Comparison of the 24-hour intraocular pressure-lowering effects of latanoprost and dorzolamide/timolol fixed combination after 2 and 6 months of treatment

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

Association between coagulation function and patients with primary angle closure glaucoma: a 5-year retrospective case-control study

OBJECTIVE

To evaluate the association between coagulation function and patients with primary angle closure glaucoma (PACG).

DESIGN

A retrospective, hospital-based, case-control study.

SETTING

Shanghai, China.

PARTICIPANTS

A total of 1778 subjects were recruited from the Eye & ENT Hospital of Fudan University from January 2010 to December 2015, including patients with PACG (male=296; female=569) and control subjects (male=290; female=623).

OUTCOME MEASURES

Sociodemographic data and clinical data were collected. The one-way analysis of variance test was used to compare the levels of laboratory parameters among the mild, moderate and severe PACG groups. Multivariate logistic regression analyses were performed to identify the independent risk factors for PACG. The nomogram was constructed based on the logistic regression model using the R project for statistical computing (R V.3.3.2).

RESULTS

The activated partial thromboplastin time (APTT) of the PACG group was approximately 4% shorter (p<0.001) than that of the control group. The prothrombin time (PT) was approximately 2.40% shorter (p<0.001) in patients with PACG compared with the control group. The thrombin time was also approximately 2.14% shorter (p<0.001) in patients with PACG compared with the control group. The level of D-dimer was significantly higher (p=0.042) in patients with PACG. Moreover, the mean platelet volume (MPV) of the PACG group was significantly higher (p=0.013) than that of the control group. A similar trend was observed when coagulation parameters were compared between the PACG and control groups with respect to gender and/or age. Multiple logistic regression analyses revealed that APTT (OR=1.032, 95% CI 1.000 to 1.026), PT (OR=1.249, 95% CI 1.071 to 1.457) and MPV (OR=1.185, 95% CI 1.081 to 1.299) were independently associated with PACG.

CONCLUSION

Patients with PACG had a shorter coagulation time. Our results suggest that coagulation function is significantly associated with patients with PACG and may play an important role in the onset and development of PACG.

24-h Efficacy of Glaucoma Treatment Options

Current management of glaucoma entails the medical, laser, or surgical reduction of intraocular pressure (IOP) to a predetermined level of target IOP, which is commensurate with either stability or delayed progression of visual loss. In the published literature, the hypothesis is often made that IOP control implies a single IOP measurement over time. Although the follow-up of glaucoma patients with single IOP measurements is quick and convenient, such measurements often do not adequately reflect the untreated IOP characteristics, or indeed the quality of treated IOP control during the 24-h cycle. Since glaucoma is a 24-h disease and the damaging effect of elevated IOP is continuous, it is logical that we should aim to understand the efficacy of all treatment options throughout the 24-h period. This article first reviews the concept and value of diurnal and 24-h IOP monitoring. It then critically evaluates selected available evidence on the 24-h efficacy of medical, laser and surgical therapy options. During the past decade several controlled trials have significantly enhanced our understanding on the 24-h efficacy of all glaucoma therapy options. Nevertheless, more long-term evidence is needed to better evaluate the 24-h efficacy of glaucoma therapy and the precise impact of IOP characteristics on glaucomatous progression and visual prognosis.

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.

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

OBJECTIVE

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

DESIGN

Retrospective, observational cohort study.

METHODS

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

RESULTS

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

CONCLUSION

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

Twenty-four hour efficacy with the dorzolamide/timolol-fixed combination compared with the brimonidine/timolol-fixed combination in primary open-angle glaucoma

AIM

The aim of this study is to compare the 24-hour efficacy of dorzolamide/timolol-fixed combination (DTFC) and brimonidine/timolol-fixed combination (BTFC) in primary open-angle glaucoma (POAG).

