JSKN016 in Combination With D-0502 for Locally Advanced or Metastatic HR-Positive, HER2-Negative Breast Cancer

January 4, 2026 updated by: Jiangsu Alphamab Biopharmaceuticals Co., Ltd

A Multicenter, Open-Label, Phase Ib/II Randomized Study of JSKN016 in Combination With D-0502 in Patients With Locally Advanced or Metastatic Hormone Receptor-Positive, HER2-Negative Breast Cancer

This is a multicenter, open-label, Phase Ib/II randomized study designed to evaluate the safety, tolerability, dose-limiting toxicities (DLTs), and preliminary antitumor activity of JSKN016 in combination with the oral selective estrogen receptor degrader (SERD) D-0502 in patients with locally advanced or metastatic hormone receptor-positive (HR+), HER2-negative breast cancer who have previously progressed on CDK4/6 inhibitor-based endocrine therapy.

Approximately 60 patients will be randomized in a 1:1 ratio to receive JSKN016 administered intravenously every 2 weeks (Q2W) or every 3 weeks (Q3W), in combination with daily oral D-0502. Each dosing cohort will include a safety lead-in phase to assess DLTs prior to cohort expansion. Tumor response will be assessed according to RECIST v1.1.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

60

Phase

  • Phase 2
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • China
      • Shanghai, China
        • Fudan University Shanghai Cancer Center
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age ≥18 years
  • Histologically or cytologically confirmed locally advanced or metastatic HR-positive, HER2-negative breast cancer
  • HR-positive defined as ER and/or PR ≥1% by IHC
  • HER2-negative per ASCO/CAP guidelines
  • At least one measurable extracranial lesion per RECIST v1.1
  • ECOG performance status 0-1
  • Prior progression on CDK4/6 inhibitor plus endocrine therapy
  • Adequate organ and cardiac function
  • Postmenopausal women, or premenopausal women receiving ovarian function suppression

Exclusion Criteria:

  • Active or untreated CNS metastases
  • Prior treatment with ADCs containing topoisomerase I inhibitor payloads
  • Active interstitial lung disease or pneumonitis
  • Uncontrolled cardiovascular disease or active infection
  • Prior malignancy within 5 years (with specific exceptions)
  • Pregnancy or breastfeeding

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: JSKN016 Q2W + D-0502
Drug: JSKN016 Q2W
4 mg/kg, intravenous infusion, every 2 weeks
Drug: D-0502
200 mg, oral, once daily
Experimental: JSKN016 Q3W + D-0502
Drug: D-0502
200 mg, oral, once daily
Drug: JSKN016 Q3W
4 mg/kg, intravenous infusion, every 3 weeks

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Incidence of dose-limiting toxicities (DLTs)
Time Frame: From first dose through the end of Cycle 1 (approximately 21 days)
From first dose through the end of Cycle 1 (approximately 21 days)
Objective Response Rate (ORR)
Time Frame: From first dose through treatment discontinuation, assessed up to 12 months
From first dose through treatment discontinuation, assessed up to 12 months
Safety and tolerability (TEAEs, TRAEs, SAEs)
Time Frame: From first dose until 30 days after the last dose of study treatment.
From first dose until 30 days after the last dose of study treatment.

Secondary Outcome Measures

Outcome Measure
Time Frame
Disease Control Rate (DCR)
Time Frame: From first dose through 24 weeks
From first dose through 24 weeks
Duration of Response (DoR)
Time Frame: From first documented objective response (CR or PR) until disease progression or death, whichever occurs first, assessed up to 24 months
From first documented objective response (CR or PR) until disease progression or death, whichever occurs first, assessed up to 24 months
Clinical Benefit Rate (CBR)
Time Frame: From first dose through 24 weeks
From first dose through 24 weeks
Progression-Free Survival (PFS)
Time Frame: From first dose until the first documented disease progression or death from any cause, whichever occurs first, assessed up to 24 months
From first dose until the first documented disease progression or death from any cause, whichever occurs first, assessed up to 24 months
Overall Survival (OS)
Time Frame: From first dose until death from any cause, assessed up to 36 months
From first dose until death from any cause, assessed up to 36 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Jiangsu Alphamab Biopharmaceuticals Co., Ltd

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

January 1, 2026

Primary Completion (Estimated)

December 1, 2027

Study Completion (Estimated)

June 1, 2028

Study Registration Dates

First Submitted

December 23, 2025

First Submitted That Met QC Criteria

January 4, 2026

First Posted (Actual)

January 13, 2026

Study Record Updates

Last Update Posted (Actual)

January 13, 2026

Last Update Submitted That Met QC Criteria

January 4, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • JSKN016-204

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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