---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-128680"
form_type: "8-K"
ticker: "SPRO"
cik: "0001701108"
company_name: "Spero Therapeutics, Inc."
filed_at: "2025-05-28T23:59:59+00:00"
generated_at: "2026-05-20T08:19:19.515083+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.9
calibrated_materiality_score: 0.9
confidence: "high"
source: SEC EDGAR
---

# Spero/GSK Phase 3 PIVOT-PO trial for tebipenem HBr meets primary endpoint, stops early for efficacy

## Summary
- Tebipenem HBr met non-inferiority vs IV imipenem-cilastatin in 1,690 cUTI patients; IDMC recommended early stop.
- No new safety concerns; diarrhea and headache most common adverse events.
- GSK plans FDA filing in second half 2025; could be first oral carbapenem for cUTIs in US.
- cUTIs affect ~2.9M US cases/year with >$6B in healthcare costs; IV-only standard currently.
- Supported by BARDA funding and QIDP/Fast Track designations from FDA.

## SEC filing metadata
- accession: 0001193125-25-128680
- form_type: 8-K
- ticker: SPRO
- cik: 0001701108
- company_name: Spero Therapeutics, Inc.
- filed_at: 2025-05-28T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.9
- calibrated_materiality_score: 0.9
- confidence: high
- sec_items: 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1701108/000119312525128680/0001193125-25-128680-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1701108/000119312525128680/d903768d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-128680
- JSON: https://secwatch.observer/filing/0001193125-25-128680.json
- Plain text: https://secwatch.observer/filing/0001193125-25-128680.txt

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