Optional Immunomodulating Therapy and Improved Vaccination Responses by Adjuvant Administration of a Cyclooxygenase Type 2 Inhibitor in Antiretroviral naïve HIV-infected Patients and Patients on ART

The current trial was based on our observations that augmented levels of cyclic adenosine monophosphate (cAMP) contribute to the T cell dysfunction in HIV-infected patients. In T cells, cAMP triggers a protein kinase A (PKA) - Csk - Lck inhibitory pathway that inhibits the proximal T cell receptor (TCR) signaling events. This mechanism may also be involved in the inhibitory function of regulatory T cells.

The investigators have hypothesized that elevated levels of cAMP in T cells from HIV-infected individuals result from increased production of prostaglandin E2 (PGE2) following activation-induced expression of cyclooxygenase type 2 (COX-2) in lymphoid tissues. Although the investigators have identified even COX-2 positive T cells in HIV-infected individuals, activated monocytes may be the major source of PGE2; high levels of COX-2 are produced de novo after a number of stimuli, particularly lipopolysaccharide (LPS). Circulating LPS is indeed increased in untreated chronic HIV infection due to enhanced translocation of microbial material and correlates to chronic immune activation and disease progression.

In three preceding clinical explorative trials, the investigators have demonstrated that COX-2 inhibition by COX-2 inhibitors (COX-2i) improves the immune functions of HIV patients, the first two studies included patients on antiretroviral treatment (ART). In the third trial the investigators also showed for the first time that treatment with a COX-2i was able to downregulate chronic immune activation and improve T cell functions (efficacy of T cell-dependent vaccine) in asymptomatic HIV-infected patients who did not use ART. In these patients, chronic immune activation was dampened as demonstrated; CD38 density on CD8+ T cells (primary endpoint) decreased by 24% by study week 12. This reduction could be extrapolated to a possible improvement of CD4+ T cell loss with 30 CD4 cells per ul per year with an approximate mean CD4 loss of 60 per ul per year. These data founded the basis for further support to this study through the GLOBVAC call program under the Norwegian Research Council (granted application for the current study).