Spero Therapeutics closes $30mm Series B round

Spero Therapeutics LLC (developing therapies to treat bacterial infections) raised $30mm in its Series B preferred equity financing to returning shareholders Atlas Venture, SR One, MRL Ventures, Lundbeckfond Ventures, The Kraft Group, and Partners Innovation Fund. Proceeds will help further develop its potentiator platform, which is designed to disrupt the cell membrane of Gram-negative bacteria, allowing access for Gram-positive antibiotics. The additional money will also help advance its dihydrofolate reductase (DHFR) program, which is aimed at expanding the antibacterial spectrum of a novel antifolate in an effort to treat trimethoprim-resistant isolates, including key Gram-negative pathogens.