What to Expect from
Clinical Trials
Retina Drugs on Outer Surface of the Eyes
Medicare
Legislation News
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(Foundation Fighting Blindness) When a person considers participating in a clinical trial, there are several things he or she should be aware of in order to have realistic expectations and adequate knowledge of possible risks and benefits: • What is the purpose of the trial? Is the intent to find a cure, or simply a treatment, or perhaps preventive measures or a diagnostic test? Don't sign up for a clinical trial unless your expectations are in line with the study's objective. • Is an experimental clinical trial appropriate for you? Have you tried the standard treatments and failed to benefit from them? Are you willing to try a treatment for which little is known, rather than try a treatment that has risks and possible benefits that are well understood? • What are the known risks and benefits of the experimental treatment? How many people have been in the experiment before you? Did they experience any harm? • Is the experimental product only slightly different from other available treatments (e.g. a slightly revised version of an existing drug), or is it a completely new approach to treatment? • Who is paying for the study? Is it supported by government funds or a commercial firm? Does your doctor have a commercial interest in the therapy (e.g. a patent, royalties, etc.)? Note: Some universities have �Conflict of Interest� committees who review these factors and decide whether a commercial conflict may influence the outcome. • Is this a �placebo controlled� trial, or will the experimental treatment be compared to the standard treatment for your disease? Is there a chance that you will receive the placebo and if so, how much risk does this represent? • If you are harmed by the experimental treatment, who will pay for your medical care? • What will happen when the study is finished? Will you be able to continue using the treatment, or will it be stopped even though you feel you are benefitting from the product? Will the manufacturer promise you continued access? • While the vast majority of experimental treatments are free, will you or your insurance be liable for any costs related to your medical care while you are participating in the clinical trial?
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| Retina Drugs on Outer Surface of the Eyes Traditional approaches that use eye drops or intraocular injections are less than optimal. Now, researchers are growing optimistic about a new approach that involves placing the drug on the outside of the eye, at the back, and letting it slowly seep through the sclera to the retina. Research to perfect the technique is yielding exciting results. This �transscleral� drug delivery system may turn out to be useful for millions of peple worldwide with vision disorders related to RP, AMD, Diabetic Retinopathy, and other diseases involving the posterior segment of the eye. Drugs being studied using the transscleral approach include Carboplatin and Cisplatin for eye tumors, and Methotrexate and Dexamethasone for reducing inflammation caused by chemicals, infection, allergy, or foreign bodies. Scientists are learning about the size of the molecules that pass through different regions of the sclera and the time course of diffusion across the sclera. Treatment to the back, inside of the eye has always been a challenge. Most ocular medicines are delivered by eye drops. Only about 2-5% of the drug in eye drops typically reaches the inside of the eye, let alone the back. Most is absorbed into the bloodstream through nearby blood vessels. The medicines are also sometimes given by mouth or injection into another part of the body where the higher amount of drug needed to produce a therapeutic effect within the eye can be associated with significant side effects. Injections right into the vitreous can have side effects like hemorrhage, infection, and cataract that compromise their use. Intravitreal sustained release implants are another new approach showing promise. They require surgery to be inserted and must be replaced periodically. Scientists at the University of California , San Francisco , are excited about this new transscleral or �periocular� delivery method. The drug is either injected beneath the conjuctiva or placed behind the eye in a sustained-release material. In both cases, the drug slowly diffuses into the eye through the sclera. Researchers are now investigating which portions of the sclera are most permeable to different sizes and types of molecules. It would be best to target the area near the optic nerve with a periocular injection or implant, yet this is where the sclera is especially thick. Reports will soon be published in the Journal of Ocular Pharmacology and Therapeutics , as well as in the Investigative Ophthalmology & Visual Science .
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Medicare Legislation News The Medicare bill, passed by Congress in late November, legislates a one-year study to produce recommendations by January, 2005 for legislative action �providing for payment for vision rehabilitation services furnished by vision rehabilitation professionals.� Other legislation expected to be passed this year would establish a funded, five-year demonstration project to provide vision rehabilitation services where they are most needed: at home and in the community.
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