XTX202 in Patients With Advanced Solid Tumors

A First-in-Human, Multicenter, Phase 1/2, Open-Label Study of XTX202 in Patients With Advanced Solid Tumors

A First-in-Human, Multicenter, Phase 1/2, Open-Label Study of XTX202 in Patients with Advanced Solid Tumors

Study Overview

• Status: Completed
• Conditions: Advanced Solid Tumor
• Intervention / Treatment: Drug: XTX202

Detailed Description

This is a first-in-human, Phase 1/2, multicenter, open-label study designed to evaluate the safety, tolerability, and efficacy of XTX202, an engineered IL-2 prodrug with its activity masked, as monotherapy in patients with advanced solid tumors.

Phase 1 Part 1a will examine XTX202 monotherapy in an accelerated and standard 3+3 dose-escalation design. Based on the results of Part 1a, Part 1b will be initiated to further examine XTX202 in patients with select advanced solid tumors and to further characterize XTX202.

Based on results of Phase 1 patients with select advanced solid tumors will be enrolled in Phase 2.

• Study Type: Interventional
• Enrollment (Actual): 95
• Phase: Phase 2; Phase 1

Contacts and Locations

Study Locations

• United States
  • California
    • La Jolla, California, United States, 92093
      • UC San Diego Moores Cancer Center
    • Los Angeles, California, United States, 90095
      • University of California Los Angeles
    • Los Angeles, California, United States, 90033
      • Norris Comprehensive Cancer Center
    • Newport Beach, California, United States, 92663
      • Hoag Memorial Hospital Presbyterian- Newport Beach
  • District of Columbia
    • Washington D.C., District of Columbia, United States, 20007
      • Georgetown University Medical Center
  • Florida
    • Tampa, Florida, United States, 33612
      • Moffitt Cancer Center
  • Iowa
    • Iowa City, Iowa, United States, 52242
      • University of Iowa Hospitals and Clinics
  • Massachusetts
    • Boston, Massachusetts, United States, 02114
      • Massachusetts General Hospital
  • Minnesota
    • Saint Paul, Minnesota, United States, 55101
      • HealthPartners Cancer Center at regions Hospital
  • New Jersey
    • Morristown, New Jersey, United States, 07960
      • Atlantic Health System/Morristown Medical Center
    • New Brunswick, New Jersey, United States, 08903
      • Rutgers Cancer Institute of NJ
  • North Carolina
    • Huntersville, North Carolina, United States, 28078
      • Carolina BioOncology Institute
  • Ohio
    • Columbus, Ohio, United States, 43210
      • The Ohio State University Wexner Medical Center James Cancer Hospital and Solove Research Institute
  • Pennsylvania
    • Pittsburgh, Pennsylvania, United States, 15213
      • UPMC Hillman Cancer Center Pavilion
  • Tennessee
    • Nashville, Tennessee, United States, 37203
      • Sarah Cannon Research Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Disease Criteria

   • Phase 1, Part 1a: 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
   • Phase 1, Part 1b: Histologically or cytologically confirmed solid tumor malignancy with one of the following tumor histologies: RCC of clear cell histology only, melanoma, squamous cell skin carcinoma, ovarian cancer, non-small cell lung cancer. Those patients who previously received immunotherapy must have derived benefit from this treatment. Additionally, patients with any of the above histologies in an advanced setting who plan to undergo debulking surgery or oligometastasectomy may be eligible to receive 2 cycles of XTX202 treatment in a "window of opportunity" subcohort".
   • Phase 2, Part 2a: Patients with metastatic RCC who have previously been treated with an anti-PD-1 and a TKI, per local and institutional SOC. Patients must have progressed on treatment with an anti-PD-1 mAb administered either as monotherapy or in combination with other therapies
   • Phase 2, Part 2b: Patients with unresectable or metastatic melanoma who have previously been treated with at least 1 prior line of therapy in the recurrent or metastatic setting. Prior therapy must have included an anti-PD-1 alone or in combination per local and institutional standard of care, and patient must have progressed on checkpoint inhibitor therapy. Patients with BRAF V600-activating mutation must have previously received targeted therapy per local and institutional standard of care.
2. ECOG performance status of 0 or 1
3. Adequate organ function
4. Part 1b only patients must be willing to provide fresh tumor biopsies before and after initiation of study treatment.

