Bimatoprost: Good Option for IOP Reduction in Nonresponders

Efficacy and Safety of Bimatoprost in Glaucoma and Ocular Hypertension in Nonresponder Patients

Brennan N, Dehabadi MH, Nair S, et al Int J Ophthalmol. 2017;10:1251-1254

Study Summary

The aim of this study was to determine whether a switch to bimatoprost 0.03% monotherapy in nonresponding patients with glaucoma or ocular hypertension provides additional intraocular pressure (IOP) reduction. Fifty-nine consecutive patients were switched from their current therapy to bimatoprost monotherapy. Demographic information, diagnosis, and any adverse events were recorded. Change in IOP after the switch was analyzed.

The mean baseline IOP for all study patients regardless of diagnosis was 23.4 mm Hg. All 59 patients were seen at least once after the switch to bimatoprost with the mean time to this follow-up appointment of 104 ± 44 days. Patient attrition reduced the number to 30 patients at the second follow-up, 18 at the third, and only eight at the fourth, which was at an average of 708 ± 160 days. The mean reduction in IOP from preswitch IOP to the first visit was 4.3 mm Hg. Patients already on monotherapy, specifically latanoprost, who were switched to bimatoprost had reduction in IOP that was even greater at 5.27 mm Hg. The maximal decrease in IOP over all visits was at the third visit at 490 ± 145 days, with an average decrease of 7.7 mm Hg in those 18 patients.

The investigators concluded that switching patients on combination or monotherapy to bimatoprost monotherapy results in significant reduction in IOP.

Viewpoint

This is the largest independent data set published to date following the progress of patients switched to bimatoprost 0.03% monotherapy due to inadequate response to previous therapy. The results of this study suggest that bimatoprost is significantly more efficacious than the other widely available prostaglandin analogs (PGAs). This is contradictory to a previous large independent study of 46 patients with primary open-angle glaucoma or ocular hypertension that found no significant benefit from a switch to bimatoprost monotherapy.^[1] This study theorizes that the improvement in IOP with bimatoprost compared with other PGAs such as latanoprost and travoprost is because those two are prodrugs, while bimatoprost is not. Poor de-esterification of latanoprost could explain the cohort of latanoprost nonresponders.^[2]

"These results sound very promising because a switch to bimatoprost may prevent the patient from needing more drops, laser therapy, or surgical intervention. Yet a few caveats exist."

These results sound very promising because a switch to bimatoprost may prevent the patient from needing more drops, laser therapy, or surgical intervention. Yet a few caveats exist. This study was performed with bimatoprost 0.03%, which is no longer commercially available in the United States. Studies state that the efficacy of bimatoprost 0.03% is similar to that of the currently available 0.01%,^[3] but the results cannot be directly extrapolated to mean that even in nonresponders there is no difference in efficacy of the two strengths.

Furthermore, the assumption is that compliance with another PGA versus bimatoprost is the same. It is possible that compliance changes. Often compliance improves when patients learn that if the new medication does not adequately lower IOP, the next options include laser or surgical intervention. Thus, a double-blinded study where some patients are switched and some patients are not switched would eliminate any compliance-related confounding variables.

Overall, the results are promising, and given the benign nature of switching medications compared with laser or surgical interventions, this option may be worth trying for nonresponders. Additional double-blinded studies with a larger cohort using bimatoprost 0.01% would provide useful information that would be more widely applicable to patients

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