Use of fixed-dose combination drugs for the treatment of glaucoma

Triple-fixed Combination of Dorzolamide/Timolol/Brimonidine: Efficacy Study in Bolivian Population

Aim and background

To assess the efficacy of 2% dorzolamide/0.5% timolol/0.2% brimonidine tartrate fixed combination (DTB-FC) eye drops in patients with intermediate glaucoma stage.

Materials and methods

A retrospective case series study was performed, including eyes diagnosed with primary open-angle (POAG) or chronic angle-closure glaucoma (CACG), which were at intermediate stage of the illness according to the Brusini grading system and were initially treated with 2% dorzolamide/0.5% timolol fixed combination (DT-FC), and switched at baseline to DTB-FC. Main outcome was intraocular pressure (IOP) baseline measured, as well as at weeks 1 and 2, months 1, 3, and 6, and 1 year after switching. IOP differences were analyzed using analysis of variance (ANOVA) repeated measures.

Results

A total of 36 eyes from 22 patients were included in the study. The median age of the participants was 61 years [interquartile range (IQR) 53-71], with 59.1% (n = 13) being female. At baseline, 1, 2 weeks, 1, 3, 6 months, and 1 year after switching to DTB-FC, the mean IOP values were 20.3 (95% CI, 19.5-21.1), 15.3 (95% CI, 14.5-16.1), 15.5 (95% CI, 14.7-16.2), 15.5 (95% CI, 14.8-16.0), 15.5 (95% CI, 14.9-16.2), 15.5 (95% CI, 14.8-16.2) and 15.3 (95% CI, 14.7-15.9) mm Hg, respectively (p > 0.001). The mean IOP reduction after 1 year of treatment was -5.0 ± (4.2-5.8) mm Hg. Treatment success rates were 86.1, 80.6, 80.6, 77.8, 72.2, and 66.7%, respectively. When stratified by diagnosis, there were no statistically significant differences in the treatment success rates between POAG and CACG (p > 0.05).

Conclusion

Therapy switching from DT-FC to DTB-FC was shown to be effective in reducing IOP of eyes with POAG or CACG during 6-12 months.

Clinical significance

The DTB-FC therapy improved the therapeutic management of POAG or CACG previously treated with DT-FC therapy, which may be relevant to prevent its progression in the future.

How to cite this article

Justiniano JM, Rodríguez GM, Passerini MS. Triple-fixed Combination of Dorzolamide/Timolol/Brimonidine: Efficacy Study in Bolivian Population. J Curr Glaucoma Pract 2024;18(4):137-141.

Understanding the treatment paradigm and the sequencing of antiglaucoma fixed-dose combinations in a tertiary center in South India

PURPOSE

To analyze the medical management of primary open-angle glaucoma (POAG) and ocular hypertension (OHT) and the placement of fixed-drug combination drugs (FDC) in the treatment paradigm at a tertiary eye care center in South India.

METHODS

Retrospective study (January 2011-December 2015) of newly diagnosed POAG and OHT patients (≥18 years) with ≥5 years follow-up. Primary outcome included percentage use of different antiglaucoma drugs (at initiation) and FDCs at the first, second, and third progression (sequencing). Secondary outcomes: Percentage discontinuation for different FDCs, efficacy parameters (decrease in intraocular pressure (IOP)/visual field), adverse events, and the median number of antiglaucoma medications (AGMs) after 5 years.

RESULTS

Three hundred and seventy eyes (198 patients) were analyzed; 84% of them had POAG. Prostaglandin analogs (PGAs) were the most common (66.2%). FDCs were started in 48 eyes (12.9%), with brimonidine + timolol combination being the most common. FDC usage at subsequent modifications was 10.1%, 24.04%, and 30.0%. Beta-blockers and PGAs were the most frequently prescribed AGMs in our practice pattern, with β-blockers being the most consistent one.

CONCLUSION

This study is a fairly large study with a minimum of a 5-year follow-up of patients with POAG and OHT and gives insights into the treatment patterns, use of FDCs, and the need for multiple medications over time.

Additive effects of brimonidine tartrate 0.1%/brinzolamide 1% fixed-dose combination in prostaglandin analog-treated Japanese glaucoma patients

PURPOSE

A brimonidine tartrate 0.1%/brinzolamide 1% fixed-dose combination (BBFC) was recently approved for glaucoma and ocular hypertension treatment in Japan. We investigated the efficacy and safety of BBFC used concomitantly with prostaglandin analogs (PG) or a PG/beta-blocker fixed-dose combination (PG/beta FC).

STUDY DESIGN

This was a prospective, open-label, multicenter study.

PATIENTS AND METHODS

We enrolled Japanese patients with open-angle glaucoma. BBFC (Ailamide) was concomitantly administered to either the PG or the PG/beta FC group, and intraocular pressure (IOP) and safety were evaluated at 4 and 12 weeks. The groups were stratified into low and high IOP baseline groups based on the median baseline IOP.

RESULTS

We enrolled 100 patients, 91 of whom completed the 12-week follow-up. The mean ages were 67.1 and 65.7 years in the PG group (n = 45, baseline IOP of 15.7 ± 2.3 mmHg) and the PG/beta FC group (n = 46, baseline IOP of 16.3 ± 2.3 mmHg), respectively. After BBFC administration, IOPs at 4 and 12 weeks were 13.0 ± 2.0 and 13.0 ± 2.6 mmHg (P < 0.0001) in the PG group, respectively, and 13.7 ± 2.4 and 13.7 ± 2.2 mmHg (P < 0.0001) in the PG/beta FC group, respectively. IOP decreased by - 2.0 ± 1.8 mmHg (P < 0.0001) and -1.9 ± 1.4 mmHg (P < 0.0001) in the low baseline PG group (14.1 mmHg) and low baseline PG/beta FC group (14.8 mmHg) at 12 weeks, respectively. Sixteen adverse events were identified, all of which were common and did not affect visual acuity.

CONCLUSIONS

BBFC can be used concomitantly with PG or PG/beta FC to reduce IOP without serious complications.

Hot-melt extruded in situ gelling systems (MeltDrops Technology): Formulation development, in silico modelling and in vivo studies

In situ gelling systems (ISGS) can prolong retention time and bioavailability of ophthalmic solutions. The complexity and cost of ISGS avert their industrial scale-up and clinical implementation. In this study, we demonstrate novel application of hot-melt extrusion (HME) technology for continuous manufacturing of ISGS (MeltDrops Technology). Timolol maleate (TIM) and dorzolamide hydrochloride (DRZ) loaded MeltDrops were successfully developed using HME for glaucoma management, thereby resolving issues with batch manufacturing of ISGS, prolonging retention time thus improving bioavailability. The MeltDrops technology involves one-step, i.e., passing all the ingredients through an extruder at a screw speed between 20-50 rpm and barrel temperature of 80 °C. The comparative evaluation of MeltDrops and batch-processed ISGS demonstrated that MeltDrops exhibited better physical and chemical content uniformity. The extrusion temperature and screw speed were critical factors influencing content uniformity and properties of the MeltDrops. MeltDrops showed sustained drug release for >12 hours in vitro (TIM= 83.07%; DRZ = 60.43%, 12hours) versus marketed eyedrops. The developed MeltDrops followed Peppas-Sahlin model, combining Fickian diffusion and swelling processes. The in vivo study in New Zealand rabbits revealed superior effectiveness and safety of the MeltDrops as compared to the marketed eyedrops. Herein we conclude, MeltDrops would serve as a cutting-edge platform technology that can be used to manufacture various ISGS with one-step processability, cost-effectiveness, and improved product quality, which are otherwise processed by batch manufacturing that involves numerous complex processing steps.

Clinical Practice Management of Primary Open-Angle Glaucoma in the United States: An Analysis of Real-World Evidence

PURPOSE

To investigate clinical management of primary open-angle glaucoma (POAG) in the United States using real-world evidence and to examine healthcare resource utilization (HCRU), medication adherence/persistence, and procedure use.

