Rib-X Pharmaceuticals Reports Positive Phase 2 Study Results for Radezolid in Community-Acquired Pneumonia
- Oxazolidinone Demonstrates Both Safety and Efficacy in the Treatment of Community-Acquired Pneumonia -
NEW HAVEN, Conn., Aug. 5 -- Rib-X Pharmaceuticals, Inc. ("Rib-X" or the "Company"), a development-stage company focused on the discovery, development and commercialization of novel antibiotics for the treatment of antibiotic-resistant infections, today announced positive results from a Phase 2 clinical trial of radezolid in the treatment of community-acquired pneumonia (CAP).
In the double-blind study, radezolid was administered orally at three different doses: 300 mg once daily (QD), 450 mg QD and 450 mg twice daily (BID). This novel oxazolidinone showed comparable efficacy across all three doses, with clinical cure rates in the clinically evaluable population ranging from 78% to 92%. Radezolid also showed excellent activity against a number of key CAP pathogens including Streptococcus pneumoniae, methicillin-sensitive Staphylococcus aureus, Haemophilus influenzae and atypical respiratory pathogens. Additionally, radezolid was well tolerated, with the most commonly reported adverse events being mild gastrointestinal upset. No hematological adverse events were reported in this study.
"We are extremely encouraged by the positive results we've seen in this Phase 2 trial of radezolid in community-acquired pneumonia," said Susan Froshauer, PhD, President and CEO of Rib-X Pharmaceuticals. "Together with the previously reported positive results of the Phase 2 trial in uncomplicated skin infections, we are confident in the potential for radezolid to offer a safe therapeutic alternative for the treatment of methicillin-resistant Staphylococcus aureus and other bacterial infections. Radezolid has been shown to be efficacious and appears to have a favorable safety profile compared to other oxazolidinone compounds. We are looking forward to progressing the development of radezolid with the intravenous formulation in a more complicated disease setting."
CAP Phase 2 Trial Design
This Phase 2 trial was a multicenter, randomized, double-blind study designed to evaluate the safety and efficacy of radezolid in the treatment of adult patients with mild to moderate community-acquired pneumonia (CAP). The study assessed the efficacy of three doses of radezolid, administered either once or twice a day for seven to 10 days. It also evaluated the safety and tolerability of the three doses. The study enrolled approximately 160 patients at 40 study centers across the U.S., Canada, and Russia. The primary efficacy endpoint was clinical response at the test of cure (TOC) visit for the clinically evaluable population.
About Community Acquired Pneumonia (CAP)
Community-acquired pneumonia (CAP) can be caused by a variety of bacteria and viruses and is the seventh most common cause of death in the United States. Bacterial CAP is most often caused by pathogens such as S. pneumoniae and H. influenzae. CAP affects approximately 5.6 million patients in the United States each year and results in approximately 2 million hospitalizations annually.
Radezolid is a novel oxazolidinone that was discovered using Rib-X's proprietary discovery process and was designed to expand the bacterial spectrum and improve the utility of this class of antibiotics relative to the only other oxazolidinone marketed in the world, Zyvox(R) (linezolid). Rib-X is developing both oral and IV formulations for use in serious Gram-positive infections, including those caused by MRSA and linezolid- and vancomycin-resistant enterococci. Radezolid has also completed a Phase 2 trial in uncomplicated skin and skin structure infections (uSSSI). In in vitro studies, radezolid has demonstrated greater potency than linezolid against a variety of Gram-positive organisms; radezolid is also active against linezolid-resistant isolates.
About Rib-X Pharmaceuticals, Inc.
Rib-X Pharmaceuticals, Inc. is a product-driven small molecule drug discovery and development company focused on the structure-based design of new classes of antibiotics. The Company's underlying drug discovery engine capitalizes on its proprietary high-resolution crystal structure of the ribosome, which performs an essential role in protein synthesis. Many known, commercially valuable antibiotics exert their effects by binding to the bacterial ribosome. The Company's integrated research strategy, which combines state-of-the-art, proprietary computational analysis, X-ray crystallography, medicinal chemistry, microbiology and biochemistry, allows it to rapidly synthesize new agents designed to avoid typical antibiotic resistance mechanisms. Rib-X's iterative intelligent engine has yielded several distinctive new antibiotics, including radezolid that can be used for the treatment of either community- or hospital-acquired infections. The Company is also pursuing two other internal discovery programs, RX-04 and RX-02. The RX-04 discovery program is developing novel classes of antibiotics active against multi-drug resistant Gram-negative bacteria and the RX-02 discovery program is focused on developing an IV/oral macrolide active against methicillin-resistant S. aureus, multidrug-resistant S. pneumoniae and S. pyogenes. In addition to these internally developed programs, Rib-X is also currently preparing to enter Phase 3 clinical trials with delafloxacin (RX-3341), a novel quinolone that is effective against quinolone-resistant Gram-positive infections.