---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-22-248772"
form_type: "8-K"
ticker: "SPRO"
cik: "0001701108"
company_name: "Spero Therapeutics, Inc."
filed_at: "2022-09-22T23:59:59+00:00"
generated_at: "2026-06-23T08:02:38.373703+00:00"
event_type: "m_and_a"
sentiment: "positive"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# Spero licenses tebipenem HBr to GSK for $66M upfront, up to $525M milestones plus tiered royalties

## Summary
- GSK gets exclusive license to develop and commercialize oral carbapenem antibiotic tebipenem HBr outside Japan and certain Asian countries.
- Spero receives $66M upfront; potential milestones: $150M Phase III delivery, $150M first sale (US/EU), $225M sales milestones up to $1B+.
- Tiered royalties low-single to low-double digit increase if net sales exceed $1B.
- GSK invests $9M in Spero common stock at ~$1.20805/share (7.45M shares), with lock-up and standstill provisions.
- Spero to start a new Phase 3 trial in 2023; closing expected Q4 2022 subject to HSR clearance.

## SEC filing metadata
- accession: 0001193125-22-248772
- form_type: 8-K
- ticker: SPRO
- cik: 0001701108
- company_name: Spero Therapeutics, Inc.
- filed_at: 2022-09-22T23:59:59+00:00
- event_type: m_and_a
- sentiment: positive
- materiality_score: 0.85
- calibrated_materiality_score: 0.85
- confidence: high
- sec_items: 1.01, 3.02, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1701108/000119312522248772/0001193125-22-248772-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1701108/000119312522248772/d370224d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-22-248772
- JSON: https://secwatch.observer/filing/0001193125-22-248772.json
- Plain text: https://secwatch.observer/filing/0001193125-22-248772.txt

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