A Phase I Clinical Study of HLX3902 in Patients With mCRPC and Other Advanced Tumours

A Phase Ia Clinical Study to Evaluate the Safety, Tolerability, and Pharmacokinetic Characteristics of HLX3902 (a STEAP1xCD3xCD28 Trispecific Antibody) in Patients With Metastatic Castration-Resistant Prostate Cancer and Other Advanced Solid Tumours

This study is an open-label first-in-human phase I clinical study to evaluate the safety, tolerability, and pharmacokinetic characteristics of HLX3902 in patients with mCRPC and other advanced solid tumours.

Study Overview

• Status: Not yet recruiting
• Conditions: mCRPC or Advanced/Metastatic Solid Tumors
• Intervention / Treatment: Drug: HLX3902

• Study Type: Interventional
• Enrollment (Estimated): 48
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Dingwei Ye; Phone Number: 021-64175590-1605; Email: fuscc2012@163.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria

1. Voluntarily signed written informed consent and willing to comply with study procedures.
2. Age: ≥ 18 years, regardless of gender.
3. Histologically confirmed advanced or metastatic solid tumours (e.g., metastatic castration-resistant prostate cancer (mCRPC), non-small cell lung cancer, or gastric cancer) following failure of standard therapy.
4. mCRPC specifics: 1）Progression or refractory status after ≥ 1 novel anti-androgen agent and failure of 1-2 taxane-based regimens.

2）Ongoing surgical or medical castration (gonadotropin-releasing hormone agonist or antagonist) with serum testosterone ≤ 50 ng/dL.

3）Documented disease progression (prostate-specific antigen, nodal, visceral, or bone) .

5. Presence of at least one measurable lesion per RECIST criteria version 1.1. 6. ECOG Performance Status of 0-1. 7. Expected survival exceeding 3 months. 8. Agreement to provide archived or fresh tumour tissue. 9. Adequate organ function. 10. Agreement to use effective contraception for both genders and negative pregnancy test for females of childbearing potential.

Exclusion Criteria

1. Presence of histological types other than adenocarcinoma in mCRPC; or neuroendocrine or small cell differentiation in other solid tumours.
2. Active or symptomatic central nervous system metastases, carcinomatous meningitis, or spinal cord compression (stable treated brain metastases meeting protocol criteria are allowed).
3. Active malignancies within two years prior to the first dose, except cured carcinoma in situ or basal cell carcinoma of the skin.
4. Prior STEAP1-targeted therapy, or Radium-223/PSMA radionuclide therapy within 6 months.
5. Major surgery, radiotherapy, chemotherapy, biological therapy, immunotherapy, or endocrine therapy (excluding LHRH/GnRH analogues) within 28 days; small molecule drugs within 14 days.
6. Vaccination with live vaccines within 28 days.
7. Systemic corticosteroids (> 10 mg/day Prednisone equivalent) or other immunosuppressants within 14 days.
8. Currently participating in another interventional study or within 4 weeks of the end of treatment in such a study.
9. Adverse events from prior therapy not resolved to Grade ≤ 1, except for alopecia, ear toxicity, or stable Grade ≤ 2 taxane-related neurotoxicity.
10. History of Grade ≥ 2 immune-related pneumonitis or myocarditis, or severe/life-threatening immune-mediated adverse events during prior immunotherapy.
11. Poorly controlled cardiovascular disease within 6 months, unstable angina, stroke, thromboembolic events, or uncontrolled hypertension or arrhythmia.
12. Evidence of interstitial lung disease, or active non-infectious pneumonitis.
13. Active or suspected autoimmune disease, hypophysitis, or unstable pituitary dysfunction requiring systemic therapy.
14. Active systemic infectious diseases requiring intravenous antibiotics within 2 weeks, active tuberculosis, or positive for HIV, active HBV (HBV DNA ≥ 500 IU/mL), or HCV.
15. History of organ transplantation, central nervous system diseases within 12 months (e.g., seizures, dementia), or any condition that makes the participant unsuitable per Investigator.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Dose Escalation; This study is an open-label, first-in-human, Phase Ia clinical trial to evaluate the safety, tolerability, PK profiles, and preliminary efficacy of HLX3902 in patients with mCRPC and other advanced solid tumours.	Drug: HLX3902; HLX3902 will be administered as an intravenous (IV) infusion.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Dose-Limiting Toxicity (DLT)	At the end of Cycle 1 (each cycle is 4 weeks)
maximum tolerated dose (MTD)	Up to approximately 2 years

Secondary Outcome Measures

Outcome Measure	Time Frame
Overall survival (OS)	Up to approximately 2 years
Objective response rate (ORR)	Up to approximately 2 years
Progression-free survival (PFS)	Up to approximately 2 years
Duration of response (DOR)	Up to approximately 2 years
Number of participants with adverse events (AEs)	Up to approximately 2 years
Number of participants with serious adverse events (SAEs)	Up to approximately 2 years
disease control rate (DCR)	Up to approximately 2 years
Prostate-specific antigen (PSA) response	Up to approximately 2 years
PK parameters of HLX3902	Up to approximately 2 years
Incidence of anti-drug antibodies (ADAs) and neutralizing antibodies (NAbs) against HLX3902	Up to approximately 2 years
PD biomarkers, including peripheral blood cytokines (e.g., IL-2, IL-6, TNF-α, and IFN-γ) and peripheral T-cell activation and proliferation.	Up to approximately 2 years

Collaborators and Investigators

• Sponsor: Shanghai Henlius Biotech

Study record dates

Study Major Dates

• Study Start (Estimated): May 25, 2026
• Primary Completion (Estimated): June 29, 2027
• Study Completion (Estimated): May 24, 2028

Study Registration Dates

• First Submitted: April 2, 2026
• First Submitted That Met QC Criteria: April 9, 2026
• First Posted (Actual): April 16, 2026

Study Record Updates

• Last Update Posted (Actual): April 16, 2026
• Last Update Submitted That Met QC Criteria: April 9, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: HLX3902-FIH101

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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