For patients with glaucoma who are already at their maximally tolerable level of medical therapy, an investigation says a rho-kinase inhibitor may be a last option before surgery. A Clinical Ophthalmology study says patients who used netarsudil experienced reduced intraocular pressures (IOP), even if they were already at their level of maximally tolerated medical therapy (MTMT).
The findings come from a retrospective study in which researchers used data from patients who had started on netarsudil at Stanford University. Treatment success, as defined as IOP reduction meeting a predetermined target, and no further medication, laser, or surgery recommended subsequently, was the primary outcome measure. The study included 62 eyes, and at first follow up, 58% (n=36) had achieved treatment success.
Patients’ mean IOPs at baseline were 19.5+5.6 mm Hg, and patients used amean of 3.5+0.7 ocular hypotensive medications. From baseline to first follow up, the mean change in IOP was -3.53 mm Hg (-17%), and in those who achieved treatment success, mean IOP change was -5.22 mm Hg (-28.0%). Compared with only 17% of eyes with baseline IOP of 21 mm Hg or greater, 69% of eyes with baseline IOP of 20 mm Hg or lower achieved treatment success (P <.05).
The researchers outline 3 possible reasons explaining their finding that netarsudil is more likely to successfully achieve a pre-specified target IOP when baseline IOP is 20 mm Hg or lower. First, they said, it may be likely that patients with a lower baseline IOP required a smaller absolute reduction in IOP, to meet their target. Also, they cite the possibility that eyes with an especially high IOP have severe aqueous outflow pathway dysfunction that is less likely to respond to netarsudil, despite being otherwise on MTMT.
“Finally,” the study explains, “netarsudil’s possible effect on episcleral venous pressure may lead to increased effectiveness in eyes with lower baseline IOP.”
Study limitations include nonuniform follow up, no control cohort, haphazard IOP measurement times and drop-instillation times, and the possibility of inconsistent medication compliance, due to its retrospective nature. Patients who had received glaucoma surgery or laser within 6 months of starting netarsudil and other modifications to the baseline medication regimen within 4 weeks of starting netarsudil were excluded.
Villegas NC, Lee WS. Effectiveness of netarsudil as an additional therapy for glaucoma in patients already on maximally tolerated medical therapy. Clin Ophthalmol. 2021;15(11):4367-4372. doi:10.2147/OPTH.S337105