in preperimetric glaucoma eye

Purpose

There is no consensus on the diagnosis or treatment policy for Preperimetric Glaucoma (PPG) because the pathogenesis of PPG is not clear at this time. Preperimetric Glaucoma Prospective Observational Study (PPGPS) is a first multicenter, prospective, observational study to clarify the pathogenesis of PPG. This article indicates study design, patient baseline characteristics, and analysis focused on optic nerve head (ONH) blood flow in PPG, as well as the intraocular pressure (IOP) -lowering effect and ONH blood flow-improving effects of Tafluprost.

Method

In this study, 122 eyes from 122 subjects (mean age: 53.1 ± 14.3) newly diagnosed as PPG were enrolled. The circumpapillary retinal nerve fiber layer thickness (cpRNFLT) was evaluated with optical coherence tomography (OCT). The ONH blood flow was measured with laser speckle flowgraphy. The therapeutic effect of Tafluprost was evaluated at Month 0 (ONH blood flow-improving effect) and Month 4 (IOP-lowering effect).

Results

The untreated IOP, cpRNFLT, and baseline Mean deviation (MD) value was 16.4 ± 2.5 mmHg, 80.4 ± 8.2 μm, and -0.48 ± 1.29 dB, respectively. In the site-specific visual field evaluation using the sector map, there was no appreciable site-specific visual field defect in the eye with PPG. The inferior region of cpRNFLT in 4-quadrant OCT sector analysis and 6 o’clock region in 12-o’clock OCT sector analysis was the highest rate of abnormality in PPG eyes. Topical administration of Tafluprost significantly reduced IOP from 16.4 ± 2.5 mmHg at baseline to 14.5 ± 2.3 mmHg at Month 4 (P < 0.001, paired t-test). In the linear regression analysis, there was a significant relationship between the increase of ONH blood flow and baseline value.

Conclusion

PPGPS is a first prospective study focusing on the pathology of PPG. This study is expected to elucidate the pathology of PPG, with evidence useful for determining a treatment strategy for PPG.

Making Basic Science Studies in Glaucoma More Clinically Relevant: The Need for a Consensus

Glaucoma is a chronic, progressive, and debilitating optic neuropathy that causes retinal damage and visual defects. The pathophysiologic mechanisms of glaucoma remain ill-defined, and there is an indisputable need for contributions from basic science researchers in defining pathways for translational research. However, glaucoma researchers today face significant challenges due to the lack of a map of integrated pathways from bench to bedside and the lack of consensus statements to guide in choosing the right research questions, techniques, and model systems. Here, we present the case for the development of such maps and consensus statements, which are critical for faster development of the most efficacious glaucoma therapy. We underscore that interrogating the preclinical path of both successful and unsuccessful clinical programs is essential to defining future research. One aspect of this is evaluation of available preclinical research tools. To begin this process, we highlight the utility of currently available animal models for glaucoma and emphasize that there is a particular need for models of glaucoma with normal intraocular pressure. In addition, we outline a series of discoveries from cell-based, animal, and translational research that begin to reveal a map of glaucoma from cell biology to physiology to disease pathology. Completion of these maps requires input and consensus from the global glaucoma research community. This article sets the stage by outlining various approaches to such a consensus. Together, these efforts will help accelerate basic science research, leading to discoveries with significant clinical impact for people with glaucoma.

An evidence-based review of unoprostone isopropyl ophthalmic solution 0.15% for glaucoma: place in therapy

Glaucoma is a progressive, neurodegenerative optic nerve disease that can cause significant visual morbidity and affects over 60 million people worldwide. The only known modifiable risk factor for glaucoma at this time is elevated intraocular pressure (IOP), which may be treated with medications, laser therapy, and/or incisional surgery. Topical ocular medications are commonly used as first-line therapy for glaucoma, although side effects may limit their use. Unoprostone is a novel 22-carbon ocular hypotensive agent that may be advantageous in treating some patients with open angle glaucoma or ocular hypertension. Unlike the 20-carbon prostanoids, such as latanoprost, that lower IOP primarily through an increase in uveoscleral outflow, unoprostone may lower IOP through increased aqueous outflow via the conventional trabecular meshwork pathway. Although not as efficacious as other prostanoids, unoprostone is effective for IOP reduction both as monotherapy and adjunctive therapy with timolol. Unoprostone has decreased affinity for the prostaglandin F2α receptor, which may explain its well tolerated ocular and systemic side effect profile compared with other prostanoids.