Exclusion Criteria:

1. Received prior treatment with IL-2 therapy
2. History of clinically significant pulmonary disease
3. History of clinically significant cardiovascular disease
4. Has a diagnosis of immunodeficiency
5. Has an active autoimmune disease that has required systemic treatment in past 2 years, including the use of disease modifying agents, corticosteroids or immunosuppressive drugs
6. Has an active infection requiring systemic therapy within 4 weeks prior to study treatment

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Sequential Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Phase 2 XTX202 Dose Expansion; Part 2A will enroll patients with metastatic renal cell carcinoma who have progressed following standard-of-care treatment. Part 2B will enroll patients with melanoma who have progressed following standard-of-care treatment.	Drug: XTX202; XTX202 Monotherapy
Experimental: Phase 1 XTX202 Dose Escalation and Pharmacodynamics Expansion; Part 1A Dose Escalation of XTX202 administered in ascending doses to patients with advanced or metastatic solid tumors to find the recommended phase 2 doses (RP2Ds). Part 1B Evaluation of XTX202 in patients with selected advanced solid tumors to further characterize the pharmacodynamic profile of XTX202	Drug: XTX202; XTX202 Monotherapy

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of Dose Limiting Toxicities (DLTs) (Phase 1 Part 1A Only)	All participants in Phase 1 Part 1A (Dose Escalation) who received at least 1 dose of XTX202 and experienced a DLT. DLTs were defined as the following: Any treatment-related Grade ≥ 3 toxicity; Any Grade febrile neutropenia; The following nonhematologic exceptions:Grade 3 nausea or vomiting lasting < 3 daysGrade 3 fatigue lasting < 7 days; Any treatment-related toxicity that resulted in a treatment delay of ≥ 7 days	Cycle 1 day 1 up to just prior to the second dose of study drug at Cycle 2 day 1 (each cycle is 21 days)
Incidence of Treatment-emergent Adverse Events (Phase 1 Only)	Treatment-emergent adverse event (TEAE) is defined as any adverse event that starts or increases in severity on or after the first dose of study drug and no later than 90 days after the last dose of study drug. Adverse events are graded using the NCI CTCAE version 5.0.	Up to 24 months
Investigator-assessed Objective Response Rate (ORR) Per RECIST 1.1 (Phase 2 Only)	Percentage of participants who achieved at least one confirmed Complete Response (CR) or Partial Response (PR). Response is based on Investigator assessment according to RECIST v1.1. In the analysis set used for ORR, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	Up to 24 months
Incidence of Changes in Clinical Laboratory Values (Phase 1 Only) - Biochemistry	Number of participants that experienced a clinical laboratory test abnormality. Abnormalities considered are those Grade 3-4 events with a >= 1 grade increase from baseline. Baseline is defined as the last available measurement taken prior to the first administration of study treatment. Laboratory data is graded using the NCI CTCAE version 5.0. Participants are included only once, in the highest level of CTCAE Grade.	Up to 24 months
Incidence of Changes in Clinical Laboratory Values (Phase 1 Only) - Hematology	Number of participants that experienced a clinical laboratory test abnormality. Abnormalities considered are those Grade 3-4 events with a >= 1 grade increase from baseline. Baseline is defined as the last available measurement taken prior to the first administration of study treatment. Laboratory data is graded using the NCI CTCAE version 5.0. Participants are included only once, in the highest level of CTCAE Grade.	up to 24 months
Incidence of Changes in Clinical Laboratory Values (Phase 1 Only) - Thyroid Function	Number of participants with shift from baseline in laboratory results. Baseline is defined as the last available measurement taken prior to the first administration of study treatment. Participants with both baseline and at least one postbaseline result are included. Participants are included only once, in the highest level of CTCAE Grade. Missing = number of patients with missing baseline and/or post baseline laboratory value.	Up to 24 months
Incidence of Changes in Clinical Laboratory Values (Phase 1 Only) - Coagulation	Number of participants with shift from baseline in laboratory results. Baseline is defined as the last available measurement taken prior to the first administration of study treatment. Participants with both baseline and at least one postbaseline result are included. Participants are included only once, in the highest level of CTCAE Grade. Missing = number of patients with missing baseline and/or post baseline laboratory value. Missing = number of patients with missing baseline and/or post baseline laboratory value	Up to 24 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Investigator-assessed Objective Response Rate (ORR) Per RECIST 1.1 (Phase 1 Only)	Percentage of participants who achieved at least one confirmed Complete Response (CR) or Partial Response (PR). Response will be based on Investigator's assessment according to RECIST v1.1.	Up to 24 months
