CPCRA 059 is a 511-person study of IL-2 in people with CD4+ cell counts of 300 and above. People received IL-2 or no IL-2 in addition to anti-HIV therapy. Volunteers had CD4+ cell counts of about 540 when they entered the study. Among those receiving IL-2, CD4+ cell counts increased to about 850 over the 12 months of study. Those who received only anti-HIV therapy experienced no change in CD4+ cell count over the study period. Viral load levels were similar between the two groups. It is anticipated that volunteers in the CPCRA 059 study will "rollover" into the larger IL-2 study called ESPRIT, which will follow people for about six years.
An ESPRIT Vanguard study in the United Kingdom enrolled 36 people with CD4+ cell counts above 300, 24 received IL-2 and 12 did not. Neither group received anti-HIV therapy. There were no differences in viral load between the two groups at 64 weeks. Those receiving IL-2 experienced CD4+ cell increases from about 400 to 650. Those receiving no IL-2 therapy experienced a slight CD4+ cell count increase from about 480 to 500. The CD4+ cell count increases observed were less pronounced than those seen in other ESPRIT Vanguard studies that included anti-HIV therapy. The researcher speculates that more profound increases can be realized with the concurrent use of anti-HIV therapy.
An AIDS Clinical Trials Groups study (ACTG 328) evaluated the use of IL-2 in people with CD4+ cell counts between 50 and 350, who achieved viral load suppression to below 5,000 copies/ml after twelve weeks of anti-HIV therapy. After twelve weeks of anti-HIV treatment resulting in viral control, people received IL-2 therapy intravenously (in the vein), by injection or no IL-2 therapy in addition to their anti-HIV treatments. A total of 161 volunteers were included in the 84-week analysis. Results after 84 weeks are summarized below in Table 1.
CD4+ Cell Count
|Anti-HIV Therapy Alone|
After 84 weeks those receiving IL-2 had substantial increases in CD4+ cell counts compared to those receiving only anti-HIV therapy. Viral levels were similar between the three groups. Those receiving IL-2 experienced expected side effects associated with five-day courses of therapy, primarily flu-like symptoms.
A study in France, ANRS 82, delivered IL-2 therapy to people who despite long-term anti-HIV therapy had not had their CD4+ cell count go above 200. Participants had CD4+ cell counts between 25 and 200 and viral load below 1,000 copies/ml, despite at least six months of anti-HIV therapy. Most had been on anti-HIV therapy for about 1½ years. At study entry the average CD4+ cell count in the IL-2 group was about 150 and about 140 in the group that did not receive IL-2 therapy (Table 2, below).
@ 24 Week
@ 80 Weeks
|Anti-HIV Therapy Alone|
After 24 weeks, the group receiving only anti-HIV therapy was offered IL-2. In essence, after the 24 week (6 month) mark, everyone received IL-2 and thus differences between the two groups can be viewed as the difference between immediate or delayed IL-2 therapy in people with CD4+ cell counts below 200.
This study lead the French government to approve IL-2 therapy for people with CD4+ cell counts below 200. After 80 weeks, except for one case of KS progression seen early in the course of the study, there have been no new AIDS-defining diseases in the group.
The National Institutes of Health (NIH) has conducted the most studies using IL-2. They have followed a number of people who have been receiving IL-2 therapy for six to seven years. The NIH conducted an analysis combining groups receiving injectable IL-2, which included 77 people who elected to participate in the extension phases from three different studies. CD4+ cell counts increased from a mean of 540 to about 1,130 over the course of observation. Each person has used about 10 five-day courses of IL-2 to achieve and maintain these numbers. The mean interval since the last course of therapy is 26 months, slightly over two years, to maintain counts.
IL-2 is not without side effects and those contemplating study participation or using IL-2 "off-label" are advised to learn about potential side effects and side effect management before initiating IL-2 therapy. IL-2 users note that side effects can be lessened and managed with proper planning. Nearly everyone taking IL-2 does experience some side effects during the course of therapy, usually worsening over the five days and resolving when therapy is stopped at the end of the five-day course. For more information on these and other studies of IL-2 presented in Chicago and/or a discussion of IL-2 and side effects, call the Project Inform hotline.
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