Pravibismane Receives FDA Orphan Drug Status for Treatment of CF Lung Infections

Pravibismane suspension, a new type of inhaled antimicrobial medication developed by Microbion, has received orphan drug designation from the U.S. Food and Drug Administration (FDA) for the treatment of lung infections in patients with cystic fibrosis (CF).

This designation provides incentives for the development of treatments for rare diseases — conditions that affect fewer than 200,000 people in the U.S. — including tax credits on the cost of clinical trials and seven years of market exclusivity.

“We are pleased to have been granted orphan drug designation for our pravibismane inhalation program,” Karim Lalji, chairman and CEO of Microbion, said in a press release. 

Pravibismane (bismuth-ethanedithiol) belongs to a new class of antimicrobial medications that have a different structure than that of clinically utilized antibiotics. It also works in a different way than traditional antibiotics, which typically kill bacteria by stopping their multiplication or interfering with the formation of the bacterial cell wall or cell components.

Pravibismane is classified as a microbial bioenergetic inhibitor, which means it disrupts the bacteria’s ability to produce the energy needed for essential cell processes like DNA, protein, and cell wall production, causing the bacteria to die.

In vitro studies have shown that pravibismane has broad-spectrum antimicrobial activity against bacteria that commonly cause infections in people with CF, including carbapenem– and multidrug-resistant Pseudomonas aeruginosa and other multidrug-resistant bacteria that are considered serious threats to CF patients. 

Another way pravibismane helps kill bacteria is by interfering with the formation of biofilms — a type of shield produced by bacterial communities that protects them from antibiotics and the person’s immune system. The presence of biofilms in the lungs of CF patients contributes to chronic and persistent pulmonary infections. 

“This designation is consistent with our steadfast commitment to develop innovative solutions to manage chronic pulmonary infections in patients with CF. We will work closely with the FDA and key stakeholders to advance inhaled pravibismane toward regulatory approval for the benefit of patients with cystic fibrosis,” Lalji said.

Aside from orphan drug designation, the FDA has also granted pravibismane qualified infectious disease product designation — given to antibacterial or antifungal medications intended to treat serious or life-threatening infections, and fast track designation — intended to facilitate the development and speed up the review of medications to treat serious conditions that fill an unmet medical need.