30 Sep Intraocular Drug Delivery Systems Gaining Momentum
Ozurdex for Retinal Vein Occlusions and Uveitis
The mainstay of treatment for retinal vein occlusions has been laser photocoagulation. This sustained release drug delivery system is an alternative to laser photocoagulation. While intravitreal injections of steroid, for example, Kenalog or Triesence, have been very successful in the past in treating the macular edema created by the RVO, I have had tremendous success using Ozurdex to treat branch or central vein occlusions. In many cases, the results of Ozurdex are superior to laser treatment.
As of September, 2010, Ozurdex is now indicated for uveitis.
Ozurdex is given as an injection in the office setting. I like to offer pre-operative antibiotics to, theoretically, reduce the chance of infection. I suggest a regimen of 4x/day for 4 days before and after the procedure. The chance of infection is comparable to that of cataract surgery. The device is injected through a thin needle. The needle is small enough to “seal,” or prevent leakage, without the need for sutures.
The device releases dexamethasone for several months and then dissolves.
Iluvien for Diabetic Retinopathy Nears FDA Approval
Iluvien also releases a steroid, fluocinolone. It is marketed by Alimera Sciences and is similar to Ozurdex. Currently, Alimera Sciences has applied for NDA (New Drug Approval) status from the FDA.
The short story, this may become available by the end of the year for the treatment of diabetic macular edema. It, too, may be a very promising alternative to laser treatment for macular swelling due to diabetes. Results from clinical trials indicate that Iluvien may be superior to the traditional laser treatment.
Iluvien will be injected into the vitreous the same way as Avastin or Ozurdex. The device will reside in the vitreous and release fluocinolone, another steroid, to treat swelling due to diabetic retinopathy.
The device does not self-absorb.
So many drugs we use routinely are used “off-label.” This may be true for both Ozurdex and Iluvien. It is an exciting time.
Ozurdex, while approved only for RVO, has the potential to be used for say, diabetic retinopathy, too. This would be an “off-label” use and is certainly a legitimate use of the drug, especially if it becomes “standard of care.”
As an example, Avastin is FDA approved for certain types of cancer, but it has become standard of care for the treatment of wet macular degeneration.
Other Drug Delivery Systems in the Pipeline
- Icon Biosciences – using the Verisome platform, this injectable “liquid” may release drug up to a year.
- Regeneron – VEGF-Trap Eye will inhibit VEGF for the treatment of AMD, but also has potential appications for vein occlusions and DME.
- Several other “players” include: Genentech, MacuClear, Neurotech, Novagali,
What Does This Mean? I didn’t try to make this an overhaul of the new devices available. Instead, I am more interested in sparking interest in a new wave of drug delivery, that is, sustained release drug delivery to the eye.
The concepts are now well established. Inject something directly into the eye where you expect the most effect. This obviates the blood brain barrier. Intraocular injections over the past few years have demonstrated the advantages of directly delivering the drugs to the target tissue. We have found that even “old” drugs, e.g. triamcinolone, can have impressive results just by delivering the drug accurately.
The next generation of sustained release systems will include drugs such as Lucentis or Avastin. Any drug now that requires repeated applications (i.e. injections) may have a future with sustained release technology.
It is appropriate to believe that the next level of therapeutics will include any condition which requires chronic therapy. For instance, glaucoma medications may be combined with sustained release delivery systems.
Imagine, glaucoma treatment becomes managed by a retina specialist. Now who would have thought?