DESIGN

A cross-sectional, retrospective analysis of Optum's de-identified Market Clarity Dataset (July 1, 2013-December 31, 2019).

PATIENTS AND METHODS

Patients ≥18 years with POAG diagnosis and continuous enrollment for 1-year pre- and post-index were eligible and categorized into four mutually exclusive cohorts: CH1, treated with antiglaucoma medication(s) only; CH2, underwent glaucoma procedure(s) only; CH3, treated with antiglaucoma medication(s) and underwent procedure(s); and CH4, received no treatment for POAG. Adherence and persistence with antiglaucoma medications, and disease-specific HCRU were analyzed. Pairwise two-sample comparisons and multivariate regressions were conducted.

RESULTS

Examined 232,572 eligible patients (CH1=60,895; CH2=4330; CH3=6027; CH4=161,320). Prostaglandin analogs were most prescribed antiglaucoma medications (CH1: 69.7%; CH3: 62.7%), of which latanoprost was most common (CH1: 51.3%; CH3: 46.1%). Disease-specific office visits occurred in 26.3%, 78.2%, 75.0%, 23.8%, and surgical services visits occurred in 3.8%, 36.3%, 42.5%, 3.3%, in CH1-CH4, respectively. Adherence was higher (medication possession ratio: 47.1% vs 39.4%; P<0.0001), and more patients remained persistent across 1-year post-index period in CH1 vs CH3 (25.4% vs 16.1%; P<0.0001). Positive predictors of medication persistence included being female, ≥55 years, and history of dyslipidemia or thyroid disease (all P≤0.0003).

CONCLUSION

Overall, 70% POAG patients might not have received antiglaucoma treatment. Since POAG is a slowly progressive blinding disease, the lack of antiglaucoma treatment and suboptimal adherence/persistence with medications are of major concerns. Targeted screening and educational approaches are needed to improve POAG management.

The use of fixed dose drug combinations for glaucoma in clinical settings: a retrospective, observational, single-centre study

BACKGROUND

The aim of study was to understand anti-glaucoma fixed dose drug combination use in real-world settings, focussing on drug selection, repeated prescription of the same active ingredient, and administration of fixed dose combinations, thus providing a reference for doctors during prescription and pharmacists during prescription review, ultimately educating patients on medication.

METHODS

A retrospective, observational, single-centre study was conducted. Outpatient prescriptions for anti-glaucoma eye drops from 01 January to 31 March 2021 were extracted. The prescriptions containing anti-glaucoma fixed dose combinations were analysed, and the rationale for each prescription was reviewed.

RESULTS

There were 10,947 ophthalmic patients with anti-glaucoma eye drop prescriptions in the study period. Of these, 4002 (36.5%) were prescribed anti-glaucoma fixed dose drug combinations. Approximately 80% of the patients were prescribed brinzolamide/timolol, while about 10% received prostaglandin analogues/timolol eye drops. Less than 40% of prescriptions were for monotherapy with fixed dose combinations. The most commonly duplicated drug class was β-receptor antagonists. An increase in prescribing drugs containing the same ingredient was observed for regimens containing various medicines.

CONCLUSION

More than 60% of the combinations were used together with other anti-glaucoma drugs. The advantages of these fixed dose combinations in improving patient compliance need to be reassessed in real-word settings. Prescriptions containing duplicated ingredients were common. However, they were not necessarily considered unreasonable because the dosage forms were administered at different times. For prescriptions containing repetitive ingredients, pharmacists should judge the rationale by evaluating the dosing frequency and drug indications and explain the appropriate administration to patients.

Simultaneous determination of dorzolamide and timolol by first-order derivative UV spectroscopy in simulated biological fluid for in vitro drug release testing

Dorzolamide hydrochloride and timolol maleate is a well-established fixed-dose combination for the treatment of glaucoma worldwide. The utilization of simulated biological fluids can give a superior understanding of the release mechanisms and practicable in vivo nature of a dosage form that can improve the predictive potential of in vitro drug release testing. No method has been reported so far for the simultaneous estimation of dorzolamide and timolol in simulated tear fluid. In the present study, a simple, precise, and accurate first-order derivative ultraviolet spectrophotometric method for the routine analysis of dorzolamide and timolol in simulated tear fluid is proposed for in vitro drug release testing. The developed method was validated as per International Conference on Harmonization guidelines Q2 (R1). First-order derivative UV spectrophotometry was successfully applied to separate the overlapping peaks of dorzolamide and timolol by measuring peak amplitude at 251.80 nm and absorbance at 295.00 nm, respectively. The method was found to be accurate and precise, with a recovery range of 98.0 -101.0% and low relative standard deviations (<2.0%). The developed method was successfully applied for in vitro drug release testing of in-house in situ gel and marketed eye drops containing dorzolamide and timolol. Various mathematical models were adopted to fit the in vitro drug release profile. It was observed that the drug release of both drugs from the in situ gel and the marketed solution were best fitted by the Higuchi and first-order kinetic models, respectively. Moreover, the analysis of variance (ANOVA) provision was used for the validation of results. Overall, with the advantages of simple and fast operations, as well as reliability, the proposed method offers an ideal platform for routine analysis as compared to other high-cost and time-consuming chromatographic techniques. Having access to such a robust method will encourage the use of simulated tear fluid for in vitro drug release testing of ocular products and help to predict the in vivo performances of ophthalmic preparations.

Dorzolamide/Timolol Fixed Combination: Learning from the Past and Looking Toward the Future

The key clinical attributes of preserved dorzolamide/timolol fixed combination (DTFC) and the emerging potential of preservative-free (PF) DTFC are reviewed with published evidence and clinical experience. The indications and role of DTFC in current glaucoma management are critically discussed. Preserved DTFC became the first intraocular pressure (IOP)-lowering fixed combination (FC) approved by the US Food and Drug Administration (FDA) and remains one of most commonly used medications worldwide. The pharmacological properties of DTFC reflect those of its two time-tested constituents, i.e., the carbonic anhydrase inhibitor dorzolamide and the non-selective beta-blocker timolol. In regulatory studies DTFC lowers IOP on average by 9 mmHg (32.7%) at peak and by 7.7 mmHg (27%) at trough. In trials DTFC shows equivalence to unfixed concomitant therapy, but in real-life practice it may prove superior owing to enhanced convenience, elimination of the washout effect from the second drop, improved tolerability, and better adherence. PF DTFC became the first PF FC approved, first in unit-dose pipettes, and more recently in a multidose format. Cumulative evidence has confirmed that PF DTFC is at least equivalent in efficacy to preserved DTFC and provides a tangible clinical benefit to patients with glaucoma suffering from ocular surface disease by improving tolerability and adherence. Finally, we identify areas that warrant further investigation with preserved and PF DTFC

Maximum Medical Therapy: Brinzolamide/Brimonidine And Travoprost/Timolol Fixed-Dose Combinations In Glaucoma And Ocular Hypertension

Introduction

Maximal medical therapy (MMT) is the use of ≥3 classes of topical anti-glaucoma agents to achieve maximal intraocular pressure (IOP) reduction while minimizing adverse effects and compliance challenges.

Purpose

To evaluate the additive IOP-lowering effect of twice-daily brinzolamide 1%/brimonidine 0.2% fixed-dose combination (BBFC) used adjunctively with once daily travoprost 0.004%/timolol 0.5% fixed-dose combination (TTFC) in patients with open-angle glaucoma (OAG)/ocular hypertension (OHT).

Methods

In this phase IV, double-masked study, patients on TTFC for ≥28 days, aged ≥18 years, with mean IOP ≥19 and ≤28 mmHg in at least 1 eye were randomized to receive BBFC+TTFC (n=67) or vehicle+TTFC (n=67) for 6 weeks. The primary endpoint was mean change in diurnal IOP from baseline (BL, averaged over 09:00 and 11:00) at Week 6.

