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ORIGINAL ARTICLE
Year : 2011  |  Volume : 14  |  Issue : 1  |  Page : 29-33

Real-life experience study of the safety and efficacy of travoprost 0.004% / timoptol 0.50% fixed combination ophthalmic solution in intraocular pressure control


1 Department of Royle Eye, Pilgrim Hospital, Boston, Lincolnshire, England
2 Department of Ophthalmology, Ahmadu Bello University, Teaching Hospital Zaria, Nigeria

Date of Acceptance13-Apr-2010
Date of Web Publication11-Apr-2011

Correspondence Address:
C Olali
Department of Royle Eye, Pilgrim Hospital, Boston, Lincolnshire
England
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1119-3077.79236

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   Abstract 

Purpose: To evaluate the safety and efficacy of timolol 0.5%/travoprost 0.004% combination (duotrav) as observed in primary open-angle glaucoma (POAG), ocular hypertension (OHT) and normal tension glaucoma (NTG) in real-life conditions.
Materials and Methods: Patients with uncontrolled intraocular pressure (IOP) on other medication and no contraindication to β-blockers were switched to duotrav in 56 eyes of 28 patients. The drop in IOP was the primary outcome measured.
Results: Switch to duotrav provided an additional IOP reduction
after 3-month follow-up that was statistically significant for those on latanoprost (P=0.02857), bimatoprost (P =0.04978) and travoprost (P =0.0078). Patients on latanotrost had an additional 25.9% drop 3 months after switching to duotrav while those on bimatoprost and travatan had 18.04% and 17.59% drop, respectively, after the switch. It was effective in lowering the IOP to clinically significant levels of ≤18.5 mmHg in POAG, NTG and OHT (12.5-17.9% drop), but not in chronic angle closure glaucoma.
Conclusion: Duotrav was well-tolerated and produced significant additional IOP reduction when switched from other anti-glaucoma drugs in patients with uncontrolled glaucoma. It also achieved IOP of ≤ 18.5 mmHg in glaucoma patients.

Keywords: Additional lowering, compliance, intraocular pressure, timolol, travoprost


How to cite this article:
Olali C, Malietzis G, Ahmed S, Samaila E, Gupta M. Real-life experience study of the safety and efficacy of travoprost 0.004% / timoptol 0.50% fixed combination ophthalmic solution in intraocular pressure control. Niger J Clin Pract 2011;14:29-33

How to cite this URL:
Olali C, Malietzis G, Ahmed S, Samaila E, Gupta M. Real-life experience study of the safety and efficacy of travoprost 0.004% / timoptol 0.50% fixed combination ophthalmic solution in intraocular pressure control. Niger J Clin Pract [serial online] 2011 [cited 2019 Sep 20];14:29-33. Available from: http://www.njcponline.com/text.asp?2011/14/1/29/79236


   Introduction Top


Intraocular pressure (IOP) control remains the cornerstone in glaucoma management because, although the disease has multiple risk factors, modulating the IOP is the only proven strategy in reducing the risk of progressive retinal ganglion cell death. Ganglion cell death results in visual field loss and unacceptable quality of life.

Drugs play a frontline role in IOP reduction in glaucoma and for years, β-blockers were the leading medicines in use because of their capacity to slow the rate of aqueous humour production. [1],[2],[3]

In the past decade and half, newer generation of anti-glaucoma drugs have emerged making this role even more significant. The prostaglandin (PG) analogs and prostamides are one such group.

Travoprost (Travatan ophthalmic solution, Alcon laboratories, Inc., Ft. Worth, TX) is a prostaglandin PGF2 -synthetic analog that is rapidly metabolized by corneal esterases to its active free acid. This has a high affinity for and full agonist efficacy at the FP receptor [4] and it is believed that interaction between the free acid and the FP receptor leads to structural changes within the ciliary body that facilitates aqueous outflow via the uveoscleral pathway. [5],[6] Travoprost is safe and quite potent in lowering IOP and is now one of the first-line agents for IOP control in glaucoma.

However, monotherapy has been found inadequate in achieving targeted IOP control in 40% of patients [7] and therefore multidrug therapy is common in glaucoma management. This is usually prescribed as separate bottles or in fixed combination where possible. Separate bottles prescription has several drawbacks-low compliance rate, more preservatives and so likely more side effects and higher cost.

