Day after UN calls for new antibiotics, FDA delivers a setback for drug from Nabriva of King of Prussia

Tens of thousands of people died last year in the United States as the result of multi-drug resistant infections.

“We may not be able to save the lives of all those people,” said Ted Schroeder, the chief executive officer of Nabriva Therapeutics, a King of Prussia-based drug developer. “But we may be able to save many of them with our new product,” Schroeder said.

That “new product,” an antibiotic called Contepo, will have to wait.

The FDA on Tuesday night temporarily denied Nabriva’s application to market the drug, citing facility inspections and deficiencies at one of Nabriva’s contract manufacturers, according to the company. The FDA did not request any new clinical data and did not raise any concerns about the drug’s safety, Nabriva said in a statement Tuesday.

“We will be working with the FDA in the coming weeks to gain a full understanding of the FDA’s comments, with the goal of bringing this important treatment to patients as quickly as possible,” Schroeder said.

Nabriva’s shares slipped in Wednesday trading, closing at $2.17, down $0.82 (27.42 percent) in Nasdaq trading.

The setback comes a day after the United Nations issued an urgent report, “No Time to Wait: Securing the Future from Drug-Resistant Infections,” calling for the rapid development of new antimicrobial drugs.

Technically, Nabriva’s Contepo — also known as fosfomycin — is not new. First developed in Spain, it has been used in hospitals across Europe and Asia since the late 1970s. Overseas, it’s been deployed as an orally delivered antibiotic to battle everything from hospital acquired pneumonia to bone and joint and intra-abdominal infections.

On Tuesday, the FDA was expected to approve Contepo as an injection for the treatment of drug-resistant complicated urinary tract infections. Contepo had been given qualified infectious disease product status and fast-track status.

“It’s a pretty useful product across a broad range of indications outside of the U.S.,” Schroeder said. “Here it could be used for the three million patients treated each year for cUTIs.”

The World Health Organization has stated that antibiotic resistance is one of the three greatest threats to human health.

There is a strong demand for new antibiotics in hospitals, said Thomas Fekete, chairman of the Department of Medicine at Temple University’s Lewis Katz School of Medicine, where he is also a professor of microbiology and immunology.

“I can’t call Contepo a startling breakthrough,” Fekete said, “but it could be particularly useful for when the patient is vomiting and can’t take oral therapy. If you know the person has severe allergies or if you have a resistant bacterium, it could be very useful.”

Nabriva employs about 100 researchers and other staffers worldwide with labs in King of Prussia and Vienna, Austria, and corporate headquarters in Dublin, Ireland. Following the introduction of Contepo, the company planned to hire about 60 sales reps in the U.S.

In August, it expects to launch another antibiotic, lefamulin, if approved by the FDA. Lefamulin would be intended to treat community-acquired bacterial pneumonia.

The introduction of the drug to the U.S. market would be significant because many older antibiotics are losing their effectiveness as pathogens evolve resistance. Schroeder said Contepo is the only drug in its class and kills bacteria in a different way from others used in American hospitals. “You’re not going to make an infection worse by using this at an earlier stage of treatment,” Schroeder said.

“It’s not for everybody who walks into the hospital, but for patients who are more at risk,” he said, adding that one disadvantage of Contepo is that it has a high salt content.

“There’s a period between a patient being diagnosed with an infection and when you get the labs back,” Schroeder said. “You don’t always know what you’re treating. You want broad coverage but you don’t want the liabilities such as toxicity or resistance. That’s where fosfomycin sits.”

Nabriva has exclusive rights to market fosfomycin as Contepo as a onetime intravenous treatment in the U.S. There could be numerous off-label uses for it.

Because it was never previously considered a first-line drug, and pharmaceutical companies had other antibiotics that were considered more effective, the fosfomycin never got a big market push. An oral preparation called Monurol rarely is used, Schroeder said.

Fosfomycin, which a study said is well-tolerated and has a low incidence of harmful side effects, recently lost its patent protection. That meant that few pharmaceutical companies wanted to take a gamble on it, figuring there was no way to develop it and make it economically viable.

But because of the 2012 GAIN Act, passed by Congress to incentivize companies to develop new antibiotics, Contepo will have a total eight years of exclusivity, Schroeder said, “and that made the prospect of returning value to shareholders a reality.”

Schroeder said that because the molecule was already in medical use outside the U.S., Contepo was “a relative bargain” to develop. “We just had to complete the studies in the U.S. so it was a much less expensive proposition.”

Pricing of the drug, he said, hasn’t yet been made public.