A randomized trial comparing the dorzolamide-timolol combination given twice daily to monotherapy with timolol and dorzolamide. Dorzolamide-Timolol Study Group

Quality by design steered approach for co-encapsulation of timolol maleate and dorzolamide hydrochloride in injectable liposomes

Glaucoma is caused by high intraocular pressure, which can causes blindness. Combinations of timolol and dorzolamide are used for its treatment with a requirement of multiple dosing with dosing being twice or four times a day. Conventional eye drops have poor pre-corneal retention and is thus less available for action. This study utilizes principles of Quality by Design for formulation of injectable liposomes coloaded with timolol maleate and dorzolamide HCl, which overcomes limitations of conventional eye drops. For implementation of Quality by Design principles a systematic approach involving defining Quality Target Product Profile, identification of Critical Quality Attributes, mapping Critical Quality Attributes to Critical Process Parameters and Critical Material Attributes, Failure Mode and Effect Analysis based risk assessment, Taguchi screening, and 32 full factorial Design of Experiments design were utilized. A robust model for formulation of coloaded liposomes was successfully developed. Design of Experiments approach allowed to obtain optimized batch having particle size of 116.1 nm, encapsulation efficiency of dorzolamide HCl of 72.12 % and encapsulation efficiency of timolol maleate of 71.94 %. In-vitro drug release showed a sustained release for 4 days. The prepared formulation was in the desired osmolarity range. Biosafety was proved using histopathological characterization. In-vivo studies for assessing the Intra Ocular Pressure reduction showed that there was no significant difference in Intra Ocular Pressure reduction between prepared liposomes and marketed formulation but were superior than marketed formulation because of less fluctuations in Intra Ocular Pressure. Prepared coloaded injectable liposomes lays the foundation for further research in the area and can be translated from to bench side for commercial clinical use.

Stable Gastric Pentadecapeptide BPC 157-Possible Novel Therapy of Glaucoma and Other Ocular Conditions

Recently, stable gastric pentadecapeptide BPC 157 therapy by activation of collateral pathways counteracted various occlusion/occlusion-like syndromes, vascular, and multiorgan failure, and blood pressure disturbances in rats with permanent major vessel occlusion and similar procedures disabling endothelium function. Thereby, we revealed BPC 157 cytoprotective therapy with strong vascular rescuing capabilities in glaucoma therapy. With these capabilities, BPC 157 therapy can recover glaucomatous rats, normalize intraocular pressure, maintain retinal integrity, recover pupil function, recover retinal ischemia, and corneal injuries (i.e., maintained transparency after complete corneal abrasion, corneal ulceration, and counteracted dry eye after lacrimal gland removal or corneal insensitivity). The most important point is that in glaucomatous rats (three of four episcleral veins cauterized) with high intraocular pressure, all BPC 157 regimens immediately normalized intraocular pressure. BPC 157-treated rats exhibited normal pupil diameter, microscopically well-preserved ganglion cells and optic nerve presentation, normal fundus presentation, nor- mal retinal and choroidal blood vessel presentation, and normal optic nerve presentation. The one episcleral vein rapidly upgraded to accomplish all functions in glaucomatous rats may correspond with occlusion/occlusion-like syndromes of the activated rescuing collateral pathway (azygos vein direct blood flow delivery). Normalized intraocular pressure in glaucomatous rats corresponded to the counteracted intra-cranial (superior sagittal sinus), portal, and caval hypertension, and aortal hypotension in occlusion/occlusion-like syndromes, were all attenuated/eliminated by BPC 157 therapy. Furthermore, given in other eye disturbances (i.e., retinal ischemia), BPC 157 instantly breaks a noxious chain of events, both at an early stage and an already advanced stage. Thus, we further advocate BPC 157 as a therapeutic agent in ocular disease.

Efficacy and safety of timolol-dorzolamide fixed-combination three times a day versus two times a day in newly diagnosed open-angle glaucoma

Objective

This study aimed to compare the therapeutic efficacy and safety of dorzolamide/timolol fixed-combination(Cosopt) in newly diagnosed primary open-angle glaucoma (POAG) patients.

Methods

In this prospective, interventional case series, newly POAG patients were included. Patients were started on Cosopt twice a day (BID) for one month and then switched to three times a day (TDS) for an additional month. Patients underwent comprehensive ophthalmic examination, diurnal intraocular pressure (IOP), blood pressure (BP), and 24-h heart rate (HR) measurements at baseline, month 1(BID), and month 2(TDS). Throughout the study, all adverse events were monitored by the investigators.

Results

In 31 POAG patients that completed the study, the mean baseline IOP was 23.1 ± 3.15 mmHg. IOP was decreased significantly 16.5 ± 2.21 at one month (p < .0001) and 13.9 ± 2.23 mmHg at 1 and 2 months follow up (p < .0001). IOP was significantly lower in month 2 compared to month 1 (p = .0004). While Cosopt BID significantly reduced the mean 24-h systolic BP and mean 24-h HR from baseline (p < .0001), the mean 24-h systolic BP and HR remained unchanged with Cosopt TDS compared to BID (p = .62).

Conclusions

Cosopt TDS has a superior IOP-lowering effect than Cosopt BID in POAG patients with comparable safety profiles.

The treatment of glaucoma using topical preservative-free agents: an evaluation of safety and tolerability

Introduction: Preservative-free (PF) medications represent a valuable treatment strategy in the lifelong management of glaucoma. By removing preservative toxicity, PF formulations provide tangible clinical benefits to glaucoma patients worldwide. They improve tolerability and adherence, leading to a positive impact in long-term intraocular pressure (IOP) control.Areas covered: A critical review of the subject is provided, including selected evidence on the safety and tolerability of currently available topical PF formulations. Cumulative evidence confirms that topical PF medications are at least equally efficacious to their preserved equivalents. There is convincing short-term evidence for superior tolerability and safety of PF formulations compared to preserved medications. The long-term benefits and success of PF therapy requires further elucidation.Expert opinion: Successful stepwise administration of medical therapy for glaucoma remains elusive. There is a greater risk for ocular toxicity and therapy failure with preserved topical glaucoma therapy. Currently available and emerging PF therapy options potentially optimize lifelong stepwise glaucoma therapy and may enhance outcome. To avert complications from preservatives leading to poor adherence, ideally, future antiglaucoma therapy should become 100% PF. There are still key aspects of PF therapy that warrant further investigation.

