Hope for advances in glaucoma management fueled by promising pipeline

A look at the therapeutic pipeline for glaucoma shows several medications representing new pharmacologic classes are currently being evaluated in clinical trials, said John R. Samples, MD, at ASCRS Glaucoma Day 2011, San Diego.

Currently, a number of companies are advancing through the clinical trial phase of investigation with a rho kinase inhibitor. These drugs act as a cytoskeletal modifier, lowering intraocular pressure by increasing aqueous humor drainage through the trabecular meshwork, and of the various classes of medications under development, a rho kinase inhibitor is likely to be the first to become FDA-approved, according to Dr Samples.

Several companies are also developing novel classes of prostaglandin analogues, which may be the next new category of drugs to reach the market. Compared with the currently available prostaglandin analogues (bimatoprost, travoprost, and latanoprost) that act as FP-receptor agonists, the investigational prostaglandin analogues bind to different prostaglandin receptors. Also among IOP-lowering compounds in development is an adenosine-1 agonist (INO-8875, Inotek Pharmaceuticals) that has been shown in early clinical trials to be well-tolerated and to act by increasing outflow through the trabecular meshwork.  

Researchers aiming to advance medical therapy for glaucoma are also targeting the development of sustained delivery technology that would minimize the impact of poor patient compliance as a factor limiting treatment success. In addition, several agents are under development as potential neuroprotectants, of which most aim to modulate glial cell activity.

“Unfortunately, there are no new neuroprotective agents on the immediate horizon, and the cost associated with conducting a lengthy clinical trial required for establishing efficacy of neuroprotective drugs represents a major obstacle to greater industry interest in this area,” said Dr Samples, clinical professor at Oregon Health and Sciences University and at Rocky Vista University, Parker, Colo.

“More imminently, ophthalmologists can expect to be hearing more about unoprostone 0.15% ophthalmic solution (Rescula, Sucampo) as a possible neuroprotectant. However, I would caution evaluating the emerging information with a critical eye.”

The glaucoma pipeline also contains new laser and ultrasound-based modalities. Laser research is focusing in part on optimizing the laser-tissue interaction through proper wavelength selection, and treatment to improve outflow using external ultrasound focused on the trabecular meshwork has shown encouraging results.