Travoprost and the β-blocker timoptol fixed combination (Duotrav) is one with complimentary mechanisms of action and with the advantage of reducing the concerns associated with using separate bottles. Earlier studies on this fixed combination have been carried out in clinical predesigned settings such as stopping earlier antiglaucoma medicines to allow for the washout periods and choosing the specific types of glaucoma for the study. While running clinics, however, we know that drug modifications in the event of lower than expected performance of earlier one (s) is effected without recourse to the above.

The purpose of this study was therefore to evaluate the safety and efficacy of this fixed combination (Duotrav) as observed in day-to-day glaucoma clinic conditions.


   Materials and Methods Top


This was a nonrandomized prospective interventional study, carried out in the department of Ophthalmology, Pilgrim Hospital, Boston, England.

The already existing specialist glaucoma clinics run by two experienced ophthalmologists were used for the study.

Patients on regular follow up for primary open-angle glaucoma (POAG), normal tension glaucoma (NTG), ocular hypertension (OHT), chronic angle closure glaucoma (CACG), with inadequately controlled IOP/progressive disease on other medications and/or post-glaucoma surgery who fulfilled the following criteria were recruited.

  1. All sex, race and age >18years.
  2. No inflammatory or rubeotic glaucoma
  3. No known contraindication to β-blocker or PG use.
  4. No documented side effect from other antigalucoma medication
The patients were seen in the regular clinic setting during morning (09.00-13.00 hrs), afternoon (14.00 -17.00 hrs and evening (17.00-19.00 hrs) sessions and once a case was identified as suitable (vida supra), detailed ocular examination was repeated and these included best corrected vision, slit lamp examination of the anterior segment looking for anterior chamber inflammatory cells, IOP, gonioscopy, dilated fundoscopy and visual field. The IOP was measured with the Goldman applantion tonometer and optic disc assessed with the +78D or +90 D aspheric lens. Also documented was the type of glaucoma, the IOP at the time of initial diagnosis as well as that before commencement of the new treatment. For the purpose of this study, the IOP before the commencement of the duotrav eye drop was taken as the baseline.

All previous treatment for the disease was recorded and the patients told that the treatment required some modification aimed at better control of the IOP and thus the disease. Informed consent was sought, potential adverse effects explained and what to do if any occurred fully communicated to each one before whatever treatment the patient was on replaced with the fixed combination of timolol 0.5% and travoprost 0.004% fixed combination (duotrav) once daily. Each patient was reviewed at 3 months or earlier if indicated at the same period (morning or evening clinic) of the day when the duotrav was commenced.and the vision, slit lamp findings, fundoscopy, IOP, fields as well as any side effects (local and systemic) recorded.

Data analysis: Statistical analysis for efficacy and was based on protocol analysis of 50 eyes (25 subjects) while safety was based on 52 eyes (26 subjects). The primary efficacy outcome was mean IOP at the time of the 3-month follow-up compared with the baseline values of the intent- to- treat data set. Secondary efficacy variables included change in mean IOP from baseline in the different types of glaucoma and the total IOP drop from onset of diagnosis.

Potential relationship of any adverse events to the medication while on the treatment was evaluated by the investigators.

Analysis was performed by the SPSS.V16 for Windows. The tests for statistically significant differences between variables were performed using the Wilcoxon W test for nonparametric data. Two-tailed P-values <0.05 were taken to indicate significance.


   Results Top


Fifty-six eyes of -28 patients were enrolled for the study of which 13 were females and 15 males. The mean age was 70 years (range 37-91). All were Caucasians.

Sixteen patients had POAG, six low tension glaucoma (LTG), four OHT and two CACG (post-YAG laser iridotomy).

Sixty percent of the patients were on monotherapy before the switch (β-blockers 4, latanoprost 4, bimatoprost 6 and travoprost 16). The others were combinations of β-blockers and PGs but not duotrav (8) and carbonic anhydrase inhibitors and β-blockers (12).

One patient with LTG relocated and another one with POAG failed to attend the 3-month follow-up clinic. One patient with POAG developed severe ocular redness with associated swelling within 4 weeks of treatment and the drug was discontinued.

