A 3-month randomized controlled trial of bimatoprost (LUMIGAN) versus combined timolol and dorzolamide (Cosopt) in patients with glaucoma or ocular hypertension

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

Efficacy of β-blocker therapy for secondary prevention for patients undergoing coronary artery bypass grafting surgery

PURPOSE OF REVIEW

The efficacy and safety of β-blockers in the treatment of cardiovascular diseases, such as ischemic heart disease, cardiac arrhythmias, and heart failure, have been well established for decades. In this article, we review the current opinions on the application of β-blockers for secondary prevention in patients undergoing coronary artery bypass grafting (CABG) surgery.

RECENT FINDINGS

As the average age of patients treated surgically for coronary artery disease (CAD) is increasing, it is not uncommon to have candidates for CABG presenting with concomitant atrial fibrillation, heart failure or hypertension, most of which were caused by excessive activation of the adrenergic nervous system. In a recent decade, a number of national quality-improvement efforts using a variety of techniques have been made to increase the use of β-blocker therapy before or following the CABG. Results from recent large observational studies among patients with CAD showed that β-blockers were associated with a lower risk of cardiac events only among those with heart failure or recent myocardial infarction. However, the consistent use of β-blockers could benefit those with or without prior myocardial infarction who underwent CABG and discharged alive.

SUMMARY

In real-world clinical practice, β-blockers are effective and safe to control heart rate and symptoms in patients with CAD, especially for those concomitant with left ventricular systolic dysfunction or prior myocardial infarction. Current evidence supports the preoperative use of β-blocker therapy for patients undergoing CABG as a prevention of new-onset atrial fibrillation. It is reasonable to continue β-blockers as chronic therapy in all CABG patients without contraindications after hospital discharge. Further strategies should be developed to understand and improve discharge prescription of β-blockers and long-term patient adherence.

Long-term medical management of primary open-angle glaucoma and ocular hypertension in the UK: optimizing cost-effectiveness and clinic resources by minimizing therapy switches

PURPOSE

The objective was to assess the long-term economic consequences of the medical management of glaucoma in the UK.

METHODS

The economic evaluation was conducted using the results from a 10-year Markov model based around 3 key triggers for a switch in medical therapy for glaucoma, namely: lack of tolerance (using hyperemia as a proxy); intraocular pressure (IOP) not meeting treatment benchmark; and glaucoma progression. Clinical data from a comprehensive systematic literature review and meta-analysis were used. Direct costs associated with glaucoma treatment are considered (at 2008/9 prices) from the perspective of the UK NHS as payer (outpatient/secondary care setting). Using this model, the economic consequences of 3 prostaglandin-based treatment sequences were compared.

RESULTS

Drug acquisition costs account for around 8% to 13% of the total cost of glaucoma and, if ophthalmologist visits are included, amount to approximately £0.80 to £0.90 per day of medical therapy. The total long-term costs of all prostaglandin strategies are similar because of a shift in resources: increased drug costs are offset by fewer clinic visits to instigate treatment switches, and by avoiding surgery or costs associated with managing low vision. Under the latanoprost-based strategy, patients would have longer intervals between the need to switch therapies, which is largely due to a reduction in hyperemia, seen as a proxy for tolerance. This leads to a delay in glaucoma progression of 12 to 13 months. For every 1000 clinic appointments, 719 patients can be managed for 1 year with a latanoprost-based strategy compared with 586 or 568 with a bimatoprost or travoprost-based strategy.

CONCLUSIONS

Drug acquisition costs are not a key driver of the total cost of glaucoma management and the cost of medical therapy is offset by avoiding the cost of managing low vision. Economic models of glaucoma should include the long-term consequences of treatment as these will affect cost-effectiveness. This analysis supports the hypothesis that the economic and clinical benefits can be optimized by minimizing therapy switches.

The use of prostaglandin analogs in the uveitic patient

Glaucoma is a disease process characterized by progressive optic nerve damage and corresponding visual field loss. It may be further categorized into either primary open-angle glaucoma or secondary glaucoma. These secondary glaucomas include glaucomas associated with uveitis and inflammation. Prostaglandin analogs (PGA) have been used to help lower intraocular pressure (IOP) in these often difficult to manage eyes. However, controversy exists concerning their use in uveitic patients due to the theoretically higher risk of anterior uveitis, development of cystoid macular edema (CME), and reactivation of herpes simplex keratitis (HSK). There is little evidence that PGA disrupt the blood-aqueous barrier and only anecdotal evidence suggesting an increased risk of these rare findings. PGA may be used in uveitic glaucoma when other topical treatments have not lowered IOP to the patient's target range.

The management of glaucoma and intraocular hypertension: current approaches and recent advances

In the last decade, numerous novel ocular hypotensive agents have been introduced for the control of intraocular pressure (IOP). Clinicians now have more options than ever in the selection of medical therapy for the treatment of glaucoma and ocular hypertension. When selecting an ocular hypotensive medication for their patients, clinicians should consider not only the IOP-lowering efficacy of an agent, but also the ability of the drug to allow patients to achieve target levels of IOP that are low enough to stop the progression of glaucomatous damage. Other considerations should include how well the drug controls diurnal IOP, the likelihood of serious adverse events, the versatility of the medication for use as an adjunctive agent, as well as other potential attributes (ie, neuroprotection).

