A Study of HLD-0117 in Patients With Metastatic Breast Cancer (HLD-0117)

May 29, 2026 updated by: Halda Therapeutics OpCo, Inc.

A Phase 1 Study of HLD-0117 in Patients With Estrogen Receptor Positive (ER+) Metastatic Breast Cancer (MBC)

Assessment of the safety and efficacy of HLD-0117 as monotherapy in patients with estrogen receptor positive (ER+) metastatic breast cancer (MBC) or locally advanced breast cancer that have progressed on prior systemic therapies.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This study is an open-label, dose-escalation and cohort expansion study evaluating the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and anti-tumor activity of oral single-agent, HLD-0117 in patients with ER+ MBC that have progressed after at least 1 prior systemic line of therapy.

During dose escalation, patients will be enrolled into monotherapy cohorts using a Bayesian optimal interval (BOIN) design. Cohorts will enroll a minimum of three patients, with staggered enrollment between cohorts. Backfilling into dose levels determined to be safe may occur to further characterize tolerability and efficacy.

The purpose of the study is to determine the maximum tolerated dose (MTD) and/or recommended dose(s) for expansion (RDEs) of HLD-0117 as a monotherapy.

Study Type

Interventional

Enrollment (Estimated)

33

Phase

  • 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

  • United States
    • Connecticut
      • New Haven, Connecticut, United States, 06510
        • Recruiting
        • Yale- New Haven Hospital- Yale Cancer Center
    • Florida
      • Sarasota, Florida, United States, 34231
        • Recruiting
        • Florida Cancer Specialists
    • Tennessee
      • Nashville, Tennessee, United States, 37203
        • Recruiting
        • SCRI Oncology Partners
    • Virginia
      • Fairfax, Virginia, United States, 22031
        • Recruiting
        • NEXT Oncology

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:

  • Female (assigned at birth), ≥18 years old, and able to provide informed consent
  • Histologically confirmed metastatic or locally advanced breast cancer
  • Postmenopausal status defined by surgical or natural menopause, or ovarian suppression with a GnRH agonist
  • Prior treatment including at least one endocrine therapy in the metastatic setting, at least one CDK4/6 inhibitor (in the adjuvant and/or metastatic setting), and no more than two prior cytotoxic regimens in the metastatic setting
  • Radiologic disease progression on the most recent therapy
  • Measurable disease per RECIST v1.1
  • Willingness to provide baseline and on-treatment tumor biopsies, unless not feasible or medically appropriate
  • ER-positive and HER2-negative status documented within 2 years
  • ECOG performance status 0-1 and life expectancy of at least 3 months
  • Adequate organ function Recovery from prior therapy-related toxicities to Grade ≤1 (except alopecia; neuropathy and endocrinopathies ≤Grade 2)
  • Ability to swallow oral medication and comply with study procedures
  • Stable dose (≥30 days) of bisphosphonates or denosumab, if applicable

Exclusion Criteria:

  • Inflammatory breast cancer or known brain metastases
  • Recent major bleeding or uncontrolled bleeding disorder
  • Ongoing corticosteroid use >10 mg/day (prednisone equivalent)
  • Recent anticancer or investigational therapy within 14 days (28 days for fulvestrant)
  • Untreated or unstable spinal cord compression
  • Significant cardiovascular disease within 6 months or ongoing uncontrolled cardiac conditions
  • Active or uncontrolled infection (controlled HIV or treated hepatitis C allowed)
  • Uncontrolled renal, pancreatic, or liver disease (excluding stable conditions such as Gilbert's syndrome or liver metastases)
  • Another malignancy requiring treatment within 2 years (except low-risk, curatively treated cancers)
  • Major surgery within 28 days
  • Any condition that may interfere with safety or study compliance
  • 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: N/A
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Arm 1
Oral HLD-0117 administered as a single agent on a 28-day treatment cycle.
Drug: HLD-0117
A treatment cycle consists of 28 days. Treatment may continue until disease progression or study discontinuation (withdrawal of consent, intercurrent illness, unacceptable adverse event or any other changes unacceptable for further treatment, etc.)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Dose Limiting Toxicities (DLTs)
Time Frame: 28 days
Frequency of dose-limiting toxicities (DLTs)
28 days
AEs, ECGs, Labs and Clinical Changes
Time Frame: 28 days
Frequency and severity of adverse events (AEs) and abnormal electrocardiogram (ECG), laboratory and clinical changes from baseline
28 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Objective response rate (ORR)
Time Frame: 56 Days
Objective response rate (ORR) per RECIST in evaluable patients
56 Days
Duration of response (DOR)
Time Frame: 28 days
Duration of response (DOR)
28 days
Progression-free survival (rPFS)
Time Frame: 56 days
Radiographic progression-free survival (rPFS)
56 days
Disease Control Rate (DCR)
Time Frame: 24 weeks
Disease Control Rate (DCR)
24 weeks

Collaborators and Investigators

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

Sponsor

Halda Therapeutics OpCo, Inc.

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 (Actual)

April 9, 2026

Primary Completion (Estimated)

April 30, 2028

Study Completion (Estimated)

April 30, 2028

Study Registration Dates

First Submitted

April 6, 2026

First Submitted That Met QC Criteria

April 6, 2026

First Posted (Actual)

April 13, 2026

Study Record Updates

Last Update Posted (Actual)

June 2, 2026

Last Update Submitted That Met QC Criteria

May 29, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HLD-0117-ONC-101

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

Yes

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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