---
schema_version: "secwatch.filing_event.v1"
accession: "0001739410-23-000019"
form_type: "8-K"
ticker: "RLYB"
cik: "0001739410"
company_name: "Rallybio Corp"
filed_at: "2023-12-20T23:59:59+00:00"
generated_at: "2026-06-07T09:54:48.152611+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.7
calibrated_materiality_score: 0.7
confidence: "high"
source: SEC EDGAR
---

# Rallybio reveals Phase 1 MAD data for RLYB116: >93% free C5 reduction at 100 mg weekly; cash runway extended to 3Q 2025

## Summary
- 100 mg weekly dose of RLYB116 achieved >93% mean reduction in free C5 at Day 29; >99% reduction 24h post-first dose.
- RLYB116 half-life >300 hours; low inter-subject variability; all adverse events mild, most common injection-site reaction (60% in 100mg cohort).
- Company deprioritizes Phase 2 start in gMG, focusing on manufacturing to improve tolerability and widen indications.
- Cash runway guidance updated: current resources expected to fund operations into Q3 2025.
- RLYB212 for FNAIT continues as lead program; near-term RLYB116 investments directed to process improvements.

## SEC filing metadata
- accession: 0001739410-23-000019
- form_type: 8-K
- ticker: RLYB
- cik: 0001739410
- company_name: Rallybio Corp
- filed_at: 2023-12-20T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.7
- calibrated_materiality_score: 0.7
- confidence: high
- sec_items: 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1739410/000173941023000019/0001739410-23-000019-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1739410/000173941023000019/rlyb-20231220.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001739410-23-000019
- JSON: https://secwatch.observer/filing/0001739410-23-000019.json
- Plain text: https://secwatch.observer/filing/0001739410-23-000019.txt

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