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

Efficacy and safety of benzalkonium chloride-free fixed-dose combination of latanoprost and timolol in patients with open-angle glaucoma or ocular hypertension

Background

Benzalkonium chloride (BAK) is a common preservative in topical ocular preparations; however, prolonged use may lead to deleterious effects on the ocular surface, affecting quality of life and reducing adherence to treatment and overall outcomes. This study compared the intraocular pressure (IOP)-lowering efficacy and safety of a novel once-daily, BAK-free, fixed-dose combination of latanoprost plus timolol with latanoprost or timolol administered as monotherapy or concomitantly.

Methods

This was a 6-week, randomized, open-label, parallel-group, active-controlled study in patients aged ≥18 years with open-angle glaucoma or ocular hypertension. A total of 227 patients were randomized to either a once-daily, BAK-free, fixed-dose combination of latanoprost 0.005%/timolol 0.5% ophthalmic solution or concomitant administration of once-daily latanoprost 0.005% plus twice-daily timolol 0.5% or once-daily latanoprost 0.005% monotherapy, or twice-daily timolol 0.5% monotherapy. Efficacy end points were assessed at three time points on visits at weeks 1, 2, 4, and 6 versus baseline.

Results

The IOP-lowering efficacy of the fixed-dose combination of latanoprost/timolol was similar to that of latanoprost plus timolol administered concomitantly at all time points (mean IOP difference and 95% confidence interval within ±1.5 mmHg; P=0.4223 to P=0.9981). The fixed-dose combination of latanoprost/timolol demonstrated significantly better IOP-lowering efficacy than timolol monotherapy at all time points (P=0.001 to P<0.0001) and significantly better IOP-lowering efficacy than latanoprost monotherapy at all time points. Responder rates on at least one time point and on at least two time points with fixed-dose combination latanoprost/timolol were similar to those with concomitant latanoprost plus timolol (85.5% versus 82.1%, P=0.6360; 78.2% versus 75%, P=0.6923), but significantly better than either latanoprost or timolol monotherapy (68.5%, P=0.0355; 55.4%, P=0.0005; 57.4%, P=0.0202; and 46.4%, P=0.0006, respectively). No significant differences in ocular and nonocular treatment-emergent adverse events were found between the treatment groups.

Conclusion

A BAK-free, fixed-dose combination of latanoprost 0.005%/timolol 0.5% was as effective and well tolerated as concomitant latanoprost and timolol for treatment of elevated IOP in patients with open-angle glaucoma or ocular hypertension.

A genome-wide association study of intra-ocular pressure suggests a novel association in the gene FAM125B in the TwinsUK cohort

Glaucoma is a major cause of blindness in the world. To date, common genetic variants associated with glaucoma only explain a small proportion of its heritability. We performed a genome-wide association study of intra-ocular pressure (IOP), an underlying endophenotype for glaucoma. The discovery phase of the study was carried out in the TwinsUK cohort (N = 2774) analyzing association between IOP and single nucleotide polymorphisms (SNPs) imputed to HapMap2. The results were validated in 12 independent replication cohorts of European ancestry (combined N = 22 789) that were a part of the International Glaucoma Genetics Consortium. Expression quantitative trait locus (eQTL) analyses of the significantly associated SNPs were performed using data from the Multiple Tissue Human Expression Resource (MuTHER) Study. In the TwinsUK cohort, IOP was significantly associated with a number of SNPs at 9q33.3 (P = 3.48 × 10(-8) for rs2286885, the most significantly associated SNP at this locus), within the genomic sequence of the FAM125B gene. Independent replication in a composite panel of 12 cohorts revealed consistent direction of effect and significant association (P = 0.003, for fixed-effect meta-analysis). Suggestive evidence for an eQTL effect of rs2286885 was observed for one of the probes targeting the coding region of the FAM125B gene. This gene codes for a component of a membrane complex involved in vesicular trafficking process, a function similar to that of the Caveolin genes (CAV1 and CAV2) which have previously been associated with primary open-angle glaucoma. This study suggests a novel association between SNPs in FAM125B and IOP in the TwinsUK cohort, though further studies to elucidate the functional role of this gene in glaucoma are necessary.

