Dacopafant

Tumor necrosis factor alpha (TNF-alpha) is overexpressed during human immunodeficiency virus (HIV) infection. RP 55778, a TNF-alpha synthesis inhibitor, decreases HIV replication in monocytes/macrophages. Therapeutic use of RP 55778 in vivo, like that of other biological response modifiers, would theoretically require association with dideoxynucleosides. We have evaluated here the combinatory effects of zidovudine (AZT) or dideoxyinosine (ddI) and RP 55778. This TNF-alpha inhibitor antagonizes the antiviral effects of both dideoxynucleosides, especially AZT. The more favorable anti-HIV activity of ddI in resting cells may explain these unequal degrees of antagonism.

Monocyte-derived macrophages (MDM) were demonstrated to be susceptible to productive infection by the monocytotropic human immunodeficiency virus type 1 (HIV-1) strain HIV-1/Ba-L and by three primary HIV-1 isolates, HIV-1/DAS, HIV-1/PAR and HIV-1/THI. Production of tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and IL-1 beta was monitored between days 3 and 26 after MDM infection. TNF-alpha and IL-6 were detected in cell culture supernatants from days 16 to 21 following HIV-1/DAS, HIV-1/PAR and HIV-1/Ba-L infection, at the time of high viral replication. IL-1 beta was not found at the same time points. TNF-alpha mRNA expression occurred around the peak of both TNF-alpha levels and supernatant RT activities. In HIV-1/THI-infected macrophage cultures no endogenously produced TNF-alpha was observed, despite high levels of HIV-1 in MDM. This result demonstrates that a primary isolate may replicate independently of TNF-alpha in MDM. To investigate the relationship between TNF-alpha and viral replication we used a TNF-alpha synthesis inhibitor, RP 55778. Treatment throughout the course of cell culture resulted in a significant decrease in both TNF-alpha levels and viral production in HIV-1/DAS-, HIV-1/PAR- and HIV-1/Ba-L-infected MDM cultures. This phenomenon is reversed by adding recombinant human TNF-alpha to the RP 55778-treated cell cultures from day 14 post-infection. No effect of RP 55778 was observed in MDM cultures infected with the primary isolate HIV-1/THI, whose replication is independent of TNF-alpha production and therefore remained unchanged after RP 55778 treatment. We conclude that the clinical value of such a drug is directly dependent on the ability of the HIV-1 strains involved to induce TNF-alpha production at the time of viral replication.