miércoles, 11 de mayo de 2016

Long-term benefits of age-related macular degeneration treatments | National Institutes of Health (NIH)

Long-term benefits of age-related macular degeneration treatments

At a Glance

Researchers examined the 5-year outcomes of using the drugs Avastin and Lucentis to treat age-related macular degeneration.
The results showed that almost half of the participants had 20/40 vision or better, confirming the long-term benefits of the therapy.

AMD blurs the sharp, central vision you need for “straight-ahead” activities such as reading. Stockbyte/Thinkstock

Age-related macular degeneration (AMD) is the leading cause of vision loss among older Americans. AMD often has few symptoms in its early stages, but causes loss of central vision in later stages. This type of vision loss interferes with the ability to see what’s in front of you, which can diminish the capacity to read, drive, or recognize faces.

Neovascular AMD is the most common cause of late-stage vision loss. In this “wet” form of AMD, fragile blood vessels grow under the retina and leak fluid. This leakage usually starts in one eye and is stimulated by a protein called vascular endothelial growth factor (VEGF).

Around 10 years ago, the best available treatment for AMD was photodynamic therapy, in which a light-sensitive drug is injected into a vein and a laser used to seal off leaking blood vessels. Two years after diagnosis, less than 15% of patients given this therapy alone retain 20/40 vision (typically good enough to drive or to read standard print). Without any treatment, less than 10% of patients retain 20/40 vision at 2 years.

Since then, VEGF-blocking drugs have come into use. In 2008, NIH’s National Eye Institute (NEI) launched the Comparison of AMD Treatments Trials (CATT) to compare Lucentis (ranibizumab) and Avastin (bevacizumab). More than 1,200 participants with neovascular AMD were randomly assigned to receive either Lucentis or Avastin for 2 years, through monthly or as-needed injections. During that time, the drugs were equally effective at preserving visual acuity.

After 2 years on their assigned drug, participants could choose their own course of therapy with their eye care providers. Over the next few years, more than half received at least 1 treatment with a drug or therapy other than the drug assigned to them. The CATT team, led by Dr. Maureen G. Maguire at the University of Pennsylvania and Dr. Daniel F. Martin at the Cleveland Cole Eye Institute, followed up with participants after 5 years. Results appeared online in Opthalmology on May 2, 2016.

The investigators obtained visual acuity measurements for 647 of the 914 participants who were still living. After 5 years, almost half the participants had 20/40 vision or better. Between 2 and 5 years, the group originally assigned to Lucentis for 2 years lost more visual acuity than the Avastin group, but there were there were no other statistically significant differences in visual acuity or retinal changes between groups.

The overall safety of the 2 drugs was also similar, except that patients who originally took Lucentis had an increased risk of heart attack and stroke (7.6% vs. 4.5%). However, since no differences were seen when the patients were actively taking the drugs during the trial, the authors believe these smaller numbers (42 patients vs. 24) aren’t meaningful.

“This is the most comprehensive study of long-term anti-VEGF therapy for AMD to date,” says NEI Director Dr. Paul A. Sieving. “It provides hard data that anti-VEGF therapy can help patients maintain their vision for years, but that there is still a need for research into alternatives.”

It’s important to note that the U.S. Food and Drug Administration approved the use of Lucentis to treat AMD in 2006 and another drug, Eylea (aflibercept), in 2011. Avastin is considerably less costly than either and commonly used as a first line therapy, but it hasn’t been FDA-approved to treat AMD.

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miércoles, 11 de mayo de 2016