Results

The study was terminated prematurely due to recruitment challenges. BL mean IOP was similar in both groups (BBFC+TTFC: 21.6±1.78 mmHg; vehicle+TTFC: 21.8±1.90 mmHg). Mean change in diurnal IOP from BL at Week 6 was greater with BBFC+TTFC (−4.25 mmHg, 95% confidence interval [CI]: −4.7, −3.8) than with vehicle+TTFC (−2.11 mmHg, 95% CI: −2.6, −1.6, treatment difference, −2.15 mmHg (95% CI: −2.8, −1.5; P<0.001). Ocular adverse events (AEs) were reported in 11.9% of patients given BBFC+TTFC and 7.5% of patients given vehicle+TTFC. The AE with highest frequency was punctate keratitis (3%) in the BBFC+TTFC group; eye irritation (3%) in the vehicle+TTFC group.

Conclusion

BBFC+TTFC as MMT demonstrated clinically relevant and statistically significant reductions in mean diurnal IOP in patients with OAG/OHT. AEs were consistent with known safety profiles of individual medications.

Efficacy of the combination of carteolol hydrochloride + latanoprost in the treatment of glaucoma and ocular hypertension

INTRODUCTION

The only evidence-based mechanism for prevention and treatment of glaucomatous optic neuropathy is decreasing the intraocular pressure (IOP). Prescribing multiple ocular hypotensive agents, such as the combination of carteolol and latanoprost, may synergistically improve IOP; however, doing so may increase the complexity of a medication regimen, in turn, impairing patient adherence. Fixed-combination glaucoma medications offer convenience and effectiveness. New to this class of glaucoma medication is fixed combination carteolol-latanoprost (FCCL). Area covered: This review intends to give the reader a better understanding of the efficacy of the combination of carteolol and latanoprost separately, and where FCCL fits into the vast medical arsenal of IOP drops. Furthermore, it outlines the particular pharmacologic mechanisms targeted, the pharmacokinetics, effectiveness, the advantages of fixed-combination administration, and tolerability. Expert opinion: The combination of carteolol and latanoprost, separately or in a fixed-combination, is more effective than either drug alone. Given the early stage in development of FCCL, it has yet to be determined how FCCL compares to other fixed-combination medications. However, pending further approval, fixed-combination carteolol-latanoprost may represent a reasonable alternative for a patient whose IOP is inadequately controlled on a prostaglandin analog alone and for whom a simplified combination is preferred.

[The role of fixed dose combinations in the treatment of primary open-angle glaucoma]

A great number of patients with primary open-angle glaucoma require combination therapy with several hypotensive drugs of different pharmacological groups to efficiently compensate the intraocular pressure (IOP) and prevent further development of glaucoma. Although glaucoma treatment usually starts with monotherapy, several preparations administered simultaneously have stronger hypotensive effect further increased by their additive action. However, the increased frequency of instillations may lead to drug washout and decreased patient compliance. Fixed dose combinations (FDCs) are a pharmacological form of eye drops that combines two or more active drugs in a single dosage form. The frequency of FDCs administration does not exceed two per day, which is convenient for long-term application and helps improve patient compliance. FDCs tolerability tends to be higher than that of simultaneous instillations of separate monotherapy drugs, while the hypotensive in clinical trials is comparable, in some real practice trials is superior. A review of existing studies showed that FDCs are superior to monotherapy in terms of cost-effectiveness. The use of FDCs was found to be beneficial for glaucoma treatment from the viewpoints of both reaching the target IOP for preserving visual functions in glaucoma patients, and minimizing the long-term treatment costs.

Adhering to the principles of clinical pharmacology - the correct fixed combinations of antihypertensive drugs

INTRODUCTION

Hypertension is one of the primary modifiable risk factor for cardiac and renal diseases with the prevalence around 30-45% of the general population, with a steep increase with ageing. The administration of blood pressure-lowering drugs is to reduce the risk of major clinical cardiovascular outcomes. Hypertension guidelines recommend combination therapy in patients with high cardiovascular risk and with subclinical organ damage as well as when monotherapy fails. Areas covered: As the etiology of essential hypertension is multifactorial, combination therapy using different classes of antihypertensive agents have greater effect than each on its own (synergistic effect), may have better tolerability (two components minimizing each other's side effects) and lead to improved patient compliance. Several studies assess the hypotensive efficacy on drug combination; there are also studies on triple drug combination. Expert commentary: At present, dual and triple combination therapy is available to hypertensive patients with good clinical outcomes, compliance and low profile of side effects. It is critical as patients' adherence to the pharmacological therapy significantly decreases the risk of long-term adverse events including mortality. It appears that combinations not only of hypotensive drugs but also with statins (as well as antidiabetics) will be widely used.

A Masked, Randomized, Phase 3 Comparison of Triple Fixed-Combination Bimatoprost/Brimonidine/Timolol versus Fixed-Combination Brimonidine/Timolol for Lowering Intraocular Pressure

OBJECTIVE

To evaluate the efficacy and safety of triple fixed-combination bimatoprost 0.01%/brimonidine 0.15%/timolol 0.5% (TFC) versus dual fixed-combination brimonidine 0.2%/timolol 0.5% (DFC) in primary open-angle glaucoma and ocular hypertension.

METHODS

Patients with intraocular pressure (IOP) ≥23 and ≤34 mmHg were randomized to twice-daily TFC or DFC. The primary variable is the change in worse eye mean IOP from baseline at week 12 (modified intent-to-treat (mITT) population). Secondary endpoints are mean IOP and mean change from baseline at weeks 1, 2, 4, 8, and 12 (mITT population). TFC superiority was demonstrated if the primary variable favored TFC (p ≤ 0.05). Sensitivity analyses were conducted, and safety was assessed at all visits.

RESULTS

TFC (n = 93) provided greater IOP reductions from baseline than DFC (n = 97) at week 12 (treatment difference, 0.85 mmHg; p = 0.028) and all other visits. TFC was also superior to DFC in patients with high baseline IOP (i.e., IOP ≥ 25 mmHg; p ≤ 0.011). Conjunctival hyperemia, ocular irritation, and dry eye were reported more often with TFC (p ≤ 0.016); however, discontinuations for ocular adverse events were similar between treatments.

CONCLUSIONS

TFC demonstrated IOP-lowering benefits that outweigh the risk of predominantly mild ocular side effects, which may be particularly relevant in patients who require greater IOP lowering to prevent/delay disease progression. This trial is registered with ClinicalTrials.gov registry number: NCT01241240.

Selective Laser Trabeculoplasty vs. Fixed Combinations with Timolol in Practice: A Replacement Study in Primary Open Angle Glaucoma

OBJECTIVES

To evaluate the potential of selective laser trabeculoplasty (SLT) in two arms (360˚ vs. 180˚) as a replacement for fixed combinations (FCs) with timolol in primary open angle glaucoma over 6 months.

MATERIALS AND METHODS

Of 40 patients in a prospective, comparative, interventional case series, 18 eyes and 22 eyes were randomized to SLT 180º and SLT 360º groups, respectively, along with 40 fellow-control eyes. FC with timolol was discontinued on the day of treatment for the eye to be operated on, while ongoing therapy was not interrupted for the contralateral eye. Eyes were examined for intraocular pressure (IOP) elevation 1 hour and 1 day after SLT. The follow-up visits were then scheduled for 1 week, 1 month, 3 months, and 6 months after, during the which the IOP of both eyes and any possible complications were evaluated.

RESULTS

There were no statistically significant differences in mean IOPs through 6 months among the groups with exception of postlaser 1 hour and postlaser 1 day (p<0.001 and p=0.010, respectively). Multiple comparison analysis showed significantly higher IOP in both SLT 180º and SLT 360º subgroups compared to their controls at postlaser 1 hour (p=0.007, p<0.001) but significantly lower IOP only in SLT 360º subgroup compared to the controls at postlaser day 1 (p=0.013).

