Phase 1/2 Study of BHB810 in Advanced Gastric and GEJ Adenocarcinoma (ChefHat-001)

May 5, 2026 updated by: BigHat Biosciences, Inc.

Phase 1/2, Open-Label, Multicenter, Dose Escalation and Expansion Study of BHB810 in Participants With Advanced Gastric and Gastroesophageal Junction Adenocarcinoma

This study is looking at how safe BHB810 is in adults with gastric and gastroesophageal adenocarcinoma (GEJ). The purpose of this study is also to look at: how well the study drug works, how the study drug moves into, through, and out of the body, and how your body reacts to the study drug. Participants will get an IV infusion of BHB810 every 2 weeks while on study treatment.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

164

Phase

  • Phase 2
  • Phase 1

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Participant must be ≥ 18 years or the legal age of consent in the jurisdiction in which the study is taking place at the time of signing the ICF.

  • Histologically confirmed advanced gastric or gastroesophageal junction (GEJ) adenocarcinoma that has progressed on, was nonresponsive to, or for which no standard or available curative therapy exists.

    • Participants in Phase 1 Backfill Cohorts & Phase 2 must be CDH17-positive by central testing.
    • Other gastrointestinal (GI) tumor types may be enrolled in Backfill Cohorts and Phase 2.
  • At least 1 measurable target lesion at baseline per RECIST 1.1 (Response Evaluation Criteria in Solid Tumors)
  • Provision of FFPE archival tumor tissue. Additional fresh biopsies at screening are required in Phase 1 Backfill Cohorts and Phase 2.
  • Adequate organ and marrow function as defined in the protocol

Exclusion Criteria:

  • Prior cancer treatment as follows, relative to the first planned dose of trial intervention:

    • Chemotherapy or targeted therapy withing 4 weeks or 5-halflives (whichever is shorter)
    • Monoclonal antibody-based therapy (including ADCs) within 4 weeks
    • Immune checkpoint inhibitors within 4 weeks
    • Wide-field radiation therapy (>30% marrow-bearing bones) within 4 weeks or < 2 weeks of focal palliative radiation to nontarget lesions
  • Prior treatment with a CDH17-directed therapy or an ADC with an auristatin (MMAE or MMAF)
  • Known hypersensitivity or allergic reaction to BHB810 or it's excipients
  • Left ventricular ejection fraction <50% or history of congestive heart failure Class III/IV
  • QTc interval > 470 msec, history of risk factors for Torsade de Pointes, or taking a medication known to prolong QT/QTc
  • Pregnant or breastfeeding females, or if you or your partner are planning to become pregnant
  • Known or suspected brain metastases, leptomeningeal disease, or spinal cord compression. Participants with stable, treated brain metastases may be enrolled.
  • Current treatment with a strong CYP3A4 inhibitor or inducer, Pgp inhibitor, or CYP3A4 sensitive substrate within 2 weeks of first dose of trial intervention
  • Any condition that may compromise participant safety, compliance, or interfere with the evaluation of the study drug.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Dose Escalation and Backfill Cohorts
Dose escalation and backfill cohorts
Drug: BHB810
Every 2 weeks IV administration
Experimental: Recommended Phase 2 Dose Level 1 (RP2D1)
Dose level 1 of 2 prospective recommended phase 2 dose levels
Drug: BHB810
Every 2 weeks IV administration
Experimental: Recommended Phase 2 Dose Level 2 (RP2D2)
Dose level 2 of 2 prospective recommended phase 2 dose levels
Drug: BHB810
Every 2 weeks IV administration

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of adverse events (AEs), serious adverse events (SAEs), and dose limiting toxicities (DLTs) per Common Terminology Criteria for Adverse Events v6.0 (CTCAE v6.0)
Time Frame: Cycle 1 Day 1 through 30 days after the last dose, an average of 6 months

Investigate the safety and tolerability of BHB810 by evaluation of AEs, SAEs, DLTs, and clinically significant changes safety assessments, like lab tests, vital signs, and other safety assessments

Phase 1 (Dose Escalation & Backfill Cohorts) and Phase 2 (Dose Optimization)

DLTs apply to Phase 1 Dose Escalation Cohorts only.
Cycle 1 Day 1 through 30 days after the last dose, an average of 6 months
Incidence of participants who have a dose modification of BHB810 due to toxicity
Time Frame: Cycle 1 Day 1 through 30 days after the last dose, an average of 6 months

Investigate the safety and tolerability of BHB810 by assessment of dose modifications due to toxicity

Phase 1 (Dose Escalation & Backfill Cohorts)
Cycle 1 Day 1 through 30 days after the last dose, an average of 6 months
Overall Response Rate (ORR)
Time Frame: Screening through End of Treatment, an average of 6 months

Identify the recommended Phase 2 dose (RP2D) by comparing 2 doses of BHB810 by evaluating the ORR of participants according to Response Evaluation Criteria in Solid Tumors (RECIST) v1.1

