Pharmaceutical therapies for presbyopia may bridge gap until surgery is needed
Two main classes of pharmaceutical therapies that use different mechanisms of action to treat presbyopia may be effective, noninvasive solutions for patients who are not yet good candidates for surgery.
Reading glasses, surgery and contact lenses are currently the only ways to treat presbyopia. However, several companies have ongoing clinical trials to investigate the use of miotic agents and lens-softening eye drops, Sheri L. Rowen, MD, told Ocular Surgery News.
“These two classes of drops are very promising new modalities of pharmaceutical treatments for the treatment of presbyopia. In addition, I see these as potentially adjunctive types of therapies. I don’t see them as being mutually exclusive. A therapy to allow the lens to continue to be mobile and not be stiff would be fantastic, and you might have an additive effect for your depth of focus as well,” she said.
Most studies are investigating therapies to extend depth of focus, which can be achieved by enhanced pseudoaccommodation with the pinhole effect and miosis, or to halt presbyopia progression by enhancing residual accommodation, OSN Technology Board Member Karolinne M. Rocha, MD, PhD, said.
These therapies would be a valuable addition to a surgeon’s armamentarium to treat early presbyopes who may not be candidates for LASIK, do not want monovision, or have early dysfunctional lens syndrome and want to preserve their corneas, she said.
“I think it’s a great option to bridge that patient in their 40s and 50s prior to needing surgery. These eye drops are generally reversible, so it’s a great option for our patients,” she said.
None of the pharmaceutical therapies are currently approved by the FDA.
Ongoing clinical trials
UNR844 (lipoic acid choline ester chloride, Novartis) works on the accommodative aspect of the lens. It is designed to be a lens-softening agent, allowing for better transport of fluid through the lens for more lens shape movement, Rowen said.
“It’s very promising because it might actually continue to allow the lens to change shape instead of becoming stiff leading to presbyopia. We love that concept as it would allow us to continue using our natural lens for near vision. The mechanism of action is breaking the disulfide bonds which cause lens rigidity and thus allowing cytosol transport through the natural crystalline lens. That’s the first class of therapy,” Rowen said.
Allergan, Presbyopia Therapies and Orasis Pharmaceuticals all have miotic therapies in various stages of development. These agents are designed to constrict the pupil from its original size to not allow for the full dilation typically reached in normal and dim light to increase the depth of focus, she said.
Allergan is currently in phase 3 FDA trials, while Presbyopia Therapies and Orasis Pharmaceuticals have completed phase 2b trials, Rowen said.
Allergan’s candidates, AGN-199201 and AGN-190584, have been studied alone and combined in patients with presbyopia. A phase 3 trial of AGN-190584 alone is currently underway.
Orasis’ CSF-1 agent reached its primary endpoint in a phase 2b clinical trial, demonstrating statistically significant improvement in distance corrected near visual acuity with a gain of three lines or more, according to the company.
Presbyopia Therapies’ PRX-100 ophthalmic solution met its primary efficacy and safety endpoint in a phase 2b study. The therapy demonstrated a three-line or greater improvement in monocular distance corrected near acuity in patients between the ages of 48 and 64 years, according to the company.
Patient selection is key
A combination of the two mechanisms of action could work as well. A patient in their 40s could regularly use lens-softening drops while occasionally using a miotic drop to improve their depth of focus, Rowen said.
Older patients with rigidity of their entire eye, such as the lens, sclera and ciliary muscles, may not find the drops to be beneficial, but younger patients will benefit from these advancements, Rocha said.
“They are fantastic options. You’re not losing the patient, but it’s just a patient that isn’t ready for surgery. We want to preserve the cornea, and a patient who isn’t ready for a lens exchange should be offered an option that is reversible first,” Rocha said.
“We are very hopeful that within a few years, we will have these nonsurgical options to offer our presbyopic patients,” Rowen said.
- Grzybowski A, et al. Asia Pac J Ophthalmol (Phila). 2020;doi:10.1097/APO.0000000000000297.
- Mukamal R. Could eyedrops replace reading glasses? www.aao.org/eye-health/news/could-eyedrops-replace-glasses-presbyopia. Published Dec. 4, 2019. Accessed Aug. 25, 2020.
- Orasis Pharmaceuticals announces CSF-1 eye drop successfully met primary endpoint in phase 2b clinical study in presbyopia. www.orasis-pharma.com/orasis-pharmaceuticals-announces-csf-1-eye-drop-successfully-met-primary-endpoint-in-phase-2b-clinical-study-in-presbyopia. Published Oct. 10, 2019. Accessed Aug. 25, 2020.
- Sutton A. Orasis CEO describes mechanism behind eye drop for presbyopia. www.healio.com/news/optometry/20190401/orasis-ceo-describes-mechanism-behind-eye-drop-for-presbyopia. Published April 2, 2019. Accessed Aug. 23, 2020.
- For more information:
- Karolinne M. Rocha, MD, PhD, can be reached at Storm Eye Institute, Medical University of South Carolina, 167 Ashley Ave., Charleston, SC 29425; email: firstname.lastname@example.org.
- Sheri Rowen, MD, FACS, can be reached at NVISION Eye Centers, 4220 Von Karman, #100, Newport Beach, CA 92660; email: email@example.com.