A Study to Evaluate the Safety and Tolerability of AB680 in Participants With Gastrointestinal Malignancies (ARC-8)

A Phase 1 Study to Evaluate the Safety and Tolerability of AB680 Combination Therapy in Participants With Gastrointestinal Malignancies

This is a Phase 1, open-label, dose-escalation, and dose-expansion, with a gated randomization portion, study to evaluate the safety, tolerability, pharmacokinetic, pharmacodynamic and clinical activity of AB680 in combination with zimberelimab (AB122), nab-paclitaxel and gemcitabine in participants with advanced pancreatic cancer.

Study Overview

• Status: Active, not recruiting
• Conditions: Advanced Pancreatic Cancer
• Intervention / Treatment: Drug: AB680; Drug: Zimberelimab; Drug: Nab-paclitaxel; Drug: Gemcitabine

Detailed Description

Dose escalation of AB680 in combination with zimberelimab (AB122), nab-paclitaxel and gemcitabine will be assessed in participants with advanced pancreatic cancer. In this dose escalation combination study, participants with advanced pancreatic cancer will receive escalating doses of AB680 in combination with zimberelimab at the recommended phase 2 dose (RP2D), and nab-paclitaxel and gemcitabine at standard doses. AB680, zimberelimab, nab-paclitaxel and gemcitabine are all administered via IV infusion.

In the dose expansion portion of the study in front-line (1L) pancreatic patients, participants will receive AB680 at the RP2D determined from the dose escalation study in combination with zimberelimab at the RP2D and nab-paclitaxel and gemcitabine at standard doses or AB680 at the RP2D in combination with nab-paclitaxel and gemcitabine at standard doses. In the dose-expansion portion of the study in second-line (2L) pancreatic patients, participants will receive AB680 at the RP2D determined from the dose-escalation study in combination with zimberelimab at the RP2D and nab-paclitaxel and gemcitabine at standard doses.

• Study Type: Interventional
• Enrollment (Actual): 196
• Phase: Phase 1

Contacts and Locations

Study Locations

• United States
  • California
    • Los Angeles, California, United States, 90025
      • Research Site
    • Santa Monica, California, United States, 90404
      • Research Site
  • Missouri
    • St Louis, Missouri, United States, 63110
      • Research Site
  • New York
    • New York, New York, United States, 10016
      • Research Site
    • New York, New York, United States, 10032
      • Research Site
    • New York, New York, United States, 10065
      • Research Site
  • Oklahoma
    • Oklahoma City, Oklahoma, United States, 73104
      • Research Site
  • Pennsylvania
    • Philadelphia, Pennsylvania, United States, 19104
      • Research Site
    • Pittsburgh, Pennsylvania, United States, 15232
      • Research Site
  • Tennessee
    • Nashville, Tennessee, United States, 37203
      • Research Site
  • Texas
    • Houston, Texas, United States, 77030
      • Research Site
    • San Antonio, Texas, United States, 78229
      • Research Site
  • Wisconsin
    • Madison, Wisconsin, United States, 53792
      • Research Site

Participation Criteria

Eligibility Criteria

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

Description

Key Inclusion Criteria:

• Histologically or cytologically confirmed metastatic pancreatic adenocarcinoma

• Naïve to any prior treatment, including chemotherapy, biological therapy, or targeted therapy for metastatic disease

  • Prior adjuvant therapy (including chemotherapy and/or radiotherapy) for pancreatic adenocarcinoma is permitted if neoadjuvant or adjuvant therapy was completed at least 6 months prior to study enrollment. Prior adjuvant therapy may include nab- paclitaxel or gemcitabine
  • Participants initially diagnosed with locally advanced pancreatic cancer who have undergone chemotherapy then resection and had no evidence of disease are eligible if relapse of metastatic disease has occurred and if the last dose of chemotherapy was received more than 6 months before study entry
• Must have at least 1 measurable lesion per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. The measurable lesion must be outside of a radiation field if the participant received prior radiation
• Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1
• Confirmation that an archival tissue sample is available; if not, a new biopsy of a tumor must be obtained
• Prior radiation therapy for metastatic disease must have been completed
• Immunosuppressive doses of systemic medications, such as corticosteroids or absorbed topical corticosteroids (doses > 10 mg/day prednisone or equivalent) must be discontinued at least 2 weeks (14 days) before investigational product administration. Physiologic doses of corticosteroids (≤ 10 mg/day of prednisone or its equivalent) or short pulses of corticosteroids (≤ 3 days) may be permitted
• Prior surgery that required general anesthesia or other major surgery as defined by the Investigator must be completed at least 4 weeks before investigational product administration
• Negative tests for hepatitis B surface antigen, hepatitis C virus antibody (or hepatitis C qualitative ribonucleic acid [RNA; qualitative]), and human immunodeficiency virus (HIV)-1 and HIV-2 antibody at screening
• Adequate organ and marrow function

