Evaluating CAZ-AVI Against Antibiotic-Resistant Gram-Negative Organisms

Madeline King, PharmD, assistant professor of Clinical Pharmacy at the University of the Sciences, Philadelphia College of Pharmacy in Philadelphia, Pennsylvania, discusses her research on the efficacy of ceftazidime-avibactam against infections caused by gram-negative organisms.

Interview Transcript (slightly modified for readability)

“We have a lot of gram-negative resistance. We’re trying to find out if this new antibiotic, [ceftazidime-avibactam], is more efficacious than what we’re already using for these really resistant gram-negative organisms. A lot of the literature out there [are] small studies [that are] looking at combinations of antibiotics, and we don’t really have good outcomes with those. [We have] poor mortality rates [and] poor clinical success. We’re hoping this antibiotic is going to be better than those.

I was looking to see what the outcomes are. This was a retrospective study that I completed, [and] it was a multi-center study, so we had a lot of hospitals involved. We were just trying to find out, is this antibiotic any good? Should we be using it by itself in these infections? One of the outcomes wasn’t to evaluate if it alone versus combination therapy was better. But, we did have patients who received this antibiotic with other antibiotics [and those who] received it alone. We’re just trying to see how it does in these type of severe infections.

Basically, since this [study] was retrospective, what we did was looked at any patient who had received this antibiotic for a carbapenem-resistant gram-negative infection, and looked at their outcomes, [such as] in-hospital mortality, microbiologic success, and clinical success. Since it was retrospective there was no control over what the patient was receiving, what dose they were receiving, and things like that. A lot of patients had been receiving concomitant antibiotics along with ceftazidime-avibactam, which could include aminoglycosides, polymyxin, colistin, carbapenems — a variety of things. We didn’t necessarily compare the two, monotherapy versus combination therapy, we weren’t really set up to do that.

In all of the previous literature for carbapenem-resistant infections, patients received monotherapy or combination therapy with any variety of things, because [it isn’t known] what the best thing is, at this point.”