secwatch.observer — SEC 8-K summary
======================================

Issuer:     Xilio Therapeutics, Inc. (XLO)
CIK:        0001840233
Form:       8-K
Filed at:   2025-11-07T23:59:59+00:00
Accession:  0001193125-25-271189
Event type: other_material
Sentiment:  positive
Materiality: 0.85
Item codes: 7.01, 9.01
LLM model:  deepseek-v4-flash:cloud@v2

Xilio reports 40% ORR in MSS mCRC with high plasma TMB; advances masked T cell engager programs
--------------------------------------------------------------------------------

- Vilastobart + atezolizumab: 40% ORR in heavily pre-treated MSS mCRC without liver mets and high plasma TMB (≥10 mut/Mb); p=0.05 correlation.
- Estimated 55% of MSS CRC patients have high plasma TMB via Guardant360 assay, vs <10% by tissue TMB.
- Preclinical masked T cell engagers show reduced systemic toxicity and enhanced durability with costimulation; PSMA candidate nominated Q3 2025.
- Phase 1 efarindodekin alfa: well-tolerated at >100-fold MTD of rhIL-12, 2 PRs in advanced solid tumors, immune infiltration.
- Vilastobart ctDNA data: deep reductions associated with response; 2 patients achieved endoscopic CR with undetectable ctDNA.

Source:
  EDGAR index:    https://www.sec.gov/Archives/edgar/data/1840233/000119312525271189/0001193125-25-271189-index.htm
  Primary doc:    https://www.sec.gov/Archives/edgar/data/1840233/000119312525271189/xlo-20251107.htm
  HTML page:      https://secwatch.observer/filing/0001193125-25-271189

License: Source filings: public domain (SEC EDGAR). Summaries (headline + bullets): CC-BY-4.0; attribute https://secwatch.observer