Key Exclusion Criteria:

• Significant cardiovascular disease (NYHA Class III-IV), myocardial infarction or cerebrovascular accident within 12 months of the first dose of investigational agent or history of arterial thromboembolic event, uncontrolled hypertension, unstable arrhythmia, or unstable angina within 3 months or venous thromboses within 1 month of the first dose of investigational agent.
• Any active autoimmune disease or a documented history of autoimmune disease or history of a syndrome that required systemic steroids or immunosuppressive medications, except for vitiligo or resolved childhood asthma/atopy. Participants with asthma who require intermittent use of bronchodilators (such as albuterol) will not be excluded from this study
• History of a syndrome that required systemic steroids or immunosuppressive medications, except for vitiligo or resolved childhood asthma/atopy. Participants with asthma who require intermittent use of bronchodilators (such as albuterol) will not be excluded from this study
• Prior malignancy active within the previous year except for locally curable cancers that have been apparently cured, such as basal or squamous cell skin cancer, superficial bladder cancer, or carcinoma in situ of the cervix, breast, or prostate cancer
• Has not recovered (ie, ≤ Grade 1 or baseline) from a non-hematologic AEs due to a previously administered agent, except ≤ Grade 2 alopecia or ≤ Grade 2 neuropathy.

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

Study Plan

How is the study designed?

Design Details

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

Number of Arms

7

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Dose Escalation; Dose escalation is a 3+3 design, including a Dose Limiting Toxicity (DLT) evaluation period. The dose expansion dose level will be determined in this part with escalating doses of AB680 in combination with zimberelimab at the recommended phase 2 dose (RP2D) and the standard nab-paclitaxel and gemcitabine chemotherapy regimen in participants with advanced pancreatic cancer.	Drug: AB680; AB680 is a Cluster of Differentiation (CD)73 Inhibitor.; Drug: Zimberelimab; Zimberelimab is a fully human immunoglobulin G4 (IgG4) monoclonal antibody targeting human PD-1.; Other Names: AB122; Drug: Nab-paclitaxel; Nab-paclitaxel is a chemotherapy agent. Chemotherapy agents are medicines that kill cancer cells.; Other Names: Abraxane; Drug: Gemcitabine; Gemcitabine is a chemotherapy agent. Chemotherapy agents are medicines that kill cancer cells.; Other Names: Gemzar
Experimental: Dose Expansion (AB680+zimberelimab+ NP/Gem): Cohort A (front-line/1L); Participants with advanced pancreatic cancer, naïve to any prior treatment will receive AB680 (at the RP2D identified during dose escalation) combined with zimberelimab and the standard nab-paclitaxel (NP) and gemcitabine (Gem) (NP/Gem) chemotherapy regimen	Drug: AB680; AB680 is a Cluster of Differentiation (CD)73 Inhibitor.; Drug: Zimberelimab; Zimberelimab is a fully human immunoglobulin G4 (IgG4) monoclonal antibody targeting human PD-1.; Other Names: AB122; Drug: Nab-paclitaxel; Nab-paclitaxel is a chemotherapy agent. Chemotherapy agents are medicines that kill cancer cells.; Other Names: Abraxane; Drug: Gemcitabine; Gemcitabine is a chemotherapy agent. Chemotherapy agents are medicines that kill cancer cells.; Other Names: Gemzar
Experimental: Dose Expansion (AB680+zimberelimab+NP/Gem):Cohort A1 (front-line/1L); Participants with advanced pancreatic cancer, naïve to any prior treatment will receive AB680 (at the RP2D identified during dose escalation) combined with zimberelimab and the standard nab-paclitaxel (NP) and gemcitabine (Gem) (NP/Gem) chemotherapy regimen	Drug: AB680; AB680 is a Cluster of Differentiation (CD)73 Inhibitor.; Drug: Zimberelimab; Zimberelimab is a fully human immunoglobulin G4 (IgG4) monoclonal antibody targeting human PD-1.; Other Names: AB122; Drug: Nab-paclitaxel; Nab-paclitaxel is a chemotherapy agent. Chemotherapy agents are medicines that kill cancer cells.; Other Names: Abraxane; Drug: Gemcitabine; Gemcitabine is a chemotherapy agent. Chemotherapy agents are medicines that kill cancer cells.; Other Names: Gemzar
Experimental: Dose Expansion (AB680 + NP/Gem): Cohort A2 (front-line/1L); Participants with advanced pancreatic cancer who are naïve to any prior treatment will receive AB680 (at the RP2D identified during dose escalation) and the standard NP/Gem chemotherapy regimen.	Drug: AB680; AB680 is a Cluster of Differentiation (CD)73 Inhibitor.; Drug: Nab-paclitaxel; Nab-paclitaxel is a chemotherapy agent. Chemotherapy agents are medicines that kill cancer cells.; Other Names: Abraxane; Drug: Gemcitabine; Gemcitabine is a chemotherapy agent. Chemotherapy agents are medicines that kill cancer cells.; Other Names: Gemzar
Experimental: Dose Expansion (AB680 + zimberelimab + NP/Gem): Cohort B (second-line/2L); Participants with advance pancreatic cancer who have received 1 prior line of treatment will receive AB680 (at the RP2D identified during dose escalation) combined with zimberelimab and NP-Gem chemotherapy regimen.	Drug: AB680; AB680 is a Cluster of Differentiation (CD)73 Inhibitor.; Drug: Zimberelimab; Zimberelimab is a fully human immunoglobulin G4 (IgG4) monoclonal antibody targeting human PD-1.; Other Names: AB122; Drug: Nab-paclitaxel; Nab-paclitaxel is a chemotherapy agent. Chemotherapy agents are medicines that kill cancer cells.; Other Names: Abraxane; Drug: Gemcitabine; Gemcitabine is a chemotherapy agent. Chemotherapy agents are medicines that kill cancer cells.; Other Names: Gemzar
Experimental: Dose Expansion (AB680 + zimberelimab + NP/Gem): Cohort C (front-line/1L); Participants with advanced pancreatic cancer naïve to any prior treatment will receive AB680 combined with zimberelimab and NP-Gem chemotherapy regimen.	Drug: AB680; AB680 is a Cluster of Differentiation (CD)73 Inhibitor.; Drug: Zimberelimab; Zimberelimab is a fully human immunoglobulin G4 (IgG4) monoclonal antibody targeting human PD-1.; Other Names: AB122; Drug: Nab-paclitaxel; Nab-paclitaxel is a chemotherapy agent. Chemotherapy agents are medicines that kill cancer cells.; Other Names: Abraxane; Drug: Gemcitabine; Gemcitabine is a chemotherapy agent. Chemotherapy agents are medicines that kill cancer cells.; Other Names: Gemzar
Experimental: Dose Expansion (AB680 + NP/Gem): Cohort D (front-line/1L); Participants with advanced pancreatic cancer naïve to any prior treatment will receive AB680 combined with NP-Gem chemotherapy regimen.	Drug: AB680; AB680 is a Cluster of Differentiation (CD)73 Inhibitor.; Drug: Nab-paclitaxel; Nab-paclitaxel is a chemotherapy agent. Chemotherapy agents are medicines that kill cancer cells.; Other Names: Abraxane; Drug: Gemcitabine; Gemcitabine is a chemotherapy agent. Chemotherapy agents are medicines that kill cancer cells.; Other Names: Gemzar