Evaluation of investigator bias in industry-funded clinical trials of latanoprost

OBJECTIVE

To determine whether sponsorship of prostaglandin analogue (PGA) clinical trials results in investigator bias in outcomes when studying intraocular pressure (IOP).

DESIGN

Retrospective, observational cohort study.

METHODS

A PubMed search was performed for latanoprost or Xalatan, bimatoprost or Lumigan, and travoprost or Travatan, with limits to humans, clinical trials, and English language. Inclusion criteria included randomized controlled trials, open-angle glaucoma, monotherapy with a PGA, baseline IOP ≥ 21 mm Hg, washout period, and minimum 1-month follow-up. Each article was reviewed by 2 independent reviewers. The results of IOP for each PGA were categorized as being sponsored by the parent company (the company manufacturing the PGA); by the competing company (the company manufacturing competing glaucoma therapy); or by a nonindustry source. The mean IOP and changes in IOP from baseline were compared among the 3 categories of sponsorship.

RESULTS

Only studies involving latanoprost were analyzed because of the low number of studies meeting the inclusion criteria for bimatoprost and travoprost. We found 29 and 13 studies that provided 1- and 3-month data, respectively, for analysis. The mean baseline IOPs in the 3 groups (parent company, competing company, nonindustry) were not significantly different (p = 0.47). The mean IOP at 1 (p = 0.72) and 3 months (p = 0.59) and the change in IOP from baseline (p = 0.83 and 0.90, respectively) were not significantly different in the 3 groups. A random-effects metaregression controlling for the covariates of blinding, naïveté to PGAs, and baseline IOP < 24 mm Hg or ≥ 24 mm Hg did not change the findings.

CONCLUSION

There was no evidence of investigator bias in determining outcomes for IOP in these clinical trials of latanoprost.

Aqueous humor concentrations of bimatoprost free acid, bimatoprost and travoprost free acid in cataract surgical patients administered multiple topical ocular doses of LUMIGAN or TRAVATAN

PURPOSE

To quantify the aqueous humor (AH) concentrations of bimatoprost (amide), travoprost (isopropyl ester), and their hydrolysis products, bimatoprost free acid (BFA) and travoprost free acid (TFA), after multiple topical ocular doses of LUMIGAN and TRAVATAN, respectively, in patients awaiting cataract surgery.

METHODS

In 2 separate open-label, sparse-sampling trials, glaucoma patients with cataracts received LUMIGAN (bimatoprost ophthalmic solution, 0.03%) or TRAVATAN (travoprost ophthalmic solution, 0.004%) bilaterally once daily for at least 21 days prior to cataract surgery. Anterior chamber paracentesis was performed at selected times up to 5 h after the last dose and an AH sample was collected. AH samples were assayed by an independent bioanalytical laboratory using a sensitive and validated tandem LC-MS/MS method. The assay lower limits of quantitation were 0.59 nM for bimatoprost, 0.29 nM for BFA, and 0.44 nM for TFA.

RESULTS

AH concentrations of BFA (17-phenyl-trinor PGF(2alpha)) were quantifiable in all but one sample at 0.5 h. The maximum concentration achieved (C(max)) of BFA was 30.9 + or - 16.41 nM (n =5), observed at 2 h postdose. AH concentrations of bimatoprost amide were lower than BFA at all time points, with a C(max) of 6.81 + or - 1.36 nM (n = 7) at 1 h postdose. For TFA, measurable AH concentrations were obtained at all time points with a TFA C(max) of 3.91 + or - 2.27 nM (n = 5), which was observed at 3 h after the dose (all data are mean + or - SEM).

CONCLUSIONS

Once daily topical ocular administration of LUMIGAN or TRAVATAN for 3 weeks resulted in significant concentrations of BFA and TFA in the AH. Quantifiable levels of bimatoprost amide were also measured. Maximum concentrations of BFA (30.9 nM) and TFA (3.91 nM) in the anterior chamber are sufficient to fully activate the FP prostanoid receptors in the target cells of the ciliary muscle and trabecular meshwork. Both bimatoprost in LUMIGAN and travoprost in TRAVATAN are essentially prodrugs that are rapidly hydrolyzed to their respective free acids that induce the IOP-lowering effect observed with both drugs in vivo.