METHODS

One eye each of 77 POAG patients was included in this prospective, observer-masked, crossover comparison. Following a 2-month timolol run-in period, patients had three intraocular pressure (IOP) measurements at 1000, 1200 and 1400 h while on timolol treatment. Patients showing at least a 20% IOP reduction on timolol were randomised to 3 months of therapy with DTFC or BTFC, and then were crossed over to the opposite therapy.

RESULTS

Sixty POAG patients completed the study. The mean 24-hour IOP was significantly reduced with both the fixed combinations compared with the timolol-treated diurnal IOP (P < 0.001). When the two fixed combinations were compared directly, DTFC demonstrated a lower mean 24-hour IOP level as compared with BTFC (mean difference: -0.7 mm Hg, 95% confidence interval (CI): (-1.0, -0.3), P < 0.001). At two individual time points, DTFC significantly reduced IOP more than BTFC: at 1800 h (-1.0 mm Hg, 95% CI (-1.6,-0.5), P = 0.001) and at 0200 (-0.9 mm Hg, 95% CI: (-1.4,-0.5), P = 0.001). No significant difference existed for the other time points.

CONCLUSION

Both the fixed combinations significantly reduce 24-hour IOP in POAG. DTFC provided significantly better 24-hour efficacy.

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.

Additive intraocular pressure reduction effect of fixed combination of maleate timolol 0.5%/dorzolamide 2% (Cosopt) on monotherapy with latanoprost (Xalatan) in patients with elevated intraocular pressure: a prospective, 4-week, open-label, randomized, controlled clinical trial

PURPOSE

To evaluate the additive effect of dorzolamide/timolol fixed combination in patients under monotherapy with latanoprost.

PATIENTS AND METHODS

In this prospective, 4-week, randomized, open-label controlled clinical trial, patients with open-angle glaucoma or ocular hypertension, which presented at least 15% intraocular pressure (IOP) reduction after a minimum period of 15 days of monotherapy with latanoprost and whose IOP level was considered above the established target-IOP level were randomized to receive fixed combination of timolol/dorzolamide twice daily in one of eyes. The fellow eye was kept under monotherapy and was included in the control group. A modified diurnal tension curve (mDTC) followed by the water drinking test were performed in the baseline and week 4 visits to evaluate IOP profile between groups.

RESULTS

Forty-nine per-protocol patients were analyzed. After latanoprost monotherapy run-in period, IOP levels were significantly reduced (P<0.001) in both control and study groups to 15.34+/-2.96 mm Hg and 15.24+/-2.84 mm Hg (30.8% and 32.2% IOP reduction, respectively; P=0.552). At week 4, mean baseline diurnal IOP levels were 15.60+/-3.09 and 14.44+/-3.03 (7.4% difference; P=0.01). Mean baseline IOP modified diurnal tension curve peak after latanoprost run-in period were 17.47+/-3.68 mm Hg and 17.02+/-3.35 mm Hg (control and study eyes, respectively; P=0.530). At week 4 visit, mean water-drinking test peaks were significantly reduced in the study eye group in comparison with the control group: 19.02+/-3.81 mm Hg and 20.39+/-4.19 mm Hg, respectively (6.7% reduction; P=0.039).

CONCLUSIONS

In our sample, dorzolamide 2%/timolol 0.5% fixed combination as add-on therapy in patients with open-angle glaucoma or ocular hypertension under monotherapy with latanoprost with IOP already in mid-teens levels may further enhance pressure reduction.

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.

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.

Ocular blood flow and oxygen delivery to the retina in primary open-angle glaucoma patients: the addition of dorzolamide to timolol monotherapy

PURPOSE

To assess the effects of adding dorzolamide to timolol monotherapy on ocular haemodynamics and retinal oxygen saturation in patients with primary open-angle glaucoma (POAG).

METHODS

Twenty-four patients (12 healthy, 12 with POAG) were treated with dorzolamide/timolol combination (DT) versus timolol maleate 0.5% twice daily in a randomized, crossover, double-blind study conducted over a period of 18 months. Patients received each treatment for 8 months then crossed over to the other treatment after a 1-month washout and second baseline. Goldmann applanation tonometry, Heidelberg retinal flowmetry (HRF), colour Doppler imaging (CDI) and retinal photographic oximetry were performed at each visit.