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.

Mixed treatment comparison of repeated measurements of a continuous endpoint: an example using topical treatments for primary open-angle glaucoma and ocular hypertension

Mixed treatment comparison (MTC) meta-analyses estimate relative treatment effects from networks of evidence while preserving randomisation. We extend the MTC framework to allow for repeated measurements of a continuous endpoint that varies over time. We used, as a case study, a systematic review and meta-analysis of intraocular pressure (IOP) measurements from randomised controlled trials evaluating topical ocular hypotensives in primary open-angle glaucoma or ocular hypertension because IOP varies over the day and over the treatment course, and repeated measurements are frequently reported. We adopted models for conducting MTC in WinBUGS (The BUGS Project, Cambridge, UK) to allow for repeated IOP measurements and to impute missing standard deviations of the raw data using the predictive distribution from observations with standard deviations. A flexible model with an unconstrained baseline for IOP variations over time and time-invariant random treatment effects fitted the data well. We also adopted repeated measures models to allow for class effects; assuming treatment effects to be exchangeable within classes slightly improved model fit but could bias estimated treatment effects if exchangeability assumptions were not valid. We enabled all timepoints to be included in the analysis, allowing for repeated measures to increase precision around treatment effects and avoid bias associated with selecting timepoints for meta-analysis.The methods we developed for modelling repeated measures and allowing for missing data may be adapted for use in other MTC meta-analyses.

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.

Clinical utility and differential effects of prostaglandin analogs in the management of raised intraocular pressure and ocular hypertension

Prostaglandin analogs (PGA) are powerful topical ocular hypotensive agents available for the treatment of elevated intraocular pressure (IOP). Latanoprost 0.005% and travoprost 0.004% are prodrugs and analogs of prostaglandin F2α. Bimatoprost 0.03% is regarded as a prostamide, and debate continues as to whether it is a prodrug. The free acids of all 3 PGAs reduce IOP by enhancing uveoscleral and trabecular outflow via direct effects on ciliary muscle relaxation and remodeling of extracellular matrix. The vast majority of clinical trials demonstrate IOP-lowering superiority of latanoprost, bimatoprost and travoprost compared with timolol 0.5%, brimonidine 0.2%, or dorzolamide 2% monotherapy. Bimatoprost appears to be more efficacious in IOP-lowering compared with latanoprost, with weighted mean difference in IOP reduction documented in one meta-analysis of 2.59% to 5.60% from 1- to 6-months study duration. PGAs reduce IOP further when used as adjunctive therapy. Fixed combinations of latanoprost, bimatoprost or travoprost formulated with timolol 0.5% and administered once daily are superior to monotherapy of its constituent parts. PGA have near absence of systemic side effects, although do have other commonly encountered ocular adverse effects. The adverse effects of PGA, and also those found more frequently with bimatoprost use include ocular hyperemia, eyelash growth, and peri-ocular pigmentary changes. Iris pigmentary change is unique to PGA treatment. Once daily administration and near absence of systemic side effects enhances tolerance and compliance. PGAs are often prescribed as first-line treatment for ocular hypertension and open-angle glaucoma.

Bimatoprost: a review of its use in open-angle glaucoma and ocular hypertension

Bimatoprost (Lumigan) is a synthetic prostamide that reduces intraocular pressure (IOP) by increasing the outflow of aqueous humour. In patients with open-angle glaucoma or ocular hypertension, long-term treatment (for up to 48 months) with once-daily bimatoprost 0.03% ophthalmic solution was more effective than timolol twice daily in providing a sustained and stable reduction in IOP. Bimatoprost 0.03% ophthalmic solution demonstrated efficacy similar to, or greater than, the prostaglandin analogues latanoprost and travoprost in reducing IOP and achieving target IOP levels. Switching to bimatoprost was as effective in maintaining diurnal IOP control as switching to a fixed combination of latanoprost/timolol (in patients with IOP levels controlled with a nonfixed combination of latanoprost plus timolol), and similarly, or more, effective in lowering IOP and providing overall diurnal IOP control than switching to a combination of dorzolamide/timolol (in patients with IOP inadequately controlled with other antiglaucoma agents including timolol). Treatment with bimatoprost was generally well tolerated, with conjunctival hyperaemia (mostly mild), growth of eyelashes and ocular pruritus being commonly reported. Other adverse events included increases in the pigmentation of the iris, perorbital areas and eyelashes.

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.

Mixed treatment comparison and meta-regression of the efficacy and safety of prostaglandin analogues and comparators for primary open-angle glaucoma and ocular hypertension

OBJECTIVES

Primary open-angle glaucoma (POAG) is a chronic condition characterised by optic neuropathy and vision loss. Elevated intraocular pressure (IOP) can damage the optic nerve and is a risk factor for glaucoma, thus treatment usually comprises topical hypotensives. This analysis aims to address methodological issues associated with the synthesis of glaucoma clinical trial data, given variations in study methodology and IOP measurement.