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

Fixed-combination Bimatoprost/Brimonidine/Timolol in Glaucoma: A Randomized, Masked, Controlled, Phase III Study Conducted in Brazil☆

PURPOSE

Many patients with open-angle glaucoma eventually require >2 medications to lower their intraocular pressure (IOP). Fixed-combination ophthalmic solutions can be advantageous in patients who require multiple medications, but the number of fixed combinations combining 3 complementary IOP-lowering agents remains limited. This study assessed the efficacy and safety of a triple fixed combination (TFC) of bimatoprost 0.01%/brimonidine 0.15%/timolol 0.5% ophthalmic solution in patients with primary open-angle glaucoma (POAG) or ocular hypertension (OHT), compared with a dual fixed combination (DFC) of brimonidine 0.2%/timolol 0.5%.

METHODS

Patients with a baseline IOP of 23-34 mm Hg in both eyes and no history of IOP-lowering procedures were eligible for participation in this multicenter, double-masked, randomized, Phase III study. After washout of previous treatment (if applicable), patients were randomized to receive TFC or DFC twice daily in each eye for 3 months. The primary efficacy variable was the change from baseline in mean IOP in the worse eye at week 12 in the modified intent-to-treat (mITT) population. TFC was superior to DFC if the treatment difference (TFC - DFC) favored TFC at week 12 (P ≤ 0.05; 2-sample t test). Secondary and sensitivity analyses were also performed. Safety, including adverse events, was assessed at all visits.

FINDINGS

The mITT/safety population included 185 patients (TFC, n = 90; DFC, n = 95). TFC superiority was demonstrated at all postbaseline visits (all, P < 0.001) through week 12 (week 12 treatment difference: ─2.17 mm Hg; 95% CI, ─3.12 to ─1.22). While treatment-related conjunctival hyperemia was more frequent with TFC than with DFC (47.8% vs 23.2%; P < 0.001), consistent with the additional presence of bimatoprost in TFC, most cases were mild and the numbers of patient discontinuations at week 12 were similar between the TFC and DFC groups (11 [12.2%] vs 7 [7.4%] patients; P = 0.266). No unexpected adverse events were reported.

IMPLICATIONS

Compared with DFC, TFC provided superior IOP lowering throughout the primary efficacy period. An acceptable tolerability profile was observed through 12 months of use of TFC, offering an effective therapeutic option in patients with POAG or OHT who require multiple medications to control their IOP. Additional studies are required for the assessment of the long-term effects of TFC. ClinicalTrials.gov identifier: NCT01217606.

Management Of Glaucoma In Developing Countries: Challenges And Opportunities For Improvement

Glaucoma is the leading cause of blindness in the developed and developing world. Not only is the clinical impact of this disease considerable, but associated economic and humanistic burdens - affecting patients, caregivers, and society - are substantial. Since glaucoma is an age-related disorder and populations in many developing countries are aging at a faster pace than in the developed world, increasing attention is being focused on ways to ameliorate the burdens of illness. In this paper, we examine the burdens of glaucoma with particular focus on developing countries, discuss some of the challenges that exist in delivering optimal glaucoma management within budget constraints, and bring into perspective how we could improve current healthcare systems, leverage technology, and strike an appropriate balance between cost and quality of care, thereby offering considerations to payors and policymakers in these countries that may result in longer-term cost savings, while concurrently striving to achieve the WHO Vision on the prevention of blindness and visual impairment.

Adrenergic agonists and antagonists as antiglaucoma agents: a literature and patent review (2013-2019)

Introduction: Glaucoma is a neurodegenerative disease of the eye characterized by selective retinal ganglion cell loss that provokes progressive defects in the visual field. Elevated intraocular pressure (IOP) is an important contributor for the progression of glaucoma. The current therapeutic arsenal for reducing IOP includes prostaglandin analogs, β-blockers, carbonic anhydrase inhibitors, α-adrenergic agonist, miotics, rho-kinase inhibitors and combinations thereof, generally administered as eye drops. Areas covered: This manuscript reviews the state of art on adrenergic modulators for treating glaucoma. Both monotherapy and fixed-drugs combinations including α₂-adrenergic agonists and β-blockers are discussed as well as drug delivery systems where these classes of drugs are used. The review then covers the patent literature involving adrenoceptors modulators over the period 2013-2019. Expert opinion: While the scientific community is moving forward novel targets and related modulators for treating glaucoma and ocular hypertension, adrenergic modulators held a prominent position in the therapy of glaucoma and related disorders. Indeed, though not embodying anymore the first-choice monotherapy, they are widely marketed worldwide ordinarily in combination with other drugs, are subjects of many studies for identifying new drug compositions and have been assessed as active ingredients in several innovative ocular drug delivery systems.

Effect of Topical Hypotensive Medications for Preventing Intraocular Pressure Increase after Cataract Surgery in Eyes with Glaucoma

PURPOSE

To compare the effects of a topical intraocular pressure (IOP)-lowering medication for preventing an IOP increase after cataract surgery in eyes with glaucoma.

DESIGN

Randomized clinical study.

METHODS

A total of 165 eyes of 165 patients with primary open-angle glaucoma or pseudoexfoliation glaucoma scheduled for phacoemulsification were randomly assigned to 1 of 3 groups to receive each medication immediately postoperatively: 1) prostaglandin F_2α analog (travoprost), 2) β-blocker (timolol maleate), or 3) carbonic anhydrase inhibitor (brinzolamide). Intraocular pressure (IOP) was measured using a rebound tonometer at 1 hour preoperatively, at the end of surgery, and at 2, 4, 6, 8, and 24 hours postoperatively. The incidence of eyes exhibiting a marked IOP increase to greater than 25 mm Hg was compared among the groups.

RESULTS

At 1 hour preoperatively and at the end of surgery, mean IOP did not differ significantly among the groups. Mean IOP increased significantly between 4 and 8 hours postoperatively and then decreased at 24 hours postoperatively in all groups (P < .0001). Mean IOP was significantly lower in the brinzolamide group than in the travoprost or timolol group at 4, 6, and 8 hours postoperatively (P ≤ .0374) and did not differ significantly among groups at 2 and 24 hours postoperatively. The incidence of an IOP spike was significantly lower in the brinzolamide group than in the travoprost and timolol groups (P = .0029).

CONCLUSIONS

Brinzolamide reduces the short-term IOP increase after cataract surgery more effectively than travoprost or timolol in eyes with glaucoma, suggesting that brinzolamide is preferable for preventing an IOP spike.

