Antisense oligodeoxynucleotide phosphorothioate complementary to Gag mRNA blocks replication of human immunodeficiency virus type 1 in human peripheral blood cells.

Gene-expression modulator 91 (GEM91) is a 25-nt antisense oligodeoxynucleotide phosphorothioate complementary to the Gag mRNA of human immunodeficiency virus type 1 (HIV-1). Cellular uptake and intracellular distribution of GEM91 within cells suggest that this oligomer is readily available for antisense activity. GEM91 inhibited HIV-1 replication in a dose-dependent and sequence-specific manner. In a comparative study, 2 microM GEM91 was as effective as 5 microM 3'-azido-3'-deoxythymidine in blocking virus replication during the 28-day treatment of an HIV-1-infected T-cell line. GEM91 also completely inhibited (> 99%) the growth of three different HIV-1 isolates in primary lymphocytes and prevented the cytopathic effect of the virus in primary CD4+ T cells. Similarly, treatment with GEM91 for 3 weeks of HIV-1/BaL-infected primary macrophages blocked virus replication. Based on GEM91 anti-HIV-activity, safety, and pharmacokinetic profile in animals, a clinical trial was started using this compound as an antisense oligonucleotide drug for the treatment of the acquired immunodeficiency syndrome.