---
schema_version: "secwatch.filing_event.v1"
accession: "0001558370-23-010481"
form_type: "8-K"
ticker: "XLO"
cik: "0001840233"
company_name: "Xilio Therapeutics, Inc."
filed_at: "2023-05-25T23:59:59+00:00"
generated_at: "2026-06-14T14:57:00.302536+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Xilio reports encouraging Phase 1 data for XTX101: partial response in PD-L1 neg NSCLC, favorable safety at RP2D

## Summary
- Preliminary data from Phase 1 trial of XTX101 in 25 patients with advanced solid tumors; RP2D set at 150 mg Q6W.
- Partial response observed at nine weeks in a PD-L1 negative advanced NSCLC patient with hepatic metastases, continuing on treatment.
- At RP2D, no Grade 4/5 treatment-related AEs, no colitis or infusion reactions; only Grade 3 AE was diarrhea (resolved).
- Evidence of tumor-selective activation: low unmasked drug in peripheral circulation and minimal immune activation in periphery.
- Plans to explore XTX101 in combination with PD-(L)1 in immunotherapy-resistant tumor types, including MSI-stable CRC.

## SEC filing metadata
- accession: 0001558370-23-010481
- form_type: 8-K
- ticker: XLO
- cik: 0001840233
- company_name: Xilio Therapeutics, Inc.
- filed_at: 2023-05-25T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1840233/000155837023010481/0001558370-23-010481-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1840233/000155837023010481/xlo-20230525x8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001558370-23-010481
- JSON: https://secwatch.observer/filing/0001558370-23-010481.json
- Plain text: https://secwatch.observer/filing/0001558370-23-010481.txt

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