GSK5733584 for Cancer

(BEHOLD-1 Trial)

Recruiting at 49 trial locations

Overseen By US GSK Clinical Trials Call Center

Age: 18+

Sex: Any

Trial Phase: Phase 1

Sponsor: GlaxoSmithKline

Must not be taking: Cytotoxic chemotherapy, Anti-tumor drugs

Disqualifiers: Brain metastasis, Cardiovascular disorders, ILD, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

385 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests the safety and tolerability of different doses of a new drug, GSK5733584, for certain types of cancer. It targets individuals with advanced solid tumors who have not responded to other treatments. There are two main groups: one for those with platinum-resistant ovarian cancer and another for those with advanced or recurrent endometrial cancer. Participants should have ongoing issues after standard treatments, such as chemotherapy, and a life expectancy of at least 12 weeks. This trial offers those struggling with these specific cancers a chance to explore a new treatment option. As a Phase 1 trial, the research focuses on understanding how the treatment works in people, providing participants the opportunity to be among the first to receive this new drug.

Will I have to stop taking my current medications?

The trial requires that you stop taking any cytotoxic chemotherapy drugs, anti-tumor traditional Chinese medicines, or other anti-tumor drugs at least 28 days before starting the study drug. If you need to continue these medications, you cannot participate in the trial.

Is there any evidence suggesting that GSK5733584 is likely to be safe for humans?

Research has shown that GSK5733584 is generally safe based on earlier studies. One study with Chinese patients who had recurring or spreading cancers demonstrated early signs of tumor reduction and considered GSK5733584 safe, as it did not cause major harmful effects. This treatment is a type of targeted therapy called an antibody-drug conjugate (ADC), designed to attack cancer cells directly.

The current trial remains in the early stages, and researchers are still collecting safety information. However, the earlier study suggests that the treatment is usually well-tolerated. Participants in that trial did not report serious side effects, which is a positive indicator for safety. It is important to remember that this treatment is still under investigation, and more information will help confirm its safety for a larger group of people. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising?

Researchers are excited about GSK5733584 for cancer because it offers a fresh approach to treating platinum-resistant ovarian cancer and endometrial cancer. Unlike traditional chemotherapy, GSK5733584 targets cancer cells with a novel mechanism that may overcome resistance to existing therapies. This specificity could lead to more effective results and fewer side effects, offering new hope for patients who haven't responded to standard treatments.

What evidence suggests that GSK5733584 might be an effective treatment for cancer?

Research has shown that GSK5733584 targets a protein called B7-H4, often found in large amounts on cancer cells. This drug acts like a guided missile, delivering cancer-fighting medicine directly to those cells. Early results suggest that this method might help treat advanced solid tumors by focusing more precisely on the cancer cells. In this trial, participants will receive GSK5733584 in either a dose escalation phase for those with advanced solid tumors or a dose expansion phase for those with platinum-resistant ovarian cancer and endometrial cancer. Although researchers are still testing GSK5733584's effectiveness, its targeted approach offers hope for patients with cancers that are difficult to treat with current methods. ^{3 5 6 7 8}

Are You a Good Fit for This Trial?

Adults with advanced solid tumors who've failed or can't tolerate standard treatments, have a life expectancy of at least 12 weeks, and are generally in stable condition (ECOG PS score of 0-2). They must have measurable cancer and provide tissue samples for biomarker analysis. Excluded are those with poor marrow or organ function, heart issues, certain ECG abnormalities, recent major surgeries or therapies.

Inclusion Criteria

Have a life expectancy of at least 12 weeks

My physical health has been stable for the last 2 weeks.

Participants have at least one target lesion as assessed per the RECIST 1.1

Exclusion Criteria

My bone marrow, liver, or kidney functions are not normal.

Left ventricular ejection fraction (LVEF) < 50%

I have received treatments targeting B7-H4.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Dose Escalation

Participants with advanced solid tumors receive escalating doses of GSK5733584 to assess safety and tolerability

Up to approximately 31 months

Dose Expansion

Participants with platinum-resistant ovarian cancer and endometrial cancer receive GSK5733584 to further evaluate safety and clinical activity

Up to approximately 28 months

Follow-up

Participants are monitored for safety and effectiveness after treatment

4-8 weeks

What Are the Treatments Tested in This Trial?

