Interleukin-2 (IL-2, Proleukin)

March 2007     View PDF     En español

How to use it?

IL-2 is given by injection under the skin in starting doses ranging from 4.5 million international units (MIU) twice daily (total daily dose of 9 MIU) to 7.5 MIU twice daily (total daily dose of 15 MIU), over a period of five consecutive days. This five-day course is repeated every eight weeks.

To manage toxicity and side effects, individuals reduce the daily dose of IL-2 in three MIU increments. For example, if 15 MIU daily schedule was very difficult for an individual to take, then the next five-day course dose would be 6 MIU twice daily (total daily dose of 12 MIU), for five consecutive days. Unlike anti-HIV therapy, lower­ing the dose of IL-2 does not lead to drug resistance.
Studies show that people who tolerate the higher starting doses (15 MIU) for three cycles are most likely to see immediate CD4+ cell count increases. People who start with the lower 4.5 MIU twice daily dose (total daily dose of 9 MIU) still get substantial increases in CD4+ cell count, but these increases usually take longer. In this situation, it often takes a number of cycles before any significant change is seen.

When trying to measure how IL-2 affects CD4+ counts, it’s important not to take the CD4+ test too quickly after using IL-2, as this produces exaggerated and false results. Immediately after taking IL-2, CD4+ cells initially are depressed and then are highly stimulated and stirred up in the blood, causing potentially meaningless changes in the CD4+ count. Great increases might be seen a few days to a few weeks after IL-2, but these immediate changes generally decline rapidly after that.

Changes in the CD4+ count are only real and mean­ingful when the CD4+ test is taken a month or more after the last use of IL-2. For many people, no significant change is seen for several months, despite the short-term “bursts” of CD4+ activity seen right after IL-2 is taken. Over time though, the average level of CD4+ cells begins to rise and remains consistently above the levels seen before IL-2 use began.

Once someone has reached a goal in terms of CD4+ cell count increase, the time between courses of IL-2 therapy will be increased by four-week periods or longer if CD4+ cell counts are sustained. Blood work for CD4+ cell counts and HIV levels should be run two weeks before an IL-2 cycle. (Note: Lab test results done within four weeks after a cycle are considered unreliable.)

When IL-2 is prescribed as part of a study or through off-label use, it’s important that a doctor or nurse teach you how to: Prepare the IL-2 (it may or may not come in pre-filled syringes, other times you will have to prepare the syringe yourself) Inject yourself Safely dispose of used syringes, and Monitor for and manage side effects (and provide you with prescriptions for side effect management medications).

 

For more information on IL-2 side effects and side effects management, see Taking IL-2 and Managing Its Side Effects.

Some people using subQ IL-2 who failed to achieve CD4+ cell increases over time attained these increases when they switched to continuous intravenous (CIV) therapy. Early studies of IL-2 involved five-day continuous intravenous (in the vein) infusions, every eight weeks. Starting doses ranged from 9–18 MIU, daily. In general, the 15–18 MIU CIV daily doses were not well tolerated. Starting doses of 9–15 MIU were slightly more tolerable in CIV IL-2 studies.

CIV IL-2 side effects are more common and severe than side effects seen with the subcutaneous injection dosing. A large percentage of people taking IL-2 will see sizable CD4+ cell count increases with the less toxic and easier-to-use subQ approach. However, for those who don’t experience CD4+ cell count increases with subQ injec­tions, CIV IL-2 represents another option. Optimally, the first few CIV IL-2 cycles should be done in a hospital or clinic setting with skilled staff to support with side effects management. For more information, see Dosing Considerations.

What about side effects?

LAST      NEXT

Where to get it?