Success at Last! Two New Glaucoma Drugs Reach the Market
It has been years since a new glaucoma drug reached the market, and thankfully, that drought is over. Two new pressure-lowering medications were recently approved by the Food and Drug Administration and are (or are about to become) available to glaucoma patients for the primary indications of open-angle glaucoma and ocular hypertension.
Several scientists associated with BrightFocus – through our National Glaucoma Research (NGR) program – did research that helped lay the scientific groundwork for these new therapeutics.
Below are details on these two new drugs, and also please see a recent article by Yvonne Ou, a BrightFocus-affiliated expert at the University of California, San Francisco.
[To learn more about the drug approval process, view our BrightFocus infographic.]
Rhopressa: First in a New Class of ROCK Inhibitors
Rhopressa® (netarsudil ophthalmic solution 0.02%; Aerie Pharmaceuticals, Irvine, CA) was approved in December 2017, two months ahead of schedule. As the first approved rho-associated protein kinase inhibitor (ROCK inhibitor), Rhopressa represents the first entirely new class of glaucoma medication to become available since Xalatan™ (latanoprost, Pfizer), the first prostaglandin analog, was approved in 1996.
Unlike most existing glaucoma eyedrops, which either work to decrease aqueous humor production or target the eye’s secondary drainage system (eg, uveoscleral pathway), Rhopressa lowers IOP by improving outflow through the trabecular meshwork (TM), the eye’s main drainage system. Earlier attempts to develop drugs targeting the TM had to be abandoned decades ago due to adverse side effects, but improvements in molecular engineering were able to overcome those obstacles. Rhopressa’s safety profile was established in clinical trials enrolling a total of 800 patients.
Along with hitting a new target (the TM), Rhopressa’s advantages include once daily administration, which simplifies use for patients. Arthur Sit, MD, PhD, of Mayo Clinic, Rochester, MN, a member of the BrightFocus committee that reviews National Glaucoma Research (NGR) grants, published results of a small clinical trial in humans which suggest that Rhopressa increased outflow through the TM and also reduced episcleral venous pressure (Kazemi et al, J Ocul Pharmacol Ther, 2018). These authors proposed that both mechanisms may be working to lower pressure.
In addition, BrightFocus NGR grantee Jeff Goldberg, MD, PhD, chair of ophthalmology at Stanford University, published results of experiments suggesting that topical administration of a ROCK inhibitor, in combination with another type of drug (norepinephrine transporters), may help protect against and repair optic nerve damage in an animal model of glaucoma (Shaw et al, Exp Eye Res, 2017). So far that idea hasn’t been tested in humans.
Rhopressa becomes available to private patients this spring but won’t reach the Medicare/Medicaid formularies until 2019.
Vyzulta: A Prostaglandin Analog with Something Special
Vyzulta™ (latanoprostene bunod 0.024%; Bausch + Lomb/Nicox), was approved in November 2017. Like other prostaglandin analogs, Vyzulta improves drainage through the uveoscleral pathway; however, an innovative component, nitric oxide (NO), has been added to dilate blood vessels, making this the first drug to lower pressure while simultaneously dilating blood vessels to improve blood flow. The rationale comes from research showing that patients with glaucoma have reduced levels of NO signaling in their eyes, and that an insufficient blood supply to the optic nerve may contribute to the onset of glaucoma.
Vyzulta became available by prescription in late December.
How BrightFocus Contributes to Emerging Glaucoma Treatments
NGR grantees have been involved in testing concepts about how these drugs, and other prospective new glaucoma medications like them, may work. Examples include Shahid Husain, PhD, a 2016-18 NGR grantee from the Medical University of South Carolina, who’s looking at how proteins produced under conditions of low oxygen levels in the eye may contribute to glaucoma pathology; and Linda Zangwill, PhD, a 2016-19 grantee from the University of California, San Diego, who’s designed a clinical trial that uses advanced imaging technology to determine whether changes in the retinal blood supply (microvasculature) precede or follow the death of cells in the optic nerve.
In addition, a host of NGR grantees are actively looking for new and better ways to detect, monitor, and treat glaucoma, as well as protect and repair the optic nerve. Please see our latest NGR grants yearbook, which summarizes the multi-year research projects of all 33 scientists currently supported by BrightFocus’ NGR program.