METHODS

Meta-regression was used to estimate how IOP varies over time for patients receiving treatment. Relative treatment effects were assessed using a random-effects mixed treatment comparison (MTC) in order to preserve randomisation and avoid selection bias. To produce clinically meaningful outputs, these analyses were combined to obtain the mean on-treatment IOP and the proportion of patients achieving different IOP targets at different time points. A further MTC estimated the probability of hyperaemia events.

RESULTS

The analysis showed that after 3 months' treatment, between 58 and 83% of patients will have a > or =20% reduction in IOP and 70-93% of patients will have an absolute IOP <20 mmHg. Latanoprost and bimatoprost were found to produce significantly lower on-treatment IOP compared with timolol (p < 0.05); the difference between latanoprost and bimatoprost was not significant. Travoprost produced a lower mean IOP compared with timolol (not significant). Latanoprost-timolol was found to produce significantly lower IOP than latanoprost alone or beta-blockers. The probability of hyperaemia-type events varied between treatments from 14.8 to 63.03%. Latanoprost had significantly lower odds of hyperaemia than travoprost, bimatoprost, travoprost-timolol, or bimatoprost-timolol.

CONCLUSION

This analysis suggests that latanoprost and bimatoprost produce a statistically significant reduction in IOP compared with timolol, but are associated with a higher risk of hyperaemia. Out of all the prostaglandins, latanoprost may achieve a good balance between tolerability and IOP efficacy. As with all forms of meta-analysis, the results are based on the assumption that the studies and intervention groupings are sufficiently similar to be compared.

A comparison of dorzolamide/timolol-fixed combination versus bimatoprost in patients with open-angle glaucoma who are poorly controlled on latanoprost

PURPOSE

The aim of this study was to evaluate the intraocular pressure (IOP) efficacy and safety of dorzolamide/timolol in fixed combination (DTFC) versus bimatoprost in open-angle glaucoma (OAG) patients poorly controlled (> or =21 mmHg) on latanoprost.

METHODS

This was a prospective, double-masked, randomized, controlled, cross-over evaluation. After a 6-week wash-out period, the patients then returned for baseline diurnal curve testing every 2 h (8 AM to 8 PM). Patients with an IOP of 22-29 mmHg inclusive at 8 AMwere randomized to either bimatoprost dosed each evening or DTFC twice-daily. Patients returned in 8 weeks for the Period 1 diurnal curve and were switched to the opposite treatment. Patients again returned in 8 weeks for the Period 2 diurnal curve.

RESULTS

Of the 29 patients, mean untreated baseline IOP (visit 2) was 24.6 +/- 2.6 mmHg and treatment mean IOP was statistically lower with bimatoprost 17.6 +/- 2.0 mmHg than for DTFC 18.8 +/- 2.5 mmHg (P = 0.03), as was the IOP range (P = 0.02) and IOP peak (P = 0.003). No significant differences were found between DTFC and bimatoprost at individual time points after a modified Bonferroni correction (>0.02). DTFC demonstrated a greater incidence of stinging or burning (n = 12) than bimatoprost (n = 0; P = < 0.0001).

CONCLUSIONS

This study suggests that OAG patients generally can obtain similar IOP control at individual time points (when a Bonferroni correction is considered) by switching to either DTFC or bimatoprost, but overall diurnal control is statistically better with bimatoprost.

Reporting of noninferiority and equivalence randomized trials for major prostaglandins: a systematic survey of the ophthalmology literature

BACKGROUND

Standards for reporting clinical trials have improved the transparency of patient-important research. The Consolidated Standards of Reporting Trials (CONSORT) published an extension to address noninferiority and equivalence trials. We aimed to determine the reporting quality of prostaglandin noninferiority and equivalence trials in the treatment of glaucoma.

METHODS

We searched, independently and in duplicate, 6 electronic databases for eligible trials evaluating prostaglandins. We abstracted data on reporting of methodological criteria, including reporting of per-protocol [PP] and intention-to-treat [ITT] analysis, sample size estimation with margins, type of statistical analysis conducted, efficacy summaries, and use of hyperemia measures.

RESULTS

Trials involving the four major prostaglandin groups (latanoprost, travoprost, bimatoprost, unoprostone) were analyzed. We included 36 noninferiority and 11 equivalence trials. Seventeen out of the included 47 trials (36%, 95% Confidence Intervals [CI]: 24-51) were crossover designs. Only 3 studies (6%, 95% CI: 2-17) reported a presented results of both ITT and PP populations. Twelve studies (26%, 95% CI: 15-39) presented only ITT results but mentioned that PP population had similar results. Thirteen trials (28%, 95% CI: 17-42) presented only PP results with no mention of ITT population results while 17 studies (36%, 95% CI: 24-51) presented only ITT results with no mention of PP population results. Thirty-four (72%, 95% CI: 58-83) of studies adequately described their margin of noninferiority/equivalence. Sequence generation was reported in 22/47 trials (47%, 95% CI: 33-61). Allocation concealment was reported in only 10/47 (21%, 95% CI: 12-35) of the trials. Thirty-five studies (74%, 95% CI: 60-85) employed masking of at least two groups, 4/47 (9%, 95% CI: 3-20) masked only patients and 8/47 (17%, 95% CI: 9-30) were open label studies. Eight (17%, 95% CI: 9-30) of the 47 trials employed a combined test of noninferiority and superiority. We also found 6 differing methods of evaluating hyperemia.

