Rho-Associated Kinase Inhibitors: Evolving Strategies in Glaucoma Treatment

Glaucoma, a group of progressive optic neuropathies with similar patterns of tissue loss, is primarily treated with medical therapy, followed by laser therapy and, later, incisional surgery. Aside from the introduction of prostaglandin analogs, topical carbonic anhydrase inhibitors, and topical alpha-agonists in the 1990s, no new pharmaceutical agents to lower intraocular pressure (IOP) have been introduced for approximately 20 years. The Rho kinase inhibitors represent a new class of glaucoma medications that inhibit the downstream pathway of the Rho family of small G-proteins to increase outflow from the conventional (trabecular) outflow pathway in the eye. Several of these Rho kinase inhibitors, ripasudil and netarsudil, have recently reached the market and are used in clinical practice in several countries. A fixed-dose combination of latanoprost and netarsudil was also very recently approved (2019) by the US FDA. Several other novel agents are undergoing clinical trials. These drugs are poised to act as adjuncts to already established medical therapy for further lowering of IOP in the treatment of glaucoma.