CONCLUSION

SLT offers promising potential as a substitute equivalent to efficacy of FCs with timolol. However, SLT 360˚ may not achieve additional IOP reduction.

Prescribing Trends in a Glaucoma Clinic and Adherence to EGS Guidelines: A Retrospective, Non-Interventional, Single-Center UK Study

INTRODUCTION

The purpose of this study was to determine prescribing trends in a specialist glaucoma clinic in the UK. Specifically, the aims were to determine which drugs were prescribed as first-, second-, and third-line treatment, the persistence of first-, second-, and third-line treatment regimens, and the proportion of treatment decisions conforming to the European Glaucoma Society (EGS) guidelines.

METHODS

A retrospective, non-interventional, single-center, case-note review was performed on a cohort of consecutive patients presenting to a specialist glaucoma clinic for follow-up. Inclusion criteria for the study were (1) a diagnosis of primary open-angle glaucoma or ocular hypertension, (2) glaucoma management entirely within the unit, and (3) minimum of 2 years of follow-up.

RESULTS

A total of 114 case notes met the inclusion criteria. Mean age was 71 years (range 40-95 years). Mean length of follow-up was 56 months (range 24-180 months). Prostaglandin analogues (PGA) were the most popular first-line treatment in 73% of patients. As second-line treatment, PGA were again the predominant class, prescribed in 87% of cases, whereas beta-blockers (BB) were prescribed in 70% of cases. Carbonic anhydrase inhibitors (CAI) and alpha-2 agonists (AA) were more popular in third-line regimens. Second-line treatment was introduced at a mean of 28.0 months after first-line treatment (range 1-120 months, 95% CI 22.1-33.9 months). Third-line treatment was introduced at a mean of 22.9 months after second-line treatment (range 1-96 months, 95% CI 17.1-28.8 months). Breaches to EGS guidelines were most common for third-line treatment and included duplication of drug classes.

DISCUSSION

There was a clear hierarchy of PGA as first-line, BB as second-line, while CAI and AA were considered third-line choices. First-line choices were generally in line with EGS guidelines. There was a tendency to breach guidelines by escalating treatment in dual steps rather than single steps (especially in third-line treatment). Combination drops were popular. In third-line treatment there was an increased incidence of prescribing errors. This data is important in terms of informing patients of the expected treatment course, to remind clinicians about best practice, and also to guide comparisons of cost-effectiveness with other treatment modalities.

Challenges for the pharmaceutical technical development of protein coformulations

Objectives

This review discusses challenges to stability, analytics and manufacturing of protein coformulations. Furthermore, general considerations to be taken into account for the pharmaceutical development of coformulated protein drug products are highlighted.

Key findings

Coformulation of two or more active substances in one single dosage form has recently seen increasing use offering several advantages, such as increased efficacy and/or the overall reduction of adverse event incidents in patients. Most marketed coformulated drug products are composed of small molecules. As proteins are not only comparatively large but also complex molecules, the maintenance of their physicochemical integrity within a formulation throughout pharmaceutical processing, storage, transport, handling and patient administration to ensure proper pharmacokinetics and pharmacodynamics in vivo already represents various challenges for single-entity products. Thus, nowadays, only sparse biologics-based coformulations can be found, as additional complexity during development is given for these products.

Summary

The complexity of the dosage form and the protein molecules results into additional challenges to formulation, manufacture, storage, transport, handling and patient administration, stability and analytics during the pharmaceutical development of protein coformulations. Various points have to be considered during different stages of development in order to obtain a safe and efficacious product.

Evaluation of the effects on choroidal thickness of bimatoprost 0.03% versus a brinzolamide 1.0%/timolol maleate 0.5% fixed combination

OBJECTIVE

To investigate the effects of two different medical treatment options on choroidal thickness (CT) in cases of open-angle glaucoma (OAG).

METHODS

Sixty-seven eyes newly diagnosed with OAG and 52 healthy eyes constituting the control group were included in the study. Glaucomatous eyes were randomly divided into two subgroups; Group I was started on bimatoprost 0.03% and Group II on a brinzolamide 1.0%/timolol maleate 0.5% fixed combination (BTFC). Intraocular pressure (IOP), ocular pulse amplitude (OPA) and subfoveal CT measurements were performed in all eyes in the study before treatment and on weeks 2, 4 and 8 after treatment.

RESULTS

Mean initial IOP values in groups I and II and the control group were 25.5 ± 4.7, 25.1 ± 5.2 and 16.1 ± 2.9 mmHg, mean OPA values were 3.7 ± 1, 3.6 ± 1.4 and 2.4 ± 0.6 mmHg and mean CT values were 269.4 ± 83, 264.5 ± 84.4 and 320.1 ± 56.6 μm, respectively. Eight weeks after treatment, mean IOP values in Groups I and II and the control group were 18.3 ± 2.6, 18.1 ± 3.4 and 15.7 ± 2.9 mmHg, mean OPA values were 2.9 ± 1.2, 2.8 ± 1.5 and 2.3 ± 0.8 mmHg and mean CT values were 290.2 ± 87.3, 271.8 ± 82.5 and 319.3 ± 56.8 μm, respectively. No significant difference was determined in terms of the decrease in IOP and OPA obtained after treatment in Group I and Group II. However, a significant difference was observed between the two groups in terms of choroidal thickening after treatment.

CONCLUSION

The use of topical ocular hypotensive medication in eyes with OAG results in an increase in CT. This increase is relatively greater with bimatoprost 0.03% therapy compared to BTFC.

Preservative-free bimatoprost 0.03%/timolol 0.5% fixed combination in patients with glaucoma in clinical practice

Purpose

The aim of this study was to evaluate the efficacy and tolerability of, and compliance to, preservative-free (PF), fixed-combination (FC) bimatoprost 0.03%/timolol 0.5% in patients with primary open-angle glaucoma or ocular hypertension in a clinical practice setting.

Patients and methods

This open-label study observed patients switched to PF FC bimatoprost 0.03%/timolol 0.5% due to insufficient intraocular pressure (IOP) control on previous therapies. IOP was measured at baseline and at ~12 weeks. Tolerability and continuation of therapy were also assessed.

Results

A total of 1,553 patients were included in the study, and the per-protocol population comprised 1,391 patients. There were some minor deviations from protocol: some patients with no prior therapy and some who switched for reasons other than insufficient IOP control were included in the analysis. The mean IOP was reduced by 27.4%, from 22.2 mmHg to 16.1 mmHg. In subgroup analyses, the mean IOP was significantly reduced from baseline, irrespective of whether previous treatment was monotherapy or combination therapy, and preserved or PF therapy. Physicians mostly (88.1%) reported the IOP-lowering efficacy of PF FC bimatoprost 0.03%/timolol 0.5% to be as expected or better than expected. Switching to PF FC bimatoprost 0.03%/timolol 0.5% resulted in reductions from baseline in the number of patients reporting ocular symptoms. Adverse events were reported by 6.2% of patients, the most common being eye irritation (1.6%) and eye pruritus (1.0%). Physicians reported treatment compliance as better or unchanged compared with prior treatment in almost all patients (93.9%). Most patients were expected to continue PF FC bimatoprost 0.03%/timolol 0.5% after the end of the study.

Conclusion

Switching to PF FC bimatoprost 0.03%/timolol 0.5% was associated with significant IOP reductions from baseline over 12 weeks. Adverse events were uncommon, and compliance was high compared with previous therapy. PF FC bimatoprost 0.03%/timolol 0.5% may be a suitable treatment for patients with inadequately controlled IOP or who are sensitive to preservatives.

