---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-178970"
form_type: "8-K"
ticker: "SPRO"
cik: "0001701108"
company_name: "Spero Therapeutics, Inc."
filed_at: "2025-08-12T23:59:59+00:00"
generated_at: "2026-05-17T14:41:07.263620+00:00"
event_type: "earnings"
sentiment: "positive"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Spero reports Q2 results and tebipenem Phase 3 success; plans FDA filing in 2H 2025

## Summary
- Q2 2025 net loss $1.7M ($0.03/share) vs $17.9M ($0.33) in Q2 2024; revenue $14.2M up from $10.2M.
- Phase 3 PIVOT-PO trial of tebipenem HBr in cUTI met primary endpoint; IDMC stopped early for efficacy.
- Spero and GSK plan to submit data to FDA in 2H 2025; potential milestone payments adjusted to up to $101M from $150M.
- Cash $31.2M at June 30 plus $23.8M GSK milestone received Aug 2025; runway expected into 2028.
- Esther Rajavelu appointed CEO/President effective May 2, 2025, continuing as CFO.

## SEC filing metadata
- accession: 0001193125-25-178970
- form_type: 8-K
- ticker: SPRO
- cik: 0001701108
- company_name: Spero Therapeutics, Inc.
- filed_at: 2025-08-12T23:59:59+00:00
- event_type: earnings
- sentiment: positive
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 2.02, 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1701108/000119312525178970/0001193125-25-178970-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1701108/000119312525178970/d97572d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-178970
- JSON: https://secwatch.observer/filing/0001193125-25-178970.json
- Plain text: https://secwatch.observer/filing/0001193125-25-178970.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.