Here are some further highlights from the Academy in San Francisco.
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Important change in treatment of chemical burns
|Helen Keller as a young woman.|
“Chemical Burns to the Eye—What Has Changed in Our Approach?” That was the topic that Claes H. Dohlman, MD, PhD, addressed in this year’s Helen Keller Lecture.
Chemical injuries pose a significant challenge for ophthalmologists, Dr. Dohlman said, even in developed societies, where most work is nonindustrial. Chemical burns actually account for up to 10 percent of all eye trauma. Alkali burns are generally worse than injuries from acids because alkalis saponify cellular fatty acids and quickly penetrate the globe. Acids, on the other hand, tend to coagulate the epithelium thus creating their own barriers to deeper structures.
Unfortunately, the management of alkali burns that has been taught to generations of ophthalmologists, Dr. Dohlman said, may be wrong. Last year, a team of German researchers found that rinsing alkali-injured eyes with ordinary isotonic saline solution had virtually no effect on intracameral pH.1 They compared several rinsing solutions and found that Cederroth Eye Wash, which contains a borate buffer and no preservatives, did significantly neutralize the burns, even at a low rate of flow.
After lavage, Dr. Dohlman said, medications are usually not helpful in reversing damage to the cornea. “Therefore, forget about the cornea for the moment; just protect it with some antibiotics and steroids and let the inflammation calm down,” he said.
More important, said Dr. Dohlman, is to attend to intraocular pressure, which can spike dramatically after chemical burns. He said alkali burns, especially, can render ganglion cells acutely sensitive to IOP, and so new, lower pressures become the goal, ideally around 10 mmHg. “Be vigilant in keeping IOP very low throughout the post-burn period!”
Cornea transplants may seem logical in these patients, but, he said, “Unfortunately, standard transplantation gives poor long-term results. Corneal transplantation combined with stem cell transplantation is controversial. Much has changed with the introduction of relatively stable keratoprostheses, but these should not be resorted to until inflammation has calmed down, perhaps half a year following the burn.”
1 Rihawi, S. et al. Burns 2008;34(7):1027–1032.
|A marbled cornea following severe alkali burn.|
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Decision expected soon on CMS rule for bevacizumab compensation
George Williams, MD, set the tone early for his update on the status of a new CMS rule that may reduce bevacizumab compensation. He had only one financial disclosure: “I’m a taxpayer.”
Earlier this month the Centers for Medicare & Medicaid Services (CMS) passed a new rule mandating compensation for Avastin (bevacizumab) based on the average price of the drug plus 6 percent—the margin that’s supposed to cover a physician’s cost as an efficient provider.
“It’s a simple calculation,” Dr. Williams explained. But CMS left out an important cost of providing the drug. “It did not consider the compounding costs, which run at $15 to $45.”
In response, the Academy actively engaged with CMS on a daily basis and worked with individual Medicare carriers. CMS’ initial response was positive, and it was thought a solution was imminent. But that was two weeks ago.
The Academy is turning up the heat, meeting with senior CMS officials, joining forces with the AARP and placing articles in national newspapers, ensuring everyone knows the issues. Congress is now involved.
“We continue to keep the pressure up and are providing continuing input so the policy makers know the issue. There is every indication that CMS intends to address the issue,” Dr. Williams said. “I can’t promise you, but I’m optimistic that we will come to a resolution in the near future,” he said.
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Gene therapy improves vision in patients with severe retinal dystrophy
Jean Bennett, MD, PhD, presented an update on her team’s ongoing development of gene therapy for Leber’s congenital amaurosis. Phase 1 study results for the treatment, the first gene therapy for a nonlethal pediatric disease and for inherited retinal degeneration in adults, were published in the Oct. 24 issue of The Lancet.
A rare autosomal recessive disease with early onset and that causes incurable retinal degeneration, Leber’s congenital amaurosis is often caused by mutations in the RPE65 gene, which is produced in the retinal pigment epithelium, where it helps to generate a vitamin A compound essential for vision. Dr. Bennett and her colleagues have developed a method to deliver a normal version of the RPE65 gene via a subretinal injection of a genetically engineered adeno-associated virus. Twelve patients ranging in age from 8 to 44 were treated in their worse eye in the phase 1 study.
Children responded best to treatment, Dr. Bennett reported, with all of them gaining ambulatory vision. Some patients improved to the extent of no longer being classified as legally blind. In addition, the pupillary light reflex was restored in eyes that were barely responsive before treatment. All patients demonstrated at least a 2-log unit response, and the subjects’ visual fields expanded. Dr. Bennett showed video of the youngest patient successfully completing an obstacle course in the laboratory using his treated eye three months after treatment, but he was unable to complete the course using only his untreated eye. The treatment appears safe and well-tolerated. A phase 3 study of the treatment is scheduled to begin in February.
Dr. Bennett reports no relevant financial disclosures.
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Genetics may influence response to ranibizumab in wet AMD patients
A study conducted by Genentech researchers suggests that genetic polymorphisms may influence ranibizumab (Lucentis) treatment outcomes in wet AMD patients. These results, if validated by further research, could help determine future population selection for clinical trials, said Jason Ehrlich, MD, who presented the study results.
The research involved a genome-wide association study on 352 ranibizumab clinical trial subjects. The investigators identified multiple single nucleotide polymorphisms associated with significant differences in mean visual acuity change after 12 months of ranibizumab treatment. Visual acuity gains were smaller in patients with fewer of the beneficial SNPs, Dr. Ehrlich said.
For his presentation, Dr. Ehrlich accepted a Best Paper award at yesterday morning’s Retina Paper session.
Dr. Ehrlich is an employee of Genentech.
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