Fixed-combination treatments for intraocular hypertension in Chinese patients - focus on bimatoprost-timolol

Glaucoma is a common eye disease that can lead to irreversible vision loss if left untreated. The early diagnosis and treatment of primary open-angle glaucoma is challenging, and visual impairment in Chinese glaucoma patients is a serious concern. Most of these patients need more than one topical antiglaucoma agent to control their intraocular pressures (IOPs). In the People’s Republic of China, the daily cost of different glaucoma medication varies greatly, and the treatment habits differ throughout the country. Prostaglandin analogs (PGAs) are recommended as first-line monotherapy, because of their efficacy and low risk of systemic side effects. Fixed-combination drops, particularly PGA-based fixed combinations, have recently been developed and used in patients with progression or who have failed to achieve their target IOPs. Here, we reviewed the current literature on the use of bimatoprost-timolol fixed combination (BTFC) in the People’s Republic of China. BTFC has achieved good efficacy and tolerability in Chinese clinical trials. In addition, BTFC is more cost effective compared with other fixed combinations available in the People’s Republic of China. Fixed-combination drops may offer benefits, such as keeping the ocular surface healthy, convenience of administration, and improvement in long-term adherence and quality of life. Therefore, BTFC has great potential for the treatment of Chinese glaucoma patients. However, the long-term efficacy of BTFC, comparisons of BTFC with other fixed-combination drugs, and treatment adherence and persistence with treatment in Chinese patients are unknown and will require further study.

Systems Pharmacology Links GPCRs with Retinal Degenerative Disorders

In most biological systems, second messengers and their key regulatory and effector proteins form links between multiple cellular signaling pathways. Such signaling nodes can integrate the deleterious effects of genetic aberrations, environmental stressors, or both in complex diseases, leading to cell death by various mechanisms. Here we present a systems (network) pharmacology approach that, together with transcriptomics analyses, was used to identify different G protein-coupled receptors that experimentally protected against cellular stress and death caused by linked signaling mechanisms. We describe the application of this concept to degenerative and diabetic retinopathies in appropriate mouse models as an example. Systems pharmacology also provides an attractive framework for devising strategies to combat complex diseases by using (repurposing) US Food and Drug Administration-approved pharmacological agents.

Efficacy and tolerability of fixed-combination bimatoprost/timolol versus fixed-combination dorzolamide/brimonidine/timolol in patients with primary open-angle glaucoma or ocular hypertension: a multicenter, prospective, crossover study

BACKGROUND

Fixed-combination ocular hypotensives have multiple advantages, but triple-therapy dorzolamide/brimonidine/timolol (dorz/brim/tim) is only available in Latin and South America, and information on its relative efficacy is limited. This study compares the efficacy and tolerability of fixed-combination bimatoprost/timolol (bim/tim) and dorz/brim/tim in Mexican patients with primary open-angle glaucoma or ocular hypertension.

METHODS

In this investigator-masked, crossover study, patients with unmet target intraocular pressure (IOP) on once-daily bim/tim or twice-daily dorz/brim/tim received the opposite medication for 3 months before returning to their pre-baseline medication for 3 months. IOP was evaluated before and after morning instillation at months 2, 3, 5 and 6. Primary endpoints were mean IOP change and Ocular Surface Disease Index© (OSDI) score at each visit. The intent-to-treat population was the a priori analysis population, but due to the number of discontinuations, the per-protocol and intent-to-treat populations were used for the primary efficacy and sensitivity analyses, respectively.

RESULTS

Seventy-eight and 56 patients were included in the intent-to-treat and per-protocol populations, respectively. At month 3, statistically significant IOP reductions from baseline were observed in the bim/tim (P < 0.01) and dorz/brim/tim (P < 0.0001) groups, regardless of assessment time. At month 6, patients returned to bim/tim exhibited no significant IOP increase (regardless of assessment time), but patients returned to dorz/brim/tim exhibited a statistically significant IOP increase (P < 0.001) when assessed before instillation of study treatment. Results were similar in both intent-to-treat and per-protocol analysis populations. In the per-protocol analysis, 70% of patients on bim/tim at month 3 had an IOP <14 mm Hg, which declined to 58% (P = 0.0061) at month 6 (ie, after 3 months of dorz/brim/tim treatment). In patients receiving dorz/brim/tim at month 3, 38% had an IOP <14 mm Hg, which remained comparable after return to bim/tim. OSDI scores and incidence of adverse events were similar in both groups.

CONCLUSIONS

In this first direct comparison of the efficacy of dorz/brim/tim and bim/tim, patients switched from dorz/brim/tim to bim/tim demonstrated improved/lower IOP; when returned to dorz/brim/tim, IOP increased to levels seen at study initiation, suggesting that once-daily bim/tim may have greater IOP-lowering efficacy. Both bim/tim and dorz/brim/tim were well tolerated with minimal ocular surface damage.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01737853 (registered October 9, 2012).

Brinzolamide plus brimonidine for the treatment of glaucoma: an update

INTRODUCTION

Glaucoma is a common sight-threatening condition that is primarily treated by lowering intraocular pressure (IOP). Today the mainstay of treatment is topical ocular hypotensive medications; many patients require more than one agent to achieve target IOP. For such patients, fixed combination formulations have several advantages including simplicity of treatment regimen, adherence to the treatment regimen, efficacy, improved ocular surface comfort and reduced cost. All currently available fixed combinations contain a β-blocker, which is contraindicated in some patients. Hence there is a clinical need for fixed-combination preparations without a β-blocker. This paper reviews the current literature on a new fixed-combination drug containing brinzolamide 1% and brimonidine 0.2% (BBFC).

AREAS COVERED

A PubMed, Embase and ClinicalTrials.gov registry search was performed to identify all relevant studies. Four published clinical papers pertaining to three randomized controlled trials were identified for review. All studies demonstrated a significant reduction (p < 0.01) in mean IOP in patients administered with BBFC compared with its individual components, brinzolamide 1% or brimonidine 0.2%. Adverse effects from BBFC were no different from each of the individual components, the most common being blurred vision, eye irritation and dysgeusia (abnormal taste sensation). Although BBFC use was associated with more adverse effects compared with the individual components used as monotherapy (p < 0.001), the cumulative adverse effect profile from BBFC did not appear greater than one would expect from the simultaneous use of the two components.

EXPERT OPINION

BBFC is a potential alternative to other fixed-combination medications and is especially useful when topical β-blockers are contraindicated. Longer-term experience will determine if additional adverse effects occur or if efficacy is maintained over longer periods.

The safety and efficacy of brinzolamide 1%/timolol 0.5% fixed combination versus dorzolamide 2%/timolol 0.5% in patients with open-angle glaucoma or ocular hypertension

PURPOSE

The aim of this study was to compare the intraocular pressure (IOP) lowering efficacy and to determine patient preference based on ocular discomfort with fixed combination brinzolamide/timolol and fixed combination dorzolamide/timolol in patients with open-angle glaucoma or ocular hypertension who required a change in therapy due to elevated IOP while receiving IOP-lowering medication.

METHODS

This was a 3-month, randomized, double-blinded, active-controlled, parallel-group trial. Patients had open-angle glaucoma or ocular hypertension, which could not be controlled with monotherapy and were randomized to twice daily therapy with either brinzolamide 1%/timolol 0.5% or dorzolamide 2%/timolol 0.5%. IOP assessments were taken at 8 AM, 10 AM, and 4 PM at week 2 as well as at months 1, 2, and 3. Patients completed ocular discomfort assessments (based on stinging, burning, feeling of heat or warmth, or sharp pain) on their current IOP lowering therapy at baseline.

RESULTS

Of the 114 patients enrolled, 57 received Brinz/Tim and 57 received Dorz/Tim twice daily. Both medications produced statistically relevant IOP reductions, which were similar in both groups at each visit. The IOP reductions with Brinz/Tim ranged from 6.42 to 9.74 mmHg (26.09%-37.46%), whereas Dorz/Tim produced mean IOP reductions ranging from 8.16 to 12.41 mmHg (31.19%-41.44%) (P>0.05). Brinz/Tim showed significantly less ocular irritation (0.5% vs. 15.7%, respectively; P=0.0004) than Dorz/Tim.

