---
schema_version: "secwatch.filing_event.v1"
accession: "0001104659-25-102317"
form_type: "8-K"
ticker: "ZBIO"
cik: "0001953926"
company_name: "Zenas BioPharma, Inc."
filed_at: "2025-10-27T23:59:59+00:00"
generated_at: "2026-05-17T02:14:37.567850+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.78
calibrated_materiality_score: 0.78
confidence: "high"
source: SEC EDGAR
---

# Zenas BioPharma announces Phase 2 MoonStone trial of obexelimab meets primary endpoint with 95% lesion reduction

## Summary
- Obexelimab showed 95% relative reduction in new GdE T1 lesions vs placebo (p=0.0009) at weeks 8 and 12.
- Adjusted mean new GdE T1 lesions per scan: 0.01 (obexelimab) vs 0.23 (placebo).
- Safety consistent with prior trials; most common were mild injection site reactions.
- Expects 24-week MoonStone data in Q1 2026; Phase 3 INDIGO (IgG4-RD) topline around year-end 2025.
- Orelabrutinib Phase 3 in PPMS ongoing; SPMS Phase 3 to initiate Q1 2026.

## SEC filing metadata
- accession: 0001104659-25-102317
- form_type: 8-K
- ticker: ZBIO
- cik: 0001953926
- company_name: Zenas BioPharma, Inc.
- filed_at: 2025-10-27T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.78
- calibrated_materiality_score: 0.78
- confidence: high
- sec_items: 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1953926/000110465925102317/0001104659-25-102317-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1953926/000110465925102317/tm2529508d1_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001104659-25-102317
- JSON: https://secwatch.observer/filing/0001104659-25-102317.json
- Plain text: https://secwatch.observer/filing/0001104659-25-102317.txt

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