CONCLUSION

The quality of reporting noninferiority/equivalency trials in the field of glaucoma is markedly heterogeneous. The adoption of the extended CONSORT statement by journals will potentially improve the transparency of this field.

A cost-effectiveness analysis of fixed-combination therapies in patients with open-angle glaucoma: a European perspective

OBJECTIVE

To compare the efficacy and cost implications of the use of the intraocular pressure-lowering prostaglandin analogues bimatoprost, travoprost, and latanoprost as fixed-combination therapies with timolol, a beta-adrenergic receptor antagonist.

METHODS

A decision analytic cost-effectiveness model was constructed. Since no head-to-head studies comparing the three treatment options exist, the analysis was based on an indirect comparison. Hence, the model was based on efficacy data from five randomized, controlled, clinical studies. The studies were comparable with respect to study design, time horizon, patient population and type of end point presented. The measure of effectiveness was the percentage reduction of the intraocular pressure level from baseline. The cost evaluated was the cost of medication and clinical visits to the ophthalmologist. All drug costs were market prices inclusive of value-added tax, and visit costs were priced using official physician fees. Cost-effectiveness analyses were carried out in five European countries: Spain, Italy, United Kingdom, Norway and Sweden. The time horizon for the analyses was 3 months.

RESULTS

The analysis showed that fixed-combination bimatoprost/timolol was more effective and less costly than fixed-combination travoprost/timolol and fixed-combination latanoprost/timolol in three out of the five countries analyzed. In two countries, bimatoprost/timolol was less costly than latanoprost/timolol, and cost the same as travoprost/timolol.

CONCLUSIONS

This cost-effectiveness analysis showed that the fixed combination of bimatoprost 0.03%/timolol 0.5% administered once daily was a cost-effective treatment option for patients with primary open-angle glaucoma. This study was limited by available clinical data: without a head-to-head trial, indirect comparisons were necessary. In the United Kingdom, Sweden, Norway, Italy, and Spain, from a health service viewpoint, bimatoprost/timolol was a slightly more effective as well as less costly treatment strategy when compared to both travoprost/timolol and latanoprost/timolol.

A multicentre evaluation of the effect of patient education on acceptance of hyperaemia associated with bimatoprost therapy for glaucoma or ocular hypertension

INTRODUCTION

The aim of this study was to evaluate the incidence of hyperaemia in patients using bimatoprost and to determine if simple interventions result in increased understanding of glaucoma and hyperaemia.

METHODS

This was a multicentre, open-label, evaluator-masked clinical trial of 106 patients. Prior to enrolling in the trial, patients were washed out from any ocular hypotensive medications and prescribed bimatoprost daily in the evening for 6 weeks. Patients were randomised to one of two groups: intervention and no intervention. Patients in the intervention group (n=63) were given a fact sheet explaining the importance of reducing intraocular pressure (IOP) and the efficacy of bimatoprost, while patients in the no intervention group (n=43) were instructed only to instil bimatoprost daily and were given no additional instructions.

RESULTS

As graded by the masked investigators, conjunctival hyperaemia peaked 1 day after commencing bimatoprost, with a mean of 1.2 (0=none, 0.5=trace, 1=mild, 2=moderate, 3=severe). By day 7, hyperaemia levels were approximately trace (0.79) and continued to decrease throughout the study. There were no significant differences between groups in mean conjunctival hyperaemia at any study visit (P> or =0.215). At every visit, patients in the intervention group were significantly more likely than patients in the no intervention group to report that lowering IOP was very important for preserving vision (P< or =0.001). At week 6, 98% of patients in the intervention group reported that IOP-lowering was very important for preserving vision, compared with 76% of patients who did not receive the intervention (P< or =0.001). Patients in the intervention group were more likely than patients in the no intervention group to be willing to continue to use bimatoprost, despite hyperaemia. This difference was statistically significant at day 1 (P=0.003).

CONCLUSION

Patients were not bothered by the trace.mild hyperaemia associated with bimatoprost therapy. Patient education can improve patient acceptance of a prescribed regimen and potentially increase compliance.

A critical review of the full economic evaluations of pharmacological treatments for glaucoma

OBJECTIVE

This literature review aimed to critically assess the 'state of the art' of the full economic evaluations (FEEs) on glaucoma pharmacological treatments. This is the first review that tries to thoroughly assess both costs and consequences of pharmacoeconomic evaluations on glaucoma.

METHODS

A literature search was done on the international databases PubMed and EMBASE, to find all the studies published in English on pharmacological treatments for glaucoma in the period 1997-2006. An economic and a clinical checklist were adopted to analyse FEEs and their clinical sources (CS). Finally, the reliability of the 33 FEEs included in the 15 articles selected was assessed from the health authorities' perspective by applying a critical appraisal checklist of 16 items derived from the economic and clinical variables previously analysed.

