---
schema_version: "secwatch.filing_event.v1"
accession: "0001125345-26-000050"
form_type: "8-K"
ticker: "MGNX"
cik: "0001125345"
company_name: "MACROGENICS INC"
filed_at: "2026-07-23T20:07:30+00:00"
generated_at: "2026-07-23T20:08:08.525998+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# MacroGenics MGC026 Phase 1 meets SCCHN Stage 1 threshold; ESMO poster accepted

## Summary
- MGC026, a B7-H3-directed ADC, achieved pre-specified Stage 1 response threshold in SCCHN cohort; Stage 2 enrollment underway.
- Dose escalation completed; 7.5 mg/kg q3W selected for expansion in SCCHN, endometrial, melanoma, soft tissue sarcoma.
- As of July 8, 2026, 74 patients enrolled; no interstitial lung disease or ocular toxicity reported.
- Interim Phase 1 results accepted for poster at ESMO 2026 (Oct 23-27, Madrid); also lorigerlimab poster on gynecologic cancers.
- CEO Eric Risser: 'look forward to sharing data at ESMO.'

## SEC filing metadata
- accession: 0001125345-26-000050
- form_type: 8-K
- ticker: MGNX
- cik: 0001125345
- company_name: MACROGENICS INC
- filed_at: 2026-07-23T20:07:30+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1125345/000112534526000050/0001125345-26-000050-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1125345/000112534526000050/mgnx-20260723.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001125345-26-000050
- JSON: https://secwatch.observer/filing/0001125345-26-000050.json
- Plain text: https://secwatch.observer/filing/0001125345-26-000050.txt

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