Changes in trend of newly prescribed anti-glaucoma medications in recent nine years in a Japanese local community

Purpose:

To investigate changes in the trend of anti-glaucoma ophthalmic solutions in 2000-2008 in a Japanese local community.

Materials and Methods:

The subjects of this study were patients with glaucoma who were registered in the database of the glaucoma clinic of University of Yamanashi Hospital or the database of the Association for Research in Supporting System of Chronic Diseases (ARSSCD). The trend of newly prescribed anti-glaucoma ophthalmic solutions from January 2000 through July 2008 was analyzed. Changes in the trend of anti-glaucoma ophthalmic solutions and the persistence of each anti-glaucoma ophthalmic solution were investigated.

Results:

A total of 1,955 glaucoma patients were enrolled. Mean intraocular pressure (IOP) significantly reduced by year (R²=0.7938, p<0.001). The number of new prescriptions for analysis in the study period was 7,831. Prostaglandin (PG) analogues accounted for approximately 40% of the prescriptions during the period, and were followed by beta-blockers and carbonic anhydrase inhibitors (CAIs). Those three anti-glaucoma ophthalmic solutions accounted for approximately 90% of all the prescriptions. Latanoprost showed the longest persistence among the anti-glaucoma ophthalmic solutions. The number of newly prescribed anti-glaucoma ophthalmic solutions gradually increased with time.

Conclusions:

PG analogues are the most frequently prescribed and latanoprost showed the longest persistence among the anti-glaucoma ophthalmic solutions. PG analogues, beta-blockers, and CAIs accounted for the majority of newly prescribed anti-glaucoma ophthalmic solutions. An increase in the number of newly prescribed anti-glaucoma ophthalmic solutions may contribute to further IOP reduction.

Predictive value of the efficacy of glaucoma medications in regulatory trials: Phase I-III to post-marketing studies

PURPOSE

To determine the predictive value of early Phase trials (I-II) for the ocular hypotensive efficacy observed in Phases III and IV.

DESIGN

A review of published literature.

METHODS

This study evaluated 12 medicines in 65 articles in the literature with at least two phases available.

RESULTS

For medicines with Phase I results available (n=3), the average reduction in intraocular pressure (IOP) from untreated baseline was 16%, 26% for Phase II, 26% for Phase III, and 24% for Phase IV. For medicines with Phase II results available (n=6), the average reduction in IOP was 23%, 24% for Phase III, and 23% for Phase IV. For medicines with Phase III results available (n=11), the average reduction in IOP was 25% and 24% for Phase IV.

CONCLUSION

This study indicates that early phase trials usually approximated the results of later regulatory studies and post-commercialization trials.

Latanoprost Nonresponders with Open-Angle Glaucoma in the Japanese Population

PURPOSE

As some patients show little response to latanoprost, one of the most powerful topical glaucoma medications, we investigated the incidence and clinical profiles of latanoprost nonresponders (LNR) in the Japanese population.

METHODS

We examined 62 glaucoma patients (62 eyes) who had received only latanoprost for more than 3 months. Their mean age was 63.8 +/- 1.8 years; the mean observation period was 9.7 +/- 0.4 months. At 1, 3, 6, and 12 months, their intraocular pressure (IOP) was measured, and the IOP reduction rate (RR) and the rate of LNR, defined as RR of 10% or less, were calculated. We statistically analyzed clinical factors involved in the LNR status of our study population.

RESULTS

At 1, 3, 6, and 12 months, RR was 20.1 +/- 2.0%, 18.8 +/- 2.3%, 21.1 +/- 2.8%, and 23.0 +/- 2.6%, respectively. At the same time points, the LNR incidence was 23.1%, 28.1%, 23.5%, and 31.8%, respectively, and significantly higher in patients whose baseline IOP was less than 15 mmHg. Patient sex and age and the glaucoma type played no significant role in the LNR status.

