Using a set of in-licensed macrolide chemistry technologies, Cempra Pharmaceuticals Inc. is developing a pipeline of macrolide antibiotics that it hopes will be effective against resistant bacteria but have safety profiles similar to marketed macrolides. The company began Phase I studies of CEM-101 in healthy volunteers this month.

Macrolides inhibit bacterial protein synthesis by binding reversibly to a peptide tunnel on the 50S subunit of the bacterial ribosome, thereby inhibiting translocation of peptidyl-tRNA. This action is mainly bacteriostatic, but can also be bactericidal at high drug concentrations.