Cempra Pharmaceuticals Inc.

Formed around a library of macrolide analogs licensed from Optimer Pharmaceuticals, Cempra Pharmaceuticals Inc.’s original intent was to build an improved version of Ketek, the ketolide antibiotic telithromycin that caused liver toxicity problems after its 2004 US launch. Cempra says its lead candidate CEM-101 is two-to-four times more potent than telithromycin. In addition to an oral form, Cempra is also developing an intravenous version that could be used to treat serious infections in the hospital.