MRX-5

MRX-5 is a novel oral oxaborole prodrug antibiotic, developed specifically for the treatment of **nontuberculous mycobacterial** (NTM) infections, with a focus on challenging pathogens such as Mycobacterium abscessus. After oral administration, MRX-5 is converted in vivo to its active metabolite MRX-6038, a benzoxazole with potent antibacterial activity against NTM species, including drug-resistant isolates. MRX-5 has demonstrated **dose-dependent efficacy and pharmacokinetics** in preclinical and clinical studies, with activity comparable to the standard-of-care in mouse models. Its **oral formulation** represents a significant advance compared to standard IV regimens for NTM. MRX-5 offers high oral bioavailability, predictable linear PK, minimal food effect, a favorable safety profile, and low resistance rates—potentially improving outcomes and compliance for patients with diseases such as cystic fibrosis, bronchiectasis, and immunosuppression.