Tebipenem HBr (previously SPR994): oral carbapenem

May 13, 2026 — Spero Therapeutics, Inc. (Nasdaq: SPRO) reported first-quarter 2026 operating results and provided a business update, highlighting progress on tebipenem HBr, an investigational oral carbapenem antibiotic for complicated urinary tract infections (cUTI) including pyelonephritis. Licensing partner GSK submitted the tebipenem HBr NDA in December 2025; the FDA set a PDUFA date of June 18, 2026. The NDA is supported by the Phase 3 PIVOT-PO trial, which was stopped early for efficacy (May 2025) and demonstrated non-inferiority versus IV imipenem-cilastatin in hospitalized cUTI patients on overall response at test-of-cure. Safety was consistent with the carbapenem class; most common adverse events were mild-to-moderate, non-serious diarrhea and headache.

Financially, Spero reported Q1 2026 net loss of $7.2M ($0.13/share) vs $13.9M ($0.25/share) in Q1 2025; revenue was $0.3M vs $5.9M. R&D expense decreased to $2.9M (from $13.6M) and G&A to $4.9M (from $6.8M). Cash and equivalents were $56.1M as of March 31, 2026, and the company maintained cash runway guidance into 2028.