PK/PD principles could tackle antibiotic resistance with single injection

08-Jun-2014 - Last updated on 09-Jun-2014 at 13:23 GMT

Single-use injection could help stop resistance from bacteria such as MRSA

A single-dose of an investigational MRSA drug could be equivalent to a ten-day course of antibiotics due to the application of PK-PD principles in its design and optimization, The Medicines Company says.

The company funded a study - carried out by Duke Medicine researchers and published in the New England Journal of Medicine (NEJM) last week - which concluded its investigational drug Orbactiv (oritavancin) given intravenously in a single-dose was non-inferior to other glycopeptide antibiotics in treating certain skin infections, including methicillin-resistant Staphylococcus aureus (MRSA).

Such infections are being complicated by “the increasing worldwide bacterial resistance to antimicrobial agents,” Mike Dudley, Chief Scientific Officer, Health Science IDC at The Medicines Company, told in-Pharmatechnologist.com, which itself is driven by patients not finishing courses of treatment.

Oritavancin, if approved, would make it possible to address this issue via a single-dose treatment, and is due to its half-life and other pharmacokinetic (PK) and pharmacodynamic (PD) features, which the firm told us are inherent attributes of this antibacterial agent.

“PK-PD approaches can allow identification of opportunities for drugs to be administered as single dose therapies,” we were told. “Likewise, PK-PD optimization can be used to rapidly identify dosage regimens that may help prevent drug resistance of new products for testing in patients.”

Currently in Phase III clinical trials, oritavacin was originally discovered and developed by Eli Lilly and acquired by The Medicines Company in 2009. In February this year the company filed a new drug application (NDA) with the US Food and Drug Administration (FDA) as an investigational intravenous antibiotic with priority review.

A randomized, double-blind trial of oritavancin was carried out by Duke with results demonstrating a single dose was as effectual as twice-daily vancomycin, administered for seven to ten days for the treatment of acute bacterial skin and skin-structure infections.

PK-PD

The NEJM study “further validates the usefulness of application of PK-PD principles in the design and optimization of antimicrobial dosage regimens,” Dudley continued, adding it “is using this approach to advance other solutions to address the critical problem of multi-drug resistant gram-negative bacteria.”

The firm is also developing Carbavence, a combination drug consisting of a carbapenem plus a novel beta-lactamase inhibitor for treatment of gram-negative pathogens, expected to enter clinical trials later this year.

“The reason for the combination is that some bacteria are resistant to carbapenem treatment alone; adding the inhibitor allows the carbapenem to be active once again against the bacteria.”