CHMP backs AZ's 'superbug' antibiotic product

AstraZeneca is months away from introducing Zavicefta, its new antibiotic product for multidrug resistant (MDR) infections, in the EU.

The Committee for Medicinal Products for Human Use (CHMP) recommended approval of Zavicefta (ceftazidime/avibactam), which combines an established antibiotic with a new drug designed to overcome bacterial resistance.

It has been backed for the treatment of complicated intra-abdominal and urinary tract infections, hospital-acquired pneumonia and infections due to aerobic Gram-negative organisms where treatment options are limited.

Ceftazidime is a third-generation cephalosporin and has been available for many years, while avibactam is a new inhibitor of beta-lactamase - an enzyme class through which bacteria develop resistance to beta-lactam antibiotics. In addition to cephalosporins, the beta lactam class also includes penicillin derivatives, monobactams and carbapenems.

The new antibiotic is particularly important as avibactam restores the activity of ceftazidime in carbapenem-resistant Enterobacteriaceae (CRE), a class of Gram-negative bacteria that includes strains of Escherichia coli and Klebsiella pneumoniae and is notoriously-resistant to treatment.

Some CRE infections are resistant to all known antibiotics and according to some reports can contribute to the death of up to 50% of patients who become infected. AZ notes that in Europe, Gram-negative bacteria are responsible for two thirds of the annually reported 25,000 deaths resulting from antimicrobial resistance.

In the US, Actavis (now operating as Allergan) has been granted FDA approval for another combination of ceftazidime and avibactam, which is sold as Avycaz. Actavis gained rights to the combination after buying Forest Labs, which originally developed avibactam, in 2014. AZ owns rights to the compound outside North America.

The CHMP's positive opinion for Zavicefta will now be passed to the European Commission, which usually translates the scientific advice into a full approval within three months.

The decision amid increasing concern about the emergence of MDR infections, with an independent UK review estimating in 2014 that by 2050 they could claim 10m lives a year and result in a cumulative loss from global output of $100trn.

There have been some signs that antimicrobial pipelines are starting to fill after years of stagnation caused by companies exiting what was perceived to be an unprofitable sector.

AZ is one company that continued to be active in this area, alongside a handful of others such as GlaxoSmithKline and smaller players such as Cubist (now part of Merck & Co/MSD), although it has reportedly been trying to sell a stake in its antibiotics business.

In 2011 AZ launched novel cephalosporin Zinforo (ceftaroline fosamil), the first drug in the class to be approved with data showing it could tackle the superbug methicillin-resistant Staphylococcus aureus (MRSA). AZ is also developing a combination of ceftaroline and avibactam.