Combination Products for Glaucoma: An Overview of Treatment Principles

Glaucoma is a leading cause of blindness and visual impairment. Treatments that lower intraocular pressure (IOP) tend to delay progression of the condition. However, the target IOP cannot be achieved with monotherapy in many patients. If monotherapy adequately controls IOP and is well tolerated, it should not be changed, but if the therapy is only partially effective, a combination may be used. Combination therapy is eventually needed in many cases of glaucoma. Combinations may be given as adjunctive or preferably as fixed therapies. The mechanism of action and contraindications of the constituent agents should be taken into account when prescribing combinations, for optimal safety and efficacy. As treatment choice expands, prescribing patterns are changing worldwide. Fixed combination therapies are increasingly prescribed in Europe in particular for the treatment of glaucoma. They should be administered according to the current evidence-based guidelines.

A Comparison of Travoprost, Latanoprost, and the Fixed Combination of Dorzolamide and Timolol in Patients with Pseudoexfoliation Glaucoma

Purpose

To compare the intraocular pressure (IOP) lowering effect and safety of latanoprost, travoprost given every evening, and the fixed combination dorzolamide + timolol (DTFC) given twice daily in pseudoexfoliation glaucoma (PXG).

Methods

This randomized, prospective, investigator-masked study has been conducted with 50 PXG patients. Patients were assigned to one of three groups: travoprost 0.004%, fixed combination of dorzolamide 2%+timolol 0.5%, or latanoprost 0.005% for 6 months. At baseline and 0.5, 1, 2, 3, 4, 5, and 6 months of therapy, IOP (8 am, 10 am, 4 pm), blood pressures, and pulse rates were measured, and ophthalmologic examination was performed. The side effects were recorded at each visit.

Results

Forty-two of the 50 patients initially enrolled completed this study. Withdrawn patients included one (latanoprost) for lack of efficacy, five (three travoprost, one latanoprost, one DTFC) for adverse events, and two (one latanoprost, one DTFC) for loss of follow-up. Each of the three drugs considerably reduced the IOP in PXG cases throughout the 6 months. Mean IOP reduction at 6 months was –9.3±2.9 mmHg in the travoprost group, -8.2±1.2 mmHg in the latanoprost group, and 11.5±3.3 mmHg in the DTFC group. Comparing the groups, DTFC is more effective than latanoprost and travoprost in lowering IOP (p<0.05). There was no difference between travoprost and latanoprost. The most common treatment-related adverse event was conjunctival hyperemia. Intensity of ocular hyperemia was greater in the travoprost group compared with the latanoprost and DTFC groups (p<0.05). There were no significant effects on systemic safety parameters.

Conclusions

The results demonstrated that DTFC is more effective in reducing IOP than latanoprost and travoprost. Latanoprost and travoprost had similar ocular hypotensive effects in patients with PXG. All three drugs were well tolerated; there were fewer ocular side effects attributable in the latanoprost group.

Glaucoma-Intraocular Pressure Reduction

Medical treatment is a mainstay for the management of glaucoma (Realini 2011; Marquis and Whitson 2005; Hoyng and van Beek 2000). Intraocular pressure (IOP) lowering has been long recognized as and still represents the primary and most widely employed treatment to prevent glaucomatous vision loss (Musch et al. 2011; Leske et al. 2003; The Advanced Glaucoma Intervention Study (AGIS) 2000). Soon after the recognition that "tension" or IOP was related to glaucoma, pharmacological agents were introduced in the mid-1800s, first with the calabar bean (Realini 2011; Proudfoot 2006). Since then, an explosion of pharmacological agents targeting numerous intracellular and molecular signaling pathways has resulted in a plethora of drugs to lower IOP and treat glaucoma. Aqueous humor dynamics provides the basis for understanding each of these medical therapies.

Brinzolamide 1%/timolol versus dorzolamide 2%/timolol in the treatment of open-angle glaucoma or ocular hypertension: prospective randomized patient-preference study

Purpose

The objective of this study was to assess preference for fixed-combination brinzolamide 1%/timolol 0.5% (BTFC) versus fixed-combination dorzolamide 2%/timolol 0.5% (DTFC) in patients with open-angle glaucoma or ocular hypertension.

Methods

In this prospective, single-masked crossover study, patients were randomized 1:1 to BTFC-DTFC or DTFC-BTFC treatment sequences. Patients self-administered each medication for 7 days, with a 48-hour washout period between treatments, and rated ocular discomfort after each treatment period. Medication preferences based on ocular comfort (primary endpoint) and anticipated adherence were assessed. Safety outcomes included adverse events and intraocular pressure. Between-group differences in treatment preference and ocular discomfort scores were analyzed using chi-square and Wilcoxon–Mann–Whitney tests, respectively. Adherence, intraocular pressure, and adverse events were summarized descriptively.

Results

In total, 112 patients were enrolled (mean ± SD age, 66±11 years), and 109 patients completed the study. Numerically, more patients in the intent-to-treat dataset preferred BTFC versus DTFC (59.3% versus 40.7%); however, this result was not statistically significant (treatment difference, 18.6%; P=0.0670). Mean ocular discomfort scores (range, 0–9) were statistically significantly lower with BTFC versus DTFC (2.6 versus 3.7; P=0.0002, Wilcoxon– Mann–Whitney test). More patients who preferred BTFC over DTFC were confident that they would adhere to their preferred medication. Treatment-related adverse events included blurred vision with BTFC and eye irritation or eye pain with DTFC.

Conclusion

BTFC and DTFC were preferred by approximately 60% and 40% of patients, respectively, and BTFC was associated with less patient-reported ocular discomfort. Greater ocular comfort of glaucoma medications may improve treatment adherence.

The impact of timolol maleate on the ocular tolerability of fixed-combination glaucoma therapies

Glaucomatous optic atrophy is the second most common cause of blindness worldwide, and lowering intraocular pressure (IOP) is the only proven method to slow or stop the progression of the disease. Approximately 40% of patients with elevated IOP will require more than one medication to obtain a modest 20% reduction in IOP, and as a result, some patients may require two medications, provided in either two separate bottles or in one bottle with the use of fixed-combination therapies. Each therapy has its own unique safety and efficacy profile. Topical beta-blockers have a particularly favorable ocular-tolerability profile, and several studies of fixed-combination medications containing the beta-blocker timolol maleate have shown a lower prevalence of some ocular adverse events for the fixed-combination therapy compared to the non-beta-blocker individual component. In this review, we examined clinical data pertaining to the ocular surface tolerability of fixed-combination medications containing timolol maleate in comparison to the individual components. In particular, preference was given to prospective, randomized, multicenter trials of 3 months in duration or longer that compared a fixed-combination therapy to monotherapy with the individual components. A review of the literature revealed that some fixed-combination therapies can provide a reduced risk of common side effects compared to their individual components, with conjunctival hyperemia and ocular allergy being less frequent in some timolol-containing fixed-combination therapies. This effect appears to be most significant for latanoprost 0.005%, bimatoprost 0.03%, and brimonidine 0.2%.