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

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

Point-of-care monitoring of perioperative intraocular pressure using portable tonometry in a patient with Posner-Schlossman syndrome: a case report

A 56-year-old man with a rotator cuff injury, scheduled for arthroscopic reconstruction surgery, had a history of recurrent symptoms of eyeball pain and blurred vision for several years. After close examination, he was diagnosed with Posner-Schlossman syndrome. Three weeks before the scheduled surgery, his intraocular pressure (IOP) increased (> 30 mmHg) and he became extremely anxious about the surgery. We monitored his IOP intraoperatively and successfully completed general anesthesia without any sequelae. As Posner-Schlossman syndrome can present with severe complications that may lead to postoperative visual loss, intraoperative monitoring of intraocular monitoring and careful anesthetic management are crucial to protect vision.

The effect of vasopressin on ciliary blood flow and aqueous flow

PURPOSE

Previous experiments have shown that arginine-vasopressin (AVP) reduces intraocular pressure (IOP) dose-dependently. The present study investigated the relationships between IOP, ciliary blood flow (CilBF), and aqueous flow (AqF) responses to AVP in anesthetized rabbits.

METHODS

CilBF was measured by laser Doppler flowmetry and AqF by fluorophotometry. Mean arterial pressure (MAP) and IOP were monitored continuously and simultaneously. Perfusion pressure (PP) was varied mechanically. Four experimental protocols were performed: the dose-response (n = 11) and the pressure-flow relationship (n = 8) for CilBF and the effects on CilBF, and AqF at low (0.08 ng/kg/min; n = 14) and high AVP infusion rates (1.33 ng/kg/min; n = 12).

RESULTS

AVP decreased CilBF and IOP dose-dependently. At the low AVP infusion rate, AqF was reduced by 21.48% ± 2.52% without changing CilBF significantly. The high AVP infusion rate caused a 24.49% ± 3.53% decrease of AqF and a significant reduction in CilBF (35.60% ± 3.58%). IOP was reduced by 9.56% ± 2.35% at low and by 41.02% ± 3.19% at high AVP infusion rates. Based on the Goldmann equation, the decrease of AqF at the low AVP infusion rate accounted for 77.1% of the IOP reduction, whereas at the high AVP infusion rate, decreased AqF accounted for 28.4% of the IOP decline.

CONCLUSIONS

The results indicate that AVP can modulate IOP by different dose-dependent physiological mechanisms. The shifts of the CilBF-AqF relationship suggest that the reduction of AqF by the low AVP infusion rate is mainly provoked by inhibiting secretory processes in the ciliary epithelium. In contrast, at the high AVP infusion rate, the AqF reduction is caused by either reduced CilBF or more likely by a combined effect of reduced CilBF and secretory inhibition.

Safety and efficacy of a fixed versus unfixed brinzolamide/timolol combination in Japanese patients with open-angle glaucoma or ocular hypertension

Background

The purpose of this study was to assess the safety and efficacy of fixed-combination brinzolamide 1%/timolol 0.5% (BRINZ/TIM-FC) compared with concomitant brinzolamide 1% and timolol 0.5% (BRINZ + TIM) in Japanese patients with open-angle glaucoma (primary open-angle, exfoliation, pigmentary) or ocular hypertension.

Methods

This randomized, double-masked, multicenter, parallel-group, positive-control, Phase III study was conducted in Japan and included patients aged ≥20 years. Baseline intraocular pressure was assessed after 4 weeks of treatment with timolol 0.5%. Patients were randomized to twice-daily BRINZ/TIM-FC or BRINZ + TIM for 8 weeks (treatment phase). The primary endpoint was mean intraocular pressure reduction from baseline to week 8 at 11 am, at which time noninferiority of BRINZ/TIM-FC versus BRINZ + TIM was evaluated. Data were analyzed using repeated-measures analysis of covariance and t-tests. Adverse events and ophthalmic/physiologic variables were assessed.

