Malaria is one of the most significant causes of childhood mortality but disease control efforts are threatened by resistance of the Plasmodium parasite to current therapies. Continued progress in combating malaria requires development of new, easy to administer drug combinations with broad ranging activity against all manifestations of the disease. DSM265, a triazolopyrimidine-based inhibitor of the pyrimidine biosynthetic enzyme dihydroorotate dehydrogenase (DHODH), is the first DHODH inhibitor to reach clinical development for treatment of malaria. We describe studies profiling the biological activity, pharmacological and pharmacokinetic properties, and safety of DSM265, which supported its advancement to human trials. DSM265 is highly selective towards DHODH of the malaria parasite Plasmodium, efficacious against both blood and liver stages of P. falciparum, and active against drug-resistant parasite isolates. Favorable pharmacokinetic properties of DSM265 are predicted to provide therapeutic concentrations for more than 8 days after a single oral dose in the range of 200–400 mg. DSM265 was well tolerated in repeat dose and cardiovascular safety studies in mice and dogs, was not mutagenic, and was inactive against panels of human enzymes/receptors. The excellent safety profile, blood and liver-stage activity, and predicted long human half-life position DSM265 as a new potential drug combination partner for either single-dose treatment or once weekly chemoprevention. DSM265 has advantages over current treatment options that are dosed daily or are inactive on the parasite liver-stage

To prevent sexually transmitted HIV, the most desirable active ingredients of microbicides are antiretrovirals (ARVs) that directly target viral entry and avert infection at mucosal surfaces. However, most promising ARV entry inhibitors are biologicals, which are costly to manufacture and deliver to resource-poor areas where effective microbicides are urgently needed. Here, we report a manufacturing breakthrough for griffithsin (GRFT), one of the most potent HIV entry inhibitors. This red algal protein was produced in multigram quantities after extraction from Nicotiana benthamiana plants transduced with a tobacco mosaic virus vector expressing GRFT. Plant-produced GRFT (GRFT-P) was shown as active against HIV at picomolar concentrations, directly virucidal via binding to HIV envelope glycoproteins, and capable of blocking cell-to-cell HIV transmission. GRFT-P has broad-spectrum activity against HIV clades A, B, and C, with utility as a microbicide component for HIV prevention in established epidemics in sub-Saharan Africa, South Asia, China, and the industrialized West. Cognizant of the imperative that microbicides not induce epithelial damage or inflammatory responses, we also show that GRFT-P is nonirritating and noninflammatory in human cervical explants and in vivo in the rabbit vaginal irritation model. Moreover, GRFT-P is potently active in preventing infection of cervical explants by HIV-1 and has no mitogenic activity on cultured human lymphocytes.AIDS ͉ lectin ͉ plant ͉ sexually transmitted ͉ tobacco mosaic virus

Significance Useful antimalarial drugs must be rapidly acting, highly efficacious, and have low potential for developing resistance. (+)-SJ733 targets a Plasmodium cation-transporting ATPase, ATP4. (+)-SJ733 cleared parasites in vivo as quickly as artesunate by specifically inducing eryptosis/senescence in infected, treated erythrocytes. Although in vitro selection of pfatp4 mutants with (+)-SJ733 proceeded with moderate frequency, during in vivo selection of pbatp4 mutants, resistance emerged slowly and produced marginally resistant mutants with poor fitness. In addition, (+)-SJ733 met all other criteria for a clinical candidate, including high oral bioavailability, a high safety margin, and transmission blocking activity. These results demonstrate that targeting ATP4 has great potential to deliver useful drugs for malaria eradication.