Figure 1: [A] Chemical Structure of Stampidine. [B] IC50 values of Stampidine against 30 ARV-resistant primary clinical HIV isolates and 6 multi-drug resistant recombinant HIV clones. Preliminary findings were reported in part in references 32 and 33. [C] Potent ARV activity of Stampidine against multi-drug resistant HIV clones at non-cytotoxic concentrations. The cytotoxicity of Stampidine against PBMC was determined as detailed in Materials and Methods. Pooled results from two independent experiments that employed two separate GMP batches of Stampidine are presented. Stampidine inhibited HIV replication at nanomolar concentrations but it was not cytotoxic to PBMC even at a 50 micromolar concentration.