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of participants with Treatment Emergent Adverse Events (TEAEs)	Safety will be assessed by monitoring adverse events and clinically relevant changes in 12 lead Electrocardiogram (ECG) and Physical examination findings	From first dose date to 90 days after the last dose (approximately 1 year)
Number of Participants With Dose Limiting Toxicities		From First dose to day 28

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Duration of response	Time at which response criteria are met for complete response or partial response (whichever occurs first) until the first date of recurrence, progression or death per RECIST v1.1	Start date of response to first progression/death, up to 1 year
Overall survival	Overall survival rate, defined as time between first dose date and date of death	First dose date to date of death, up to 1 year
AB680 peak plasma concentration (Cmax)	Peak plasma concentration (Cmax) of AB680	Day 1 (sequential), day 2, day 3, day 8, day 15, day 29, day 36, day 43, day 57, day 85, day 197, day 309, day 421, 30 days after last dose, and 90 days after last dose
AB680 time of peak concentration (Tmax)	Time of peak concentration (Tmax) of AB680	Day 1 (sequential), day 2, day 3, day 8, day 15, day 29, day 36, day 43, day 57, day 85, day 197, day 309, day 421, 30 days after last dose, and 90 days after last dose
AB680 area under the plasma concentration versus time curve (AUC)	Area under the plasma concentration versus time curve (AUC) of AB680	Day 1 (sequential), day 2, day 3, day 8, day 15, day 29, day 36, day 43, day 57, day 85, day 197, day 309, day 421, 30 days after last dose, and 90 days after last dose
Overall response rate	Number of Participants with Complete or Partial Response per Response Evaluation Criteria In Solid Tumors Criteria (RECIST) v.1.1	First dose date to progression or last tumor assessment, up to 1 year
Disease control rate	Number of participants with complete response, partial response, or stable disease for greater than 6 months per RECIST v1.1	First dose date to first progression/death
Progression free survival	Number of participants without disease progression per RECIST v1.1	First dose date to first progression/death
Zimberelimab peak plasma concentration (Cmax)	Peak plasma concentration (Cmax) of zimberelimab	Day 1 (sequential), day 2, day 3, day 8, day 15, day 29, day 43, day 57, day 85, day 197, day 309, day 421, 30 days after last dose, and 90 days after last dose
Zimberelimab time of peak concentration (Tmax)	Time of peak concentration of zimberelimab	Day 1 (sequential), day 2, day 3, day 8, day 15, day 29, day 43, day 57, day 85, day 197, day 309, day 421, 30 days after last dose, and 90 days after last dose
Zimberelimab area under the plasma concentration versus time curve (AUC)	Area under the plasma concentration versus time curve (AUC) of zimberelimab	Day 1 (sequential), day 2, day 3, day 8, day 15, day 29, day 43, day 57, day 85, day 197, day 309, day 421, 30 days after last dose, and 90 days after last dose
Immunogenicity indicators: anti-drug antibodies (ADA)	Number of participants who develop anti-drug antibodies to zimberelimab	Day 1, day 15, day 29, day 57, day 85, day 197, day 309, and day 421