Duration of Response (DOR) (Phase 2 Only)	Duration of response is defined as time from first documentation of a subsequently confirmed objective response (CR or PR) to the date of the first documentation of radiographic disease progression according to Investigator assessment by RECIST v1.1, or death due to any cause, whichever occurs first. Participants who do not have an observed documented disease progression or death from any cause will be censored at the latest tumor response assessment date.	Up to 24 months
Disease Control Rate (Phase 2 Only)	Disease Control Rate (DCR) is defined as percentage of participants with confirmed BOR of CR, PR or SD (minimum duration of 6 weeks) according to RECIST v1.1, after the first dose of study treatment. In the analysis set used for DCR, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	Up to 24 months
Overall Survival (OS) (Phase 2 Only)	OS is defined as the time from first administration of study treatment to death due to any cause. For participants without a record of death, OS will be censored at the date they were last known alive. In the analysis set used for OS, participants are assigned to a treatment group based on the initial dose received.. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group	Up to 24 months
Progression-free Survival (PFS) (Phase 2 Only)	PFS is defined as the time from first administration of study treatment until first documentation of radiographic PD according to RECIST v1.1, or death due to any cause, whichever occurs first. Participants who do not have an observed documented disease progression or death from any cause will be censored at the latest tumor response assessment date. In the analysis set used for PFS, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group	Up to 24 months
Incidence of Treatment-emergent Adverse Events (Phase 2 Only)	Treatment-emergent adverse event is defined as any adverse event (AE) that starts or increases in severity on or after the first dose of study drug and no later than 90 days after the last dose of study drug. AEs are graded using the NCI CTCAE version 5.0.	Up to 24 months
Incidence of Changes in Clinical Laboratory Values (Phase 2 Only) - Hematology	Number of participants that experienced a clinical laboratory test abnormality. Abnormalities considered are those Grade 3-4 events with a >= 1 grade increase from baseline. Baseline is defined as the last available measurement taken prior to the first administration of study treatment. Laboratory data is graded using the NCI CTCAE version 5.0. Participants are included only once, in the highest level of CTCAE Grade.	Up to 24 months
Incidence of Changes in Clinical Laboratory Values (Phase 2 Only) - Biochemistry	Number of participants that experienced a clinical laboratory test abnormality. Abnormalities considered are those Grade 3-4 events with a >= 1 grade increase from baseline. Baseline is defined as the last available measurement taken prior to the first administration of study treatment. Laboratory data is graded using the NCI CTCAE version 5.0. Participants are included only once, in the highest level of CTCAE Grade.	Up to 24 months
Incidence of Changes in Clinical Laboratory Values (Phase 2 Only) - Thyroid Function	Number of participants with shift from baseline in laboratory results. Baseline is defined as the last available measurement taken prior to the first administration of study treatment. Participants with both baseline and at least one postbaseline result are included. Participants are included only once, in the highest level of CTCAE Grade. Missing = number of patients with missing baseline and/or post baseline laboratory value.	Up to 24 months
Incidence of Changes in Clinical Laboratory Values (Phase 2 Only) - Coagulation	Number of participants with shift from baseline in laboratory results. Baseline is defined as the last available measurement taken prior to the first administration of study treatment. Participants with both baseline and at least one postbaseline result are included. Participants are included only once, in the highest level of CTCAE Grade. Missing = number of patients with missing baseline and/or post baseline laboratory value.	Up to 24 months
Plasma Concentrations of Total XTX202	Plasma Concentration of Total XTX202 by Nominal Time (h) From End of Infusion Following a Single IV Administration of XTX202. In the analysis set used for PK, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	0.00, 0.0167, 0.250, 0.500, 1.50, 3.00, 24.0, 72.0, 144, 312, 504 hours post-dose following a single administration of XTX202 on Cycle 1
Plasma Concentrations of Intact XTX202	Plasma Concentration of Intact XTX202 by Nominal Time (h) From End of Infusion Following a Single IV Administration of XTX202. In the analysis set used for PK, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	0.00, 0.0167, 0.250, 0.500, 1.50, 3.00, 24.0, 72.0, 144, 312, 504 hours post-dose following a single administration of XTX202 on Cycle 1
Total XTX202 Plasma Trough Concentration	Plasma Trough Concentration of Total XTX202 Following Multiple IV Administrations of XTX202. In the analysis set used for PK, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group	From Cycle 1 to up to Cycle 18 (21 days per cycle)
