---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-26-221567"
form_type: "8-K"
ticker: "SPRO"
cik: "0001701108"
company_name: "Spero Therapeutics, Inc."
filed_at: "2026-05-13T20:02:03+00:00"
generated_at: "2026-05-13T22:23:35.939879+00:00"
event_type: "earnings"
sentiment: "neutral"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Spero posts Q1 net loss of $7.2M; tebipenem HBr PDUFA date June 18, 2026

## Summary
- Net loss of $7.2M ($0.13 diluted EPS) vs $13.9M loss ($0.25 EPS) in Q1 2025.
- Total revenue of $0.3M, down from $5.9M in prior-year quarter.
- Cash and equivalents of $56.1M as of March 31, 2026; cash runway into 2028.
- GSK-led NDA for tebipenem HBr in cUTI under FDA review with PDUFA date June 18, 2026.
- R&D expenses fell to $2.9M from $13.6M due to Phase 3 trial completion.

## SEC filing metadata
- accession: 0001193125-26-221567
- form_type: 8-K
- ticker: SPRO
- cik: 0001701108
- company_name: Spero Therapeutics, Inc.
- filed_at: 2026-05-13T20:02:03+00:00
- event_type: earnings
- sentiment: neutral
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 2.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1701108/000119312526221567/0001193125-26-221567-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1701108/000119312526221567/d147628d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-26-221567
- JSON: https://secwatch.observer/filing/0001193125-26-221567.json
- Plain text: https://secwatch.observer/filing/0001193125-26-221567.txt

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