, 2014). In cell culture assays, BCX4430 is active against
Ebola and Marburg viruses, (EC50 ca 1 μM). With BCX4430 at 30 μM, there was no detectable incorporation into host DNA or RNA. In rats, BCX4430 is efficiently activated (phosphorylated) to the triphosphate. In a primer-extension assay, there is some read-through beyond a single residue of BCX4430, but there is effective chain termination after the first BCX4430 residue where the template has two consecutive uridine residues. BCX4430 has been tested in rodent and nonhuman primate models of Marburg hemorrhagic fever. In mice, there was a dose response (30, 20, 3.3 and 1.1 mg/dose, bid) with full protection at the two higher doses (survivors, 100%, 100%, 95% and 83% respectively). In an experiment with dosing starting at different find more times (4 h pre-infection, 24, 48, 72, 96 and 120 h post-infection vs placebo), the placebo-treated mice died on days 6, 7 and 8 with one survivor (10%). In the treated groups, the percent survival was 80, 100, 80, 100, 100 and 30, respectively. In guinea pigs, BCX4430 (bid) with treatment starting at different times (1 h pre-infection, 24, 48 and 72 h post-infection) there was full protection (100% survival) for the pre-infection and 24 h groups, with reduced efficacy at the later start times. In cynomolgus monkeys, BCX4300 treatment was started at 1, 24 and 48 h post-infection. In the placebo group,
Quizartinib supplier all 6 animals died within days 9 to 12. In all the treated groups, virus loads were reduced by more than log103. There was one late death in the 1 h group but the other 17 monkeys survived. Various markers of potential organ damage were reduced in all treated groups. Encouraged by these results, 14-day toxicology trials have
recently been completed without any serious concerns. BioCryst is developing BCX4430 under the FDA Animal Rule and IND-enabling work is ongoing. When asked about viral resistance, Travis explained PAK6 that it is not ethically permissible to create resistant strains of Marburg virus, but samples collected from the monkeys are being sequenced to look for mutations indicative of drug resistance. As yet, mitochondrial toxicity has not been examined. Mario Stevenson, University of Miami, Miami, FL, USA Even after successful and prolonged ART, invariably plasma HIV load increases within 20 days of stopping therapy. Of all the millions of HIV-infected people, there has been only one documented cure – the “Berlin” patient (see above). Two Boston patients, who had similar bone marrow transplants, initially seemed to have been “cured” but HIV was detected after 70 and 200 days, respectively. Latent HIV can survive in various long-lived cells for decades, especially in memory T cells. When these cells proliferate, the integrated HIV genome is duplicated as the cell divides and the cells survive so long as HIV remains silent. Compounds known to activate all T-cells are too toxic to become a clinical therapy.