Solid TumorsPhase 1NCT07123103
A Study of XB371 Administered in Participants With Locally Advanced or Metastatic Solid Tumors
A Phase 1 study testing XB371 in people with Solid Tumors, run by Exelixis at 9 sites in United States.
Trial summary
The primary purpose of the study is to characterize the safety and tolerability of XB371. The dose-escalation cohorts and Part B of the expansion cohorts are non-randomized. Part A of the expansion cohorts is randomized. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Solid Tumors
- What is being tested?
- XB371
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 150 participants
- Where
- 9 sitesUnited States
- Study dates
- 18 Aug 2025to Feb 2028
- Phase
- Phase 1
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1.
- Minimum life expectancy of ≥ 12 weeks.
- Recurrent locally advanced or metastatic solid tumors.
- Adequate end organ and bone marrow function.
Who cannot join
- Primary brain tumors or known active brain metastases, leptomeningeal, or cranial epidural disease.
- History of interstitial lung disease (ILD) of any grade or history of organizing pneumonia.
- Has acute ocular infection, acute or chronic ulcerative/cicatricial condition of conjunctiva or cornea.
- Known history of immunodeficiency virus (HIV) unless specific criteria are met.
- Active infection with hepatitis C virus (HCV) defined as positive for HCV antibody.
- Major surgery within 4 weeks before the first dose of study treatment.
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- Received radiation therapy within 2 weeks before the first dose of study treatment.
- Received prior systemic anticancer therapy including investigational agents within 4 weeks before the first dose of study treatment.
- NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.
Trial locations and contacts
9 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Backup or International contact
9 sites in 1 country
United States9 sites, 9 recruiting
- Recruiting
Exelixis Clinical Site #3
Grand Rapids, Michigan, 49546
- Recruiting
Exelixis Clinical Site #8
Houston, Texas, 77030
- Recruiting
Exelixis Clinical Site #2
Huntersville, North Carolina, 28078
- Recruiting
Exelixis Clinical Site #9
Los Angeles, California, 90033
- Recruiting
Exelixis Clinical Site #7
New Brunswick, New Jersey, 08901
- Recruiting
Exelixis Clinical Site #4
Orlando, Florida, 32827
- Recruiting
Exelixis Clinical Site #5
Rogers, Arkansas, 72758
- Recruiting
Exelixis Clinical Site #1
San Antonio, Texas, 78229
- Recruiting
Exelixis Clinical Site #6
Washington D.C., District of Columbia, 20057
About this study
Official title: A Dose Escalation and Expansion Study of XB371 Administered in Participants With Locally Advanced or Metastatic Solid Tumors
The primary purpose of the study is to characterize the safety and tolerability of XB371. The dose-escalation cohorts and Part B of the expansion cohorts are non-randomized. Part A of the expansion cohorts is randomized.
- Conditions
- Solid Tumors
- Being tested
- XB371
- Keywords
- Advanced Solid Tumors, Metastatic Solid Tumors
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
XB371Drug
Intravenous (IV) infusion.
| Study group | Role | What they receive |
|---|---|---|
| Dose-escalation Cohorts | Experimental | Participants will receive escalating doses of XB371 every 3 weeks of a 21-day cycle (alternate schedules may be evaluated) until meeting the criteria for treatment discontinuation. Receives: Drug: XB371 |
| Dose-expansion Cohorts: Part A | Experimental | Participants with Tumor Type 1 (tumor type will be selected based on available data) will be randomized to receive XB371 at one of two recommended dose levels (recommended dose [RD]-1 or RD-2) every 3 weeks of a 21-day cycle (alternate schedules may be evaluated) until meeting the criteria for treatment discontinuation. Receives: Drug: XB371 |
| Dose-expansion Cohorts: Part B | Experimental | Participants with Tumor Type 2 (tumor type will be selected based on available data) will receive XB371 at the recommended dose level every 3 weeks of a 21-day cycle (alternate schedules may be evaluated) until meeting the criteria for treatment discontinuation. Receives: Drug: XB371 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants with a Dose-limiting Toxicity (DLT)
Measured: Up to the end of the first cycle (Up to Day 21 of a 21-day cycle)
Number of Participants with a Treatment-emergent Adverse Event (TEAE)
Measured: Up to approximately 7 months
Secondary outcomes (8)
Area Under the Plasma Concentration-time Curve (AUC) of XB371, Total Antibody and Unconjugated Belotecan
Measured: Up to approximately 7 months
Maximum Observed Plasma Concentration (Cmax) of XB371, Total Antibody and Unconjugated Belotecan
Measured: Up to approximately 7 months
Time to Maximum Observed Plasma Concentration (Tmax) of XB371, Total Antibody and Unconjugated Belotecan
Measured: Up to approximately 7 months
Trough Observed Plasma Concentration (Ctrough) of XB371, Total Antibody and Unconjugated Belotecan
Measured: Up to approximately 7 months
Number of Participants with Antidrug Antibodies to XB371
Measured: Up to approximately 7 months
Dose-escalation Cohorts Only: Recommended Dose(s) for Expansion
Measured: Through completion of dose-escalation (up to approximately 18 months)
Dose-expansion Cohorts Only: Objective Response Rate as Assessed by the Investigator per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST v1.1)
Measured: Up to approximately 18 months
Dose-expansion Cohorts Only: Duration of Response as Assessed by the Investigator per RECIST v1.1
Measured: Up to approximately 18 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Aug 2025
- Study start18 Aug 2025
- Primary completionNov 2027 (estimated)
- Study completionFeb 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Solid TumorsStudies of the same condition, open and under way.
- More trials run by ExelixisThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Enrolment
- 150 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Exelixis
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Medical Director, Study director, Exelixis
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07123103
- Sponsor's protocol ID
- XB371-101
- Status last verified
- Feb 2026
- First submitted
- 8 Aug 2025
- Last updated
- 17 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No