Safety and efficacy of fixed-combination travoprost/timolol in patients with open-angle glaucoma or ocular hypertension not controlled with timolol monotherapy

Objective

To assess the intraocular pressure (IOP)-lowering effect of travoprost 0.004%/timolol 0.5% fixed-dose combination (TRAV/TIM–FC) in patients not achieving the target IOP of ≤18 mmHg while on timolol 0.5% (TIM) monotherapy.

Methods

A multicenter, prospective, open-label study (NCT01336569) was conducted in patients with open-angle glaucoma or ocular hypertension. Eligible patients were receiving TIM monotherapy with a screening/baseline IOP of 19–35 mmHg in ≥1 eye. TIM was discontinued on the baseline visit day (no washout period) and TRAV/TIM–FC was initiated and administered once daily at 8 pm for 4–6 weeks. The primary efficacy variable was mean change in IOP from TIM-treated baseline to study end, measured by Goldmann applanation tonometry. Results were analyzed by analysis of variance and paired samples t-test (5% significance).

Results

A total of 49 patients were enrolled (mean age, 63 [range, 42–82] years; 55.1% White; 73.5% women), and 45 were included in the intent-to-treat (ITT) population. Mean duration of treatment with TRAV/TIM–FC was 31 days. Mean ± standard deviation IOP reduction from baseline (TIM) to the follow-up visit (TRAV/TIM–FC) was −5.0±3.6 mmHg. IOP decreased significantly (P<0.0001) from baseline (22.1±2.6 mmHg) to study end (17.1±3.9 mmHg) in the ITT population, with a mean IOP reduction of 22.3%. Most patients (n=33/45; 73.3%) achieved IOP ≤18 mmHg. Two patients experienced a total of four adverse events (AEs), including a patient who reported one serious AE (enterorrhagia) that was considered unrelated to treatment, and a patient who reported one event each of drug-related redness, pruritus, and foreign body sensation. Most patients (n=47/49; 95.9%) reported no AEs.

Conclusions

TRAV/TIM–FC lowered IOP in patients who were not at target IOP while receiving TIM monotherapy, with most patients achieving an IOP ≤18 mmHg with TRAV/TIM–FC. TRAV/TIM–FC was well tolerated in this population.

Combination of brinzolamide and brimonidine for glaucoma and ocular hypertension: critical appraisal and patient focus

Glaucoma is one of the leading causes of blindness and is characterized by optic nerve damage that results in visual field loss. Elevated intraocular pressure (IOP) has been associated with glaucoma progression; thus, IOP-lowering medications are the standard of care for glaucoma. Guidelines suggest monotherapy with IOP-lowering agents such as β-blockers (eg, timolol), prostaglandin analogs, carbonic anhydrase inhibitors (eg, brinzolamide), and α2-receptor agonists (eg, brimonidine). However, monotherapy may provide insufficient IOP reduction in some patients, thereby necessitating the use of multiple IOP-lowering medications. Multidrug regimens may be complex, may increase the risk of preservative-related ocular symptoms, and may potentially reduce overall drug exposure as a consequence of drug washout during closely timed sequential administrations; these difficulties may reduce overall drug efficacy and decrease patient persistence and adherence with multidrug treatment regimens. Fixed-combination medications that provide two IOP-lowering therapies within a single solution are available and may overcome some of these challenges. However, all currently available fixed combinations combine timolol with another IOP-lowering agent, indicating that additional fixed-combination alternatives would be beneficial. To meet this demand, a novel fixed combination of brinzolamide 1% and brimonidine 0.2% (BBFC) has recently been developed. In two randomized, double-masked, multinational clinical trials, BBFC had greater IOP-lowering efficacy than brinzolamide or brimonidine monotherapy after 3 months of treatment in patients with open-angle glaucoma or ocular hypertension. In both studies, the overall safety profile of BBFC was consistent with that of brinzolamide and brimonidine. Comparative studies with BBFC versus other IOP-lowering monotherapy and fixed-combination medications are not available, but the IOP reductions observed with BBFC are similar to or greater than those reported in the literature for other glaucoma treatments; thus, BBFC provides an additional fixed-combination therapeutic option for patients who require further efficacious IOP reduction and improved convenience and tolerability versus concomitant administration of two separate medications.

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.

Clinical options for the reduction of elevated intraocular pressure

Elevated IOP in clinical practice is usually seen in glaucoma or ocular hypertension. Glaucoma affects 60 million people worldwide and 8.4 million are bilaterally blind from this chronic disease.1 Options for reducing IOP rely on pharmacological agents, laser treatments and surgery which may be penetrating or non-penetrating. The last twenty years has seen significant changes in all of these strategies. This review aims to cover these clinical options and introduce some of the new technologies currently in development for the clinical lowering of IOP.

Intraocular pressure reduction of fixed combination timolol maleate 0.5% and dorzolamide 2% (Cosopt) administered three times a day

Purpose

To evaluate the safety and efficacy in intraocular pressure (IOP) reduction of increasing Cosopt dosage from twice to three times a day.

Methods

The study included patients with primary open-angle glaucoma or ocular hypertension. After a washout period, IOP was measured at baseline, after 4 weeks of treatment with Cosopt twice a day, and after another 4 weeks of treatment with Cosopt three times a day. Blood pressure, heart rate, and oxygen saturation levels were also recorded.

Results

Twenty-nine eyes of 29 patients were included. Increasing Cosopt dosage resulted in a statistically significant (P < 0.001) additional reduction in IOP of 2.2 ± 1.58 mmHg (10.69% ± 7.49% of the baseline IOP values). There were no local or systemic adverse effects.

Conclusion

Treatment with Cosopt three times a day was more effective in reducing IOP than twice a day, with no effect on safety.

