A Study to Evaluate HLX22 in Combination With HLX87 in Patients With HER2-Positive Recurrent or Metastatic Breast Cancer

An Open-Label, Randomized, Multicenter, Phase II/III Clinical Study to Evaluate HLX22 (Recombinant Humanized Anti-HER2 Monoclonal Antibody Injection) in Combination With HLX87 (HER2 ADC) as First-Line Treatment in Patients With HER2-Positive Recurrent or Metastatic Breast Cancer

The study is being conducted to evaluate the clinical efficacy of HLX22 in combination with HLX87 as first-line treatment in patients with HER2-positive recurrent or metastatic breast cancer

Study Overview

• Status: Recruiting
• Conditions: HER2 + Breast Cancer
• Intervention / Treatment: Drug: HLX87 + HLX22; Drug: HLX87 + Pertuzumab; Drug: T-Dxd + Pertuzumab; Drug: THP

Detailed Description

The study consists of two stages Stage I is an open-label, multicenter, randomized, parallel-controlled phase II clinical study, and its primary objective is to evaluate the clinical efficacy of HLX22 in combination with HLX87 as first-line treatment in patients with HER2-positive recurrent or metastatic breast cancer based on ORR and PFS results.

Stage II is an open-label, multicenter, randomized, parallel-controlled phase III clinical study, and its primary objective is to evaluate the clinical efficacy of HLX22 in combination with HLX87 as first-line treatment in patients with HER2-positive recurrent or metastatic breast cancer based on PFS results.

• Study Type: Interventional
• Enrollment (Estimated): 706
• Phase: Phase 2; Phase 3

Contacts and Locations

• Study Contact: Name: Maoqing Fu, Dr; Phone Number: 021-33395800; Email: Maoqing_fu@henlius.com
• Study Contact Backup: Name: Ma; Phone Number: 01067781331; Email: Mafei@163.com

Study Locations

• China
  • Beijing Municipality
    • Beijing, Beijing Municipality, China, 100021
      • Recruiting
      • Cancer hospital, Chinese Academy of Medical Sciences
      • Contact: Fei Ma, Dr; Phone Number: 86-010-87788888; Email: Feima2011@169.com

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• 1. Have a full understanding of the study content, and sign the informed consent form (ICF); 2. Aged ≥ 18 years at the time of signing the ICF, male or female; 3. Histopathologically confirmed breast cancer that meets the following criteria:

  1. Advanced or metastatic breast cancer.
  2. HER2-positive as determined by the central laboratory, defined as IHC 3+, or IHC 2+ and ISH+.
  3. Positive or negative for hormone receptor HR (including estrogen receptor [ER] and progesterone receptor [PgR]) as determined by the central laboratory 4. No prior chemotherapy or HER2-targeted therapy for advanced or metastatic breast cancer (1 line of endocrine therapy is allowed).

  5. At least one measurable lesion as assessed by central imaging according to RECIST v1.1.

  7. Eastern Cooperative Oncology Group performance status score within 7 days prior to the first dose of study drugs: 0-1.

  8. Life expectancy ≥ 12 weeks. 9. Adequate organ functions

Exclusion Criteria:

• 1. History of a second malignancy within 3 years prior to signing the ICF. 2. Previous use of doxorubicin with a concentration of > 360 mg/m2 (or equivalent).

  3. Prior treatment with ADCs including exatecan derivatives that contain topoisomerase I inhibitors.

  4. Uncontrolled or significant cardiovascular diseases 5. Cerebrovascular accidents within 6 months prior to the first dose of study drugs.

  6. ILD/pneumonitis, or suspected ILD/pneumonitis or clinically significant lung-specific intercurrent illness .

  7. Active infection . 8. Presence of spinal cord compression or clinically symptomatic central nervous system metastases.

  9. Residual toxicity from previous anti-tumor therapy that has not resolved to Grade ≤ 1 as per NCI-CTCAE V6.0 or baseline level (except for alopecia).

  10. Presence of active tuberculosis. 11. Have received treatment with live attenuated vaccines within 30 days prior to the first dose of study drugs.

  12. Known history of severe allergic reaction to macromolecular protein preparations, hypersensitivity to the ingredient of the investigational products, or severe hypersensitivity to any excipient of the study drugs.

  13. Known history of abuse of psychotropic drugs or drug addiction. 14. Pregnant or lactating women.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: HLX87+ HLX22; Patients will receive the treatment once every 3 weeks (Q3W) until progressive disease (PD) , initiation of new anti-tumor therapy, death, intolerable toxicity, withdrawal of informed consent, or end of the study (whichever occurs first).	Drug: HLX87 + HLX22; HLX87 is a novel HER2-targeted ADC with a similar mechanism of action to trastuzumab deruxtecan. HLX22 is a novel monoclonal antibody targeting HER2 .
Experimental: HLX87+ Pertuzumab; atients will receive the treatment once every 3 weeks (Q3W) until progressive disease (PD) , initiation of new anti-tumor therapy, death, intolerable toxicity, withdrawal of informed consent, or end of the study (whichever occurs first).	Drug: HLX87 + Pertuzumab; HLX87 is a novel HER2-targeted ADC with a similar mechanism of action to trastuzumab deruxtecan
Active Comparator: T-Dxd + Pertuzumab; Patients will receive the treatment once every 3 weeks (Q3W) until progressive disease (PD) , initiation of new anti-tumor therapy, death, intolerable toxicity, withdrawal of informed consent, or end of the study (whichever occurs first).	Drug: T-Dxd + Pertuzumab; T-Dxd is a HER2-targeted ADC
Active Comparator: THP; Patients will receive the treatment once every 3 weeks (Q3W) until progressive disease (PD) , initiation of new anti-tumor therapy, death, intolerable toxicity, withdrawal of informed consent, or end of the study (whichever occurs first).	Drug: THP; Pertuzumab+ Trastuzumab+Docetaxel

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Objective response rate (ORR) (assessed by the blinded independent central review [BICR] as per RECIST v1.1)	up to 26 months
Progression-free survival (PFS) (assessed by BICR as per RECIST v1.1)	up to 37 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
● ORR (assessed by the investigator as per RECIST v1.1)		up to 26 months
● PFS (assessed by the investigator as per RECIST v1.1)		up to 37 months
Second progression-free survival (PFS2)		up to 37 months
Overall survival (OS)		up to 37 months
Incidence and severity of adverse events (AEs)	severity determined according to National Cancer Institute Common Terminology Criteria for Adverse Events [NCI CTCAE] Version 6.0	up to 37 months

Collaborators and Investigators

• Sponsor: Shanghai Henlius Biotech
• Investigators: Principal Investigator: Fei Ma, Dr, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China

Study record dates

Study Major Dates

• Study Start (Actual): February 27, 2026
• Primary Completion (Estimated): January 15, 2028
• Study Completion (Estimated): December 30, 2030

Study Registration Dates

• First Submitted: December 8, 2025
• First Submitted That Met QC Criteria: December 8, 2025
• First Posted (Actual): December 19, 2025

Study Record Updates

• Last Update Posted (Actual): March 20, 2026
• Last Update Submitted That Met QC Criteria: March 17, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Breast Neoplasms; pertuzumab
• Other Study ID Numbers: HLX87-BC001

Drug and device information, study documents

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