CONCLUSIONS

The incidence of LNR in the Japanese population, including normal-tension glaucoma (NTG) patients, is higher than among European or American patients. Only low baseline IOP was a significant clinical factor among LNR.

Intraocular metabolites of isopropyl unoprostone

PURPOSE

It is still unknown which metabolite of isopropyl unoprostone is responsible for reducing intraocular pressure. This study was carried out to measure intraocular metabolites of isopropyl unoprostone in the aqueous humor of primate and human eyes.

METHODS

Nine monkeys were randomly divided into three groups, all of which received isopropyl unoprostone. In group I, the drug was scheduled to be instilled at 0 hr, in group II at 1 hr, and in group III at 2 hr, prior to aqueous humor aspiration in order to determine metabolite concentration. Furthermore, 27 patients scheduled for cataract surgery and intraocular lens implantation were divided into five groups that received isopropyl unoprostone. In group A, the drug was scheduled to be instilled at 0 hr, in group B at 1 hr, in group C at 2 hr, in group D at 3 hr, and in group E at 4 hr, prior to surgery. At the beginning of the operation, the aqueous humor was aspirated. Metabolites of isopropyl unoprostone in the aqueous humor were determined by high-performance liquid chromatography.

RESULTS

M1 (3-[(1R,2R,3R,5S)-3,5-dihydroxy-2-(3-oxodecyl)cyclopentyl]propionic acid) (unoprostone free acid) and M2 ((Z)-7-[(1R,2R,3R,5S)-3,5-dihydroxy-2-(3-oxodecyl)cyclopentyl]hept-5-enoic acid), an intraocular oxidized metabolite of isopropyl unoprostone, were measured. M1:M2 in monkeys was respectively 0:0 ng/ml in group I, 150.2 +/- 45.1:9.5 +/- 1.7 (p < 0.05) in group II, and 74.6 +/- 31.4:19.2 +/- 5.3 (p < 0.01) in group III. M1:M2 in humans was respectively 0:0 ng/ml in group A, 50.6 +/- 22.3:3.2 +/- 1.3 (p < 0.05) in group B, 125.0 +/- 23.1:12.2 +/- 3.4 (p < 0.001) in group C, 144.9 +/- 33.8:24.5 +/- 6.2 (p < 0.01) in group D, and 56.7 +/- 21.5:18.7 +/- 5.3 (p < 0.05) in group E.

CONCLUSIONS

A free acid of isopropyl unoprostone is the major intraocular metabolite of isopropyl unoprostone that is expected to act on target tissues in the eyes of both monkeys and humans.

Effect of Different Dose Schedules of 0.15% Unoprostone Isopropyl on Intraocular Pressure and Pupil Size in the Glaucomatous Beagle

The changes in intraocular pressure (IOP) and pupil size (PS) after instillations of 0.15% unoprostone isopropyl (Rescula, Novartis Ophthalmics, Duluth, GA) were investigated in the spontaneous glaucoma Beagle model. From the first-day baseline IOP of 27.3+/-3.2 mmHg placebo eye and 32.8+/-5.1 mmHg control eye, the mean+/-standard error of the mean (SEM) diurnal changes after 0.15% unoprostone, at 8 AM once-daily for the next 4 days, were 15.5+/-1.3 mmHg, 14.7+/-1.9 mmHg, 16.1+/-1.1 mmHg, and 17.0+/-1.5 mmHg, respectively, and were significantly different from the control eye. After 0.15% unoprostone was instilled at 8 PM, the mean+/-SEM baseline changes from the baseline IOP (insert drug eye 9 AM) in the drug eyes were 5.9+/-2.5 mmHg, 5.2+/-4.1 mmHg, 9.7+/-2.5 mmHg, and 3.6+/-3.6 mmHg, respectively. When 0.15% unoprostone was instilled twice-daily, the mean+/-SEM baseline IOP (insert drug eye 9 AM) changes were 13.6+/-0.7 mmHg, 13.9+/-1.4 mmHg, 11.3+/-1.0 mmHg, and 9.3+/-1.4 mmHg, respectively, and were significantly different from the control eyes. Miosis occurred within 2 hours and lasted several hours. Unoprostone isopropyl instilled once-daily (AM or PM), as well as twice-daily, produces significant decreases in IOP and PS in the glaucomatous Beagle.