Managing refractory glaucoma with a fixed combination of bimatoprost (0.03%) and timolol (0.5%)

Glaucoma is a chronic progressive optic neuropathy characterized by progressive loss of retinal ganglion cells, which manifests clinically with loss of optic disc neuroretinal rim tissue, defects in the retinal nerve fiber layer, and deficits on functional visual field testing. The goal of glaucoma treatment is to reduce the intraocular pressure to a level that prevents or minimizes the progressive loss of vision. The current standard of management for the newly diagnosed primary open angle glaucoma (PAOG) patient is to start topical medication. Available topical medications include: beta-adrenergic antagonists, alpha-adrenergic agonists, carbonic anhydraze inhibitors, prostaglandin analogues and miotics. In some patients, IOP is not adequately controlled by monotherapy. In those refractory patients, where more efficacy is required, shifting to another medication or adding a second medication is indicated. The complimentary action between two drugs serves as the basis for combination medications. One avenue of delivering a second medication is through a fixed combination medication that has the advantage of providing two medicines within one drop. Bimatoprost/timolol represents a new fixed combination which is clinically and statistically more effective than either of its active constituents for patients with refractory glaucoma. As regard the safety of the combination, there were no signs or symptoms of intolerance and the incidence of conjunctival hyperemia was clinically and statistically significantly less than each of the two components separately. Bimatoprost/timolol fixed combination offers cost and time savings, which may enhance compliance; also reducing the amount of preservative applied to the eye, will improve tolerability and may also favorably improve eventual surgical outcomes in patients who might require filtering procedures.

Rational use of the fixed combination of dorzolamide - timolol in the management of raised intraocular pressure and glaucoma

Glaucoma is a multifactorial optic neuropathy in which the main therapeutic target is lowering of intraocular pressure (IOP) in order to retard the progression of existing structural and functional damage. The three mainstays of treatment are pharmacologic, laser, and surgical. The primary standard therapy in patients with open-angle glaucoma or ocular hypertension is topical medication. When monotherapy does not adequately lower the intraocular pressure, one or more agents are added or substituted. Combination pharmacotherapy such as Cosopt^® is available to improve efficacy and simplify medication regimen. A fixed combination of two ocular hypotensive drugs (the carbonic anhydrase inhibitor dorzolamide and the beta-adrenoceptor antagonist timolol), Cosopt^® is indicated for the treatment of elevated IOP in patients with open-angle glaucoma or ocular hypertension insufficiently responsive to topical beta-adrenoceptor antagonist monotherapy. Compared with concomitant therapy with the individual components, the primary advantage of fixed combination dorzolamide – timolol is convenience, which may also improve compliance. Clinical trials have demonstrated that the fixed combination dorzolamide – timolol is safe, effective and generally well tolerated in lowering IOP in patients with open angle glaucoma or ocular hypertension, including individuals uncontrolled on beta-adrenoceptor antagonist or other monotherapy.

Fixed combination of topical brimonidine 0.2% and timolol 0.5% for glaucoma and uncontrolled intraocular pressure

Lowering IOP is the most readily modifiable risk factor to delay the development and progression of glaucoma (POAG). The fixed combination of brimonidine tartrate 0.2% and timolol maleate 0.5% (FCBT) combines a highly selective α2-adrenergic agonist (brimonidine) with a non-selective β-blocker (timolol). FCBT reduces aqueous production and enhances uveoscleral outflow. Concomitant brimonidine and timolol have additive effects on reducing intraocular pressure (IOP). Multi-center randomized control trials have documented superiority of FCBT twice daily on IOP control compared with monotherapy with the individual components, and equal efficacy compared with concomitant therapy. IOP reduction with FCBT versus fixed combination dorzolamide 2% and timolol 0.5% (FCDT) was similar in a small study. Other studies (n > 293) evaluating concomitant brimonidine and timolol have shown that it is not inferior to FCDT. However, concomitant brimonidine and timolol administered twice daily was significantly less efficacious in IOP reduction than fixed combination latanoprost 0.005% and timolol 0.5% (FCLT). There are no published studies comparing FCBT with FCLT. The side effect profile for FCBT reflects that of its individual components. FCBT was generally well tolerated, with less ocular side effects than brimondine alone, but more than timolol alone. Documented systemic effects were few, although this could be confounded by selection bias. FCBT is a safe and effective IOP lowering agent for POAG and ocular hypertension.

Safety, tolerability, and efficacy of fixed combination therapy with dorzolamide hydrochloride 2% and timolol maleate 0.5% in glaucoma and ocular hypertension

Glaucoma is a collection of diseases characterized by multifactorial progressive changes leading to visual field loss and optic neuropathy most frequently due to elevated intraocular pressure (IOP). The goal of treatment is the lowering of the IOP to prevent additional optic nerve damage. Treatment usually begins with topical pharmacological agents as monotherapy, progresses to combination therapy with agents from up to 4 different classes of IOP-lowering medications, and then proceeds to laser or incisional surgical modalities for refractory cases. The fixed combination therapy with the carbonic anhydrase inhibitor dorzolamide hydrochloride 2% and the beta blocker timolol maleate 0.5% is now available in a generic formulation for the treatment of patients who have not responded sufficiently to monotherapy with beta adrenergic blockers. In pre- and postmarketing clinical studies, the fixed combination dorzolamide–timolol has been shown to be safe and efficacious, and well tolerated by patients. The fixed combination dorzolamide–timolol is convenient for patients, reduces their dosing regimen with the goal of increasing their compliance, reduces the effects of “washout” when instilling multiple drops, and reduces the preservative burden by reducing the number of drops administered per day.

Effectiveness of dorzolamide–timolol (COSOPT) in patients who were treatment naive for open-angle glaucoma or ocular hypertension: the COSOPT first-line study

PURPOSE

The aim of this study was to assess the effectiveness of dorzolamide-timolol (DT) in the management of open-angle glaucoma (OAG) and ocular hypertension.

METHODS

An open-label, 12-week, multicenter, Canadian study was conducted. Patients with untreated OAG or ocular hypertension received DT for 12 weeks to reduce intraocular pressure (IOP). If target IOP was not reached after the first 6-week treatment period, a prostaglandin (PG) (latanoprost) was added for the remaining 6 weeks. Primary outcome measures were changes in IOP from baseline to 6 and 12 weeks of treatment, and secondary outcome measures included the proportion of patients achieving target IOP and the proportion of patients achieving therapeutic response defined as a reduction of 5.0 mmHg or 20% in IOP from baseline. IOP values were the mean of 2 measures taken before and at least 2 h after patients administered the study medication.