Interventions

• GSK5733584

Trial Overview The trial is testing GSK5733584's safety and how the body processes it at different doses in people with advanced solid tumors. It will involve regular monitoring to determine the appropriate dosage levels and observe any clinical response to the treatment.

How Is the Trial Designed?

Group I: Part 2: Dose Expansion Experimental Treatment 1 Intervention

Participants with platinum-resistant ovarian cancer (PROC) and endometrial cancer (EC)

Group II: Part 1: Dose Escalation Experimental Treatment 1 Intervention

Participants with advanced solid tumors who are refractory or intolerant to established standard therapies

Who Is Running the Clinical Trial?

GlaxoSmithKline

Lead Sponsor

Trials

4,834

Recruited

8,389,000+

Headquarters

London, UK

Known For

Vaccines & Medicines

Top Products

**Advair (salmeterol, fluticasone propionate)**, **Shingrix (shingles vaccine)**, **Augmentin (amoxicillin/clavulanate potassium)**, **Ventolin (salbutamol sulfate)

Dame Emma Walmsley

GlaxoSmithKline

Chief Executive Officer since 2017

MA in Classics and Modern Languages from Oxford University

Dr. Hal Barron

GlaxoSmithKline

Chief Medical Officer since 2018

MD from Harvard Medical School

Citations

1. clinicaltrials.gov clinicaltrials.gov/study/NCT06796907

A Study of GSK5733584 in Combination With Anti-cancer ... This study is looking at how safe and tolerable GSK5733584 is, how the body handles it, and how well it works when used with other cancer medicines.

2. gskusmedicalaffairs.com gskusmedicalaffairs.com/oncology/scientific-meetings/sgo-2025/

Oncology - Scientific Meetings BEHOLD-1: A phase 1 dose escalation study of GSK5733584, a B7-H4-targeted antibody-drug conjugate, in patients with advanced solid tumors, including dose ...

3. dana-farber.org dana-farber.org/clinical-trials/24-453

A Phase I Clinical Study to Evaluate the Safety, Tolerability ... The goal of this study is to assess the safety and tolerability of GSK5733584. The study will also see how the levels of GSK5733584 change over time at ...

4. clinicaltrials.eu clinicaltrials.eu/inn/gsk5733584/

GSK5733584 – Application in Therapy and Current Clinical ... GSK5733584: A New Investigational Drug for Advanced Solid Tumors. GSK5733584 is an investigational drug currently being studied in clinical trials for the ...

5. clinicaltrials.gov clinicaltrials.gov/study/NCT06431594

NCT06431594 | A Study to Evaluate the Safety, Tolerability ... The goal of this study is to assess the safety and tolerability of GSK5733584. The study will also see how the levels of GSK5733584 change over time at ...

6. gynecologiconcology-online.net gynecologiconcology-online.net/article/S0090-8258(25)00354-3/abstract

A phase 1 dose escalation study of GSK5733584, a B7-H4 ... GSK'584 (HS-20089) has shown preliminary antitumor activity and an acceptable safety profile in a phase I study in Chinese patients with recurrent/metastatic ...

7. hspharm.com hspharm.com/news/news-detail-513373.htm

ESMO 2025 | Hansoh Pharma Presents the phase 2 study ... HS-20089 (licensed to GSK as GSK5733584) is the first B7-H4-directed antibody-drug conjugate (ADC) to demonstrate promising efficacy in heavily pretreated ...

8. centerwatch.com centerwatch.com/clinical-trials/listings/NCT06431594/a-study-to-evaluate-the-safety-tolerability-pharmacokinetics-and-clinical-activity-of-gsk5733584-for-injection-in-participants-with-advanced-solid-tumors

A Study to Evaluate the Safety, Tolerability ... The goal of this study is to assess the safety and tolerability of GSK5733584. The study will also see how the levels of GSK5733584 change over time at ...