Adding an experimental drug to antiviral therapy may help persons with advanced HIV infection rebuild their immune systems faster than antiviral therapy alone, suggest early results from AIDS Clinical Trials Group (ACTG) 328, supported by the National Institute of Allergy and Infectious Diseases (NIAID). Principal investigator Dr. Ronald Mitsuyasu presented the findings Oct. 25 at the 5th International Congress on Drug Therapy in HIV Infection in Glasgow.
"We believe our findings point to a new strategy for helping people with very low T-cell counts fight advanced HIV disease," said Mitsuyasu, director of the UCLA Clinical AIDS Research and Education (CARE) Center and associate director of clinical services for the UCLA AIDS Institute.
Mitsuyasu and his colleagues supplemented highly active antiretroviral therapy (HAART) - the so-called AIDS drug "cocktail" and current gold standard for HIV treatment -- with interleukin-2 (IL-2), a naturally occurring human protein shown to stimulate the production of immune cells. They compared the results from 161 randomly assigned patients possessing CD4-cell counts as low as 50. The AIDS virus spreads by systematically targeting and destroying these T-cells in the immune system.
A group of 109 patients received a daily regimen of HAART, plus a five-day course of IL-2 every eight weeks. Fifty-five patients received HAART alone. Researchers found that the persons who received the combination therapy showed a dramatic increase in new CD4 cells.
While HAART alone increased CD4 cells by a median of 32 percent, the addition of IL-2 increased CD4-cells up to a median of 137 percent. Before the advent of HAART, this feat had always eluded earlier studies of IL-2 on advanced-HIV patients.
The findings suggest that IL-2 works in concert with the powerful antiviral drugs to help the immune system regenerate itself after damage by the AIDS virus. First HAART suppresses replication of the virus and diminishes the patient's viral load -- then IL-2 spurs the creation of new T-cells to replenish the immune system.
In a surprise finding, Mitsuyasu and his associates also found that patients taking IL-2 experienced fewer episodes of AIDS-related illnesses, such as Kaposi's sarcoma, lymphoma and pneumonia. He cautioned against premature conclusions about IL-2's impact on AIDS-related illnesses, however, because researchers did not design the study's size and timeline to test for this specific outcome.
Still, said Mitsuyasu, "We found it remarkable that we could observe a measurable difference in opportunistic infections after only 60 weeks." The complete study runs 84 weeks.
In its third finding, the study determined that injection of IL-2 beneath the skin - which patients can self-administer - offers the same therapeutic benefits as intravenous injection. This means greater convenience for patients, who can take IL-2 at home without preparing an intravenous catheter. Because IL-2 breaks down in the digestive system, patients cannot ingest the drug orally.
Chiron Corporation, the manufacturer of IL-2, has launched plans for an international Phase III trial to test the drug on a larger population. The company is currently recruiting 1,400 advanced-HIV patients to determine whether the drug reduces AIDS-related illnesses and extends life expectancy. For more information, call (800) 244-7668 or see www.silcaat.com.
The National Institute of Allergy and Infectious Diseases (NIAID) funded the UCLA study through its AIDS Clinical Trials Group (ACTG), the largest for HIV in the world. One of 32 facilities chosen across the country, UCLA's CARE Center has participated since the NIAID launched the clinical trials network in 1986.
For more information on clinical research trials taking place at the UCLA CARE Center for adults, children and pregnant women with HIV and AIDS, please call (310) 206-6414 or see http://www.medsch.ucla.edu/aidsinst/care/.
The above story is based on materials provided by University Of California, Los Angeles Health Sciences. Note: Materials may be edited for content and length.
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