Phase 2 (Dose Optimization)
Screening through End of Treatment, an average of 6 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Clinical Benefit Rate (CBR)
Time Frame: Screening through End of Treatment, an average of 6 months

Investigate preliminary antitumor activity of BHB810 as assessed by radiological response per RECIST v1.1

Number of participants who achieve stable disease (SD) for at least 6 months, or PR or CR for any duration

Phase 1 (Dose Escalation & Backfill Cohorts)
Screening through End of Treatment, an average of 6 months
Duration of Response (DOR)
Time Frame: Screening through End of Treatment or last scan, an average of 6 months

Investigate preliminary antitumor activity of BHB810 as assessed by radiological response per RECIST v1.1

Time from PR or CR to disease progression

Phase 1 (Dose Escalation & Backfill Cohorts) Phase 2 (Dose Optimization)
Screening through End of Treatment or last scan, an average of 6 months
Progression Free Survival (PFS)
Time Frame: Screening through End of Treatment, an average of 6 months

Investigate preliminary antitumor activity of BHB810 as assessed by radiological response per RECIST v1.1

Time from first dose to first documented date of progression per RECIST v1.1

Phase 1 (Dose Escalation & Backfill Cohorts) Phase 2 (Dose Optimization)
Screening through End of Treatment, an average of 6 months
Overall Survival (OS)
Time Frame: Screening through End of Study, an average of 10 months

Investigate preliminary antitumor activity of BHB810

Time from first dose to death from any cause

Phase 1 (Dose Escalation & Backfill Cohorts) Phase 2 (Dose Optimization)
Screening through End of Study, an average of 10 months
Pharmacokinetics: Area under the concentration-time curve (AUC)
Time Frame: At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months

To characterize the PK profile of BHB810 in blood samples

Phase 1 (Dose Escalation & Backfill Cohorts)
At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months
Pharmacokinetics: Area under the concentration-time curve from zero to the end of a dosing interval at steady-state (AUC0-tau)
Time Frame: At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months

To characterize the PK profile of BHB810 in blood samples

Phase 1 (Dose Escalation & Backfill Cohorts) Phase 2 (Dose Optimization)
At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months
Pharmacokinetics: Maximum concentration of BHB810 (Cmax) Phase 1 (Dose Escalation & Backfill Cohorts) Phase 2 (Dose Optimization)
Time Frame: At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months
To characterize the PK profile of BHB810 in blood samples
At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months
Pharmacokinetics: Time to reach maximum drug concentration of BHB810 (Tmax)
Time Frame: At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months

To characterize the PK profile of BHB810 in blood samples

Phase 1 (Dose Escalation & Backfill Cohorts) Phase 2 (Dose Optimization)
At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months
Pharmacokinetics: Area under the concentration-time curve from zero to infinity (AUC0-inf)
Time Frame: At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months

To characterize the PK profile of BHB810 in blood samples

Phase 1 (Dose Escalation & Backfill Cohorts) Phase 2 (Dose Optimization)
At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months
Pharmacokinetics: Terminal elimination half-life (t1/2)
Time Frame: At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months

To characterize the PK profile of BHB810 in blood samples

Phase 1 (Dose Escalation & Backfill Cohorts) Phase 2 (Dose Optimization)
At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months
Pharmacokinetics: Volume of drug distribution during terminal phase (Vz)
Time Frame: At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months

To characterize the PK profile of BHB810 in blood samples

Phase 1 (Dose Escalation & Backfill Cohorts)
At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months
Pharmacokinetics: Total body clearance of the drug (CL)
Time Frame: At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months

To characterize the PK profile of BHB810 in blood samples

Phase 1 (Dose Escalation & Backfill Cohorts) Phase 2 (Dose Optimization)
At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months
Pharmacokinetics: Area under the concentration-time curve from zero to last measurable concentration sample time (AUC0-last)
Time Frame: At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months

To characterize the PK profile of BHB810 in blood samples

Phase 2 (Dose Optimization)
At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months
Incidence of antidrug antibodies (ADAs) in blood before and after BHB810 administration
Time Frame: At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months

To characterize the ADAs and PK profile of BHB810 in blood samples

Phase 1 (Dose Escalation & Backfill Cohorts) Phase 2 (Dose Optimization)
At protocol defined intervals starting at Cycle 1 Day 1 through End of Treatment, an average of 6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

BigHat Biosciences, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 1, 2026

Primary Completion (Estimated)

December 1, 2028

Study Completion (Estimated)

December 1, 2028

Study Registration Dates

First Submitted

April 1, 2026

First Submitted That Met QC Criteria

April 7, 2026

First Posted (Actual)

April 14, 2026

Study Record Updates

Last Update Posted (Actual)

May 8, 2026

Last Update Submitted That Met QC Criteria

May 5, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • BHB810-001

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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