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Testing AB598 alone and with other treatments for advanced cancers

A Phase 1/1b Study to Evaluate the Safety and Tolerability of AB598 Monotherapy and Combination Therapy in Participants With Advanced Malignancies

PHASE1 · Arcus Biosciences, Inc. · NCT05891171

This study is testing a new treatment called AB598, on its own and with other therapies, to see if it can help people with advanced cancers like bladder and cervical cancer who haven't had success with standard treatments.

Quick facts

PhasePHASE1
Study typeInterventional
Enrollment87 (estimated)
Ages18 Years and up
SexAll
SponsorArcus Biosciences, Inc. (industry)
Drugs / interventionschemotherapy, radiation
Locations20 sites (Phoenix, Arizona and 19 other locations)
Trial IDNCT05891171 on ClinicalTrials.gov

What this trial studies

This study evaluates the safety and tolerability of AB598, both as a standalone treatment and in combination with other therapies, in patients with advanced malignancies. Participants must have measurable lesions and a performance status that allows for treatment. The study includes various advanced cancers, such as bladder and cervical cancer, and aims to determine the effectiveness of AB598 in patients who have not responded to standard therapies.

Who should consider this trial

Good fit: Ideal candidates are individuals with advanced or metastatic solid tumors that have not responded to standard treatments.

Not a fit: Patients with early-stage cancers or those who have not yet undergone standard treatment may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide a new treatment option for patients with advanced cancers who have limited alternatives.

How similar studies have performed: Other studies have shown promise with similar immunotherapy approaches, but the specific combination of AB598 and the other agents is novel.

Eligibility criteria

Show full inclusion / exclusion criteria 
Key Inclusion Criteria:

* Must have at least 1 measurable lesion per Response Evaluation Criteria in Solid Tumors (RECIST) guidance
* Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1
* Prior systemic radiation or whole brain radiation therapy must have been completed at least 4 weeks before investigational product (IP) administration. Other palliative radiotherapy must be completed 2 weeks before investigational product administration, if radiation therapy-related AEs have resolved to Grade ≤ 1.
* Monotherapy-specific criteria for dose escalation and PD cohorts:

  * Dose Escalation: Participants may have any pathologically confirmed advanced or metastatic solid tumor for which standard therapy has proven ineffective, intolerable, or is considered inappropriate.
  * Pharmacodynamic Cohorts: Participants may have any pathologically confirmed advanced or metastatic solid tumors for which standard therapy has proven ineffective, intolerable, or is considered inappropriate. Participants must be able to undergo collection of a fresh frozen biopsy during screening, as well as provide an on-treatment fresh frozen biopsy.
* Dose Expansion cohort criteria:

  * Histologically confirmed, documented diagnosis of HER2-negative locally advanced unresectable or metastatic gastric or GEJ adenocarcinoma.
  * No prior systemic treatment for locally advanced unresectable or metastatic disease.
  * Cannot have progressed within 6 months of prior platinum-based chemotherapy for earlier stage disease.

Key Exclusion Criteria:

* Use of any live vaccines against infectious diseases (eg, influenza, varicella) within 4 weeks (28 days) of initiation of study
* Underlying medical conditions or AEs that, in the investigator or sponsor's opinion, will make the administration of the study drugs hazardous
* Any active or documented history of autoimmune disease including but not limited to inflammatory bowel disease, celiac disease, Wegner syndrome, Hashimoto syndrome, systemic lupus erythematosus, scleroderma, sarcoidosis, or autoimmune hepatitis, within 3 years of the first dose of study treatment
* History of trauma or major surgery within 28 days prior to the first dose of study drug
* Treatment with systemic immunosuppressive medication within 2 weeks prior to initiation of study treatment, or anticipation of need for systemic immunosuppressant medication during study treatment with certain protocol specified exceptions

Note: Other protocol defined Inclusion/Exclusion criteria may apply.

Where this trial is running

Phoenix, Arizona and 19 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: Advanced Cancer, Advanced Malignancies, Bladder Cancer, Cervical Cancer, Esophageal Cancer, Gastric Cancer, Gastroesophageal-junction Cancer, Head and Neck Squamous Cell Carcinoma

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.