CONCLUSIONS

Both Brinz/Tim and Dorz/Tim showed similar significant and clinically relevant IOP-lowering efficacy, whereas Brinz/Tim provided superior outcomes in terms of ocular comfort.

Preference for a fixed combination of brinzolamide/timolol versus dorzolamide/timolol among patients with open-angle glaucoma or ocular hypertension

Objective

To assess ocular discomfort upon instillation and patient preference for brinzolamide/timolol relative to dorzolamide/timolol, in patients with open-angle glaucoma or ocular hypertension.

Methods

This was a multicenter, prospective, patient-masked, randomized, crossover study. On day 0, patients received one drop of brinzolamide/timolol in one eye and one drop of dorzolamide/timolol in the contralateral eye. On day 1, patients were randomly assigned to receive one drop of either brinzolamide/timolol or dorzolamide/timolol in both eyes; on day 2, patients received one drop of the alternate treatment in both eyes. Measures included a patient preference question on day 2 (primary) and mean ocular discomfort scale scores on days 1 and 2 (secondary). Safety assessments included adverse events, visual acuity, and slit-lamp examinations.

Results

Of 120 patients who enrolled, 115 completed the study. Of these, 112 patients instilled both medications and expressed a study medication preference on day 2. A significantly greater percentage preferred brinzolamide/timolol to dorzolamide/timolol (67.0% versus 30.4%; P < 0.001). The ocular discomfort (expressed as mean [standard deviation]) with brinzolamide/timolol was significantly lower than with dorzolamide/timolol (day 2:1.9 [2.3] versus 3.7 [2.8], respectively [P = 0.0003]; both days combined: 2.1 [2.5] versus 3.5 [2.9], respectively [P = 0.00014]). On day 1, five patients receiving brinzolamide/timolol reported five nonserious adverse events (AEs): flu (n = 1), bitter taste (n = 2), and headache (n = 2). Four events, bitter taste (two events) and headache (two events), were considered related to brinzolamide/timolol. Events were mild in intensity, except bitter taste of moderate intensity reported by one patient. No AEs were reported at day 2. All AEs resolved without additional treatment. No clinically relevant changes from baseline were observed in best-corrected visual acuity or slit-lamp examinations of ocular signs.

Conclusion

Patients had less discomfort with brinzolamide/timolol than with dorzolamide/timolol, and more expressed a preference for brinzolamide/timolol. Both treatments were generally safe and well tolerated.

Intraocular pressure-lowering effects of commonly used fixed-combination drugs with timolol: a systematic review and meta-analysis

Background

The first goal of medical therapy in glaucoma is to reduce intraocular pressure (IOP), and the fixed-combination medications are needed to achieve sufficiently low target IOP. The aim of this systematic review and meta-analysis is to evaluate IOP-lowering effect of the commonly used fixed-combination drugs containing 0.5% timolol.

Methods

Pertinent publications were identified through systematic searches. Over 85% of the patients had to be diagnosed with primary open-angle glaucoma (POAG) or ocular hypertension (OHT). Forty-one randomized clinical trials were included in the meta-analysis. The main efficacy measures were the absolute and relative values of mean diurnal IOP reduction, and the highest and lowest IOP reductions on the diurnal IOP curve. The pooled 1- to 3-month IOP-lowering effects after a medicine-free washout period was calculated by performing meta-analysis using the random effects model, and relative treatment effects among different fixed combinations were assessed using a mixed-effects meta-regression model.

Results

The relative reductions for mean diurnal IOP were 34.9% for travoprost/timolol, 34.3% for bimatoprost/timolol, 33.9% for latanoprost/timolol, 32.7% for brinzolamide/timolol, 29.9% for dorzolamide/timolol, and 28.1% for brimonidine/timolol. For the highest IOP decrease, relative reductions ranged from 31.3% for dorzolamide/timolol to 35.5% for travoprost/timolol; for the lowest IOP decrease, those varied from 25.9% for dorzolamide/timolol to 33.1% for bimatoprost/timolol. Both latanoprost/timolol and travoprost/timolol were more effective in lowering mean diurnal IOP than brimonidine/timolol (WMD: 5.9 and 7.0) and dorzolamide/timolol (WMD: 3.8 and 3.3).

Conclusions

All six commonly used fixed-combination drugs containing timolol can effectively lower IOP in patients with POAG and OHT, and both latanoprost/timolol and travoprost/timolol might achieve better IOP-lowering effects among the six fixed-combination agents.

Overview of the [corrected] travoprost /timolol BAK-free fixed combination

INTRODUCTION

Glaucoma is the second leading cause of blindness globally, representing a significant public health concern. More than 60 million people are affected by glaucoma worldwide; as this population ages, the number is expected to increase. Glaucoma is a collection of heterogeneous diseases sharing common clinical characteristics. The goal of treatment is to prevent significant visual dysfunction through reduction of intraocular pressure (IOP).

AREAS COVERED

This is a review of the current literature about combination therapeutic regimens for the reduction of IOP, focusing on the risk : benefit profile of a fixed-combination therapy using travoprost and timolol.

EXPERT OPINION

Since the debut of prostaglandin analogues in the 1990s, only modest innovation has occurred in glaucoma pharmacology. A growing body of research has established that the preservative benzalkonium chloride (BAK) might not be the benign contributor expected of excipient ingredients. Thus, BAK-free treatments were developed, with the goal of IOP reduction without furthering ocular surface disease symptoms. The BAK-free travoprost/timolol combination represents an important addition to glaucoma medication options and may fill an unmet need in this therapeutic arena.

Balancing efficacy and tolerability of prostaglandin analogues and prostaglandin-timolol fixed combinations in primary open-angle glaucoma

BACKGROUND

Lowering intraocular pressure (IOP) is currently the only therapeutic approach that preserves visual function in primary open-angle glaucoma. In making treatment decisions for first- and second-line therapy, the clinician needs to provide an appropriate balance of efficacy and tolerability. Prostaglandin analogues (PGAs) are frequently used as first-line monotherapy, because of their efficacy and low risk of systemic side effects. Similarly, PGA-based fixed combinations are frequently used in patients who progress or fail to achieve the target IOP.

SCOPE

We have reviewed the literature on the management of primary open-angle glaucoma with PGAs, both as monotherapies and in fixed combinations.

FINDINGS

In the clinical trial and meta-analysis data identified, bimatoprost 0.03% seems to be associated with a greater overall ability to lower IOP compared with latanoprost, travoprost or tafluprost, at the cost of a slightly higher incidence of conjunctival hyperaemia. Studies indicate that patients' adherence to treatment is generally better with PGAs than with many other monotherapies. In patients requiring more than one IOP-lowering agent, fixed combination treatments may provide improved adherence and tolerability benefits compared with concomitant use of individual treatments. Bimatoprost/timolol fixed combination appears to be slightly more efficacious than latanoprost/timolol or travoprost/timolol, and tolerability differences between the fixed combinations appear to be slight, probably because the addition of timolol to the PGA component lessens the associated hyperaemia. Surveys on EU physician attitudes appear largely in line with these clinical data.

CONCLUSION

An appropriate balance between efficacy and tolerability ensures optimum IOP lowering and reduces the risk of non-adherence. PGAs largely fulfil this need as monotherapies and as components of combinations.

Travoprost 0.004%/timolol 0.5%-fixed combination with and without benzalkonium chloride: a prospective, randomized, doubled-masked comparison of safety and efficacy

PURPOSE

The purpose of this study is to compare the safety and intraocular pressure (IOP)-lowering efficacy of travoprost/timolol in a benzalkonium chloride (BAK)-free fixed combination preserved with polyquaternium-1 (TRA/TIM BAK-free), with travoprost/timolol-fixed combination preserved with BAK (TRA/TIM), in patients with open-angle glaucoma or ocular hypertension.

