Stealth BioTherapeutics Corp (Nasdaq: MITO) (the "Company"), a clinical-stage biotechnology company focused on the discovery, development and commercialization of novel therapies for diseases involving mitochondrial dysfunction, today announced that it has entered into a definitive agreement with a single healthcare-focused institutional investor to purchase in a registered direct offering 5,583,028 American Depositary Shares (the "Registered ADSs"), representing 66,996,336 ordinary shares of the Company, at a purchase price of $0.6269 per Registered ADS for gross proceeds of approximately $3.5 million, before deducting placement agent fees and other offering expenses payable by the Company. Each ADS represents 12 ordinary shares. In a concurrent private placement, the Company also agreed to issue to the purchaser of the Registered ADSs a warrant to purchase up to 44,217,588 ordinary shares of the Company, representing 3,684,799 American Depositary Shares. The warrant will have an exercise price of $0.6269 per American Depositary Share, will be exercisable six (6) months from that date of issuance, and will expire five years from the initial exercise date