A Study of A166 Versus Trastuzumab Emtansine (T-DM1) in Patients With HER2-Positive Unresectable or Metastatic Breast Cancer Previously Treated With Trastuzumab and Taxane Therapy

NCT06968585 | Active Not Recruiting Phase 3 DMC

• 1 other identifier: KL166-III-06
• Study Type: interventional
• Target: 365
• Locations: 1 country
• Sites: 1

Brief Summary

Evaluation of the efficacy of A166 versus trastuzumab emtansine (T-DM1) in Patients with HER2-Positive unresectable or metastatic breast cancer previously treated with trastuzumab and taxane therapy

Conditions

HER2-positive Breast Cancer

Outcome Measures

Primary Outcomes (1)

• Progression-free survival (PFS)

  PFS as assessed by BICR according to RECIST v 1.1

  Randomization up to approximately 39 months

Secondary Outcomes (4)

• Overall survival (OS)

  Randomization up to approximately 48 months

• Objective response rate(ORR)

  Randomization up to approximately 39 months

• Disease control rate(DCR)

  Randomization up to approximately 39 months

• Duration of response(DOR)

  Randomization up to approximately 39 months

Study Arms (2)

A166

EXPERIMENTAL

A166 is administered intravenously at a dose of 4.8 mg/kg every 21 (±3) days (q3w).

Drug: A166

T-DM1

ACTIVE COMPARATOR

T-DM1 is administered intravenously at a dose of 3.6 mg/kg every 21 (±3) days (q3w).

Drug: T-DM1

Interventions

A166 DRUG

intravenous(IV) infusion (Q3W)

A166

T-DM1 DRUG

intravenous(IV) infusion (Q3W)

T-DM1

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Male or female patient ≥ 18 years and ≤ 75 years when signing the informed consent form.
• Breast cancer patients by histopathology and/or cytology documented.
• Disease progression after receiving a trastuzumab-based regimen (or a commercially available trastuzumab biosimilar or inetetamab) in the advanced or metastatic setting, or disease progression/recurrence within 12 months during or after (neo)adjuvant therapy (with a trastuzumab-based regimen or commercially available trastuzumab biosimilar).
• Have previously received taxanes.
• Patients must have experienced disease progression or intolerance during or after the most recent treatment prior to randomization.
• At least one measurable lesion according to RECIST 1.1 criteria

You may not qualify if:

• Previous treatment with A166 or any HER2-targeted antibody-drug conjugate (ADC) with a microtubule inhibitor payload.
• Known history of severe hypersensitivity to other monoclonal antibodies, or allergy to A166 , T-DM1 (trastuzumab emtansine) or their components.
• Permanent discontinuation of trastuzumab or its biosimilars due to any toxicity in prior treatments.
• Presence of severe corneal epithelial disease at baseline; or inability to perform daily activities without contact lenses.
• Presence of spinal cord compression or clinically active central nervous system (CNS) metastases.
• Other conditions considered by the investigator to make the patient unsuitable for participation in the study

Sponsors & Collaborators

• Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd.: lead

Study Sites (1)

Fudan University Shanghai Cancer Center

Shanghai, Shanghai Municipality, 200032, China

Location

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 26, 2025
• First Posted: May 13, 2025
• Study Start: July 18, 2023
• Primary Completion: November 30, 2025
• Study Completion (Estimated): March 31, 2028
• Last Updated: May 13, 2025

Record last verified: 2025-04

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)