RESULTS

A total of 164 patients were enrolled. Mean [standard deviation (SD)] population age was 63.0 (12.3) years and 53.0% of the patients were men. At week 6, the mean (SD) absolute and percent change in IOP for the total population was (-11.1) (4.9) and (-36.4)% (13.9%), respectively, and 92.1% of the patients achieved a reduction in IOP of at least 5 mmHg. Therapeutic target was achieved by 136 (82.9%) patients (DT subgroup) at 6 weeks, whereas 28 (17.1%) patients were changed to a combination therapy of DT and latanoprost [DT plus PG (DT & PG) subgroup]. Between weeks 6 and 12, DT was effective in sustaining the IOP within therapeutic target, whereas addition of latanoprost reduced the IOP of the DT & PG subgroup by an additional 6.3 mmHg or 22.1% (20.1%). At week 12, patients in the DT subgroup experienced a clinically and statistically significant mean (SD) decrease in IOP from a baseline of 12.2 mmHg or 40.4% (11.9%) (P < 0.001), whereas these values corresponded to 13.4 mmHg and 39.7% (15.7%) (P < 0.001), respectively, in the DT & PG subgroup. The proportion of patients who achieved therapeutic response during the entire 12-week study period was over 82%. Treatment-related adverse events (AEs) were reported by 19 (14.0%) patients in the DT subgroup and by 6 (21.4%) patients in the combination subgroup. Eye disorders and nervous system disorders were among the most common treatment-related AEs in both subgroups. No serious AEs were reported during the study period.

CONCLUSION

DT alone and DT in combination with a PG are effective in significantly reducing IOP in patients with untreated OAG or ocular hypertension. The treatment was safe and well tolerated with a low incidence of AEs.

Comparison of the effects of dorzolamide/timolol and latanoprost/timolol fixed combinations upon intraocular pressure and progression of visual field damage in primary open-angle glaucoma

OBJECTIVE

To report the long-term effect of the dorzolamide/timolol (DTFC) and latanoprost/timolol (LTFC) fixed combinations on intraocular pressure (IOP) and visual field defects over time in naïve primary open-angle glaucoma (POAG) patients.

STUDY DESIGN AND METHODS

Prospective, 4-year, open-label, interventional study.

SETTING

high-volume outpatient clinic.

PATIENTS

178 patients were assigned to receive medical treatment with either DTFC or LTFC.

INTERVENTION

over 4 years, tri-monthly IOP and yearly visual field assessment (Octopus 101, Program G2). outcomes: effect of treatment on IOP, visual field indices mean defect (MD), and visual field indices variance loss (VL) over time.

RESULTS

DTFC and LTFC significantly (p < or = 0.001) reduced mean IOP over time (from 22.6 +/- 3.0 to 13.8 +/- 1.9 mmHg and from 22.3 +/- 4.0 to 14.7 +/- 1.9 mmHg, respectively). In all, 56 patients (70.9%) and 14 (17.9%) showed a significant MD improvement in the DTFC- and LTFC-treated groups, respectively, p = 0.0001. DTFC progressively and significantly decreased mean VL (from 30.21 +/- 23.88 to 8.11 +/- 8.50 dB). Mean sensitivity slopes during follow-up were 1.14 dB/year and -0.34 dB/year for DTFC and LTFC treatment groups, respectively; p = 0.028.

CONCLUSION

Both treatments significantly reduced IOP as compared with baseline. Additionally, treatment with dorzolamide/timolol fixed combination seem to be effective in preventing glaucomatous visual field progression. This study has some limitations that should be noted, among them its open-label design.

Predictors for visual field progression and the effects of treatment with dorzolamide 2% or brinzolamide 1% each added to timolol 0.5% in primary open-angle glaucoma

PURPOSE

This study aims to identify progression factors in patients with primary open-angle glaucoma (POAG), including the effects of treatment with dorzolamide 2% or brinzolamide 1%, each added to timolol 0.5%.

METHODS

A sample of 161 POAG patients were prospectively randomized to receive either dorzolamide 2% (DT) or brinzolamide 1% (BT) b.i.d., each added to timolol 0.5%, during a 60-month, evaluator-masked study. Progression was determined by perimetric criteria. Factors associated with visual field progression were estimated using a conditional Cox hazard model with patient intraclass correlation and were expressed as hazard ratios (HRs) with 95% confidence intervals (95% CIs).

RESULTS

Predictive baseline factors were lower diastolic blood pressure (DBP), lower mean arterial pressure (MAP), antihypertensive treatment, lower end-diastolic velocity (EDV) in the ophthalmic artery (OA) and short posterior ciliary artery (SPCA), and a higher resistivity index (RI) in the OA and SPCA. Progression risk decreased by approximately 30% and 20% with each centimetre per second increase of EDV in the OA and SPCA, respectively, from baseline to the last follow-up visit. Each RI decrease (or increase) of 0.01 unit in the OA or SPCA was associated with an approximate 20% decrease (or increase) in risk for progression. In a multivariate analysis, progression risk was significantly lower in eyes treated with DT (HR=0.65, 95% CI 0.41-0.90) compared with those treated with BT.

CONCLUSIONS

Progression increased with lower DBP, lower MAP, antihypertensive medication, lower EDV in the OA and SPCA, and higher RI in the OA and SPCA. The risk for progression in patients treated with DT was half that in patients treated with BT.

Tolerability and effectiveness of preservative-free dorzolamide-timolol (preservative-free COSOPT) in patients with open-angle glaucoma or ocular hypertension

PURPOSE

To assess the effect of preservative-free dorzolamide-timolol on nonvisual symptoms and intraocular pressure (IOP) in newly diagnosed and untreated patients with open-angle glaucoma or ocular hypertension.

METHODS

This was a prospective, 8-week, open-label, Canadian multicenter study. All patients were treated with preservative-free dorzolamide-timolol formulation. The primary outcome was the change in the nonvisual symptom score of the Glaucoma Symptom Scale (GSS-SYMP-6) from baseline to 8 weeks. Secondary effectiveness outcome measures were absolute and percent changes in IOP from baseline to 4 and 8 weeks.

RESULTS

One hundred and seventy-eight patients were enrolled. Mean (SD) age was 65.6 (12.1) years and 90 (50.6%) were females. There were 92 patients diagnosed with open-angle glaucoma, 62 with ocular hypertension, and 23 with both diseases (diagnosis was missing for one patient). The mean (SD) GSS-SYMP-6 score increased from 73.6 (21.8) at baseline to 76.1 (20.7) at 8 weeks (P = 0.097). Mean (SD) IOP significantly decreased by 11.7 (5.1) mmHg at 4 weeks (P < 0.001) and by 11.5 (5.3) mmHg at 8 weeks (P < 0.001), representing reductions of -38.5% (P < 0.001) and -38.0% (P < 0.001), respectively.

CONCLUSION

Preservative-free dorzolamide-timolol does not increase eye discomfort while significantly reducing IOP in patients with open-angle glaucoma or ocular-hypertension.

