SPR720: The First Oral Antibiotic Designed to Treat Non-tuberculous Mycobacterial Disease, a Rare Orphan Disease.

Non-tuberculous Mycobacterium (NTM) disease is a growing global health concern and major unmet medical need because of the lack of new medications being developed to combat these bacteria.

NTM are ubiquitous environmental pathogens that can cause progressive lung damage and respiratory failure, particularly in patients with compromised immune systems or underlying pulmonary disorders.  Although rare, the incidence of pulmonary NTM disease is increasing worldwide. It is estimated that approximately 130,000 patients suffer from NTM in the U.S. and Europe, a figure that is growing at a rate of 8% annually. The elderly and people with compromised immune or lung function are at greatest risk, as are patients with bronchiectasis for whom it is estimated that up to 50% may also have active NTM lung disease.

Treatment of NTM pulmonary disease requires prolonged therapy (continuing for approximately 12 to 24 months) with a combination of drugs approved for other infections and is frequently complicated by tolerability and/or toxicity issues. There are currently no oral antibiotics specifically approved for use to treat NTM pulmonary disease. NTM is also associated with high healthcare costs and high mortality. In 2014, the annual cost in the U.S. alone was estimated at $1.7 billion.

Spero Therapeutics is currently developing SPR720, a novel oral agent to treat NTM pulmonary disease.

SPR720 is an orally administered antimicrobial agent being developed for the treatment of NTM pulmonary disease. SPR720 represents a novel class of antibacterial agents that target enzymes essential for bacterial DNA replication.  

We are currently enrolling patients in a Phase 2a clinical trial evaluating SPR720 in patients with NTM pulmonary disease. The Phase 2a clinical trial is a multi-center, partially blinded, placebo-controlled proof-of-concept clinical trial of SPR720 that will enroll approximately 90 treatment-inexperienced patients with NTM-PD due to Mycobacterium avium complex (MAC). Additional information on the SPR720 Phase 2a clinical trial can be found here. 

The Phase 2a clinical trial is supported by data from its first-in-human Phase 1 clinical trial of SPR720 in healthy volunteers and pharmacokinetic/pharmacodynamic data that suggested that predicted therapeutic exposures could be attained with a 500 – 1,000 mg once daily oral dose.  The collective pre-clinical data to date suggests that SPR720 has an acceptable safety profile, encouraging target pathogen efficacy, and drug distribution to key sites of infection, such as the lung. Pre-clinical in vitro and in vivo studies have demonstrated potency for SPR720 against Mycobacterium tuberculosis (TB) and a range of bacteria that cause NTM infections, including Mycobacterium avium complex and Mycobacterium abscessus.