Testing XB628 for advanced or metastatic solid tumors

A Phase 1 Study of XB628 in Participants With Recurrent Advanced or Metastatic Solid Tumors

PHASE1 · Exelixis · NCT06952010

This study is testing a new treatment called XB628 to see if it can help people with advanced or metastatic solid tumors by finding the right dose that is safe and effective.

Quick facts

PhasePHASE1
Study typeInterventional
Enrollment75 (estimated)
Ages18 Years and up
SexAll
SponsorExelixis (industry)
Drugs / interventionsmonalizumab, radiation
Locations10 sites (San Francisco, California and 9 other locations)
Trial IDNCT06952010 on ClinicalTrials.gov

What this trial studies

This phase 1, first-in-human, open-label, dose-escalation study evaluates XB628, a bispecific antibody designed to engage natural killer (NK) cells by targeting NKG2A and PD-L1. The study aims to determine the maximum tolerated dose (MTD) and recommended dosage(s) for expansion of XB628 as a single agent in participants with recurrent advanced or metastatic solid tumors. Participants will receive escalating doses of XB628 to assess safety and efficacy.

Who should consider this trial

Good fit: Ideal candidates are adults with recurrent advanced or metastatic solid tumors who have received prior systemic anticancer therapy.

Not a fit: Patients with primary brain tumors or known active brain metastases may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could provide a new therapeutic option for patients with difficult-to-treat advanced or metastatic solid tumors.

How similar studies have performed: Other studies involving bispecific antibodies and NK cell engagement have shown promise, indicating potential for success in this novel approach.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1.
* Minimum life expectancy of ≥ 12 weeks.
* Have a recurrent advanced or metastatic solid tumor that is histologically or cytologically confirmed.
* Adequate organ and marrow function.
* Not amenable to curative treatment with surgery or radiation.
* Received at least 1 line of prior systemic anticancer therapy in the recurrent or metastatic setting.
* Acceptable alternative therapy was received, refused, intolerable, or no longer effective.
* Capable of understanding and complying with the protocol requirements and provide signed informed consent according to the protocol and local requirements.

Exclusion Criteria

* Primary brain tumors or known active brain metastases.
* Major surgery (eg, gastrointestinal surgery, removal or biopsy of brain metastasis) within 4 weeks before the first dose of study treatment.
* Received radiation therapy within 1 week before the first dose of study treatment or clinically relevant ongoing complications from prior radiation therapy.
* Received prior therapy targeting NK cells (eg, monalizumab).
* A woman of childbearing potential has a positive serum pregnancy test within 7 days prior to study treatment.

Where this trial is running

San Francisco, California and 9 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Solid Tumor, Advanced Solid Tumor, Metastatic Solid Tumor, Immune Sensitive Tumor, XB628, Solid tumor, Advanced solid tumor, Metastatic solid tumor

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.