Fixed combinations of dorzolamide-timolol and brimonidine-timolol in the management of glaucoma

IMPORTANCE OF THE FIELD

The emergence of fixed-combination drugs for the treatment of glaucoma has, to some extent, changed the medical management of glaucoma. The potential benefits of these drugs include a reduction in the total number of drops and preservatives instilled per day and improved patient comfort factors, which may contribute to better compliance. Combination medications may also improve therapeutic efficacy and play an important role in controlling medication cost. However, the fixed dosing may be a disadvantage in some cases.

AREA COVERED IN THIS REVIEW

This review describes the composition, pharmacokinetics, mode of action, efficacy, side effects, and safety profile of fixed-combination dorzolamide-timolol and fixed-combination brimonidine-timolol.

WHAT THE READER WILL GAIN

Understanding of the pros, cons, and safety profile of two FDA approved fixed-combination antiglaucoma medication.

TAKE HOME MESSAGE

Fixed-combination medications may be a reasonable adjunct to prostaglandins if a large drop in the intraocular pressure (IOP) is desired and adding only one medication is unlikely to reach the target IOP range. Both mentioned drugs are effective in reducing the IOP and further clinical studies will help identify differences in efficacy between the two. The clinician must make an individualized assessment of the medication's risk-benefit profile for each patient.

Efficacy, safety and tolerability of combination therapy with timolol and dorzolamide in glaucoma and ocular hypertension

Combination pharmacotherapy has simplified and improved glaucoma medication regimens. This update focuses on the previous and recent studies on efficacy and tolerability profile of dorzolamide–timolol in adult ocular hypertension and open angle glaucoma patients. Dorzolamide–timolol has been shown to be efficacious and well tolerated in clinical trials and the adverse effects reflect those of the individual components.

Comparison of the efficacy and tolerability of preservative-free and preservative-containing formulations of the dorzolamide/timolol fixed combination (COSOPT™) in patients with elevated intraocular pressure in a randomized clinical trial

BACKGROUND

The aim of this study was to compare the efficacy and tolerability of preservative-free (PF) and preservative-containing (PC) formulations of the dorzolamide/timolol fixed combination (COSOPT™) in patients with elevated intraocular pressure (IOP).

METHODS

A parallel, randomized, double-masked study was conducted. After a 3-week run-in on timolol, patients with ocular hypertension, as confirmed by an IOP ≥22 mmHg, were randomized 1:1 to receive PF or PC dorzolamide/timolol twice daily for 12 weeks. IOP was measured at hour 0 (drug trough) and hour 2 (drug peak) at baseline (last day of 3-week timolol run-in), and weeks 2, 6 and 12.

RESULTS

A total of 261 patients were randomized. Mean baseline IOPs were 23.7 mmHg for both treatments at hour 0 and 21.2 mmHg for PF dorzolamide/timolol and 21.4 mmHg for PC dorzolamide/timolol at hour 2. At all study time points (trough and peak at weeks 2, 6, and 12), the difference between treatments in mean change from baseline IOP was <0.5 mmHg. The 95% confidence intervals for the estimated treatment difference (PF minus PC) in mean change from baseline IOP at week 12 was -0.86 to 0.23 mmHg for trough (primary endpoint) and -0.39 to 0.67 mmHg for peak (secondary endpoint). The most common adverse events were ocular burning/stinging, reported by 16.0% and 21.5% of patients receiving PF and PC dorzolamide/timolol respectively, and taste perversion, reported by 3.1% and 5.4% of patients receiving PF and PC dorzolamide/timolol respectively.

CONCLUSIONS

In patients with elevated IOP, PF and PC dorzolamide/timolol were equivalent in efficacy for change in trough and peak IOP, and had generally similar tolerability.

Efficacy and safety of travoprost/timolol vs dorzolamide/timolol in patients with open-angle glaucoma or ocular hypertension

Purpose:

To compare the intraocular pressure- (IOP-) lowering efficacy of fixed combinations travoprost 0.004%/timolol 0.5% and dorzolamide 2%/timolol 0.5% in patients with ocular hypertension or open-angle glaucoma.

Methods:

In this prospective, multicenter, double-masked, randomized clinical trial, 319 qualifying patients received either travoprost/timolol once daily in the morning (n = 157) or dorzolamide/timolol twice daily (n = 162). IOP was assessed morning and evening at 2 and 6 weeks. The primary outcome measure was mean diurnal IOP.

Results:

Baseline mean IOP values were similar between groups. Mean pooled diurnal IOP was significantly lower in the travoprost/timolol group (16.5 mmHg ± 0.23) than in the dorzolamide/timolol group (17.3 mmHg ± 0.23; P = 0.011). Mean IOP was significantly lower in the travoprost/timolol group compared to the dorzolamide/timolol group at the 9 AM time point both at Week 2 (P = 0.006) and Week 6 (P = 0.002). The travoprost/timolol combination produced mean IOP reductions from baseline of 35.3% to 38.5%, while the dorzolamide/timolol combination produced mean IOP reductions from baseline of 32.5% to 34.5%.

Conclusions:

The fixed combination travoprost 0.004%/timolol 0.5% dosed once daily in the morning demonstrated superior mean diurnal IOP-lowering efficacy compared to dorzolamide 2%/timolol 0.5% dosed twice daily in patients with ocular hypertension or open-angle glaucoma.

A network meta-analysis combined direct and indirect comparisons between glaucoma drugs to rank effectiveness in lowering intraocular pressure

OBJECTIVE

It is difficult to rank treatments according to their effect size when several treatments are available and not all treatments have been compared directly. The purpose of this study was to show a new statistical technique (network meta-analysis) to address this problem and to rank glaucoma drugs according to their intraocular pressure (IOP)-reducing effect.

STUDY DESIGN AND SETTING

Network meta-analysis of randomized controlled trials was used to combine direct and indirect estimates of the effect of eight drugs and placebo from 28 randomized controlled trials in patients with primary open-angle glaucoma or ocular hypertension patients, 6,841 for the peak effect and 6,953 patients for the trough effect.

RESULTS

All drugs differ from placebo in lowering IOP. At the peak, the rank order from high to low in terms of the mean IOP reduction reached is bimatoprost, travoprost and latanoprost, brimonidine, timolol, dorzolamide, betaxolol, brinzolamide. At the trough, this rank order is bimatoprost, latanoprost, travoprost, timolol, betaxolol, dorzolamide, brinzolamide, brimonidine. The results based on direct or indirect estimates were similar. This ranking differed from the ranking based on the mean IOP change from baseline of all arms including the study drug from all randomized controlled trials.

