---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-22-217351"
form_type: "8-K"
ticker: "SPRO"
cik: "0001701108"
company_name: "Spero Therapeutics, Inc."
filed_at: "2022-08-10T23:59:59+00:00"
generated_at: "2026-06-24T01:28:37.010992+00:00"
event_type: "earnings"
sentiment: "negative"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# Spero Q2 net loss widens to $28.7M; tebipenem HBr NDA receives CRL; Phase 2 SPR720 trial set for Q4 2022

## Summary
- Net loss $28.7M ($0.87/share) vs $18.6M ($0.63/share) in Q2 2021; revenue $2.0M down from $5.1M.
- FDA issued Complete Response Letter for tebipenem HBr NDA; Type A meeting completed to discuss path forward.
- Phase 2 trial of SPR720 in NTM-PD expected to start Q4 2022; interim data mid-2023.
- SPR206 regulatory milestone achieved under Pfizer license; $5M payment expected in Q3 2022.
- Cash, equivalents and marketable securities $45.4M; believes funding into late 2023 via restructuring.

## SEC filing metadata
- accession: 0001193125-22-217351
- form_type: 8-K
- ticker: SPRO
- cik: 0001701108
- company_name: Spero Therapeutics, Inc.
- filed_at: 2022-08-10T23:59:59+00:00
- event_type: earnings
- sentiment: negative
- materiality_score: 0.85
- calibrated_materiality_score: 0.85
- confidence: high
- sec_items: 2.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1701108/000119312522217351/0001193125-22-217351-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1701108/000119312522217351/d297960d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-22-217351
- JSON: https://secwatch.observer/filing/0001193125-22-217351.json
- Plain text: https://secwatch.observer/filing/0001193125-22-217351.txt

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