In Brief: Immune-Based Therapies
HIV-1 Immunogen (Remune®) Study Closure
A Data Safety and Monitoring Board or DSMB (the group charged with monitoring the safety of a study) recommended the closure of a large study of HIV-1 Immunogen (Remune®). The study included thousands of volunteers and continued for a number of years. On a monthly basis, half of them received the injectable product, Remune®, and half received a placebo injection, monthly. All were permitted to use any other antiviral drugs or combinations of their choosing.
The DSMB reviewed the results of these 2,500 volunteers to date and observed no difference in HIV disease progression rates (opportunistic infections and deaths) between the two groups. Further, the DSMB did not believe that any notable differences would likely emerge if the study continued.
Confounding the study results was broader availability and wide-scale use of protease inhibitor therapy over the course of the study. Due to the effects of potent anti-HIV therapy, HIV progression rates (~1%) were so low that it was impossible to detect incremental benefits or harm the HIV-1 Immunogen may contribute. One interpretation is that whatever benefits Remune® might offer, they were largely insignificant against the background of more powerful therapies. The sponsor, however, says the people who receiving Remune® were more likely to see an improvement in a particular marker of immune function related to HIV. Whether or not this makes any difference to a patient's health, however, was not established by the study. The company has now begun a new study designed to determine if Remune® has a significant effect on viral load or durability of HAART regimens.
The bottom line, however, is that the jury is still out on this product after many years of research. To date, absolutely no claims can be made in terms of its benefits.
GM-CSF (Leukine®) Study Results Announced
A 309-person study of an immune-based therapy called GM-CSF* (Leukine®) was completed with inconclusive results. GM-CSF is a naturally occurring immune chemical, which in laboratory tests enhances the ability of a kind of immune cell (macrophage) to fight and prevent opportunistic infections. The therapy is approved for preventing infections in immune compromised individuals who have undergone bone marrow transplantation.
In the recent study, which included people with low CD4+ cell counts, half received GM-CSF and half received placebo, by injection three times every week. No overall differences were observed with regard to developing new or recurrent opportunistic infections. However, volunteers receiving GM-CSF were more likely to experience more complete viral suppression (all volunteers were on standard anti-HIV therapy) than those who received the placebo. Whether this observation holds true over time, and whether it leads to improved survival, remains unknown.
*GM-CSF is granulocyte macrophage colony stimulating factor. G-CSF, granulocyte colony stimulating factor (filgrastim, Neupogen®) is commonly used to treat neutropenia (low neutrophil cell counts, associated with increased risk of bacterial infections) associated with HIV disease and some therapies to treat AIDS-related infections (e.g. anti-CMV therapies) and cancers.
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