NovaBay's Aganocide compounds effective against multidrug-resistant bacteria

Sep 15 2009

NovaBay(R) Pharmaceuticals, Inc. (NYSE-AMEX: NBY) (http://www.novabaypharma.com), a clinical stage company developing novel anti-infective compounds for the treatment or prevention of a wide range of bacterial, viral and fungal infections, presented in two poster sessions today at the 49th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in San Francisco. These two separate laboratory studies of its Aganocide(R) compounds reveal potent activity in killing bacteria that have developed resistance to antiseptics and antibiotics and that the compounds demonstrate rapid bactericidal and anti-biofilm activity in the presence of plasma, serum or albumin.

The two studies conducted by NovaBay scientists advance the company's efforts to provide solutions to the global problem of multidrug-resistant bacteria, which are rapidly diminishing the effectiveness of antibiotics and antiseptics for the treatment and prevention of many common infections. While multi-drug resistance to antibiotics has received much attention over the past few years, resistance to antiseptics is becoming an increasing concern.

"Modern medicine faces an urgent need to develop new classes of drugs that do not develop resistance to antibiotics and antiseptics," said Ron Najafi, president and CEO of NovaBay. "Our Aganocide compounds are an example of such a drug and they are on the bioequivalent of the natural anti-microbial compounds produced in white blood cells that have remained effective against invading pathogens for millions of years."

The first study examined the bactericidal activity of NovaBay's lead Aganocide compound NVC-422 against antiseptic and antibiotic-resistant Staphylococcus aureus. Efflux pumps in bacterial cells are common mechanisms for resistance, and in S. aureus, the genes qacA/B, qacC and norA encode multidrug-transporter pumps. The genes have been previously identified as key to the development of antiseptic resistance.

The researchers compared the effectiveness of NVC-422 with chlorhexidine, pentamidine and proflavine against S. aureus strains that expressed the resistance genes. Measurements were made of the minimum inhibitory concentration (MIC), which is the lowest concentration of an antimicrobial that will inhibit the visible growth of a microorganism after overnight incubation, and the minimum bactericidal concentration (MBC), which is the lowest concentration of antibiotic required to kill an organism. The subset of S. aureus clinical strains that tested positive for qacA/B were found to be resistant to chlorhexidine, pentamidine and proflavine, consistent with MIC values reported in the literature. But, these strains exhibited no resistance to NVC-422, with MBC values similar to the MBC value of a S. aureus antiseptic-sensitive strain.

In the second study, NovaBay scientists evaluated the effectiveness of the Aganocides NVC-422 and NVC-612, as well as endogenous N-chlorotaurine (NCT) produced by white blood cells, against S. aureus, Escherichia coli and Candida albicans in the presence of human plasma, serum and albumin (HSA). NVC-422 was also tested against biofilm. Results showed that the Aganocide compounds were effective against the selected microbes, including biofilms.

"This second study is exciting because it shows effectiveness of the Aganocides within the critical environments found in the human body," said Ron Najafi, president and CEO of NovaBay. "These compelling data further support our efforts in advancing our current clinical studies and moving other pre-clinical programs to human testing."