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BEHOLD-1 Study: Mocertatug Rezetecan for Advanced Solid Tumors

This study, called BEHOLD-1, is testing a new drug called Mocertatug Rezetecan for people with advanced solid tumors (cancers that start in organs like the breast, lung, or colon). The main goals are to see if Mocertatug Rezetecan is safe and how well your body tolerates it. Researchers will also study how the drug moves through your body at different doses. You might be able to join if you are 18 or older, have advanced solid tumors that have not responded to standard treatments, and specifically if you have certain types of ovarian, primary peritoneal, or fallopian tube cancer. Success in the study will be measured by how many participants experience serious side effects and how many see their tumors shrink or disappear. The study is currently recruiting participants.

Study design
This is an interventional study with a planned enrollment of 675 participants. It will look at the safety and effectiveness of Mocertatug Rezetecan.
What's involved
Not specified in the trial record.
Compensation
Not stated in the trial record.
Follow-up
The study will measure how many participants respond to treatment for up to approximately 28 months.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT06431594

A Study to Evaluate the Safety,Tolerability, Pharmacokinetics and Clinical Activity of Mocertatug Rezetecan for Injection in Participants With Advanced Solid Tumors (BEHOLD-1)

Recruiting
PHASE1Ages 18+InterventionalTreatment
GlaxoSmithKline
~675 participants
Updated 2026-06-25 on ClinicalTrials.gov
What's tested:Mocertatug rezetecan

At a glance

Recruiting sites
64 of 65 listed sites are recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Part 1: Number of participants with dose limiting toxicity (DLT)
Measured over Up to 21 days
+1 more outcome measured

Conditions

Solid Tumors
Neoplasms

Explore related trials

Endometrial CarcinomaFallopian Tube CarcinomaMalignant Ovarian NeoplasmPrimary Peritoneal CancerSolid NeoplasmFolate Receptor Alpha

Where it's being run

65 sites across 28 states
Spain8
Italy5
Argentina4
South Korea4
Brazil3
Ontario3
Finland3
France3

Who to contact

US GSK Clinical Trials Call Center
[email protected]
877-379-3718
Email the study team

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Do you actually qualify for this trial?

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Eligibility criteria

Inclusion

Males or females aged 18 years or older (≥18 years).
Participants with pathologically confirmed advanced solid tumor (who have failed or are intolerant to standard of care.
PROC cohort
Endometrial cancer cohort
Participants have at least one target lesion as assessed per the RECIST 1.1
Tumor tissue from a newly obtained biopsy or archival tumor tissue is required for retrospective detection of B7 homolog 4 (B7-H4) expression by IHC in central laboratory and other biomarker analysis. Tissue from a newly obtained biopsy is preferred. If a newly obtained biopsy is not feasible, archival tumor tissue within 2 years prior to the first dose of study drug is acceptable.
Eastern Cooperative Oncology Group Performance Status (ECOG PS) score of 0 to 2 and no deterioration within 2 weeks before the first dose.
Have a life expectancy of at least 12 weeks.

Exclusion

Have received any B7-H4-targeted therapy
Have received any of cytotoxic chemotherapy drugs, anti-tumor traditional Chinese medicines or other anti-tumor drugs within 28 days prior to the first dose of study drug; or need to continue these drugs during the study.
Have received locoregional radiation therapy within 2 weeks prior to the first dose of study drug; more than 30% of bone marrow irradiation or wide-field radiation therapy within 4 weeks prior to the first dose of study treatment.
Presence of pleural/abdominal effusion/ascites requiring clinical intervention; presence of pericardial effusion
Major surgery within 28 days prior to the first dose of study treatment.
Evidence of brain metastasis unless asymptomatic;
Has inadequate bone marrow reserve or hepatic/renal functions .
Mean Fridericia-corrected QT interval (QTcF) QTcF \>450 msec or QTcF \>480 msec for participants with bundle branch blocK;
Evidence of current clinically significant arrhythmias or ECG abnormalities
Left ventricular ejection fraction (LVEF) \< 50%.
Have severe, uncontrolled or active cardiovascular disorders, serious or poorly controlled hypertension, clinically significant bleeding symptoms or serious arteriovenous thromboembolic events
Has current active pneumonitis/ILD or any history of ILD, any history of pneumonitis requiring steroids or immunomodulatory treatment within 90 days of planned randomization/enrollment or any history of drug-induced pneumonitis/ILD.Have received prior therapy with topoisomerase inhibitors or topoisomerase inhibitor Antibody-drug conjugate (ADCs)
PROC
Endometrial cancer a. Mesenchymal tumors of the uterus (uterine sarcomas) not permitted.

What this trial measures

  • Part 1: Number of participants with dose limiting toxicity (DLT)Up to 21 days
  • Part 2-Confirmed Objective Response Rate (ORR) assessed by investigatorUp to approximately 28 months

    ORR is defined as the proportion of participants with at least one confirmed Complete Response (CR) or Partial Response (PR) as defined by Response Evaluation Criteria in Solid Tumors (RECIST 1.1)