Eyeworld

EW GLAUCOMA 52 by Maxine Lipner Making first contact Drug-eluting lens delivers glaucoma medications continuously I magine telling your glaucoma patients that instead of taking drops at least once a day, treat- ment consisted of simply putting in an extended-wear contact lens just once a month. Such is the promise of a new lens. Results with a new drug-eluting con- tact lens indicate that continuous month-long dispensing of the glaucoma medication latanoprost is possible, according to Joseph B. Ciolino, MD, assistant professor of ophthalmology, Harvard Medical School, and Massachusetts Eye and Ear Infirmary, Boston. The outcomes published in the January issue of Biomaterials indicated that achieving latanoprost concentrations with the lens, comparable to those attained with topical drops of the medica- tion, is possible. Dr. Ciolino, and Daniel S. Kohane, MD, professor of anesthe- sia, Harvard Medical School, and Boston Children's Hospital, have been developing the lens as a means of improving patient compliance and better delivering agents. "What's unique about this lens is that inside of a traditional hydro- gel lens, we have placed a very thin drug-containing polymer film, and that helps to control the release of the medication out of the contact lens," Dr. Ciolino explained. Early close encounters So far, results conducted in rabbit eyes with the lens have been promis- ing. "We've found extended release with an early burst followed by a fairly steady-state delivery over the course of a month," Dr. Ciolino said. In fact, investigators found that the lens could be used for an even longer period. Dr. Kohane noted that such results have exceeded expectations. "When we made our first prototype, we guessed it would work well," Dr. Kohane said. "We had no idea that it would work this well, by which I mean at least 3 months of sustained release of large amounts of drug with near linear release kinetics." After 3 months, the study was stopped, not because of any problem with the lens but because investiga- tors felt there was no market for a lens that released drugs for that length of time. "We suspected that it was unlikely that a device that re- leased drug for that long would find use, at least in America where right now a month is probably the outer limits of what would be done," Dr. Kohane said. Extended-wear lenses are not worn in the U.S. for more than a month, he stressed. To date, Dr. Ciolino reported there have been no complications with the lens. "So far we've tested the lens in cell culture and found it to be safe," he said. "We have also placed multiple lenses (in succes- sion) in rabbit eyes for 30 days each." Over a 3-month period with the successive lenses, investigators have not noticed any adverse lens- related effects. To determine if the latanoprost itself is effective when dispensed this way, investigators are now moving toward new animal models. "We have studied the lens in rabbits and found that it delivers what appears to be a therapeutic amount of drug for 1 month," he said. "However, unfortunately rabbits do not re- spond to latanoprost the way hu- mans do." As a result, investigators could not show that latanoprost released from the lens was effective because the drug is not effective in lowering IOP in rabbits. "Therefore we're moving to animal models that have a response to latanoprost similar to that of humans," Dr. Ciolino said. Rocketing beyond latanoprost Dr. Kohane stressed that latanoprost is by no means the only compound that would work with the lens. "We've shown that it releases a wide range of compounds, and the reason for the recent focus on latanoprost has to do with the most likely area of broad application more than anything else," he said. Indeed, the lens has the capabil- ity to handle even combinations of agents. "This is a platform technol- ogy so it should be applicable with many different drugs," Dr. Kohane said. "There are limits, but without getting into exotic drug types, it should be fine to use with most things." Dr. Ciolino concurs. "Beyond glaucoma I think that this platform can be used to deliver a range of medications," he said. Going forward, Dr. Ciolino views this lens as an elegant means for treating conditions such as corneal ulcers, microbial keratitis, and even ocular surface tumors, as well as other diseases. "I think that this would be a very elegant device that could be used after cataract sur- gery, placed at the time of surgery by the surgeon and then removed at the 1-week follow-up," Dr. Ciolino said. "I think there are a range of indications that this can treat, and it's just the tip of the iceberg with our lead (latanoprost) molecule." EW Reference Ciolino JB, Stefanescu CF, Ross AE, Salvador- Culla B, Cortez P, Ford EM, Wymbs KA, Sprague SL, Mascoop DR, Rudina SS, Trauger SA, Cade F, Kohane DS. In vivo performance of a drug-eluting contact lens to treat glaucoma for a month. Biomaterials. 2014 Jan: 35 (1): 432–9. Editors' note: Drs. Ciolino and Kohane are inventors on a related patent. Contact information Ciolino: Joseph_Ciolino@meei.harvard.edu Kohane: Daniel.Kohane@childrens.harvard.edu February 2011 April 2014 This unique hydrogel lens has a very thin polymer film that helps to control the release of medication. Source: Joseph B. Ciolino, MD

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