RESULTS

The major weakness of the articles reviewed seemed to be the extensive recourse to expert panel opinions and assumptions at each phase of the economic analysis. About one-third of the FEEs even based their clinical efficacy on non-evidence-based sources. The critical appraisal of the CS methodological characteristics showed that their quality was not high either.

CONCLUSION

This review showed that most FEEs on glaucoma suffer substantial methodological limits, mainly due to the scarce quality of available CSs, so public authorities should consider their results very cautiously for healthcare decision making.

Topical dorzolamide 2%/timolol 0.5% ophthalmic solution: a review of its use in the treatment of glaucoma and ocular hypertension

Topically administered dorzolamide 2%/timolol 0.5% (dorzolamide/timolol ophthalmic solution; Cosopt) is a fixed combination of two ocular hypotensive drugs (the carbonic anhydrase inhibitor dorzolamide and the beta-adrenoceptor antagonist timolol) that have an additive effect on lowering intraocular pressure (IOP) when administered together. This product is indicated for the treatment of elevated IOP in patients with open-angle glaucoma or ocular hypertension (OH) who are insufficiently responsive to topical beta-adrenoceptor antagonist monotherapy. As such, it can be considered for use in individuals who, as a consequence of failing to achieve target IOP with beta-adrenoceptor antagonist monotherapy, require the addition or substitution of another class of topical antiglaucoma medication. Clinical trials have demonstrated that dorzolamide/timolol (1 drop per eye twice daily) is an effective and generally well tolerated fixed combination for lowering IOP in patients with open angle glaucoma or OH, including individuals uncontrolled on beta-adrenoceptor antagonist monotherapy. Compared with concomitant therapy with the individual components, the primary advantage of fixed combination dorzolamide/timolol is convenience.

Comparison of the ocular hypotensive effects of bimatoprost and timolol-dorzolamide combination in patients with elevated intraocular pressure: a 6-month study

PURPOSE

To compare the ocular hypotensive efficacy and safety of topical bimatoprost and timolol-dorzolamide combination in patients with primary open-angle glaucoma (POAG) or ocular hypertension during 6 months of treatment.

METHODS

A sample of 65 patients with a diagnosis of POAG or ocular hypertension were randomized to receive either bimatoprost 0.03% once daily or timolol-dorzolamide combination twice daily. Study visits occurred at baseline and after 2 weeks and 1, 3 and 6 months of therapy. Intraocular pressure (IOP) measurements were performed at 12.00 hours at all study visits and also at 08.00 hours and 16.00 hours at baseline and 6-month visits. At each visit, local and systemic side-effects that occurred during the treatment period were recorded. Student's t-test was used to compare the differences between IOP values.

RESULTS

Differences in IOP between the bimatoprost and timolol-dorzolamide groups were statistically insignificant at all study visits (p > 0.05). In the bimatoprost-treated group, the IOP reduction was 6.2 +/- 1.8 mmHg, whereas it was 6.5 +/- 2.3 mmHg in the timolol-dorzolamide group after 6 months of treatment. The difference was not statistically significant (p = 0.48).

CONCLUSIONS

The IOP-lowering efficacies of bimatoprost and timolol-dorzolamide combination were similar over a 6-month follow-up. Both bimatoprost and the timolol-dorzolamide combination were well tolerated. Bimatoprost can be used as a longterm monotherapy agent in the treatment of POAG and ocular hypertension.

The side effects of the prostaglandin analogues

In the last decade topically applied prostaglandin F2alpha analogues (bimatoprost, latanoprost, travoprost and unoprostone) have become widely used as a means to reduce elevated intraocular pressure in patients with glaucoma and ocular hypertension. These molecules all have similar side-effect profiles, which include both side effects that occur frequently (e.g., conjunctiva hyperaemia, increase of iris pigmentation and eyelash changes) and rare adverse reactions (e.g., periocular pigmentation, damage to the blood-aqueous barrier and cystoid macular oedema). Conjunctiva hyperaemia, eyelash changes and cystoid macular oedema are reversible, but certain other side effects, such as increased iris pigmentation, are not. However, the systemic side-effect profile is favourable for all the prostaglandin analogues, and some of the local side effects are only of cosmetic significance. Numerous clinical studies suggest that discontinuing treatment with prostaglandin analogues on account of their side effects is rare in clinical practice.

Intraocular Pressure–Lowering Effect of Adding Dorzolamide or Latanoprost to Timolol

OBJECTIVE

To estimate the intraocular pressure (IOP)-lowering effect of 2% dorzolamide or 0.005% latanoprost when added to 0.5% timolol.

DESIGN

Meta-analysis of randomized clinical trials.

PARTICIPANTS

Seventeen articles reporting on 19 study arms with 5 possible treatment combinations and 4 study arms serving as controls.

METHODS

Articles written in English, German, French, or Dutch and published up to December 2004 were identified in Medline, Embase, the Cochrane Controlled Trials Register, and references from relevant articles. For the article to be considered, over 85% of the patients had to have primary open-angle glaucoma or ocular hypertension. The pooled 1- to 3-month additional IOP-lowering effect after a run-in phase on timolol was calculated by performing meta-analysis using the random effects model.

MAIN OUTCOME MEASURES

Absolute and relative changes in IOP after run-in on timolol for peak moment, trough moment, or mean diurnal curve.

