Could a New Class of Glaucoma Medications Be Around The Corner

An exciting new class of potential glaucoma medications include what are termed the ROCK and ROCK/NET inhibitors. And it’s about time! Twenty years have passed since the last new class of medications (prostaglandin analogs) were approved for the treatment of glaucoma.

It is thought that the trabecular meshwork is the problem in the most common type of glaucoma, primary open angle glaucoma. Rho-kinase (aka “ROCK”) is an enzyme involved in the transport of fluid out of the eye through the trabecular meshwork. Inhibition of Rho-kinase relaxes the trabecular meshwork cells allowing fluid to exit the eye. As fluid exits the eye the intraocular pressure (IOP) drops. The most exciting thing about this therapeutic class is that it is already being evaluated in human trials. At least two companies have ROCK inhibitors in clinical trials: Amakem Therapeutics and Aerie Pharmaceuticals.

AMA0076

In the spring of 2014 Amakem Therapeutics announced that it was initiating a human trial of its investigational glaucoma agent known only as AMA0076. What is encouraging about this particular ROCK inhibitor is that it appears to work without resulting in significant ocular hyperemia (red eye) – a side effect that has dogged almost all glaucoma medications.

Rhopressa^TM 

Norepinephrine transporters ( aka “NET”) are important in the production of aqueous fluid. Inhibit NET and there should be less fluid in the eye resulting in a lower IOP.

Aerie pharmaceuticals has developed a combination ROCK/NET inhibitor that will hopefully gain FDA approval for the treatment of glaucoma in the next few years. Early clinical results of their inhibitor named Rhopressa™ (previously designated AR-13324), demonstrated a 6mmHg IOP reduction after one month of once-daily dosing. Only a quarter of study participants experienced hyperemia.

Roclatan^TM

In the summer of 2014 Aerie announced positive results of a short-term trial of a fixed combination of Rhopressa™ and latanoprost (called Roclatan™, previously known as PG324). Nearly 300 patients were enrolled in this study. On average, Roclatan™ lowered intraocular pressure (IOP) by 34%. This was 2mmHg lower than the IOP achieved by latanoprost alone. Granted, 2mmHg may not seem like much. However, considering that (1) latanoprost is already one of the most effective medications used to treat glaucoma, and (2) Roclatan™ was also dosed once daily, any additional reduction is noteworthy and of significant potential benefit to patients with glaucoma.

Any downside? Of course – every treatment comes with a price, and there are at least two that can be expected with Roclatan™:

1. 40% of patients who used Roclatan™ experienced hyperemia. That’s about what is expected with latanoprost so this is, unfortunately, par for the glaucoma drop treatment course.
2. Although pricing will not be known until Roclatan™ has been approved by the FDA (if approved), you can expect that as a brand new class of glaucoma medication this is going to come with an eye-popping price. I’d expect around $200 for a monthly supply. And, don’t hold your breath for commercial insurances to pick up the tab. Considering that latanoprost is now available as a $40 generic drug and can achieve IOP control to within 2mmHg of Roclatan™ I’d expect insurances to be pretty stingy with their process for approving payment of this new class of glaucoma treatment. Nonetheless, I’d love to have this as an option for my patients whose glaucoma is advancing despite already using a prostaglandin analog such as latanoprost.