Predictors of CD4 count change over 8 months of follow up in HIV-1-infected patients with a CD4 count>or=300 cells/microL who were assigned to 7.5 MIU interleukin-2

Immunological success is predicted by enfuvirtide but not interleukin-2 therapy in immunodepressed patients

OBJECTIVES

To evaluate the efficacy of adding interleukin-2 (IL-2) to an optimized background treatment in HIV-1 patients with advanced failure.

DESIGN

Randomized, open-label, multicentre controlled trial.

METHODS

Patients with CD4 T-cell count of less than 200 cells/microl, plasma HIV-1 RNA of more than 10 000 copies/ml and a genotypic sensitivity score showing two or less active drugs were randomized to either eight IL-2 cycles with optimized background treatment or optimized background treatment alone. Optimization was made according to genotypic sensitivity score. Enfuvirtide was added in enfuvirtide-naive patients. Evaluation was performed at week 52 on the proportions of patients with CD4 cell count of at least 200 cells/microl (primary outcome), of patients with a CD4 cell count increase of at least 50 cells/microl from week 0, on plasma HIV-1 RNA and HIV-related events.

RESULTS

Fifty-six patients were analysed. Median age was 43 years, 61% were at Center for Disease Control and Prevention stage C, 43% had a genotypic sensitivity score of 0, median baseline CD4 cell count and plasma HIV-1 RNA values were 64 cells/microl and 4.9 log10 copies/ml, respectively. Treatment could be optimized in 23 patients. At week 52, in the IL-2 and control groups, the proportion of patients with CD4 cell count of at least 200 cells/microl (14 and 18%) or a CD4 cell count increase of at least 50 cells/microl (25 and 32%) and median plasma HIV-1 RNA were not significantly different. In multivariate analysis, optimization with enfuvirtide and baseline CD4 cell count were statistically associated with CD4 cell count of at least 200 cells/microl at week 52 (P = 0.003 and P = 0.01). Optimization with enfuvirtide was the only factor associated with a CD4 cell count gain of at least 50 cells/microl (P < 0.001). There was no difference in the rate of AIDS events between groups.

CONCLUSION

IL-2 failed to increase CD4 cell count in immunocompromised patients with multiple therapeutic failures. Enfuvirtide use was highly associated with success.

Inferiority of IL-2 alone versus IL-2 with HAART in maintaining CD4 T cell counts during HAART interruption: a randomized controlled trial

OBJECTIVE

To evaluate whether interleukin (IL)-2 in patients with chronic HIV infection can maintain CD4 T cell counts during 6 months of HAART interruption.

DESIGN

Prospective, randomized, controlled, open-label phase II noninferiority trial comparing IL-2 with HAART interruption or continuous HAART.

METHODS

Forty-one IL-2-experienced (three or more prior cycles) HIV-1-infected adults with CD4 cell count at least 500 cells/microl were randomized in the ratio 2: 1 to interrupted (I = 27) or continuous (C = 14) HAART for 6 months following an initial IL-2 cycle. Subsequent IL-2 cycles were triggered by CD4 T cell counts less than 90% of baseline. Immune, metabolic, and quality of life indices were compared (Mann-Whitney and Fisher's exact tests), defining noninferiority as a percentage difference (C- I) in treatment success (CD4 T cells > or =90% of baseline at 6 months) with a 95% confidence interval (CI) lower limit greater than -20%.

RESULTS

Demographic and immune parameters were similar between the groups at baseline. Median CD4 T cell count, HIV viral load, and treatment success differed significantly at 6 months (I: 866 cells/microl, 39,389 copies/ml, 48.1%; C: 1246 cells/microl, <50 copies/ml, 92.3%; P < or = 0.001). Group I was inferior to C (% difference = -44.2%; 95% CI: -64.2%, -11.2%; P = 0.013). Minor statistically significant differences in HgbA1c and energy level occurred at 6 months (I > C). Following HAART interruption, single cases of acute retroviral syndrome, secondary syphilis, non-Hodgkin's lymphoma, and Kaposi's sarcoma recurrence were observed.

CONCLUSION

IL-2 alone was inferior to IL-2 with HAART in maintaining baseline CD4 T cell counts. HAART interruption had a small impact on metabolic parameters and quality of life.

CD4 T cell survival after intermittent interleukin-2 therapy is predictive of an increase in the CD4 T cell count of HIV-infected patients

Administration of interleukin (IL)-2 to human immunodeficiency virus (HIV)-infected patients leads to significant increases in CD4 T cell counts. We previously have shown that IL-2 induces increased proliferation and survival of CD4 T cells. Deuterium labeling studies were undertaken to study the relationship between IL-2-induced increases in the CD4 T cell count and the effects of IL-2 on cell proliferation and survival. A strong inverse correlation was noted between the rate of decay of the label in CD4 cells and increases in CD4 cell counts (R =or- 0.67; P<.001). This correlation was not seen with the level of proliferating cells. Although the CD4 cell count at baseline and the number of CD4 cells expressing CD25 were also predictive of increases in the CD4 cell count, the rate of decay remained the most statistically significant predictor in multivariate regression models. Thus, an increase in the survival of CD4 T cells appears to be the critical mechanism leading to sustained increases in the CD4 cell counts of HIV-infected patients receiving intermittent IL-2 therapy.

Long-term effects of intermittent interleukin-2 therapy in chronic HIV-infected patients (ANRS 048-079 Trials)

OBJECTIVE

Interleukin (IL)-2 therapy leads to significant CD4 cell increases in HIV-infected patients. Since phase III trials are ongoing, studies supporting the long-term feasibility of this strategy are needed.

METHODS

We studied the long-term outcomes of 131 patients treated with IL-2 in two studies initiated either before (ANRS 048) or following (ANRS 079) the advent of HAART.

RESULTS

At the last assessment (median follow-up 3.4 years), these patients experienced a gain of 428 cells/microl and a decrease in plasma HIV RNA to 1.70 log10 copies/ml. In both studies, high CD4 cell counts were maintained with a median of ten 5-day cycles of subcutaneous IL-2. Median time since the last cycle was 2 years. At last assessment, 59% of 048 patients maintained a non-HAART regimen. Detailed analysis at week 170 showed that median CD4 cell counts were 856 (048) and 964 (079) cells/microl. This corresponded to a gain from baseline of 515 (048) and 627 (079) cells/microl. The median viral load decreases from baseline and corresponded to 1.70 (048) and 1.88 (079) log10 copies/ml. Comparisons across the studies showed that CD4 gains and viral load changes were similar whether HAART or non-HAART was used. The frequency of cycling, but not CD4 cell counts, viral loads or antiviral regimen at baseline, was predictive of long-term CD4 gain (P = 0.03).

CONCLUSION

Altogether, these observations support IL-2 as a long-term therapeutic strategy in HIV infection.