Interleukin-2 (IL-2, Proleukin)

March 2007     View PDF     En español

Commentary

In recent years it has become obvious that preserving the immune system is necessary for people with HIV to live longer lives. IL-2 shows much promise as part of a total treatment plan for people living with HIV, and it is currently the only immune based therapy to produce such significant and easily measured results. It may eventually become standard care to use an immune modulator (like IL-2) with anti-HIV therapies in order to maintain a person’s immune system at healthy levels. However, as with any drug, the benefits of IL-2 must be weighed against the severity of its side effects.

Two major obstacles in developing IL-2 for HIV disease are the difficulty of taking the therapy and its side effects. Some people may not be willing to undergo twice daily injections for five days, every two months. Moreover, people who other­wise feel good might be unwilling to endure the flu-like symptoms. Because IL-2 has had such a pronounced and sustained increase on CD4+ cell counts, enthusiasm for it continues despite the challenges that taking the drug and side effects pose.

Despite pronounced and significant increases in CD4+ cell counts induced by IL-2 therapy, there is as yet no clear proof that these increases result in longer life or longer disease-free time. At the heart of the debate is whether increased CD4+ cells from IL-2 therapy function properly. So far, data overwhelmingly suggest that these cells do function properly, and in general those with sustained CD4+ cell increases have not experienced opportunistic infections at abnor­mally high CD4+ cell counts. When the cells are tested they appear normal and functioning, yet researchers readily admit that the tests to measure cell function leave a lot to be desired. These tests, however limited, suggest that the cells work at least as well as new CD4+ cells produced through anti-HIV therapy.

As of February 2007, one of the two largest studies of IL-2 is in jeopardy. Despite nearly two decades of drug developing in HIV under the auspices of Chiron Corporation, another company (Novartis Pharmaceuticals) bought out Chiron. Novartis originally seemed to suggest it would honor its obligations to the HIV affected community and complete these studies. In the eleventh hour, however, they seem not committed to carrying this important research to fruition and will abandon years of effort and turn their backs on the HIV affected communities. If this should be the case, it should not be allowed to happen without large public outcry.