New antibiotic passes through the first phase of clinical trials with ease

A new antibiotic, developed in Australia, which might help address the burgeoning problem of antibiotic resistance, has successfully completed the first stage of clinical trials.

The drug, called QPX9003, is a promising candidate for tackling Gram-negative bacteria which cause serious infections like pneumonia, urinary tract infections, peritonitis and meningitis.

Gram-negative “superbugs” are becoming increasingly hard to treat, as they develop resistance to most common antibiotics.

QPX9003 was administered in both single 400mg doses, and multiple doses totalling 600mg per day over two weeks, with no adverse effects and no-one dropping out of the trial.

“The drug has an excellent safety and tolerability profile, and we anticipate that the drug would also be effective in patients in terms of targeting these drug-resistant bacteria,” says Dr Kade Roberts, a research fellow at Monash’s Biomedicine Discovery Institute, and the Chemistry Team Leader of the group that’s developed the antibiotic.

Getting the antibiotic to this point has taken a decade of work, and funding from multiple sources – including both the Australian and US governments’ health research funds.

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It started when a research team, headed up by Monash’s Professor Jian Li, began investigating a class of antibiotics called polymyxins.

“They’re a very old class of antibiotics that were discovered in the 1940s. They’re now used as a last resort therapy when nothing else works,” says Roberts.

This is because polymyxins can be toxic to people at clinical doses, and they don’t target infections well in the lungs, which can be a major site for antibiotic resistant infections.

“We re-engineered the polymyxins to come up with a new drug that’s more effective at targeting infections in the lungs, and also prevents the toxicity issues associated with this particular drug class,” says Roberts.

The new drug is a type of compound called a lipopeptide.

US biopharmaceutical company Qpex Biopharma Inc has licenced the drug from Monash, and worked with researchers to develop the drug.

If QPX9003 makes it through Phase II and III clinical trials and onto the market, it will be the first new lipopeptide antibiotic that targets Gram-negative bacteria in over 60 years.

“These particular Gram-negative bacteria which our drug targets have been highlighted by the World Health Organization as being the top priority for the development of new antibiotic drugs,” says Roberts.

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The drug is still several years away from pharmacy shelves – it still needs to get through bigger clinical trials to demonstrate its efficacy. Then, there’s economics to consider.

“The financial incentive for pharmaceutical companies to invest money into developing new antibiotic drugs is just not the same as for it is other medical indications such as oncology and the development new cancer drugs,” says Roberts.

“Companies can make a lot more money developing new cancer drugs than they can developing new antibiotics. So it’s been left up to smaller biotech companies and academic research groups to fill that critical void.”

The results from the Phase I placebo-controlled randomised trial for QPX9003 have been presented at the Infectious Diseases Society of America  conference in Washington DC, US.

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