---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-242007"
form_type: "8-K"
ticker: "SNSE"
cik: "0001829802"
company_name: "Sensei Biotherapeutics, Inc."
filed_at: "2025-10-17T23:59:59+00:00"
generated_at: "2026-05-17T03:25:29.504980+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# Sensei Biotherapeutics reports 50% 6-month PFS for solnerstotug in PD-(L)1 resistant tumors at ESMO 2025

## Summary
- 6-month PFS of 50% in 15 mg/kg dose cohort in PD-(L)1 resistant patients vs historical ~10-20% for docetaxel.
- Complete response in Merkel cell carcinoma patient; duration of response 54+ weeks. Four of six responders had late onset responses (18-54 weeks).
- Favorable safety: only six mild Grade 1 CRS events across all 98 patients; no new safety signals.
- Phase 2 studies planned in 2L NSCLC and Merkel cell carcinoma in 2026, subject to FDA feedback and capital raise.

## SEC filing metadata
- accession: 0001193125-25-242007
- form_type: 8-K
- ticker: SNSE
- cik: 0001829802
- company_name: Sensei Biotherapeutics, Inc.
- filed_at: 2025-10-17T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.85
- confidence: high
- sec_items: 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1829802/000119312525242007/0001193125-25-242007-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1829802/000119312525242007/d223319d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-242007
- JSON: https://secwatch.observer/filing/0001193125-25-242007.json
- Plain text: https://secwatch.observer/filing/0001193125-25-242007.txt

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