Additional IOP lowering that was statisitcally significant (P<0.05) was seen in patients on latanoprost (5.25 mmHg; 25.9 % drop), bimatoprost (4.33 mmHg; 18.04% drop) and travoprost (3.38 mmHg; 17.59% drop) on switching to the Duotrav [Table 1] and [Figure 1]. Although there was 3 mmHg (14.3%) drop for those switched from the β-blockers, this did not reach statistical significance (P= 0.5714). No significant IOP drop was achieved on switching from β-blockers plus other PGs or other combinations.
Figure 1 : Additional IOP lowering effect after switch to duotrav

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Table 1: Differences in intraocular pressure at baseline and 3 months after the switch

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The fixed combination produced clinically relevant IOP reduction from baseline [Table 2] and [Figure 2] for patients with OHT, POAG and LTG, but not those with CACG. For those with POAG and NTG, statistically significant (P<0.05) reduction was achieved.
Figure 2 : The mean intraocular pressures at diagnosis, on other treatments and 3 months after replacement with travatan/timolol fixed combination

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Table 2: Mean intraocular pressures before and 3 months post-tomolol/travatan fixed combination for the different types of glaucoma

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The mean IOP reduction was ≤18.5mmHg (12.5-17.9% drop) in those with POAG, NTG and OHT. As shown in [Figure 2], the degree of IOP drop for each case from the time of diagnosis was quite significant for the three types of glaucoma. The mean IOP was, however, higher post-duotrav in the CACG group.

Two patients with POAG developed marked lid and conjunctival swelling and redness-one occurring a week to onset of treatment and the other 3 weeks into it. The drug was discontinued in both cases but a third that developed mild and transient conjunctival hyperemia remained on the course. None had any anterior chamber inflammation or systemic side effect. Thus withdrawal of treatment as a direct result of adverse effect from the drug occurred only in 3.84% of cases.


   Discussion Top


IOP control remains the most significant strategy for glaucoma treatment and drugs are known to do this quite well. The clinical efficacy of multiple drug therapy is well proven but the drawback (low compliance, more side effects, less tolerance, higher cost, etc.) from the patients perspective has made fixed combination formulations attractive. In the study by Patel and Speath, [8] it was shown that percentage compliance rose from 51.1 % for patients on multiple topical medications to 67.7% for those on monotherapy. This difference becomes even more significant against the backdrop of the evidence that 70% of blindness in glaucoma patients on treatment is due to drug non-compliance. [9]

Concomitant use of PG and β-blocker led to further IOP reduction as against levels achieved by either drug possibly due to their synergistic mechanism of action. The β-blocker reduces aqueous secretion thereby reducing the preload, while the PGs increase the uveoslceral outflow and so reduce the aqueous volume leading to low IOP.

Orengo-Nania and associates [10] have demonstrated the efficacy of this combination in their study where timolol 0.5%/travoprost 0.004% combination (with the travoprost as an adjunct) was shown to lower the IOP by 23.1-27.7% from baseline.

Other studies [11],[12] done which involved washout of the earlier anti-galucoma medications before commencing the dosing with the timolol 0.5% /travoprost 0.004% fixed combination showed similar clinically and statistically significant IOP reduction from baseline.

We, however, carried out our study as we would have the patients in real-life conditions. In the study, patients came in for the routine glaucoma follow-up evaluation and once the drug(s) he/she was on was found inadequate in lowering the IOP to the expected target level, this was switched to the timolol 0.5%/travoprost 0.004% fixed combination (Duotrav) once suitability has been ascertained. The 3-month follow-up results showed additional IOP reduction that was statistically significant for those on latanoprost (P=0.02857), bimatoprost (P =0.04978) and travoprost (P =0.0078). Patients on latanotrost had an additional 25.9% drop 3 months after switching to duotrav while those on bimatoprost and travatan had 18.04% and 17.59% drop, respectively, after the switch. These results did not differ from those of Raber [13] in his multicenter study under similar clinic conditions. Although, the drop for those who were initially on β-blockers alone did not reach statistical significance (P=0.5714), the 14.3 % drop was clinically significance considering that 1 mmHg IOP drop reduces the risk of visual field loss by 10%. [14] The study, however, showed that switching from other combinations or β-blockers/other PGs to duotrav did not lower the IOP to significant levels.

The study also demonstrated that this fixed combination reduced IOP equally well in OHT, POAG and NTG (between 12.5 and 17.9% additional IOP drop). The drop I patients with POAG (P=0.0027) and LTG (P =0.0284) reach statistical significance. However, it was unsuitable in cases of CACG. Although the data for this group was small, the non-response could not be explained by the mechanism of action of the drugs, since timolol reduces the preload and the PGs act via the uveoslceral outflow. The main drawback of the study was the small number of patients though the results still corroborated other similar ones. Also, there was no wash-off period to enable independent effect of the duotrav to be observed. However, the results should be considered clinically relevant because, in real life this is what patients and clinicians do.