RESULTS

The pooled change from baseline [mean (95% confidence interval)] for 0.5% timolol varied from -0.7 mmHg (-1.2 to -0.2, for the mean diurnal curve) to -2.0 mmHg (-1.3 to -2.7, at peak). Pooled changes for 2% dorzolamide in concomitant use with 0.5% timolol were -4.1 mmHg (-4.4 to -3.8) at trough and -4.9 mmHg (-5.3 to -4.5) at peak. The fixed 2% dorzolamide and 0.5% timolol combination resulted in a pooled change of -3.8 mmHg (-4.2 to -3.4) at trough and -4.9 mmHg (-5.3 to -4.5) at peak. The concomitant use of 0.005% latanoprost and 0.5% timolol gave a pooled change from baseline of -6.0 mmHg (-6.8 to -5.2) at the mean diurnal curve. The fixed combination of 0.005% latanoprost and 0.5% timolol resulted in a mean change of -3.0 mmHg (-3.8 to -2.2) at the mean diurnal curve.

CONCLUSION

In this meta-analysis of clinical trials, the addition of dorzolamide or latanoprost further lowers IOP in eyes on timolol. This result may not be generalizable because these trials may have included nonresponders to timolol.

Diurnal IOP control with bimatoprost versus latanoprost in exfoliative glaucoma: a crossover, observer-masked, three-centre study

AIM

To evaluate the diurnal intraocular pressure (IOP) control and safety of bimatoprost versus latanoprost in exfoliative glaucoma (XFG).

METHODS

One eye of 129 consecutive patients with XFG (mean (SD) age 66.5 (8.3) years) was included in this prospective, observer-masked, three-centre, crossover comparison. After a 4-6 week medicine-free period patients were randomised to bimatoprost or latanoprost monotherapy for 3 months. Patients were then switched to the opposite treatment for another 3 months. At the end of the washout and the treatment periods diurnal IOP was measured at 0800, 1300, and 1800.

RESULTS

At baseline the IOP (mean (SD)) was 28.0 (4.0), 26.9 (3.6), and 25.9 (3.6) mm Hg, at the three time points, respectively. Both treatments significantly reduced mean diurnal IOP at month 3. Mean diurnal IOP was 26.9 (3.5) mm Hg at baseline, 17.6 (3.3) mm Hg with bimatoprost, and 18.6 (3.6) mm Hg with latanoprost (p<0.0001). Furthermore, lower IOP values were obtained with bimatoprost at all time points (17.9 (3.4), 17.3 (3.3), and 17.6 (3.5) mm Hg, respectively) compared with latanoprost (18.7 (3.6), 18.5 (3.6), and 18.6 (4.1) mm Hg, respectively). The corresponding mean differences (0.8, 1.1, and 1.0 mm Hg, respectively) were all significant (p<0.001 for each comparison). Significantly more patients with XFG obtained a target diurnal IOP <17 mm Hg with bimatoprost than with latanoprost, 55/123 (45%) v 34/123 (28%); (p = 0.001), and significantly fewer patients were non-responders with bimatoprost than with latanoprost (5 v 13, p = 0.021). More patients reported at least one adverse event with bimatoprost than with latanoprost (58 v 41 at 3 months; p = 0.0003).

CONCLUSION

This crossover study suggests that better diurnal IOP control is obtained with bimatoprost than with latanoprost in patients with XFG.

Ocular hypotensive effects of an intratracheally delivered liposomal delta9-tetrahydrocannabinol preparation in rats

This study investigated the effect of an intratracheal (i.t.) administration of a liposome-entrapped Delta9-tetrahydrocannabinol (LTHC) preparation on intraocular pressure (IOP) in nonanaesthetized Brown Norway rats. The ocular hypotensive effects of i.t. LTHC were compared to that of intraperitoneal (i.p.) LTHC administration. All i.t. LTHC doses >0.05 mg/kg significantly decreased IOP (P < 0.05) within 30 min of administration, and doses of i.t. LTHC >0.1 mg/kg decreased IOP within 15 min of administration. A maximal reduction in IOP of 2.32 +/- 0.27 mmHg (n = 4) was seen with 1.0 mg/kg of i.t. LTHC. In comparison, no significant IOP drop was apparent prior to 30 min with all doses (0.01-1.0 mg/kg) of i.p. LTHC tested, although a similar maximum drop in IOP (2.15 +/- 0.12 mmHg; n = 8) was obtained with 1.0 mg/kg of LTHC. The ED(50) for i.t. and i.p. LTHC was 0.08 mg/kg and 0.12 mg/kg, respectively. The IOP-lowering effects of i.p. LTHC (0.2 mg/kg) were reduced by 14% and 80% by 0.25 mg/kg (n = 6) and 2.5 mg/kg (n = 6), respectively, of the CB1R antagonist, SR141716A. In conclusion, i.t. LTHC was superior to i.p. LTHC in producing a more rapid and potent decrease in IOP. The IOP-lowering effect of LTHC was blocked by the CB1R-selective antagonist, SR141716A, suggesting that CB1Rs contribute to the ocular hypotensive effect of Delta9-tetrahydrocannabinol.