METHODS

In this prospective randomized controlled trial, subjects with IOP of at least 22  mm Hg in one or both eyes at 0900  h, and IOP of at least 21  mm Hg in one or both eyes at 1100  h and 1600  h at two eligibility visits were randomly assigned to receive either TRA/TIM BAK-free (n=195) or TRA/TIM (n=193), dosed once daily in the morning (0900  h) for 6 weeks. IOP was assessed at 0900  h, 1100  h, and 1600  h at each scheduled visit (baseline, 2 and 6 weeks after randomization).

RESULTS

Mean IOP reduction across all visits and time points was 8.0  mm Hg in the TRA/TIM BAK-free group and 8.4  mm Hg in the TRA/TIM group (P=0.0943). The difference in mean IOP between groups ranged from 0.2 to 0.7  mm Hg across visits and time points, with a mean pooled difference of 0.4  mm Hg (95% CI: -0.1 to 0.8), demonstrating equivalence of the two formulations. The most common drug-related adverse event was hyperemia of the eye (ocular hyperemia and conjunctival hyperemia combined), occurring in 11.8% of the TRA/TIM BAK-free group and 13.0% of the TRA/TIM group.

CONCLUSION

Travoprost/timolol BAK-free demonstrated equivalence to travoprost/timolol preserved with BAK in efficacy. No clinically relevant differences in the safety profiles of travoprost/timolol BAK-free and travoprost/timolol preserved with BAK were identified.

Role of fixed combinations in the management of open-angle glaucoma

The first-line option for lowering intraocular pressure (IOP) is a single hypotensive agent, but patients frequently require additional IOP-lowering agents to reach their target pressures. Disadvantages of this multi-therapy approach include washout effect, inconvenience and poor adherence. Fixed combinations (FCs) combine two or more hypotensive agents in a single bottle, providing a convenient once-daily therapy, which tends to improve adherence. FCs generally offer equivalent efficacy to concomitant use of the individual components, with equivalent or superior tolerability. Studies also show that FCs can be more cost effective than nonfixed combinations. In terms of optimizing IOP control, minimizing visual field deterioration, preventing visual disability and minimizing associated healthcare costs, FCs are an important component of glaucoma management.

A patient preference comparison of Azarga (brinzolamide/timolol fixed combination) vs Cosopt (dorzolamide/timolol fixed combination) in patients with open-angle glaucoma or ocular hypertension

Purpose

To determine patient preference of and ocular discomfort with fixed combination brinzolamide/timolol compared with fixed combination dorzolamide/timolol.

Methods

In a prospective, double-masked, randomized, active-controlled, crossover, multicenter study, patients received 1 drop of brinzolamide/timolol and dorzolamide/timolol in both eyes on consecutive days in random order. Ocular discomfort was rated 1 minute after instillation of each medication, and preference was noted on Day 2. Adverse events, if any, were solicited at each visit.

Results

127 subjects with ocular hypertension or open-angle glaucoma were included in the intent-to-treat analysis. Of the 106 subjects who expressed a drug preference, 79.2% preferred brinzolamide/timolol (p < 0.0001). Ocular discomfort scores were significantly higher with dorzolamide/timolol than brinzolamide/timolol (2.9 vs 1.4, respectively; p < 0.0001). Significantly more patients reported ocular pain and discomfort after dorzolamide/timolol instillation and transient blurred vision after brinzolamide/timolol instillation.

Conclusions

Patients with ocular hypertension or open-angle glaucoma preferred the brinzolamide/timolol fixed combination over the dorzolamide/timolol fixed combination. This is likely due to the greater ocular discomfort associated with dorzolamide/timolol. The differences in preference, discomfort, and adverse events are likely attributable to formulation differences given the similarities of the active ingredients. Stronger patient preference for brinzolamide/timolol may lead to better therapeutic compliance.

Comparison of Travoprost and Bimatoprost plus timolol fixed combinations in open-angle glaucoma patients previously treated with latanoprost plus timolol fixed combination

PURPOSE

To compare the ocular hypotensive effect of bimatoprost plus timolol and travoprost plus timolol fixed combinations in glaucoma patients whose disease was controlled but had not reached their target intraocular pressure (IOP) with the fixed combination of latanoprost plus timolol.

DESIGN

A 2 × 3-month, multicenter, prospective, randomized, double-masked, cross-over clinical trial.

METHODS

Eighty-nine open-angle glaucoma (OAG) patients were included. After a 6-week run-in period with latanoprost plus timolol, patients were randomized to either travoprost plus timolol or bimatoprost plus timolol for 3 months. Patients then switched to the opposite therapy for 3 additional months. The primary end point was the comparison of mean daily IOP after 3 months of each treatment.

RESULTS

At baseline, mean IOP was 16.5 mm Hg (95% confidence interval, 16.0 to 17.0 mm Hg) with treatment with latanoprost plus timolol. Both bimatoprost plus timolol and travoprost plus timolol statistically significantly reduced the mean IOP from baseline (P < .0001). Mean IOP at month 3 was statistically significantly lower in the bimatoprost plus timolol group compared with the travoprost plus timolol group (14.7 mm Hg [95% confidence interval, 14.3 to 15.3 mm Hg] vs 15.4 mm Hg [95% confidence interval, 15.0 to 15.9 mm Hg]; P = .0041). IOP was lower during bimatoprost plus timolol treatment at all time points and statistical significance was reached at 8 am, 11 am, and 5 pm, but not at 2 pm and 8 pm. Both treatments showed similar tolerability profile.

CONCLUSIONS

Bimatoprost plus timolol and travoprost plus timolol can provide additional IOP-lowering effect in patients not fully controlled with latanoprost plus timolol. The observed additional IOP reduction was greater with bimatoprost plus timolol with a similar tolerability profile.

Timolol activates the enzyme activities of human carbonic anhydrase I and II

Timolol, a beta-blocker, has been shown to be an effective ocular hypotensive agent when used alone or with carbonic anhydrase inhibitor on ocular hypertensive or open angle glaucoma patients. The effect of timolol hemihydrate on the CO(2) hydration activities of human carbonic anhydrase (HCA) I and II and their reaction mechanisms were investigated. Timolol activates the enzyme activities of HCA I and HCA II. In HCA I and II, the enzyme kinetic results clearly showed that timolol increases the value of V(max) but does not influence the value of K(m). The enzyme kinetic method showed that timolol noncompetitively activates HCA I and II activities through the formation of a ternary complex consisting of the enzyme, the substrate, and timolol. These results indicate that timolol binds apart from the narrow cavity of the active site. AutoDocking results showed that timolol binds at the entrance of the active site cavity in a region where the proton shuttle residue, His 64, of HCA I or II, is placed. The enzyme kinetic and AutoDocking results showed that timolol might weakly bind near the proton shuttle residue, His 64, to accelerate the proton transfer rate from His 64 to the buffer components. It is known that efficient activators of carbonic anhydrase possess a bulky aromatic/heterocyclic moiety and a primary/secondary amino group in their molecular structure. Timolol has a heterocyclic moiety and a secondary amino group, which are typical structures in efficient activators of carbonic anhydrase.

Comparison of ocular hypotensive actions of fixed combinations of brimonidine/timolol and dorzolamide/timolol

OBJECTIVE

To compare brimonidine/timolol fixed combination (BrTFC; Combigan *) with dorzolamide/timolol fixed combination (DTFC; Cosopt dagger) in terms of ability to lower intraocular pressure (IOP) in primary open-angle glaucoma (POAG).

