By Tamara Mathias

(Reuters) – Paratek Pharmaceuticals Inc’s new antibiotic for bacterial pneumonia and skin infections is not inferior to current treatments, U.S. Food and Drug Administration staff reviewers said on Monday.

If approved, omadacycline will be Paratek’s first drug in the market and also the first of a new class of antibiotics called aminomethylcyclines, which can be made in both oral and injectable forms due to their chemical structure, the company said.

Paratek’s shares rose 6.6 percent to $10.45 in early trading.

The FDA staffers’ comments come two days ahead of an advisory committee meeting, where a panel of independent experts will evaluate the drug’s safety and effectiveness.

Rising levels of antibiotic resistance in the United States have fueled demand for new medicines that can treat the about 2 million Americans infected by treatment-resistant bacteria every year.

“The injectable version allows rapid administration in hospitals and the oral formulation allows doctors to quickly switch patients onto a treatment that can be continued outside the hospital, reducing hospital costs,” Chief Development Officer Evan Tzanis told Reuters.

Omadacycline could bring in U.S. sales of $192 million as a treatment for skin infections and $343 million as a therapy for community acquired bacterial pneumonia in 2025, according to brokerage Guggenheim Securities.

However, FDA staff flagged the “imbalance in mortality” rates in the trial testing omadacycline as a treatment for community acquired bacterial pneumonia.

“What is notable is that, in our view, the FDA appears to possibly justify the death imbalance,” Guggenheim’s Adnan Butt said.

“Omadacycline is likely approvable … though the question of whether both dosage forms will be approved for both treatments is outstanding.”

The advisory committee meeting on Wednesday will vote for or against the drug’s approval, and while the FDA is not mandated to adhere to the recommendations, the agency typically does.

Paratek’s application for approval is based on three late-stage studies, one of which tested both the tablet and the shot in pneumonia patients.

The company is also testing omadacycline as a treatment for urinary tract infections.

“There’s a lot of companies looking for revenue growth. So a product like ours, if it turns out to be successful, could be something that larger pharma may want over time,” Tzanis said.

(Reporting by Tamara Mathias in Bengaluru; Additional reporting by Manas Mishra; Editing by Sriraj Kalluvila)