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XTX301

Phase 1

Advanced Solid Tumor | Small molecule | Oncology |Xilio Therapeutics, Inc.|Last Updated: Jun 23, 2026

Target and mechanism

Molecular targetIL-12
Target classCytokine
ModalitySmall molecule

Success Probability

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Market & Valuation

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Trial Design

CONTROLLED
Total Trials1
Total Enrollment358

FDA Designations

No designations recorded

Clinical trial landscape

XTX301 · 1 trial · 1 indication

Phase 1 1
NCT05684965XTX301 in Patients With Advanced Solid TumorsAdvanced Solid Tumor
RECRUITING358 Analytics
PHASE1RECRUITING
XTX301 in Patients With Advanced Solid Tumors
Advanced Solid TumorUnlock trial analytics

Study Endpoints

Primary Endpoints

Incidence of Dose Limiting Toxicities (DLTs) (Part 1A only)
From the first dose of the study drug at Cycle 1 Day 1 up to next applicable cycle visit (Cycle 2 Day 1 or Cycle 3 Day 1). Approximately 21 to 42 days. Each cycle is 21 days.
Incidence of treatment-emergent adverse events (TEAEs) and changes in clinical laboratory values
Up to 24 months
Investigator-assessed objective response rate (ORR) per RECIST 1.1 (for all Phase 2 disease specific cohorts except CRPC/APMR-PC)
up to 24 months
PSA50 response rate and Investigator-assessed ORR per RECIST 1.1 by CT/MRI for patients with measurable disease (for Phase 2 CRPC/APMR-PC cohort only)
up to 24 months

Secondary Endpoints

Plasma concentrations of XTX301
Up to 24 months
Maximum observed plasma concentration (Cmax)
Up to 24 months
Time of maximum observed concentration (Tmax)
Up to 24 months
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Study Design & Arms

AllocationNON_RANDOMIZED
MaskingNONE
ModelSEQUENTIAL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Phase 1 - XTX301 Monotherapy Dose Escalation and Pharmacodynamics ExpansionEXPERIMENTALPart 1A Dose Escalation of XTX301 administered in ascending doses to patients with advanced solid tumors to assess the safety and tolerability and determine/define MTD and/or the highest recommended Phase 2 dose (RP2D). Part 1B Evaluation of XTX301 in patients with selected advanced solid tumors to further characterize the pharmacodynamics profile of XTX301.
Phase 2 - XTX301 Monotherapy Dose Expansion in Disease-Specific CohortsEXPERIMENTALPhase 2 will further evaluate the safety and antitumor activity/efficacy of XTX301 monotherapy in disease-specific expansion cohorts of patients with select tumors, namely: * Cohort 2A: head and neck squamous cell carcinoma (HNSCC) * Cohort 2B: melanoma (patients with uveal melanoma are excluded) * Cohort 2C: non-small cell lung cancer (NSCLC) * Cohort 2D: ovarian cancer * Cohort 2E: castrate-resistant prostate cancer (CRPC)/androgen pathway modulation-resistant prostate cancer (APMR-PC) * Cohort 2F: triple-negative breast cancer (TNBC)

Interventions

NameTypeDescription
XTX301DRUGXTX301 monotherapy
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites12

Inclusion Criteria: • Disease Criteria: Part 1A - Any histologically or cytologically confirmed solid tumor malignancy that is locally advanced or metastatic and has failed standard therapy, standard therapy does not confer survival benefit, or standard therapy is not available. Part 1B- Any histo...

Countries:United States
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Competitive Landscape -Other Solid Tumors 9 trials (matched to "Advanced Solid Tumor")

Recent Changes (Last 90 Days)

MEDIUMJun 23, 2026NCT05684965primaryCompletionDate: changed
MEDIUMJun 23, 2026NCT05684965primaryCompletionDate: changed

Frequently asked questions about XTX301

What is XTX301 used for in Advanced Solid Tumor?

XTX301 is an investigational small molecule being developed for the treatment of advanced solid tumors. It is currently in Phase 1 clinical development, meaning it has not yet been approved by regulatory authorities. The drug is being studied in patients with advanced solid tumors to evaluate its safety and potential efficacy.

What does XTX301 target?

XTX301 targets IL-12, a cytokine involved in immune signaling. By modulating IL-12 activity, the drug aims to enhance the body's immune response against tumor cells. This mechanism is being explored in the context of advanced solid tumors, where immune activation may help control cancer growth.

Who makes XTX301?

XTX301 is being developed by Xilio Therapeutics, Inc., a biopharmaceutical company. Xilio Therapeutics is publicly traded under the ticker symbol XLO. The company is conducting clinical trials to evaluate the safety and efficacy of XTX301 in patients with advanced solid tumors.

What phase is XTX301 in?

XTX301 is in Phase 1 clinical development. It is an investigational drug, meaning it has not been approved by the FDA or other regulatory agencies. The ongoing Phase 1 trial is designed to assess the drug's safety, tolerability, and preliminary activity in patients with advanced solid tumors.

What clinical trials is XTX301 in?

XTX301 is being studied in a Phase 1 clinical trial with the identifier NCT05684965. This trial, titled 'XTX301 in Patients With Advanced Solid Tumors,' is currently recruiting participants in the United States. The study aims to enroll approximately 358 patients aged 18 years and older with advanced solid tumors.

Is XTX301 the same as IL-12?

No, XTX301 is not the same as IL-12. XTX301 is a small molecule drug that targets IL-12, a cytokine involved in immune regulation. While IL-12 is a naturally occurring protein, XTX301 is a synthetic compound designed to interact with IL-12 pathways to potentially treat advanced solid tumors.