RESULTS

DT significantly reduced intraocular pressure (IOP) in both glaucomatous [right eye (OD) -13.15%, left eye (OS) -14.43%; p < 0.036] and non-glaucomatous (OD -12.4%, OS -13.88%; p < 0.039) patients compared to timolol after 8 months of treatment. DT significantly reduced the number of zero blood flow pixels in the superior (-39.72%; p < 0.014) and inferior (-51.44%; p < 0.008) retina in the non-glaucomatous group and inferior retina in the glaucomatous group (-55.38%, p < 0.006). The continuation of timolol monotherapy from baseline did not change (p < 0.05) any measured parameter and neither treatment had a significant effect (p < 0.05) on retinal oximetry or CDI parameters.

CONCLUSION

The addition of dorzolamide to timolol monotherapy decreases IOP and increases retinal blood flow in the superficial retinal vasculature in both glaucomatous and healthy patients following 8 months of treatment. The combination of increased retinal blood flow with consistent oxygen saturation may potentially increase oxygen delivery to the retina.

Efficacy and safety of fixed combinations of latanoprost/timolol and dorzolamide/timolol in open-angle glaucoma or ocular hypertension

AIMS

To compare intraocular pressure (IOP) reductions with fixed-combination (FC) latanoprost/timolol once daily in the evening vsFC dorzolamide/timolol twice daily.

METHODS

This evaluator-masked, multicentre, controlled clinical trial randomized subjects with primary open-angle glaucoma or ocular hypertension with IOP insufficiently responsive to beta-blocker therapy (screening IOP>21 and <37 mm Hg) to FC latanoprost-timolol (N=135) or FC dorzolamide/timolol (N=135). At screening, baseline, and after 4 and 12 weeks of therapy, IOP was measured three times at 0800, 1200, and 1600 hours. Adverse events were recorded at each visit. The primary efficacy end point was whether either FC could be shown to be inferior to the other with respect to change in mean daytime IOP from baseline to week 12.

RESULTS

Mean daytime IOP levels were similar at baseline. Mean reductions in daytime IOP from baseline to week 12 were -9.7 mm Hg for FC latanoprost-timolol and -9.5 mm Hg for FC dorzolamide/timolol. The difference between FC latanoprost/timolol-FC dorzolamide-timolol was -0.2 mm Hg (95% confidence interval (CI), -0.8 to -0.4 mm Hg). The upper bound of the 95% CI was <1.5 mm Hg, indicating that neither FC is inferior to the other. However, a significantly greater percentage of subjects treated with FC latanoprost/timolol achieved IOP levels<or=16 and <or=15 mm Hg (P<or=0.01). Both treatments were well tolerated.

CONCLUSIONS

When beta-blocker therapy is inadequate, either FC may achieve the desired IOP level, but FC latanoprost/timolol more often achieves a pressure of <or=16 mm Hg. Both FCs were well tolerated.

Efficacy and tolerability of latanoprost compared to dorzolamide combined with timolol in the treatment of patients with elevated intraocular pressure: a meta-analysis of randomized, controlled trials

OBJECTIVE

The aim of this study was to evaluate the efficacy and tolerability of latanoprost, compared with the combination of dorzolamide and timolol, in the treatment of patients with elevated intraocular pressure (IOP).

METHODS

Pertinent randomized, controlled trials were identified through systematic searches of the Cochrane Library, PubMed, EMBASE, Chinese Biomedicine Database, and internet searches of meeting abstracts and the manufacturers' databases. The main efficacy measures were the IOP reduction (IOPR), including diurnal mean IOPR, and 10:00 IOPR. The main tolerability measure was withdrawal due to adverse events and individual adverse events.

