MAR 2014

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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E W GLAUCOMA 132 by Tony Realini, MD Facts and myths about generic formulations of ophthalmic products T he ophthalmic pharmaceu- tical marketplace is a multi- billion dollar space where market share is hard earned a nd heavily defended. Branded products—protected by patents—are generally considered to be the big money makers, but gener- ics—the products that follow when patent exclusivity expires—are in fact quite profitable as well. "In 2012, 84% of all prescrip- tions were dispensed as generics," according to Wiley Chambers, MD, deputy director of the Division of Transplant and Ophthalmic Prod- ucts at the Food and Drug Adminis- tration (FDA). This had the effect of l owering the overall amount of money Americans spent on prescrip- tion drugs in 2012 compared to previous years, he added. Some clinicians believe—rightly or wrongly—that generic formula- tions are inferior to their branded counterparts. This belief may be informed by a misunderstanding of e xactly what is a generic formula- tion. What is a generic? Technically, "a generic is expected to have the same active and inactive ingredients in the same concentrations as the innovator," Dr. Chambers explained, "and is i ntended to copy the safety and efficacy of the innovator or branded product." Because the formulation of a generic is required to copy that of the branded product, the generic is assumed to have similar safety and e fficacy and is not evaluated in clinical trials in humans. Those who argue against gener- ics often cite the perceived differen- tial prevalence of corneal melting associated with Falcon's "generic" diclofenac versus Ciba Vision's "branded" Voltaren. In fact, the Falcon formulation w as not a generic, said Dr. Chambers. It was evaluated in clinical trials, including one with a Voltaren comparison arm. "It was not submitted to the FDA for approval as a generic product," he said. Since it was not intended to be a copy of Voltaren, it should not be expected to have the same efficacy a nd safety as Voltaren, he said. Likewise, Allergan's formulation of prednisolone acetate (Pred Forte) and Alcon's formulation (Econopred Plus) were both branded products evaluated in clinical trials. One is not a generic version of the other, and thus there is no expectation t hat they would have equivalent safety and efficacy profiles. If perceived differences between these drugs is the basis for believing that generics are inferior to branded products, that reasoning is flawed as these drugs do not have brand- generic relationships. When a generic isn't a generic In the current marketplace, the patent expirations of Pfizer's branded latanoprost (Xalatan) and Merck's branded timolol/dorzo- lamide fixed combination (Cosopt) have brought a plethora of generic formulations of these drugs to the marketplace. Once again, there are c oncerns by some that these generic formulations do not appear to have the same efficacy as their branded counterparts. In fact, some patients in the U.S. may be on formulations that are neither branded or generic. When patients obtain their prescription medications by mail order, it is not unusual for them to receive drugs manufactured outside the United States. "Latanoprost formulations man- ufactured overseas are not copies of branded Xalatan and are thus not generics and are not expected to be equivalent to Xalatan," said Dr. Chambers. Upsides to generics If the formulation is a true generic, Dr. Chambers said, we should have confidence that it will have equiva- lent safety and efficacy to the branded product. "A generic by definition has exactly the same ingredients in the bottle that the branded product has." If available, Dr. Chambers en- courages the use of generic formula- tions. "They provide the same reliable safety and efficacy as the branded product, at less cost to the patient," he said. "This may lead to greater availability and to increased compliance with therapy." Downsides to generics Generic formulations are not without their limitations. Malik Kahook, MD, University of Colorado, pointed out that while the contents of the bottle may be identical to the branded product, the bottle itself may be different. February 2011 March 2014 In this video from Hawaiian Eye 2014, John Vukich, MD, reports on results of his study showing essentially no difference in post-cataract endophthalmitis outcomes between generic and brand-name antibiotics. Related videos on ewreplay.org ewreplay.org Hawaiian Eye 2014 Tuesday 130-135 Glaucoma_EW March 2014-DL2_Layout 1 3/7/14 10:48 AM Page 132

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