Only in 7.6% of cases was the drug withdrawn because of side effect. The fixed combination has less preservative compared to the individual bottles, and this improves its tolerability.

Our study has demonstrated the effectiveness of duotrav in IOP reduction and its safety. These, coupled with the fewer dosing and possibly less cost compared with the individual drugs, should improve compliance. Better compliance would in turn lead to lower risk of disease progression and sustained good quality of life; the primary goal of glaucoma management.

 
   References Top

1.LeBlanc RP, Saheb NE, Krip G. Timolol: long-term Canadian multicentre study. Can J Ophthalmol 2000;130:429-40.  Back to cited text no. 1
    
2.Zimmerman TJ, Kaufman HE. Timolol. A beta-adrenergic blocking agent for the treatment of glaucoma. Arch Ophthalmol 1977;95:601-4.  Back to cited text no. 2
    
3.Coakes RL, Brubaker RF. The mechanism of timolol in lowering intraocular pressure. In the normal eye. Arch Ophthalmol 1978;96:2045-8.  Back to cited text no. 3
    
4.Griffin BW, Williams GW, Crider JY, Sharif NA. FP prostaglandin receptors mediating inositol phosphates generation and calcium mobilization in Swiss 3T3 cells: a pharmacological study. J Pharmacol Exp Ther 1997;281:845-4.  Back to cited text no. 4
    
5.Schachtschabel U, Lindsey JD, Weinreb RN. The mechanism of action of prostaglandins on uveoscleral outflow. Curr Opin Ophthalmol 2000;11:112-5.  Back to cited text no. 5
    
6.Weinreb RN, Kashiwagi K, Kashiwagi F, Tsukahara S, Lindsey JD. Prostaglandins increase matrix metalloproteinase release from human ciliary smooth muscle cells. Invest Ophthalmol Vis Sci 1997;38:2772-80.  Back to cited text no. 6
    
7.Kass MA, Heuer DK, Higginbotham EJ, Johnson CA, Keltner JL, Miller JP, et al. The Ocular Hypertension Treatment Study: a randomized trial determines that topical ocular hypotensive medication delays or prevents the onset of primary open-angle glaucoma. Arch Ophthalmol 2002;120:701-3.  Back to cited text no. 7
    
8.Patel SC, Spaeth GL. Compliance in patients prescribed eyedrops for glaucoma. Ophthalmic Surg 1995;26:233-6.  Back to cited text no. 8
    
9.McGavock. Pulse. 22 Sept. 2003.   Back to cited text no. 9
    
10.Orengo-Nania S, Landry T, Von Tress M, Silver LH, Weiner A, Davis AA. Evaluation of travoprost as adjunctive therapy in patients with uncontrolled intraocular pressure while using timolol 0.5%. Am J Ophthalmol 2001;132:860-8.  Back to cited text no. 10
    
11.Barnebey HS, Orengo-Nania S, Flowers BE, Samples J, Mallick S, Landry TA, et al. The safety and efficacy of travoprost 0.004%/timolol 0.5% fixed combination ophthalmic solution. Am J Ophthalmol 2005;140:1-7.  Back to cited text no. 11
    
12.Schuman JS, Katz GJ, Lewis RA, Henry JC, Mallick S, Wells DT, et al. Efficacy and safety of a fixed combination of travoprost 0.004%/timolol 0.5% ophthalmic solution once daily for open-angle glaucoma or ocular hypertension. Am J Ophthalmol 2005;140:242-50.  Back to cited text no. 12
    
13.Raber T. Results of an observational study of glaucoma patients switched to the fixed combination Travoprost 0.004% / Timolol 0.5% (Duotrav) in Germany. Poster presentation, 6 th International Glaucoma symposium. Athens, Greece; 2007.  Back to cited text no. 13
    
14.Leske MC, Heijl A, Hussein M, Bengtsson B, Hyman L, Komaroff E. Factors for glaucoma progression and the effect of treatment: the early manifest glaucoma trial. Arch Ophthalmol 2003;121:48-56.  Back to cited text no. 14
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2]



 

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