Spero Therapeutics Q2 2025 Earnings Call: Tepipenem HBR Success, Financial Improvements, and SPR 720 Disappointment

Spero Therapeutics' Q2 2025 earnings call highlights positive results for tepipenem HBR in a phase 3 trial for complicated urinary tract infections, meeting its primary endpoint and achieving non-inferiority to imipenem cilastatin. The trial's early stopping for efficacy extended the company's cash runway into 2028. Total revenue increased to $14.2 million, and R&D expenses decreased to $10.7 million. However, the SPR 720 program did not meet its primary endpoint in a phase 2A proof of concept study, and potential dose-limiting safety signals were observed.

Spero Therapeutics (Nasdaq: SPRO) reported significant developments during its Q2 2025 earnings call, highlighting the early termination of the Phase 3 PIVOT-PO trial for tebipenem HBr due to meeting efficacy endpoints in treating complicated urinary tract infections (cUTI). The trial demonstrated non-inferiority compared to intravenous treatment, with plans for FDA submission in the second half of 2025, in partnership with GSK.

The company's financial results showed a reduced net loss of $1.7 million (vs $17.9 million in Q2 2024), revenue of $14.2 million (up from $10.2 million), and a cash position of $31.2 million. The receipt of a $23.8 million milestone payment from GSK in August 2025 extended the company's runway into 2028. Despite these positive financials, the SPR720 program for NTM-PD was suspended in Q4 2024 after failing to meet primary endpoints in Phase 2a trials, and potential dose-limiting safety signals were observed.

The Phase 3 trial's early stopping for efficacy signals strong potential for FDA approval in 2025. The trial demonstrated non-inferiority of oral tebipenem HBr compared to intravenous imipenem-cilastatin in complicated urinary tract infections, positioning tebipenem as potentially the first oral carbapenem antibiotic approved in the US. If approved, tebipenem HBr could significantly reduce hospital stays, lower healthcare costs, and improve patient quality of life.

Spero's financial position is solid, with a cash position of $31.2 million and a milestone payment of $23.8 million from GSK. The company projects a runway into 2028, providing substantial operational flexibility. The GSK partnership validates the commercial potential of tebipenem and provides development expertise and commercial infrastructure.

The planned FDA submission in H2 2025 should be strengthened by the robust efficacy demonstrated in the PIVOT-PO trial. If approved, tebipenem would address a significant unmet need in treating multi-drug resistant infections and could become standard of care for complicated UTIs, potentially generating substantial revenue for both Spero and GSK.

References:
[1] https://www.stocktitan.net/news/SPRO/spero-therapeutics-announces-second-quarter-2025-operating-results-rcznsw2gm5f4.html