Epetraborole Granted Orphan Drug Designation for NTM Lung Disease

In a news release from February 16, 2022, clinical-stage biopharmaceutical company AN2 Therapeutics, Inc. (“AN2”) shared that its therapy epetraborole was granted Orphan Drug designation for the treatment of non-tuberculous mycobacteria (NTM) lung disease. Orphan Drug designation is granted to drugs or biologics intending to treat, diagnose, or prevent rare conditions. For the purpose of this designation, “rare” is considered any condition affecting under 200,000 Americans. AN2 also receives a variety of benefits with this status, including tax credits, fee waivers, increased regulatory assistance, and 7 years market exclusivity upon approval.


So what exactly is epetraborole? According to AN2, epetraborole is:

a boron-containing, orally-available, small molecule inhibitor of bacterial leucyl-tRNA synthetase, or LeuRS, an enzyme that catalyzes the attachment of leucine to transfer RNA, or tRNA, molecules, an essential step in protein synthesis. Epetraborole forms a complex with a tRNALEU molecule, trapping the terminal ribonucleotide of tRNALEU in the editing site of the enzyme, which prevents the synthetic site from attaching leucine to tRNALEU thus shutting down tRNA leucylation and leading to a block in protein synthesis.

The treatment is designed to be given once every day. Outside of Orphan Drug designation, this therapy has also received both Fast Track and Qualified Infectious Disease Product designations.

About NTM Lung Disease

Nontuberculous mycobacterial (NTM) lung disease is an infectious disease which is caused by various mycobacteria. These harmful germs can be found naturally in soil and water. However, not everyone exposed to mycobacteria become sick. Rather, underlying health conditions or being immunocompromised increase the risk of developing NTM lung disease, a chronic lung infection. Typically, NTM lung disease affects older individuals. Risk factors include having a weakened immune system, being postmenopausal, older age, previously having tuberculosis, or having other conditions such as cystic fibrosis, bronchiectasis, or chronic obstructive pulmonary disease (COPD). NTM lung disease treatments often require prolonged treatment over months or even years, with an estimated 35% of patients having treatment-resistant infections.

Symptoms of NTM lung disease can include:

  • Shortness of breath and/or difficulty breathing
  • A severe, persistent cough which may produce blood
  • Frequent or recurrent infections, particularly respiratory infections
  • Unintended weight loss
  • Excessive mucus production
  • Chest pain
  • Fever
  • Fatigue
  • Night sweats
Jessica Lynn

Jessica Lynn

Jessica Lynn has an educational background in writing and marketing. She firmly believes in the power of writing in amplifying voices, and looks forward to doing so for the rare disease community.

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