MicuRx Unveils New Antibiotic Findings at 7th World Bronchiectasis Conference

Shanghai MicuRx Pharmaceutical Co., Ltd. ("MicuRx") recently highlighted the promising developments of their antibiotic pipeline products, MRX-5 and MRX-8, at the 7th World Bronchiectasis Conference (WBC) held in Dundee, Scotland, from July 4 to 6, 2024. These advancements are providing new hope for treating Nontuberculous Mycobacteria (NTM) lung disease and Pseudomonas aeruginosa infections.

The World Bronchiectasis Conference is a premier global forum for discussing bronchiectasis research and treatment, bringing together leading scientists and clinicians to share the latest advancements and strategies.

During the conference, MicuRx showcased three important research findings supporting the efficacy of MRX-5 and MRX-8.

The first study examined the in vitro and in vivo activity of MRX-6038, a leucyl-tRNA synthetase inhibitor, against Mycobacterium abscessus. MRX-6038 showed exceptional potency against M. abscessus clinical isolates, with a minimum inhibitory concentration (MIC90) of 0.5 mg/L, compared to 4 mg/L for clarithromycin. Furthermore, MRX-6038 significantly lowered the resistance frequency of several standard care drugs. In mouse models, the oral prodrug MRX-5 demonstrated efficacy against M. abscessus lung infections, including strains both sensitive and resistant to clarithromycin.

The second study focused on MRX-6038's activity against Mycobacterium avium complex. MRX-6038 exhibited strong in vitro activity against M. avium isolates, even those not susceptible to clarithromycin. Combining MRX-6038 with standard drugs like clarithromycin, rifabutin, amikacin, and ethambutol greatly reduced the resistance frequency. This study suggests MRX-6038 merits further investigation for treating Mycobacterium avium pulmonary disease.

The third study evaluated MRX-8, a novel antibiotic from the polymyxin class, against Pseudomonas aeruginosa. MRX-8 showed potent in vitro activity against various P. aeruginosa strains, including those resistant to tobramycin and amikacin. In mouse models, nebulized MRX-8 treatment significantly reduced bacterial load in lung tissues infected with both tobramycin-sensitive and tobramycin-resistant isolates, demonstrating its bactericidal activity.

MRX-8, developed by MicuRx, aims to treat severe infections caused by multidrug-resistant Gram-negative bacteria. Traditional polymyxins are limited by nephrotoxicity and neurotoxicity, but MRX-8's design enhances therapeutic efficacy while reducing these toxic risks. MRX-8 completed Phase I clinical trials in the United States in 2022 and Phase I enrollment in China in 2023, with primary results released in June 2024. These trials indicated MRX-8 achieved desired therapeutic levels for infections caused by Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii. Additionally, MicuRx is exploring an inhaled formulation to target chronic lung infections.

MRX-5 is a novel benzoxaborole antibiotic targeting NTM infections, a common cause of bronchiectasis. The incidence of NTM diseases has risen significantly, posing a public health challenge. Mycobacterium avium complex and Mycobacterium abscessus complex are the primary culprits, responsible for 70%-95% of NTM diseases, leading to symptoms like persistent cough, sputum production, chest pain, shortness of breath, fatigue, weight loss, and malaise.

Preclinical data indicates MRX-5 has potent antibacterial activity against most common NTM pathogens and shows good safety in animal studies. Its minimal drug interactions, low resistance potential, and oral availability make it an ideal candidate for treating chronic infections. Currently, MRX-5 is in Phase I clinical trials, offering a promising new option for patients with NTM diseases.

MicuRx, founded in 2007, focuses on innovative therapies for infectious diseases, addressing the growing issue of global antimicrobial resistance.