Switch to BAK-free PGA improves dry eye

Fort Lauderdale, FL-Disability from symptoms of dry eye disease among patients using latanoprost 0.005% (Xalatan, Pfizer) may be significantly improved by switching to a benzalkonium chloride (BAK)-free formulation of travoprost 0.004% (Travatan Z, Alcon Laboratories), according to the results of a multicenter, randomized, double-masked, 12-week clinical trial reported at the annual meeting of the Association for Research in Vision and Ophthalmology.

"The findings of this study have important implications for the medical management of . . . ocular hypertension or glaucoma since ocular surface disease is quite common within this population as a result of topical medication use and their generally older age," said Gregory Katz, MD, one of the study's principal investigators and a glaucoma specialist in private practice with Huron Ophthalmology, Ypsilanti, MI.

"Ocular surface disease can lead to tolerability issues that can be a barrier to medication compliance," he said. "Therefore, when choosing topical ocular hypotensive therapy, practitioners should consider tolerability as well as IOP-lowering efficacy of the available options."

The intent-to-treat study population included 674 patients who were predominantly female (65%) and older (64% aged ≥65) with a mean duration of latanoprost therapy of about 2 years. Based on entry OSDI scores, patients considered to have mild dry eye disease (OSDI score 13 to 24) represented the largest subgroup (41%); 26% were categorized as moderate (score 23 to 32) and 33% as severe (score 33 to 100).

Patients were randomly assigned 1:1 either to continue treatment with latanoprost for 12 weeks or switch to BAK-free travoprost.

Among patients in the mild OSDI subgroup, comparisons between the two prostaglandin analogue (PGA) groups for a variety of outcomes based on OSDI scores showed consistent differences favoring switching to BAK-free travoprost.

Considering the mild OSDI subgroup, there was no significant difference between patients switched to BAK-free travoprost and those continuing to take latanoprost in baseline mean OSDI scores (16.6 versus 17.2; p = 0.08).

After 6 weeks, the mean OSDI score was significantly reduced (improved) from baseline in both treatment groups, but there was no significant difference comparing the two groups with respect to either the mean score or change from baseline.

However, at week 12, the mean OSDI score in the BAK-free travoprost group had decreased further, falling to 11.6 (within the normal range), and was significantly lower (p = 0.04) than the mean OSDI score in the latanoprost group, 14.4, which had slightly worsened from the week 6 value.

The mean reduction from baseline OSDI was 5.0 for the BAK-free travoprost group and 2.7 for the latanoprost group (p = 0.10).

At week 12, the percentage of patients whose OSDI scores had improved to the normal range (0 to 12) was significantly higher in the BAK-free travoprost group compared with the latanoprost group (62.9% versus 47.0%; p < 0.01).

"It was impressive to see that within 3 months of switching to a BAK-free therapy, such a large proportion of patients affected by symptoms of dry eye disease showed evidence of improvements in their ocular surface health, and the effect of switching PGA therapies was not only statistically significant, but clinically important as well," Dr. Katz said.

"Results of a recent study by Miller et al. [Ophthalmology 2010;128:94-101] established that among patients with mild or moderate dry eye disease, a mean change of 4.5 in the OSDI score represents a clinically important difference, and the change from baseline OSDI score exceeded this minimal threshold only in the BAK-free travoprost group," he said.