CONCLUSIONS

A network meta-analysis can be used to combine direct and indirect treatment effects in a formal way. Applied to glaucoma medications, it shows that there is a rank order in treatment effects on IOP.

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.

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

Glaucoma is a leading cause of irreversible visual loss. This potentially blinding disease is a progressive optic neuropathy associated with elevated intraocular pressure (IOP). Initial therapy for glaucoma typically consists of topical medications or laser treatment to lower IOP. Frequently, more than one medication is required to achieve adequate control of IOP. However, more medications means more bottles and greater complexity for the patient. There are several potential benefits of fixed combination medications compared with using the individual components separately. These include a reduction in the total number of drops and preservative instilled per day, cost savings, improved tolerability and compliance and avoiding the washout effect resulting from rapid-sequence instillation of multiple drops. Attempts to develop effective fixed combinations of glaucoma medications date back several decades. In recent years, fixed combinations of commonly paired drugs have been approved by various regulatory bodies in different countries and have gained wide acceptance. Current commercially available, fixed combination drugs include the topical beta-adrenoceptor antagonist timolol 0.5% combined with a prostaglandin, a topical carbonic anhydrase inhibitor or an alpha-adrenoceptor agonist. Although there is no uniformity among registration trial designs, most published literature compares the efficacy of the fixed combination to the individual components and to concomitant use of both components. Various factors inherent to study design such as medication run-in, washout periods and peak and trough effects have to be taken into consideration when analysing the demonstrated efficacy of fixed combinations. Fixed combination treatments offer effective IOP control while reducing the washout effect and exposure to preservatives. They are also convenient. However, fixed combinations also remove the possibility of titrating the individual components both in terms of concentration and timing of administration. In addition, fixed combinations might not always provide the same efficacy as proper use of the individual components. The clinician must make individualised assessments when weighing the convenience of these medications against their limitations for specific patients.

24-hour control of intraocular pressure with 2% dorzolamide/0.5% timolol fixed-combination ophthalmic solution in open-angle glaucoma

OBJECTIVE

To evaluate the 24-hour efficacy and tolerability of 2% dorzolamide/0.5% timolol fixed combination (DTFC) solution in open-angle glaucoma and ocular hypertension.

RESEARCH DESIGN AND METHODS

Randomized, parallel, double-masked, multicenter study. Patients with insufficiently controlled intraocular pressure (IOP > or = 22 mmHg) were randomized to DTFC (N = 117) or timolol (N = 115). IOP was measured at baseline, 6 weeks, and 8 weeks, with measurements taken at 6 p.m., 8 p.m., 10 p.m., 2 a.m., 6 a.m., 8 a.m., 10 a.m., and 2 p.m. ClinicalTrials. gov identifier: NCT00108017 MAIN OUTCOME MEASURES: Statistically significant change in IOP from untreated baseline for DTFC at all hours at week 8. Secondary outcome measures included: IOP-lowering at week 6 at all individual time points, change from baseline to 8 weeks in mean daytime IOP (average of 8 a.m., 10 a.m., 2 p.m., 6 p.m., and 8 p.m. IOPs) and night-time IOP (10 p.m., 2 a.m., 6 a.m.), and comparison of DTFC with timolol after 8 weeks.

RESULTS

Patients receiving DTFC had a statistically significant and clinically relevant reduction in IOP at week 8 compared with baseline at all eight time points (p < 0.001). Significant IOP reductions were also seen at all time points at week 6 (p < 0.001). DTFC significantly lowered mean daytime IOP and night-time IOP ( p < 0.001 for both). Timolol alone also significantly reduced IOP from baseline at 8 weeks for all diurnal time points, and mean daytime and night-time IOP ( p < 0.001 for all). Compared with timolol alone, there were significantly greater reductions with DTFC at 10 a. m. (p = 0.003) and 2 p. m. (p = 0.016), and for mean daytime IOP (p = 0.025) at 8 weeks. Significant between-treatment differences were not observed at other time points. Both treatments were well-tolerated, with no differences observed in the safety profiles between the treatment groups.

CONCLUSIONS

Both DTFC and timolol provided significant IOP reduction over the entire 24-hour measurement period. Although this study was not designed or powered to compare DTFC and timolol, DTFC exhibited greater IOP-lowering than timolol during the daytime, but not at night.

Effectiveness and Safety of Dorzolamide – Timolol Alone or Combined with Latanoprost in Open-Angle Glaucoma or Ocular Hypertension

BACKGROUND:

Treatment of glaucoma is aimed at reducing intraocular pressure (IOP) to prevent further damage to the optic nerve. For patients who do not respond to monotherapy, combination treatment may be effective in achieving therapeutic reduction or target IOP.

OBJECTIVE:

To evaluate the effectiveness and safety of dorzolamide 2% with timolol 0.5% alone or combined with latanoprost in reducing IOP in a real-world setting.

METHODS:

A prospective, open-label, multicenter, nonrandomized interventional study was designed. Three hundred fifty patients with primary open-angle glaucoma or ocular hypertension and uncontrolled IOP after latanoprost monotherapy for 4 or more weeks were treated with combination dorzolamide–timolol twice daily added to their existing latanoprost therapy (D/T-Add-On; n = 280) or dorzolamide–timolol twice daily monotherapy (D/T-Switch; n = 70). The primary effectiveness outcome measure was the change in IOP after 6 and 12 weeks of treatment.

RESULTS:

Of the total population, 313 patients completed this trial (248 D/T-Add-On; 65 D/T-Switch). After 12 weeks, the mean ± SD IOP decrease was −6.3 ± 3.6 mm Hg (–28.1%) and −5.8 ± 4.9 mm Hg (–23.5%) in the D/T-Add-On and D/T-Switch groups, respectively (both p < 0.001). Therapeutic response rates (defined as IOP reduction >20%) after 12 weeks of treatment for the D/T-Add-On and the D/T-Switch groups were 66.4% (186/280) and 52.9% (37/70), respectively. There were 116 predominantly mild, nonserious adverse events attributed to the study drugs, reported by 86 (24.6%) patients. The most frequent adverse events were eye irritation (n = 42; 12.0%) and taste perversion (n = 15; 4.3%). No serious adverse events related to the study medications were reported.

CONCLUSIONS:

In patients with primary open-angle glaucoma or ocular hypertension and elevated IOP while on monotherapy with latanoprost, switching to dorzolamide–timolol or combining dorzolamide–timolol with latanoprost are effective and safe treatment options for reducing IOP and achieving therapeutic response.