Peak pressures: crossover study of timolol and latanoprost

Comparative Efficacy and Tolerability of Topical Prostaglandin Analogues for Primary Open-Angle Glaucoma and Ocular Hypertension

Objective: To systematically review the efficacy and tolerability of 4 prostaglandin analogues (PGAs) as first-line monotherapies for intraocular pressure (IOP) lowering in adult patients with primary open-angle glaucoma or ocular hypertension. Data Sources: A literature search was performed in PubMed (1965-June 2013) and the Cochrane Library (1980-June 2013) using the search terms ocular hypertension, open-angle glaucoma, prostaglandin analogues, bimatoprost, latanoprost, tafluprost, and travoprost. Additional studies were searched from the reference lists of identified publications. Study Selection and Data Extraction: In all, 32 randomized controlled trials comparing between PGAs (bimatoprost 0.03%, latanoprost 0.005%, tafluprost 0.0015%, and travoprost 0.004%) or PGA with timolol were selected. Data Synthesis: A network meta-analysis was conducted. Using timolol as reference, the relative risks (RRs) of achieving treatment success, defined as the proportion of patients achieving at least 30% IOP reduction, with 95% CIs, were as follows: bimatoprost, 1.59 (1.28-1.98); latanoprost, 1.32 (1.00-1.74); travoprost, 1.33 (1.03-1.72); and tafluprost, 1.10 (0.85-1.42). The mean IOP reductions after 1 month were 1.98 (1.50-2.47), 1.01 (0.55-1.46), 1.08 (0.59-1.57), and 0.46 (−0.41 to 1.33) mm Hg, respectively, and the results were sustained at 3 months. Bimatoprost was associated with the highest risk of developing hyperemia, whereas latanoprost had the lowest risk, with RRs (95% CI) of 4.66 (3.49-6.23) and 2.30 (1.76-3.00), respectively. Conclusions: Bimatoprost achieved the highest efficacy in terms of IOP reduction, whereas latanoprost had the most favorable tolerability profile. This review serves to guide selection of the optimal PGA agent for individual patient care in clinical practice.

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 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).

Efficacy of Garcinia kola 0.5% Aqueous Eye Drops in Patients with Primary Open-Angle Glaucoma or Ocular Hypertension

Purpose:

To evaluate the intraocular pressure (IOP) lowering efficacy of Garcinia kola 0.5% aqueous solution eye drops in patients with newly diagnosed primary open-angle glaucoma or ocular hypertension (POAG/OH).

Materials and Methods:

A randomized, double-masked, multicenter, active-controlled prospective study. Patients who met the inclusion criteria were randomly assigned in equal numbers to receive Timolol 0.5% eye drops as a control medication (A = Group 1 eyes) or Garcinia kola 0.5% eye drops as the study medication (B = Group 2 eyes). All drops were instilled at 6 am and 6 pm daily. Goldman applanation tonometry was performed at 9 am, 12 pm and 3 pm at baseline, week-6, week-12 and week-24 visits. Voluntary and actively elicited reports of adverse events were documented. The mean change in IOP over 24 weeks was the primary outcome measure. Both groups were compared for statistically significant differences at all visits. A P < 0.05 was considered statistically significant.

Results:

A total of 178 patients were randomly assigned to G. kola and Timolol groups. At baseline there were no differences in mean IOP between groups, based on age, sex, or diagnosis. At the end of the study period (24^th week), the mean (± SD) reduction in IOP was 12.93 ± 2.3 mmHg (47.8% ± 0.8% reduction) in G. Kola group and 13.09 ± 2.8 mm Hg (48.2% ± 1.03% reduction) in the Timolol group (P > 0.05). Adverse events were mild in nature with no statistically significant differences between groups (P > 0.05).

Conclusions:

Garcinia kola ophthalmic solution significantly reduces IOP as compared to baseline. The IOP lowering effect of both treatments was equivalent.

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.

Latanoprost Nonresponders with Open-Angle Glaucoma in the Japanese Population

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Continuous Monitoring of Circadian Variations in Intraocular Pressure by Telemetry System Throughout a 12-Week Treatment with Timolol Maleate in Rabbits

AIM

The aim of this study was to examine the effect of a 12-week treatment with two formulations of timolol maleate on the amplitude of the circadian fluctuation in intraocular pressure (IOP).

METHODS

Conscious Japanese White rabbits housed under a controlled 12-hour light-dark cycle were used. IOP was measured by a telemetry system. Each animal was treated topically for 12 weeks with 0.5% timolol solution (TM) twice-daily, 0.5% timolol gel-forming solution (TM-gel) once-daily, or saline twice-daily, and the circadian variation in IOP was measured every week.

RESULTS

Administration of TM or TM-gel did not change IOP in the light phase, but significantly reduced it in the dark phase in each of the 12 weeks. The IOP reductions at 2 h after administration in the TM and TM-gel groups over the 12 weeks were, respectively, 3.6 +/- 0.3 mmHg and 3.4 +/- 0.2 mmHg versus the Saline group. The amplitudes of the circadian fluctuations in IOP in the TM group in weeks 3, 6, and 12 were 15%, 15%, and 18% smaller than those in the Saline group, while the corresponding values for the TM-gel group were 18%, 16%, and 19%, respectively.

CONCLUSIONS

TM-gel administered once-daily was as effective at lowering IOP as TM administrated twice-daily over the 12-week experimental period. This study reveals that, in rabbits, both formulations of the timolol maleate induced significant IOP reductions in the dark phase and decreased the amplitudes of the circadian fluctuations in IOP for 12 successive weeks.

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.

Glaucoma management in developing countries: medical, laser, and surgical options for glaucoma management in countries with limited resources

PURPOSE OF REVIEW

Most people affected by glaucoma live in developing countries. Recent trials and reports provide sound evidence for management of glaucoma. This review extrapolates relevant articles to the developing world.

RECENT FINDINGS

The predictive value of gonioscopy for progression of primary angle closure suspects (PACS) to primary angle closure (PAC) is only 22% (95% CI: 9.80-34.2). PACS are not uncommon; laser peripheral iridotomy (LPI) is neither indicated nor feasible for all. Twenty-eight and a half percent of PAC progress to primary angle closure glaucoma; the number needed to treat (NNT) for LPI to prevent progression is only 4. Laser peripheral iridoplasty controls acute angle closure glaucoma (AACG) faster than medical therapy alone. Primary lens extraction has also been suggested as treatment for AACG after control of the acute attack. A 5-year NNT for ocular hypertension (OH) of 20 is too high to allow treatment of all OH. High-risk OH and primary open angle glaucoma (POAG) have an NNT of 5 to 6 and merit treatment. Latanoprost and brimonidine are effective in lowering IOP in Asian eyes with POAG, but primary surgical therapy may be a more viable option. For cataract and coexistent glaucoma requiring filtration, trabeculectomy combined with the Blumenthal technique of cataract surgery may be as effective as trabeculectomy combined with phacoemulsification.

SUMMARY

The principles of glaucoma management should be the same the world over. Considering the paucity of resources and competing opportunity costs, countries with limited resources have to extrapolate available information in a sensible and cost-effective manner.