RESULTS

Fourteen (14) studies involving 2149 patients were included in the meta-analysis. Latanoprost was significantly more effective in lowering diurnal mean IOP than combined dorzolamide and timolol in patients with IOP insufficiently controlled by timolol alone, with a weighted mean difference (WMD) for the diurnal mean IOPR% of 3.12 (95% confidence interval, 0.47-5.78) at 3 months, and latanoprost was as effective as the combination of dorzolamide and timolol in patients without baseline timolol treatment. The combination of dorzolamide and timolol was associated with numerically greater reductions in 10:00 IOP, compared with latanoprost in patients with or without timolol treatment at baseline: only the result in patients with baseline timolol treatment at 1 month was statistically significant (WMD -4.14: range, -5.78 to -2.50). The combination of dorzolamide and timolol was less tolerated than latanoprost, with pooled relative risk for withdrawals due to adverse events being 0.34 (range, 0.13-0.84).

CONCLUSIONS

Latanoprost was associated with significantly greater efficacy in lowering diurnal mean IOP than combined dorzolamide and timolol in patients with IOP insufficiently controlled by timolol alone, and latanoprost was as effective as combined dorzolamide and timolol in patients without baseline timolol treatment. The combination of dorzolamide and timolol was less tolerated than latanoprost.

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.

Meta-analysis of 24-hour intraocular pressure studies evaluating the efficacy of glaucoma medicines

PURPOSE

To evaluate efficacy and safety data of currently available ocular hypotensive medicines derived from 24-hour studies, of similar design, in patients with primary open-angle glaucoma (POAG), exfoliative glaucoma, or ocular hypertension (OH).

DESIGN

Meta-analysis of published articles evaluating patients with POAG, exfoliative glaucoma, or OH.

METHODS

We included articles that were randomized, prospective, single- or double-masked, comparative studies of ocular hypotensive therapies over 24 hours. Each article selected contained an untreated baseline, >or=4-week treatment period, >/=20 patients per treatment arm, and >or=6 time points not spaced >5 hours apart and used Goldmann applanation or Tonopen tonometry (supine measurements) to measure intraocular pressure (IOP).

MAIN OUTCOME MEASURE

Twenty-four-hour IOP efficacy.

RESULTS

This analysis included 864 separate 24-hour treatment curves from 386 patients in 28 treatment arms from 11 studies. A statistical difference in the mean diurnal pressure decrease existed between monotherapy treatments for POAG/OH patients, with bimatoprost (29%) and travoprost (27%) showing the greatest 24-hour reduction (P = 0.026). Timolol 0.5% was less effective than latanoprost (24% vs. 19% reduction) but decreased the pressure at each night time point (P = 0.0003). Dorzolamide showed a 19% 24-hour pressure reduction and brimonidine 0.2% a 14% one. In exfoliative glaucoma patients, latanoprost and travoprost showed higher baseline and treatment pressures, although the pressure reductions (29% and 31%, respectively) were greater generally than observed with POAG/OH. An evening-dosed latanoprost/timolol fixed combination reduced the pressure 33%, and the dorzolamide/timolol fixed combination (DTFC), 26%. However, the power to detect a difference for this specific comparison was probably low, due to the limited number of patients (n = 20) in the DTFC group. A statistical difference between evening-dosed (24%) and morning-dosed (18%) latanoprost (P<0.0001) was noted, but not between evening (27%) and morning (26%) travoprost (P = 0.074). The mean reduction of night time points was statistically lower than day time points for latanoprost (P = 0.031), timolol (P = 0.032), and brimonidine (P = 0.050), but not for dorzolamide. Dorzolamide (P = 0.60), travoprost (P = 0.064), and bimatoprost (P = 0.057) did not demonstrate nighttime pressures lower than daytime ones. The mean reduction of night time points was statistically lower than that of day time points for latanoprost (P = 0.031), timolol (P = 0.032), and brimonidine (P = 0.050), but not for dorzolamide (P = 0.60), bimatoprost (P = 0.057), travoprost (P = 0.064).

CONCLUSIONS

Similar relative efficacies generally exist in various classes of ocular hypotensive agents during night and day hours.