---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-22-008944"
form_type: "8-K"
ticker: "RLYB"
cik: "0001739410"
company_name: "Rallybio Corp"
filed_at: "2022-05-10T23:59:59+00:00"
generated_at: "2026-06-25T21:50:48.306773+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.8
calibrated_materiality_score: 0.8
confidence: "high"
source: SEC EDGAR
---

# Rallybio in-licenses RLYB331 from Sanofi; Q1 net loss $14.5M, cash $161.4M

## Summary
- Exclusive worldwide license from Sanofi for preclinical anti-MTP-2 antibody RLYB331; upfront $3M, up to $43M development & $150M commercial milestones.
- Q1 2022 net loss of $14.5M ($0.48 per share) vs. $13.3M ($0.60) in Q1 2021; R&D spend $7.6M, G&A $6.7M.
- Cash, equivalents & marketable securities $161.4M as of March 31, 2022.
- Phase 1b proof-of-concept study for RLYB212 (FNAIT) initiated; initial data expected in Q3 2022.
- Phase 1 study of RLYB116 (complement inhibitor) ongoing; single-dose data expected in H2 2022.

## SEC filing metadata
- accession: 0000950170-22-008944
- form_type: 8-K
- ticker: RLYB
- cik: 0001739410
- company_name: Rallybio Corp
- filed_at: 2022-05-10T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.8
- calibrated_materiality_score: 0.8
- confidence: high
- sec_items: 1.01, 2.02, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1739410/000095017022008944/0000950170-22-008944-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1739410/000095017022008944/rlyb-20220505.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-22-008944
- JSON: https://secwatch.observer/filing/0000950170-22-008944.json
- Plain text: https://secwatch.observer/filing/0000950170-22-008944.txt

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