BETHESDA, Md--Intermittent infusions of interleukin-2 (IL-2, aldesleukin)
have led to significant increases in CD4+ T cell counts in HIV-infected
patients with early disease, a study from the National Institute
of Allergy and Infectious Diseases (NIAID) has found.
"This study provides the strongest evidence so far that it
may be possible to rebuild and maintain the damaged immune systems
of HIV-infected individuals," said H. Clifford Lane, MD,
NIAID clinical director. Dr. Lane was the lead investigator along
with Dr. Joseph A. Kovacs of the NIH Clinical Center's Critical
Care Medicine Department.
Whether the increases in CD4 counts will translate into clinical
benefits will be determined by ongoing trials, Dr. Lane told Oncology
News International in an interview.
The study included 25 patients, 10 with baseline CD4 counts greater
than 200/mm³ (early disease) and 15 with baseline CD4 counts
less than 200/mm³ (advanced disease). Patients received IL-2
intravenously for 5 consecutive days every 2 months. All participants
also took at least one approved antiretroviral drug such as zidovudine
(AZT, Retrovir) or didanosine (ddI, Videx) during the study.
In six of 10 patients with early disease, CD4 counts rose by more
than 50% after 12 months. In several of these patients, the rise
was dramatic, from 554 to 1,998 in one individual. The remaining
four patients had stable counts or a slight decline. Follow-up
of several of these patients has shown that CD4 increases have
persisted for more than 2 years (N Engl J Med 332:567-575, 1995).
Dr. Lane pointed out that as a patient's CD4 counts improve with
use of IL-2, infusions can be spaced out longer. One of the best
responders in the study received six 5-day infusions over the
course of a year. "When we stopped the infusions, his count
was around 2,000; then over 8 months, it came down to around 1,000
at which time he got a single IL-2 infusion, and the count went
back up," he said.
Thus, the increases in CD4 counts seen with IL-2 therapy appear
to be a "reproducible phenomenon," he said, noting that
unlike the antiviral drugs, resistance to IL-2 should not be a