Recent Updates
Recently added Catalysts

vilastobart

Phase 1

Advanced Solid Tumor | Small molecule | Oncology |Xilio Therapeutics, Inc.|Last Updated: May 5, 2026

Success Probability
Approval Probability 71%
TA Base Rate26%
Adjusted LOA41%
ML RiskLOW_RISK
Premium
Market & Valuation
rNPV $3.2B
Market Size $9.4B
Revenue Basis $1.6B
Competitors 6
Premium
Trial Design
CONTROLLEDBiomarker
Total Trials1
Total Enrollment136
FDA Designations
No designations recorded
Clinical Trials (1)
NCT IDTitlePhaseStatusEnrollmentVelocityDesignStartCompletionLast UpdatedSitesCountries
NCT04896697Vilastobart (XTX101) Monotherapy and Vilastobart and Atezolizumab Combination Therapy in Advanced Solid TumorsPHASE1 ACTIVE NOT_RECRUITING 136 — — Sep 13, 2021Jun 12, 2026May 5, 202619 United States
Unlock Drug Trial Details
Study Endpoints
Primary Endpoints
Incidence of Dose Limiting Toxicities (DLTs) in Part 1A
Cycle 1 Day 1 up to just prior to the second dose of study drug at Cycle 2 day 1 (approximately 3 weeks)
Incidence of Dose Limiting Toxicities (DLTs) in Part 1C
Cycle 1 Day 1 up to Cycle 3 Day 1 (approximately 6 weeks)
Incidence of treatment-emergent adverse events in Part 1
Up to 24 months
Incidence of changes in clinical laboratory abnormalities in Part 1
Up to 24 months
Investigator-assessed objective response rate (ORR) per iRECIST in Phase 2
Up to 24 months
Secondary Endpoints
Investigator-assessed objective response rate (ORR) per iRECIST in Part 1
Up to 24 months
Antidrug antibody (ADA) occurrence and titer in serum in Part 1
Up to 24 months
Plasma concentrations of vilastobart (XTX101) (total and intact) in Part 1 and Phase 2
Up to 24 months
Unlock Study Endpoints
Study Design & Arms
AllocationNON_RANDOMIZED
MaskingNONE
ModelSEQUENTIAL
PurposeTREATMENT
Treatment Arms
ArmTypeDescription
Part 1A - vilastobart (XTX101) Monotherapy Dose EscalationEXPERIMENTALPart 1A Dose Escalation of vilastobart (XTX101) administered in ascending doses to patients with advanced or metastatic solid tumors to find the recommended phase 2 dose (RP2D).
Part 1B - Pharmacodynamic (PD) Dose ExpansionEXPERIMENTALPart 1B vilastobart (XTX101) at the RP2D will be administered to further examine vilastobart (XTX101) as monotherapy in patients with select advanced solid tumors.
Part 1C - vilastobart (XTX101) Dose Escalation and Dose Expansion in Combination with AtezolizumabEXPERIMENTALPart 1C will receive a labeled dose of atezolizumab in combination with vilastobart (XTX101).
Phase 2 - vilastobart (XTX101) Dose Expansion in Combination with AtezolizumabEXPERIMENTALPhase 2 will receive a labeled dose of atezolizumab in combination with vilastobart (XTX101) at the RP2D(s) in patients with MSS CRC.
Interventions
NameTypeDescription
vilastobart (XTX101)DRUGvilastobart (XTX101) monotherapy
AtezolizumabDRUG1200 mg administered every 3 weeks in combination with vilastobart (XTX101)
Unlock Study Design Details
Eligibility Criteria
Age Range18 Years — N/A
SexALL
Healthy VolunteersNo
Study Sites19

Inclusion Criteria: Disease Criteria - * Part 1A and 1C: Any histologically or cytologically confirmed solid tumor malignancy that is locally advanced or metastatic and has failed standard therapy, or standard therapy is not curative or available; * Part 1B: * Any histologically or cytologicall...

Countries:United States
Unlock Eligibility Criteria
Competitive Landscape -Other Solid Tumors 9 trials
CompanyTickerTrialsLead PhaseDrugs
Merck & Co., Inc.MRK2PHASE2pembrolizumab, V503, GARDASIL
Incyte CorporationINCY1PHASE2Chemotherapy, Retifanlimab
Novartis AG Sponsored ADRNVS1PHASE1KFA115, pembrolizumab
Iovance Biotherapeutics IncIOVA2PHASE2E7 TCR-T cells, Aldesleukin
AstraZeneca PLCAZN1 — Trastuzumab deruxtecan
Unlock Competitive Intelligence
Recent Changes (Last 90 Days)
MEDIUMMay 26, 2026NCT04896697Status: RECRUITING → ACTIVE_NOT_RECRUITING
LOWMay 24, 2026NCT04896697studyFirstPostDate: changed