One of the challenges of treating glaucoma is that for most people, it’s a condition without notable symptoms. What this means is that the treatment is often more bothersome than the condition itself (at least early on in the disease).
Take for example, medication. Medications aren’t always covered by insurance or can be expensive. They may have to be taken multiple times a day. They can be associated with side effects—whether just local around the eye, or systemic (as we say), which is full body side effects. Because of these issues, pharmaceutical companies are looking for better medical treatment. And one of the areas where there’s a lot of interest among pharmaceutical companies is in the area of “Sustained Release Implants”. These are actually implants—that would be placed inside the eye—that have medication saturating the implant, which is designed to slowly release the medication.
The benefit of a sustained release implant would be, of course, that you’d have it implanted once and not have to worry about it for many, many months.
Now, I have to admit that I’ve not been all that excited about this direction that the pharmaceutical industry has taken. And that reason for that is that most of the initial implants that are being researched are using a type of medication called a “prostaglandin analogue” class of medication. Now, to my way of thinking, this is not a class of medication that is in need of a sustained release solution. The reason why I say this, is that the prostaglandin analogue class is…generally well-tolerated, with (for the most part) just local side effects, without notable systemic side effects, it only has to be taken once a day, and for most people, it’s either covered by insurance or available generically for $20 a month, on average. So it’s not high on my list of the class of medication that I think would really benefit most from sustained-release.
To my way of thinking, the classes of medication that would benefit most from sustained-released would be those classes that are either expensive, require treatment multiple times a day, or just not tolerated because of side effects. And the prostaglandin analog class really doesn’t meet that criteria. So for these reasons, I’ve not been hugely excited about the prostaglandin analog class being the first class of sustained release implant.
Now, part of my reason is based on cynicism. Drug companies, of late, have been just horrific in their pricing of new medications. Sometimes hundreds of dollars a month, which means that after just one year of medication, pretty much surgery could have been paid for. I have no doubt that the sustained release implants are going to be priced on par with surgery. And so, whether or not that something is affordable for patients or whether insurance will cover it, is far from being determined.
The other reason why I’m not that excited about this solution is that medications for the most part—although they have side effects—are rarely associated with risk of loss of vision. But any time something is injected or implanted in the eye, there is the risk of infection. Though low, infection can lead to permanent loss of vision, chronic inflammation, corneal decompensation… So these are things that have to be taken into account.
The reason why I’m excited about the development of Bimatoprost SR or BMSR (…is the brand name maybe), is due to the recent presentation of Dr. Ike Ahmed at the American Glaucoma Society meeting in San Francisco in March 2019.
During that presentation, Ike Ahmed did show that the results were pretty impressive in terms of what was expected. What was expected is that the implant would actually work to keep the intraocular pressure down for four months. The idea being, that every 4 months, some of them would come back into the office and have it re-implanted. So that was successful. But what was unexpected—and in fact pretty much nothing short of amazing—is that for those who had three implants (implanted at zero, then four months, and eight months), almost 90% of those people had sustained Intraocular Pressure control over two years after the last implant was placed. So that’s essentially three years of Intraocular pressure control with 3 implants. That was really unexpected and very exciting.
So, how’s that possible? I mean, the implant itself was devoid of any active medication after the four month mark. So what’s causing the change? What’s allowing this treatment to keep the pressure down for years after the last implant was placed in the eye? So the short answer is, “we don’t know” but Dr. Ahmed showed a theory that the higher concentration of medicine is possible from an implant in the eye versus an eye drop on the surface of the eye, results in long term and permanent changes to the trabecular meshwork (that’s the outflow system in the eye).
If true this is exciting for multiple reasons. Not only because sustained intraocular pressure reduction may be possible even years after the last implant, but because it means that medications can result in a permanent change not just a short-term change that lasts only for hours.
In summary these mind-blowing results have completely changed my mind about how excited one should be about the sustained release implants. Only time will tell whether these medications in sustained release form will be affordable or covered by insurance, but these early results are both exciting and humbling. “Exciting” because of the unexpected results and “humbling” because it indicates how little we actually know about how these medications work and what’s possible in terms of the long-term treatment of glaucoma.
I hope that you found this information to be exciting as well and I’ll continue to share updates with you, as they relate to eye-related diseases, as I learn about them.
- Sustained Drug Delivery for Glaucoma Treatment – An Update from the American Glaucoma Society (AGS) 2017 Annual Meeting
- FDA Approves Preservative-Free Xelpros™ for Open-Angle Glaucoma
- PolyActiva Commences Clinical Trial of Biodegradable Ocular Implant for Glaucoma
- The SENSIMED Triggerfish® Sensor Device
- Simple Drops™ – Glaucoma Treatment Eye Drops
David Richardson, MD
Medical Director, San Marino Eye
David Richardson, M.D. is recognized as one of the top cataract and glaucoma surgeons in the US and is among an elite group of glaucoma surgeons in the country performing the highly specialized canaloplasty procedure. Morever, Dr. Richardson is one of only a few surgeons in the greater Los Angeles area that performs MicroPulse P3™ "Cyclophotocoagulation" (MP3) glaucoma laser surgery. Dr. Richardson graduated Magna Cum Laude from the University of Southern California and earned his Medical Degree from Harvard Medical School. He completed his ophthalmology residency at the LAC+USC Medical Center/ Doheny Eye Institute. Dr. Richardson is also an Ambassador of Glaucoma Research Foundation.