Results

In total, 319 patients of mean age 64±12 years were enrolled in the treatment phase. BRINZ/TIM-FC and BRINZ + TIM were associated with reductions in mean intraocular pressure from baseline throughout the study (ranges −2.5 to −3.4 mmHg and −2.7 to −3.3 mmHg, respectively). Mean between-group differences in intraocular pressure reduction ranged from 0 to −0.3 mmHg; the upper limit of the 97.5% confidence interval for week 8 at 11 am was <1.1 mmHg, indicating noninferiority of BRINZ/TIM-FC. Treatment-related adverse events were observed in 3% and 12% of patients receiving BRINZ/TIM-FC and BRINZ + TIM, respectively. No substantial changes in other safety parameters were reported.

Conclusion

Twice-daily BRINZ/TIM-FC reduced intraocular pressure by levels similar to concomitant BRINZ + TIM in Japanese patients with open-angle glaucoma or ocular hypertension and was noninferior to BRINZ + TIM. Both treatments were well tolerated.

Efficacy and tolerability of the fixed combinations latanoprost/timolol versus dorzolamide/timolol in patients with elevated intraocular pressure: a meta-analysis of randomized controlled trials

Objective

To evaluate the efficacy and tolerability of the fixed combination of Latanoprost/Timolol versus Dorzolamide/Timolol in the treatment of patients with elevated intraocular pressure (IOP).

Methods

A comprehensive literature meta-analysis was performed according to the Cochrane Collaboration methodology to identify randomized clinical trials comparing latanoprost/timolol FC (FCLT) with dorzolamide/timolol (FCDT) in patients with elevated IOP. The efficacy estimates were measured by the weight mean difference (WMD) for the IOP reduction (IOPR) from baseline to end point, including the diurnal mean IOPR, 8 AM IOPR, 12 PM IOPR, and 4 PM IOPR. The tolerability estimates were measured by RR for adverse events. All outcomes were reported with a 95% confidence interval (CI). The data were synthesized by Stata 12.0 SE for Windows.

Results

Eight studies involving 841 patients (841 eyes) were included in the meta-analysis. With a WMD of IOPR in the diurnal mean of 0.16 mmHg (95% CI, -0.31 to 0.63), the FCLT was as effective as FCDT in lowering IOP in patients with elevated IOP (P = 0.51). The WMDs of IOPR were 0.58 mmHg (95% CI: -0.002 to 1.17) at 8 AM, -0.07 mmHg (95% CI: -0.50 to 0.36) at 12 PM, and 0.41 mmHg (95% CI: -0.18 to 1.00) at 4 PM, and there were no significant difference between FCLT and FCDT. FCLT was associated with a significantly lower incidence of eye pain, bitter taste, and irritation/stinging than FCDT, with pooled RRs of 0.34 (95% CI: 0.14 to 0.82), 0.06 (95% CI:0.008 to 0.42), and 0.35 (95% CI: 0.14 to 0.85), respectively.

Conclusion

FCLT was associated with equivalent efficacy in IOP lowering comparing with FCDT. However, FCLT was better tolerated than FCDT.

How ocular surface disease impacts the glaucoma treatment outcome

The treatment goals for glaucoma are lowering the intraocular pressure and preservation of vision. Topical hypotensive drops are the standard form of therapy which is often associated with some symptoms of toxicity, ocular inflammation, allergy, or ocular surface disease (OSD). OSD is a common comorbidity in glaucoma patients, and its prevalence with glaucoma increases with age. Use of topical treatment could additionally increase symptoms of OSD mostly due to preservatives added to multidose medication bottles used to reduce the risk of microbial contamination. This toxicity has been particularly associated with BAK, the most commonly used preservative which damages conjunctival and corneal epithelial cells and significantly aggravates OSD symptoms. OSD adversely affects patients' quality of life causing discomfort and problems with vision which in turn may result in noncompliance, lack of adherence, and eventually visual impairment. In the management of glaucoma patients OSD symptoms should not be overlooked. If they are present, topical glaucoma treatment should be adapted by decreasing the amount of drops instilled daily, using BAK-free or preservative-free medication and lubricants if necessary. Awareness of the presence and importance of OSD will in turn improve patients' adherence and compliance and thus ultimately the preservation of long-term vision.