A report on the research appears in the May 29 issue of the New England Journal of Medicine.
"This is one of the most important studies performed to date in HIV-infected patients who have already received highly active antiretroviral therapy (HAART) and a landmark study for the field of HIV," said Dr. Joseph Eron of the University of North Carolina at Chapel Hill and a report author.
"The clinical work clearly demonstrates that a completely new class of anti-HIV medication, developed by a local company, Trimeris, is highly effective in a very large randomized study," said Eron, associate professor of medicine at the UNC School of Medicine.
"Enfuvirtide, or T-20, works by blocking HIV entry into CD4 + lymphocytes or T-cells and will benefit patients who already have HIV that is resistant to current therapy."
CD4+ lymphocytes, also known as T-cells, are a key part of the body's immune system for fighting off disease-causing viruses, bacteria and various other organisms, he said. HIV is so deadly because it kills those defenders and leaves patients vulnerable to a wide variety of debilitating illnesses.
Fuzeon is enfuvirtide's trade name.
Another report of a second study with similar results carried out in Europe and Australia also appears in the May 29 issue of the journal. Eron and Dr. J. Michael Kilby of the University of Alabama at Birmingham have a third article in the journal describing T-20 and other drugs now in development in the new class of HIV medications called entry inhibitors.
Dr. Jacob P. Lalezari of Quest Clinical Research, Mount Zion Hospital and the University of California at San Francisco led the research in North and South America.
Patients from 48 hospitals and clinics in the United States, Canada, Mexico and Brazil who had had at least six months of treatment with retroviral drugs or resistance to those drugs or both and also carried at least 5,000 copies of viral RNA per millimeter of plasma participated in the Western trial. Two-thirds of the nearly 500 patients received enfuvirtide plus a regimen of three to five antiretroviral drugs, while the remaining third -- the control group -- received only the antiretrovirals.
The two groups were otherwise similar in all ways, Eron said.
Twenty-four weeks after treatment, patients receiving the new drug showed an average increase of 76 CD4+ cells per millimeter of plasma as compared to an average increase of 32 cells per millimeter in the control group, researchers found. The amount of HIV in the blood of enfuvirtide-treated patients decreased almost 10 times more than the amount in the blood of control patients.
About 98 percent of patients in the T-20 treatment group showed moderate localized skin reactions at the injection sites, but most of those did not have to limit their activities or take pain medications for discomfort. Doctors also saw a few more pneumonias in the novel treatment group.
"In our study, enfuvirtide resulted in significant improvement in virologic and immunologic responses as compared with individualized, optimized combination antiretroviral therapy alone," the authors wrote. "…The introduction of enfuvirtide as the first of this new class of antiretroviral agent could make an important contribution to the successful, individualized treatment of growing numbers of patients who have limited remaining treatment options."
Said Eron, "In our review of this new class of HIV medications, Dr. Kilby and I point out that T-20 is the first in what HIV researchers hope will be a long line of effective and safe agents that will be developed over the next two to five years."
By DAVID WILLIAMSON
UNC News Services
No. 308
Note: Eron can be reached at 919-966-7199 or 843-2722.
Contact: David Williamson, 919-962-8596.
Journal
New England Journal of Medicine