IL-2 still available in UK in ESPRIT study, safety management guidelines expanded

Simon Collins, HIV i-Base

ESPRIT is large randomised international NIH (UD)-lead study using the immune modulating cytokine IL-2 together with HAART with 24 UK sites and is the largest ever HIV clinical trial. Randomisation to IL-2 or no IL-2 is 1:1.

The study aims to follow 4000 patients using doses of 1.5 – 7.5 MIU BID in multiple 5 day cycles with follow up to 2007. A minimum of three cycles are recommended, many people benefit from a fourth cycle in the first year. Preliminary reports from previous studies indicate that a single ‘top-up’ cycle every 2-3 years may continue to extend this benefit and sustain this raised CD4. Patients in the study retain the option to access subsequent IL-2 cycles until 2007.

The UK has been allocated about 300 places on this study, and current enrolment stands at just over 200.

Updated toxicity management guidelines to increase awareness of psychiatric, cardiac, hepatic and renal disease in both new and currently enrolled patients have now been issued. These additional guidelines are to be welcomed.

General information and the management guidelines are available from Mary Pearson, UK trial manager for ESPRIT, at the MRC on 020 7670 4781 ( The website for this study:


Although IL-2 is available on a named patient basis in the UK the cost for this has severely limited access. This study therefore provides the only opportunity to access to this treatment for the near future. The UK is not included in the parallel SILCAAT study in patients with CD4 50-300. IL-2 treatment is expected to approximately double the baseline CD4 count over the first year of treatment and might be of particular interest to patients looking to boost their CD4 count prior to a treatment interruption.

Previous research indicates that IL-2 causes an increase of both naive and memory CD4 cells. Previously, this increase was thought to be mainly due to an increased rate of division of CD4 cells but recent research has shown that that IL-2 can dramatically extend the half life of these cells even in the few patients who generate only a minimal CD4 increase. This may be the main explanation for the sustained increase in CD4 cells long after taking IL-2.

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