Rib-X Pharmaceuticals raised $20 million in a financing round to support development of its broad-spectrum antibiotics pipeline, including a Phase IIb study with its lead fluoroquinolone antibiotic, delafloxacin. The financing was led by current investor Warburg Pincus.
Rib-X is exploiting its structure-based design and optimization platform to generate and develop small-molecule antibiotics that bind to bacterial ribosomes. The platform combines proprietary computational analysis, x-ray crystallography, medicinal chemistry, microbiology, and biochemistry techniques for the identification and synthesis of broad-spectrum antibiotics, including completely new antibiotic drug classes, which reportedly avoid typical antibiotic-resistance mechanisms. Rib-X claims its competitive advantage hinges on its understanding of the three-dimensional structure of the bacterial ribosome, which has led to new insights into the binding properties of antibiotics, including binding in the presence of mutations that confer the bacterium with drug resistance.
Rib-X’ pipeline is headed by two clinical-stage programs; the next-generation quinolone delafloxacin (RX-3341), and the oxazolidinone candidate radezolid (RX-1741). The firm says delafloxacin has demonstrated activity against methicillin-resistant Staphylococcus aureus (MRSA) and recently successfully completed a Phase II study in patients with complicated skin and soft tissue infections (cSSTI). RX-1741, meanwhile, has completed two separate Phase II studies for community acquired pneumonia (CAP) and uncomplicated skin and soft tissue infections (uSSTI).
The firm’s preclinical-stage programs include Rχ-02, and Rχ-04. Project Rχ-02 is focused on developing a next-generation macrolide to treat uSSTI in the community. Rχ-04 aims to design and develop molecules with a novel chemical scaffold that can be used to treat serious hospital Gram-negative infections. Rib-X says it expects to nominate an initial development candidate from the Rχ-04 program during early 2011, for the potential treatment of multidrug resistant Gram-negative bacteria.