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pharmacodynamic effects of AB680	Enzymatic activity of CD73 measured in participant blood samples	Day 1, day 2, day 8, day 15, day 29, day 36, day 43, day 57, and day 85
AB680 cytokines	Cytokines may be summarized by dose group and subject over time by aggregating data from exploratory biomarkers collected from peripheral blood samples	Day 1, day 2, day 8, day 15, day 29, day 36, day 43, day 57, and day 85
AB680 immunophenotyping	Immunophenotyping may be summarized by dose group and subject over time by aggregating data from exploratory biomarkers collected from peripheral blood samples	Day 1, day 2, day 8, day 15, day 29, day 36, day 43, day 57, and day 85
AB680 gene expression	Gene expression may be summarized by dose group and subject over time by aggregating data from exploratory biomarkers collected from peripheral blood samples	Day 1, day 2, day 8, day 15, day 29, day 36, day 43, day 57, and day 85

Collaborators and Investigators

• Sponsor: Arcus Biosciences, Inc.
• Investigators: Study Director: Medical Director, Arcus Biosciences, Inc.

Publications and helpful links

General Publications

• Wainberg ZA, Manji GA, Bahary N, Ulahannan SV, Pant S, Spigel DR, Uboha NV, Oberstein PE, Saeed A, Beagle B, Kim JY, Wang N, Weeder B, Shitole S, Mrouj K, Scott JR, Ensign LG, DiRenzo DM, Walters MJ, Wu W, Kaplan A, Cho S, Kabbarah O, O'Reilly EM. Quemliclustat and chemotherapy with or without zimberelimab in metastatic pancreatic adenocarcinoma: a randomized phase 1 trial. Nat Med. 2026 Apr;32(4):1267-1277. doi: 10.1038/s41591-026-04283-z. Epub 2026 Mar 30.

Helpful Links

• ARC-8 - Public website

Study record dates

Study Major Dates

• Study Start (Actual): November 6, 2019
• Primary Completion (Estimated): May 1, 2027
• Study Completion (Estimated): May 1, 2027

Study Registration Dates

• First Submitted: September 23, 2019
• First Submitted That Met QC Criteria: September 24, 2019
• First Posted (Actual): September 26, 2019

Study Record Updates

• Last Update Posted (Actual): June 2, 2026
• Last Update Submitted That Met QC Criteria: May 29, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Pancreatic cancer; AB680; Zimberelimab
• Additional Relevant MeSH Terms: Endocrine System Diseases; Neoplasms by Site; Neoplasms; Digestive System Neoplasms; Digestive System Diseases; Endocrine Gland Neoplasms; Pancreatic Diseases; Pancreatic Neoplasms; Amino Acids, Peptides, and Proteins; Proteins; Organic Chemicals; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Hydrocarbons; Cycloparaffins; Hydrocarbons, Alicyclic; Hydrocarbons, Cyclic; Terpenes; Taxoids; Cyclodecanes; Diterpenes; Deoxycytidine; Cytidine; Pyrimidine Nucleosides; Pyrimidines; Albumins; Paclitaxel; Albumin-Bound Paclitaxel; Gemcitabine; 130-nm albumin-bound paclitaxel; zimberelimab; quemliclustat
• Other Study ID Numbers: ARC-8 (AB680CSP0002)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

IPD Plan Description

Arcus will provide access to individual de-identified participant data and related study documents (e.g., protocol, Statistical Analysis Plan [SAP], Clinical Study Report [CSR]) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions.

For more information, please visit our website.

• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No