Role of Netarsudil as an addition to prostaglandin analog monotherapy in glaucoma patients having an intraocular pressure below 21 mmHg

Dear Editor, Glaucoma is the leading cause of irreversible blindness throughout the world.[1] Raised intraocular pressure (IOP) is the only modifiable risk factor for glaucoma progression, and risk increases with each mmHg rise in IOP.[2] Recent studies have begun reporting the efficacy of Netarsudil as an adjunctive therapy. However, the majority of these studies either are retrospective or use Netarsudil as an adjuvant to maximum tolerated medical therapy.[3,4] With this background, our study was designed as a prospective study which reports the IOP-lowering efficacy of Netarsudil in patients already on Prostaglandin analog (PGA) monotherapy. Netarsudil is a Rho associated protein kinase (ROCK) and Nor-epinephrine Transporter inhibitor and has got a unique mechanism of action. It decreases IOP primarily by increasing outflow facility by expanding the juxtacanalicular tissue of the trabecular meshwork. It also decreases episcleral venous pressure and decreases aqueous production. Thus, for patients requiring further reduction of IOP, it can be a good adjunct to PGA which has a different mechanism of action and works by enhancing the uveo-scleral outflow. We performed a study to evaluate the safety and additional IOP lowering effect of Netarsudil (0.02%) ophthalmic solution on primary open angle glaucoma (POAG) patients having IOP below 21 mmHg with PGA monotherapy. In this prospective interventional nonrandomized institution-based study conducted between May 2022 and May 2023, 31 POAG patients (age 57 ± 10.68 years), undergoing PGA monotherapy having IOP below 21 mmHg were studied. Netarsudil (0.02%) ophthalmic solution was administered as an adjuvant in one of the eyes. Visual acuity (VA), IOP, optic disc, and visual field changes were recorded during baseline and follow-up visits at 1 and 3 months. Glaucoma was graded as mild, moderate, or severe according to optic nerve head evaluation by 90D slit-lamp biomicroscopy where mild was considered when cup disc ratio <0.65, moderate 0.7–0.85, and severe ≥0.9. Any systemic or local side effects were noted. Statistical calculations were done by using repeated measure ANOVA. A P value of < 0.05 was considered significant. The study population had 15 (49%) males and 16 (51%) females. 24 (77%) patients were using Travoprost and 7 (23%) were using Latanoprost ophthalmic solution in both the eyes prior to enrolment. 11 (35.5%) patients were in the mild stage, 18 (58%) patients were in the moderate stage, and 2 (6.5%) were in the advanced stage. The baseline IOP was 17.32 ± 2.27 mmHg and 15.06 ± 2.22 mmHg in the study and contralateral control eye, respectively (P = 0.0002) [Table 1]. There was significant IOP reduction from baseline in the study eye at both 1 month 2.58 ± 0.196 mmHg (15.09 ± 6.81%) and 3 months 4.36 ± 1.6 mmHg (25.25 ± 9.3%) (P < 0.001) [Table 2]. But the reduction in IOP of the control eye was not statistically significant at both the time points. Hyperemia (48.4%) was the most common side effect which was transient and not serious. Similar to our study results, a multicenter, open-label study by Zaman et al.[5] tried to evaluate Netarsudil for its effectiveness in reducing elevated IOP in patients with open-angle glaucoma or ocular hypertension in a real-world setting. They observed that adding Netarsudil to monotherapy with prostaglandin analogs (PGAs) or beta-blockers (BBs) resulted in an additional IOP reduction of 4.3 (±2.88) mmHg or 20.5% (±12.94) from baseline. In conclusion, 0.02% Netarsudil, once daily, can further lower IOP significantly in POAG patients, having low baseline IOP with PGA monotherapy.Table 1: IOP measurement at baseline, 1 month, and 3 monthsTable 2: Pairwise comparison of IOP measurementsFinancial support and sponsorship: Nil. Conflicts of interest: There are no conflicts of interest.