---
schema_version: "secwatch.filing_event.v1"
accession: "0001104659-26-000402"
form_type: "8-K"
ticker: "ZBIO"
cik: "0001953926"
company_name: "Zenas BioPharma, Inc."
filed_at: "2026-01-05T23:59:59+00:00"
generated_at: "2026-05-16T11:44:01.528063+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.9
calibrated_materiality_score: 0.9
confidence: "high"
source: SEC EDGAR
---

# Zenas BioPharma reports positive Phase 3 INDIGO trial of obexelimab in IgG4-RD; plans BLA in Q2 2026

## Summary
- Obexelimab met primary endpoint: 56% reduction in IgG4-RD flare risk vs placebo (HR 0.443, p=0.0005).
- All four key secondary endpoints met with high statistical significance (p≤0.0049).
- Safety profile favorable: SAEs 10% obexelimab vs 19% placebo; fewer infections.
- Preliminary cash $360.5M as of Dec 31, 2025; expected to fund operations through end of 2026.
- BLA submission to FDA planned Q2 2026; MAA to EMA H2 2026.

## SEC filing metadata
- accession: 0001104659-26-000402
- form_type: 8-K
- ticker: ZBIO
- cik: 0001953926
- company_name: Zenas BioPharma, Inc.
- filed_at: 2026-01-05T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.9
- calibrated_materiality_score: 0.9
- confidence: high
- sec_items: 2.02, 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1953926/000110465926000402/0001104659-26-000402-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1953926/000110465926000402/tm261774d1_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001104659-26-000402
- JSON: https://secwatch.observer/filing/0001104659-26-000402.json
- Plain text: https://secwatch.observer/filing/0001104659-26-000402.txt

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