METHODS

This was a prospective, randomized, double-masked, crossover study. After 6 weeks of therapy with timolol maleate 0.5% twice daily, patients were randomized to BrTFC twice daily or DTFC twice daily for 6 weeks, before being crossed over to the other treatment arm for a further 6 weeks. At all follow-up visits, IOP was measured at 09.00 (pre-instillation) 12.00 and 16.00. The primary outcome measure was change in mean diurnal IOP from baseline at 6 weeks. The secondary outcome was percentage of patients with IOP <18 mmHg at 6 weeks. Data were analyzed from all patients who completed the study.

RESULTS

Twenty-five patients were randomized and 20 completed the study. Mean diurnal IOP (mean +/- standard deviation [SD]) was 20.28 +/- 2.03 mmHg at timolol-treated baseline. After 6 weeks, mean diurnal IOP was 16.28 +/- 2.07 mmHg following BrTFC and 17.23 +/- 2.29 mmHg following DTFC (difference: 0.95 mmHg, 95% CI 0.10-1.80, p = 0.03). Mean IOP at 09.00 was 20.95 +/- 2.31 mmHg at baseline. This was reduced to 15.85 +/- 2.56 mmHg following BrTFC and 17.55 +/- 2.67 mmHg following DTFC (difference: 1.70, 95% CI 0.80-2.60, p = 0.001). For the 12.00 and 16.00 timepoints, the mean changes from baseline in the two arms were comparable. Percentages of patients achieving a target IOP of <18 mmHg were 85% following BrTFC and 60% following DTFC (p = NS [not significant]). No treatment-related adverse events were reported with either therapy. Key limitations include the small size of the study population and the 6-week duration of treatment periods, which prevents drawing conclusions regarding long-term therapy.

CONCLUSION

Reductions from baseline in mean diurnal IOP and morning IOP were greater with BrTFC than with DTFC.

Role of fixed-combination brinzolamide 1%/timolol 0.5% in the treatment of elevated intraocular pressure in open-angle glaucoma and ocular hypertension

Brinzolamide 1%/timolol 0.5% is a new fixed-combination for the treatment of open-angle glaucoma or ocular hypertension. Brinzolamide/timolol has a favorable safety profile, with an incidence of ocular burning and stinging <5%. Published data show that brinzolamide 1%/timolol 0.5% and dorzolamide 2%/timolol 0.5% have similar efficacies for lowering intraocular pressure (IOP). There is some evidence that brinzolamide/timolol may be more comfortable. Although patients receiving brinzolamide/timolol may experience more blurred vision on instillation, some data show a preference for brinzolamide/timolol over dorzolamide/timolol. Although available data to assess the role of brinzolamide/timolol in daily clinical practice are still limited, these first results suggest the agent to be a reasonable alternative for patients who do not reach target IOP with monotherapy.

Three-month, randomized, parallel-group comparison of brimonidine-timolol versus dorzolamide-timolol fixed-combination therapy

OBJECTIVE

Fixed combinations of 0.2% brimonidine-0.5% timolol and 2% dorzolamide-0.5% timolol are used to lower intraocular pressure (IOP). The objective of this study was to evaluate the IOP-lowering efficacy and ocular tolerability of brimonidine-timolol compared with dorzolamide-timolol when used as monotherapy or as adjunctive therapy to a prostaglandin analog (PGA) in patients with glaucoma or ocular hypertension.

STUDY DESIGN AND METHODS

Pooled data analysis of two randomized, investigator-masked, 3-month, parallel-group studies with identical protocols (ten sites). In all, 180 patients with open-angle glaucoma or ocular hypertension who were in need of lower IOP received topical brimonidine-timolol BID or dorzolamide-timolol BID as monotherapy (n = 101) or as adjunctive therapy to a PGA (latanoprost, bimatoprost, or travoprost) (n = 79).

CLINICAL TRIAL REGISTRATION

The studies are registered with the identifiers NCT00822081 and NCT00822055 at http://www.clinicaltrials.gov.

MAIN OUTCOME MEASURES

IOP was measured at 10 a.m. (peak effect) at baseline and at months 1 and 3. Tolerability/comfort was evaluated using a patient questionnaire.

RESULTS

There were no statistically significant between-group differences in patient demographics. Most patients were Caucasian, and the mean age was 68 years. There were also no statistically significant differences between treatment groups in baseline IOP. At month 3, the mean (SD) reduction from baseline IOP for patients on fixed-combination monotherapy was 7.7 (4.2) mmHg (32.3%) with brimonidine-timolol versus 6.7 (5.0) mmHg (26.1%) with dorzolamide-timolol (p = 0.040). The mean reduction from PGA-treated baseline IOP for patients on fixed-combination adjunctive therapy was 6.9 (4.8) mmHg (29.3%) with brimonidine-timolol versus 5.2 (3.7) mmHg (23.5%) with dorzolamide-timolol (p = 0.213). Patients on brimonidine-timolol reported less burning (p < 0.001), stinging (p < 0.001), and unusual taste (p < 0.001) than patients on dorzolamide-timolol.

CONCLUSIONS

Fixed-combination brimonidine-timolol provided the same or greater IOP lowering compared with fixed-combination dorzolamide-timolol. Both fixed-combination medications were safe and well-tolerated. Brimonidine-timolol received higher ratings of ocular comfort than dorzolamide-timolol. The duration of the studies was 3 months, and additional studies will be needed to compare the efficacy and tolerability of brimonidine-timolol and dorzolamide-timolol during long-term treatment.

Bimatoprost/timolol: a review of its use in glaucoma and ocular hypertension

Topically administered bimatoprost 0.03%/timolol 0.5% ophthalmic solution (bimatoprost/timolol: Ganfort) comprises the synthetic prostamide bimatoprost (structurally related to prostaglandin F2 alpha) and the beta-adrenergic receptor antagonist timolol. Bimatoprost/timolol (one drop administered in the affected eye[s] once daily in the morning or evening) is an effective and well tolerated fixed combination for lowering intra-ocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension (OHT), including individuals uncontrolled on monotherapy with a beta-adrenergic receptor antagonist or prostaglandin analogue/prostamide.

A one-week comfort study of BID-dosed brinzolamide 1%/timolol 0.5% ophthalmic suspension fixed combination compared to BID-dosed dorzolamide 2%/timolol 0.5% ophthalmic solution in patients with open-angle glaucoma or ocular hypertension

PURPOSE

The aim of this study was to evaluate the ocular discomfort of brinzolamide 1%/timolol 0.5% ophthalmic suspension fixed combination dosed twice-daily compared to dorzolamide 2%/timolol 0.5% ophthalmic solution fixed combination dosed twice-daily.

METHODS

This was a prospective, double-masked, parallel-group, randomized, clinical trial. Patients had open-angle glaucoma or ocular hypertension and were randomized to twice-daily therapy with either brinzolamide 1%/timolol 0.5% or dorzolamide 2%/timolol 0.5%. Patients completed ocular discomfort assessments (based on burning, stinging, a feeling of heat or warmth, sharp pain, or smarting pain) on their current intraocular pressure-lowering therapy at baseline and on study medication after 1 week of dosing.

RESULTS

In the intent-to-treat analyses, mean ocular discomfort scores at 1 week were significantly lower in eyes receiving brinzolamide 1%/timolol 0.5% than dorzolamide 2%/timolol 0.5% (0.77 vs. 1.53; P = 0.0003). Mean increases from baseline in ocular discomfort scores were statistically significant in both groups but were smaller in eyes receiving brinzolamide 1%/timolol 0.5% (0.49; P = 0.0028) than dorzolamide 2%/timolol 0.5% (1.32; P < 0.0001). Over threefold more patients on brinzolamide 1%/timolol 0.5% (23/47, 49%) than dorzolamide 2%/timolol 0.5% (7/47, 15%) reported no ocular discomfort after 1 week of therapy (P = 0.0004).

CONCLUSIONS

Brinzolamide 1%/timolol 0.5% ophthalmic suspension is associated with a statistically significantly less ocular discomfort profile than dorzolamide 2%/timolol 0.5% ophthalmic solution.