Clinical pharmacology of bimatoprost

Bimatoprost (Lumigan), Allergan) is a highly efficacious ocular hypotensive agent that provides good diurnal control of intraocular pressure in glaucoma and ocular hypertensive patients. Bimatoprost is a synthetic molecule that is structurally and pharmacologically similar to prostamide F(2), and appears to mimic the activity of the prostamides. Consistent with prostamide-mimetic activity, bimatoprost has potent inherent pharmacological activity in prostamide-sensitive preparations and essentially remains intact in the living primate eye. This is sufficient to explain its potent and efficacious ocular hypotensive activity, and suggests that bimatoprost is a pharmacologically unique compound.

Cost considerations in the medical management of glaucoma in the US: estimated yearly costs and cost effectiveness of bimatoprost compared with other medications

INTRODUCTION

The aim of this study was to evaluate the cost effectiveness of glaucoma treatment with bimatoprost compared with other intraocular pressure (IOP)-lowering medications in adult patients with chronic glaucoma or ocular hypertension (IOP of between 22 mm Hg and 34 mm Hg), from a US healthcare payers' perspective.

METHODS

Estimated yearly costs and cost per treatment success for 0.03% bimatoprost once daily (Lumigan) were compared with 0.5% timolol twice daily (generic), 0.005% latanoprost once daily (Xalatan) and the fixed combination of 0.5% timolol and 2.0% dorzolamide twice daily (Cosopt). The model was based on year 2003 medical resource costs (physician visits and drug acquisition costs) and treatment success rates from published clinical trials. The clinical measure utilised was the percentage of patients achieving target IOPs.

RESULTS

A higher percentage of patients achieved target IOPs with bimatoprost than with each of the other medications. At most target pressures, the cost per treatment success for patients starting treatment on bimatoprost was less than that for patients started on other drugs. This was true despite that, when looking at costs alone, the estimated yearly costs for bimatoprost (averaged over both patient success and patient failures) were similar to or greater than those for the other drugs. The greatest differences in cost per treatment success were seen at target pressures < or =15 mm Hg. For example, at a target pressure of 13 mm Hg, the cost per treatment success based on the model was 9238-10,229 US dollars for bimatoprost, 23,218 US dollars for timolol, 21,943 US dollars for latanoprost and 16,034 US dollars for timolol/dorzolamide. The incremental cost of achieving additional clinical success for bimatoprost ranged from 800 US dollars to 1,700 US dollars versus generic timolol, and from 300 US dollars to 3,100 US dollars versus timolol/dorzolamide. Bimatoprost was more effective and less costly than latanoprost.

CONCLUSION

In our simplified model of cost per treatment success based on responder rates at varying IOPs, the greater efficacy of bimatoprost resulted in a cost per treatment success that was generally lower for bimatoprost than for timolol, latanoprost or timolol/dorzolamide. This was most pronounced at target pressures <15 mm Hg.

Analytic review of bimatoprost, latanoprost and travoprost in primary open angle glaucoma

OBJECTIVE

The objective of this review was to evaluate different measures of efficacy of the intraocular pressure (IOP) lowering lipid class agents bimatoprost, latanoprost and travoprost in the treatment of primary open angle glaucoma. Study arms of timolol in trials including the above mentioned lipid class drugs were also included.

METHODS

MEDLINE and EMBASE were searched for randomized clinical trials including one or more of the lipid class drugs bimatoprost, latanoprost and travoprost. The study results were pooled, and the simple, weighted IOP-lowering efficacy was compared among the lipid class drugs and timolol, where data were available. Efficacy parameters were reviewed, including mean reduction of IOP and percentage of patients achieving different levels of IOP.

RESULTS

161 articles were identified of which 42 were included in the analysis. A total of 9295 patients participated in the included trials. Based on all studies, timolol on average had a weighted mean IOP reduction of 22.2%, while latanoprost, travoprost and bimatoprost had a weighted mean IOP reduction of 26.7%, 28.7% and 30.3%, respectively. Analysis of target achievement to various IOP levels shows that bimatoprost seems more efficacious than latanoprost. The direct comparisons (head-to-head studies) also show that bimatoprost is the most efficacious treatment, however it is not conclusive whether latanoprost or travoprost is better in reducing IOP.

CONCLUSIONS

This review shows that bimatoprost seems to be the most efficacious treatment in lowering IOP. Head-to-head studies confirm this.

Timolol/dorzolamide combination therapy as initial treatment for intraocular pressure over 30 mm Hg

PURPOSE

To determine the intraocular pressure (IOP)-lowering effect of a fixed timolol/dorzolamide combination (Cosopt) for patients with IOP over 30 mm Hg.

STUDY DESIGN

Prospective interventional case series.

METHODS

Eighteen patients being seen on the Wills Eye Hospital Glaucoma Service with at least one eye with an IOP > 30 mm Hg were recruited. None had used any glaucoma medications for at least 1 month. IOP was confirmed by diurnal testing. Cosopt was administered at 9 am and 9 pm. Trough IOP measurements were made at 9 am and peak IOP measurements at 11 am at baseline, 1 month, and 2 months. Pretreatment and posttreatment IOPs were compared using a paired-samples independent t test.

