Researchers at the National Institutes of Health have discovered that a combination of protease inhibitors and other anti-HIV drugs used to treat people with AIDS can prevent or delay the progression of cytomegalovirus (CMV) retinitis, a potentially blinding eye complication of AIDS. A letter detailing these findings is published in the May 21, 1997 issue of the Journal of the American Medical Association (JAMA).
This discovery is significant because it suggests that, under certain circumstances, people with CMV retinitis can stop taking standard anti-CMV medications and the disease would not progress," said Dr. Carl Kupfer, director of the National Eye Institute, one of the Federal government's National Institutes of Health (NIH). "The standard anti-CMV medications can be toxic and some require daily intravenous administration. This new drug therapy may lead to a significant improvement in the quality of life for people with AIDS who have CMV retinitis."
NEI researchers discovered that certain CMV retinitis patients were able to stop standard CMV treatment, which can cause kidney toxicity and low blood cell counts, without progression of the disease. These patients were placed on both protease inhibitors and other anti-HIV medications, and subsequently experienced an elevation of CD4 cell counts, which are blood cells that fight infection. These combinations of protease inhibitors and other anti-HIV medications, called highly active antiretroviral therapy (HAART), also decreased the amount of HIV in the patients' blood.
CMV retinitis is a common complication of AIDS and mostly occurs in the disease's later stages, when the patient's immune system is severely affected. CMV retinitis had been increasing in frequency as people with AIDS live longer, with up to 40% of all adults with AIDS eventually developing the disease. Standard treatment for CMV retinitis, which can cause blindness if left untreated, requires life-long medication with a variety of anti-CMV drugs that can be cumbersome, costly, and toxic. It is estimated that current yearly treatment cost for CMV retinitis ranges between $50-100,000 per patient.
Our findings suggest that the combination of protease inhibitors and other anti-HIV medications can restore the immune system to a point where it can fight the CMV retinitis infection on its own," said Dr. Scott Whitcup, clinical director of NEI and first author of the JAMA letter. "In fact, we have recently noticed a significant decrease in the number of new cases of CMV retinitis in our patients with AIDS." Protease inhibitors are a class of promising drugs recently introduced that, when taken with other HIV-fighting medications, have shown success in prolonging the lives of people with AIDS.
The use of anti-HIV drug combinations, when accompanied by an increase in CD4 cell counts, may allow us to change standard treatment for CMV retinitis," Dr. Whitcup said. "We are encouraged that some patients having favorable immune responses to this new drug therapy may be able to stop standard anti-CMV retinitis medication for a period of time. Even a brief period off the costly and inconvenient anti-CMV medications may be beneficial to patients."
This initial observation is based on only four patients," said Dr. Whitcup. "We will need more information before recommending that all people with CMV retinitis and elevated CD4 counts stop their anti-CMV retinitis medication." The National Eye Institute is seeking to recruit AIDS patients for a larger clinical study at the NIH clinical center in Bethesda, Maryland. These patients must have CMV retinitis that does not immediately threaten sight, a CD4 count above 150, and must be taking anti-CMV medication. "There's still a chance that some patients, despite increased CD4 counts, may not have the appropriate immune cells to fight the CMV retinitis," Dr. Whitcup said. "The National Eye Institute's larger clinical trial will examine this more closely."
People with AIDS and their doctors who are interested in participating in the NEI study can contact Cheryl Perry, R.N. at 301-435-4559 or by e-mail at firstname.lastname@example.org.