Intact XTX202 Plasma Trough Concentration	Plasma Trough Concentration of Intact XTX202 Following Multiple IV Administrations of XTX202. In the analysis set used for PK, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	from Cycle 1 to up to Cycle 18 (21 days per cycle)
Maximum Observed Plasma Concentration (Cmax) of Total XTX202	Cmax following a single IV infusion of XTX202. In the analysis set used for PK, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	up to 21 days following a single IV infusion of XTX202 on Cycle 1
Maximum Observed Plasma Concentration (Cmax) of Intact XTX202	Cmax following a single IV infusion of XTX202. In the analysis set used for PK, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	up to 21 days following a single IV infusion of XTX202 on Cycle 1
Time of Maximum Observed Concentration (Tmax) of Total XTX202	Time of maximum observed concentration (Tmax) of total XTX202 following a single IV infusion of XTX202. In the analysis set used for PK, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	up to 21 days following a single IV infusion of XTX202 on Cycle 1
Time of Maximum Observed Concentration (Tmax) of Intact XTX202	Time of maximum observed concentration (Tmax) of intact XTX202 following a single IV infusion of XTX202. In the analysis set used for PK, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	up to 21 days following a single IV infusion of XTX202 on Cycle 1
Area Under the Curve From Time 0 to 504 Hours (AUC0-504) of Total XTX202	Area under the curve (AUC)of total XTX202 following a single IV infusion of XTX202. In the analysis set used for PK, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	up to 21 days following a single IV infusion of XTX202 on Cycle 1
Area Under the Curve From Time 0 to 504 Hours (AUC0-504) of Intact XTX202	Area under the curve (AUC) of intact XTX202 following a single IV infusion of XTX202. In the analysis set used for PK, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	up to 21 days following a single IV infusion of XTX202 on Cycle 1
Half-life (T1/2) of Total XTX202	Half-life (T1/2) of total XTX202 following a single IV infusion of XTX202. In the analysis set used for PK, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	up to 21 days following a single IV infusion of XTX202 on Cycle 1
Half-life (T1/2) of Intact XTX202	Half-life (T1/2) of intact XTX202 following a single IV infusion of XTX202. In the analysis set used for PK, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	up to 21 days following a single IV infusion of XTX202 on Cycle 1
Systemic Clearance (CL) of Total XTX202	Systemic clearance (CL) of Total XTX202 following a single IV infusion of XTX202. In the analysis set used for PK, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	up to 21 days following a single IV infusion of XTX202 on Cycle 1
Systemic Clearance (CL) of Intact XTX202	Systemic clearance (CL) of intact XTX202 following a single IV infusion of XTX202. In the analysis set used for PK, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	up to 21 days following a single IV infusion of XTX202 on Cycle 1
Volume of Distribution (Vd) of Total XTX202	Volume of distribution (Vd) of total XTX202 following a single IV infusion of XTX202. In the analysis set used for PK, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	up to 21 days following a single IV infusion of XTX202 on Cycle 1
Volume of Distribution (Vd) of Intact XTX202	Volume of distribution (Vd) of intact XTX202 following a single IV infusion of XTX202. In the analysis set used for PK, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	up to 21 days following a single IV infusion of XTX202 on Cycle 1
Antidrug Antibody (ADA) Occurrence and Titer in Serum (Phase 1 Only)	Overall ADA Incidence Following a Single IV Administration of XTX202 In the analysis set used for ADA, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 1 Part 1B initially received XTX202 2.8 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	from Cycle 1 Day 1 to up to 24 months
Incidence and Persistence of ADAs (Including Neutralizing ADAs) and Titers (Phase 2 Only)	Overall ADA Incidence Following a Single IV Administration of XTX202. In the analysis set used for ADA, participants are assigned to a treatment group based on the initial dose received. In the Participant Flow module, participants are assigned to a treatment group based on the highest dose received. One participant in Phase 2 Part 2B initially received XTX202 1.4 mg/kg, then increased the dose to 4.0 mg/kg at a later cycle and was therefore included in the XTX202 4.0 mg/kg dose group.	From Cycle 1 Day 1 to up to 24 months

Collaborators and Investigators

• Sponsor: Xilio Development, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): January 18, 2022
• Primary Completion (Actual): March 22, 2025
• Study Completion (Actual): March 25, 2025

Study Registration Dates

• First Submitted: August 23, 2021
• First Submitted That Met QC Criteria: September 10, 2021
• First Posted (Actual): September 22, 2021

Study Record Updates

• Last Update Posted (Actual): May 28, 2026
• Last Update Submitted That Met QC Criteria: April 30, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms
• Other Study ID Numbers: XTX202-01/02-001

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No