CRS-3123, also known as REP-3123, is a methionyl-tRNA synthetase inhibitor potentially for the treatment of enteric infections. CRS-3123 is in Phase 1 clinical development for the treatment of Clostridium difficile Infection (CDI). CRS-3123 is a small molecule protein synthesis inhibitor that acts on the novel target methionyl-tRNA synthetase (MetRS). REP-3123 has been shown to be active in vitro against clinical isolates of C. difficile including epidemic strains such as B1/ NAP1/027; MIC values of REP-3123 for C. difficile are typically 0.5 -- 1.0 mg/l. REP-3123 is also active against a range of clinically important aerobic Gram-positive bacteria including methicillin-susceptible and -resistant Staphylococcus aureus (MIC90 values of 0.06 and 0.25 mg/l, respectively), Streptococcus pyogenes (MIC90 0.5 mg/l) and enterococci (MIC90 32 mg/l). CRS-3123 has numerous potential advantages over current CDI therapies. In addition to being highly potent against all clinical isolates of C. difficile tested, CRS-3123 has several desirable qualities for the treatment of CDI which include: Narrow spectrum for C. difficile, which may substantially reduce the disruption of normal intestinal flora compared to current therapies; Inhibition of toxin production, potentially leading to lower morbidity and mortality; Inhibition of sporulation, potentially leading to lower rates of transmission and recurrence; A novel mechanism of action, which means that its use will not compromise the utility of systemic antibiotics while maintaining activity against pre-existing resistance mechanisms.

Lumicitabine (formerly called ALS-8176), a first-in-class orally administered nucleoside analogue is being developed by Alios BioPharma for the treatment of respiratory syncytial virus infections. Lumicitabine converts to plasma-circulating ALS-8112, and then to the 5'-active nucleoside triphosphate (NTP) form within host cells. Extensive and rapid RSV reduction occurred after lumicitabine treatment (EC50 = 1.79 uM), with >99% viral inhibition at 2 h after loading dose. Clinical trials of Lumicitabine for the treatment of respiratory syncytial virus infection are ongoing.

Vaccenic acid (VA) (t11 octadecenoic acid) is a positional and geometric isomer of oleic acid (c9-octadecenoic acid), and is the predominant trans monoene in ruminant fats (50%–80% of total trans content). Dietary VA can be desaturated to cis-9,trans-11 conjugated linoleic acid (c9,t11-CLA) in ruminants, rodents, and humans. Hydrogenated plant oils are another source of VA in the diet, and it has been recently estimated that this source may contribute to about 13%–17% of total VA intake. In contrast to suggestions from the epidemiological studies, the majority of studies using cancer cell lines (Awad et al. 1995; Miller et al. 2003) or rodent tumors (Banni et al. 2001; Corl et al. 2003; Ip et al. 1999; Sauer et al. 2004) have demonstrated that VA reduces cell growth and (or) tumor metabolism. Animal and in vitro studies suggest that the anti-cancer properties of VA are due, in part, to the in vivo conversion of VA to c9,t11-CLA. However, several additional mechanisms for the anti-cancer effects of VA have been proposed, including changes in phosphatidylinositol hydrolysis, reduced proliferation, increased apoptosis, and inhibition of fatty acid uptake. In conclusion, although the epidemiological evidence of VA intake and cancer risk suggests a positive relationship, this is not supported by the few animal studies that have been performed. The majority of the studies suggest that any health benefit of VA may be conferred by in vivo mammalian conversion of VA to c9,t11-CLA. VA acts as a partial agonist to both peroxisome proliferator-activated receptors (PPAR)-α and PPAR-γ in vitro, with similar affinity compared to commonly known PPAR agonists. Hypolipidemic and antihypertrophic bioactivity of VA is potentially mediated via PPAR-/-dependent pathways.