0001701108 2026-06-23 2026-06-23 false 0001701108 --12-31 8-K 2026-06-23 SPERO THERAPEUTICS, INC. DE 001-38266 46-4590683 675 Massachusetts Avenue 14th Floor Cambridge MA 02139 (857) 242-1600 false false false false Common Stock, $0.001 par value SPRO NASDAQ false