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24 EW NEWS & OPINION August 2012 Pharmaceutical focus Dynamic duos: Combination glaucoma agents getting results by Maxine Lipner Senior EyeWorld Contributing Writer Combination punch While practitioners can simply prescribe two separate medications, offering a fixed combination agent may be very appealing, finds Reay H. Brown, M.D., clinical professor, Emory University, Atlanta. He cites compliance as likely being enhanced with such medications. "The major advantage is that they only have to use one bottle and one drop, let's say twice a day, rather than two bot- tles and two separate drops twice a day," Dr. Brown said. "I think the more that you can reduce the bur- den, the more likely people are to be compliant." Dr. Shaarawy likewise finds that The appeal of fixed glaucoma combinations W hen it comes to glau- coma medications, the use of fixed com- bination glaucoma drugs is very com- mon, according to Tarek Shaarawy, M.D., University of Geneva, Switzer- land, and associate executive vice president, World Glaucoma Associa- tion. Dr. Shaarawy pegs the need for Ophthalmic continued from page 23 that both residents and practitioners will easily be able to adapt to. "The micro-needle doesn't penetrate in- side of the vitreous cavity during the intravitreal injection, and that re- duces the risk of surgical complica- tions—that's what patients and physicians are afraid of," Dr. Peyman said. "Similarly, the eye wall cannot be penetrated by the needle during the subconjunctival injection." He finds that placement of the injection is also easy. "For intravit- real injection you always know where the pars plana will be once you position the edge of the flange at the limbus," Dr. Peyman said. "This automatically positions the needle about 3 mm behind the lim- bus at the edge of the pars plana." When it comes to subconjunctival injections he pointed out that these can be injected anteriorly or all the way at the back of the eye without fear of the micro-needle piercing the eye wall, since the needle doesn't penetrate all of the way inside the sclera. Dr. Peyman sees the jet injector as a boon for nervous patients as well. "Because the needle doesn't penetrate the eye wall it can be very reassuring for the patient," he said. In addition, the injection process takes less than one second to per- form. "The patient hardly notices it and the procedure is over," he said. In the future, Dr. Peyman envi- sions the jet injector as becoming available as a disposable drug-device instrument, for more commonly used indications, preloaded with medication. "It makes the dosing of medication more precise, and poten- tially mistakes with regard to the dosing and concentration can be avoided because the device and medication can be fabricated ahead of time by the manufacturers," he said. This would also eliminate po- tential contamination that can occur during the typical reconstitu- tion process as has been reported. "We think that it can make us more confident that the wrong medica- tion is not injected and that the medication has the correct concen- tration," he said. EW Editors' note: Dr. Peyman and his associates have financial interests in the jet injector. Contact information Peyman: gpeyman1@yahoo.com these as encompassing more than 50% of cases. "It's a minority of patients that can be controlled after a couple of years of therapy on one molecule," he said. Gary D. Novack, Ph.D., presi- dent, PharmaLogic Development Inc., San Rafael, Calif., concurs. "The rule of thumb in America is that about half the patients who are on therapy are on monotherapy," he said. "That means that the other half are on multiple therapy." convenience is very important. "People can comply better with one bottle than two," he said. He also pegs the potential for side effects as a key factor. "If you give them two bottles and each bottle has its own preservative then it becomes a double amount of preservative that you bombard the surface of the eye with," he said. "That would poten- tially create ocular surface disease." A study that Dr. Novack worked on together with Alan L. Robin, M.D., and other fellow investigators substantiates the compliance issue. In the study, published in the Octo- ber 2007 issue of the American Jour- nal of Ophthalmology, the aim was to consider the adherence of subjects to using a once-daily prostaglandin agent or to using two-drug therapy. The findings showed that while pa- tients readily adhered to taking one medication, with a mean coverage of 97.2%, this dropped to 85.6% when the second agent was part of the equation. "When we added the two bottles, the compliance fell off," Dr. Novack said. "So there is data that the more complicated regimens are harder for the patient to follow." Current combos Presently, combination glaucoma medications in the U.S. are limited to three: Combigan (brimonidine tartrate/timolol maleate ophthalmic solution, Allergan, Irvine, Calif.), Cosopt (dorzolamide/timolol, Merck, Whitehouse Station, N.J.), and now Cosopt PF (preservative- free dorzolamide/timolol, Merck), which got the FDA nod in February. Most of the combinations in Europe are carbonic anhydrase inhibitors with beta blockers, ac- cording to Dr. Shaarawy. In addition, there are prostaglandin combina- tions available outside of the U.S. The prostaglandin beta blocker combination is dubbed Xalacom (latanoprost/timolol, Pfizer, New York), according to Dr. Novack. A second prostaglandin combination available in Europe is Ganfort (bi- matoprost/timolol, Allergan), and a third is DuoTrav (travoprost/timolol, Alcon, Fort Worth, Texas). One weakness Dr. Shaarawy finds is the common link for all the combinations—the beta blocker, timolol. "All combination therapies have a beta blocker, and a good percentage of our patients has a contraindication to using a beta blocker," he said. "That is the main drawback to using them in those cases."