Spero Therapeutics, Inc. is a clinical-stage biopharmaceutical company. The Company is focused on identifying and developing novel treatments for rare diseases and diseases caused by multi-drug resistant (MDR) bacterial infections with unmet need. Its product candidate SPR720 is an investigational, chemically stable phosphate ester prodrug that is converted in vivo to SPR719 for the treatment of nontuberculous mycobacterial (NTM) pulmonary disease. Its clinical stage product candidate, tebipenem HBr is an investigational oral carbapenem antibiotic being developed for the treatment of complicated urinary tract infections (cUTIs) including acute pyelonephritis (AP) to help patients potentially reduce duration of in-patient therapy.