RESULTS

Mean pretreatment IOP was 37.5 +/- 1.0 mm Hg. Baseline posttreatment IOP was 18.4 +/- 0.5 mm Hg (P < 0.01). At 2 months, the mean trough IOP was 21.1 +/- 0.9 mm Hg and the peak, 17.6 +/- 0.6 mm Hg (each, P < 0.01, as compared with pretreatment baseline IOP). One patient did not respond to Cosopt; two had a clinically insufficient response and did not complete the study. Data from these patients were included in the analysis.

CONCLUSIONS

Over 80% of the eyes responded to Cosopt, with an average trough IOP reduction of 40% at 2 months.

Management of glaucoma: focus on pharmacological therapy

Glaucoma represents a major cause of vision loss throughout the world. Primary open-angle glaucoma, the most common form of glaucoma, is a chronic, progressive disease often, though not always, accompanied by elevated intraocular pressure (IOP). In this disorder, retinal ganglion cell loss and excavation of the optic nerve head produce characteristic peripheral visual field deficits. Patients with normal-tension glaucoma present with typical visual field and optic nerve head changes, without a documented history of elevated IOP. A variety of secondary causes, such as pigment dispersion syndrome and ocular trauma, can result in glaucoma as well. Treatment of all forms of glaucoma consists of reducing IOP. With proper treatment, progression of this disease can often be delayed or prevented. Treatment options for glaucoma include medications, laser therapy and incisional surgery. Laser techniques for the reduction of IOP include argon laser trabeculoplasty and selective laser trabeculoplasty. Both techniques work by increasing outflow of aqueous humour through the trabecular meshwork. Surgical options for glaucoma treatment include trabeculectomy, glaucoma drainage tube implantation and ciliary body cyclodestruction. While each of these types of procedures is effective at lowering IOP, therapy usually begins with medications. Medications lower IOP either by reducing the production or by increasing the rate of outflow of aqueous humour within the eye. Currently, there are five major classes of drugs used for the treatment of glaucoma: (i) cholinergics (acetylcholine receptor agonists); (ii) adrenoceptor agonists; (iii) carbonic anhydrase inhibitors (CAIs); (iv) beta-adrenoceptor antagonists; and (v) prostaglandin analogues (PGAs). Treatment typically begins with the selection of an agent for IOP reduction. Although beta-adrenoceptor antagonists are still commonly used by many clinicians, the PGAs are playing an increasingly important role in the first-line therapy of glaucoma. Adjunctive agents, such as alpha-adrenoceptor agonists and CAIs are often effective at providing additional reduction in IOP for patients not controlled on monotherapy. As with any chronic disease, effective treatment depends on minimising the adverse effects of therapy and maximising patient compliance. The introduction of a variety of well tolerated and potent medications over the past few years now allows the clinician to choose a treatment regimen on an individual patient basis and thereby treat this disorder more effectively.

[Bimatoprost in the treatment of ocular hypertension and chronic glaucoma]

PURPOSE

The aim of this study was to evaluate the efficacy and the safety of bimatoprost in an outpatient glaucoma practice and to correlate the responsiveness to this treatment with the central corneal thickness.

MATERIALS AND METHODS

Our retrospective analysis included 55 consecutive patients (mean age, 66 years). Bimatoprost was administered in monotherapy in 32 patients and in combined treatment in 23. Mean follow-up was 5.5 months. In bilateral treatments (33/55 patients), only one eye (with the more severe defect and/or the higher IOP) was included in the analysis. The patients were considered as responders to bimatoprost when the observed reduction of IOP was > or = 20% and/or at least 3 mmHg compared with the pretreatment IOP. The mean central corneal thickness (CCT) was extrapolated from five consecutive measurements with the ultrasonic pachymeter Pachette.

RESULTS

Overall, the mean IOP was reduced from a pretreatment value of 21.1 mmHg to 17.3 mmHg at the last visit (mean IOP decrease, 3.6 mmHg, or 17%) (p < 0.05). Except for four patients (7.3%) who discontinued bimatoprost secondary to local or systemic adverse effects, ocular tolerance of bimatoprost was excellent in 62%. Moderate conjunctival hyperemia was present in 18%. The mean IOP reduction was 19% in monotherapy and 15% in combined treatments. Concomitantly, the percentage of responders was slightly higher in patients only receiving bimatoprost than in patients receiving bimatoprost associated with other medication (s). In monotherapy, bimatoprost induced a further IOP decrease of 12% compared with a previous association of two medications that did not include a prostaglandin (10 patients). In the 20 patients in whom bimatoprost had replaced another prostaglandin, a further mean IOP reduction of 11% was observed. The frequency of distribution of the responders to bimatoprost was not correlated with CCT (chi2, p > 0.05).

CONCLUSIONS

Considering the limits of this study, our results suggested that bimatoprost was effective and well tolerated in most patients. The decrease in IOP and responsiveness to treatment appeared to be slightly higher in monotherapy than in combined treatments, equivalent to a combination of two medications without prostaglandin and equivalent to or slightly higher than other prostaglandins. The degree of responsiveness did not seem to be correlated with CCT.