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AzTrials

Breast CancerPhase 1NCT06959537

A Phase Ib Study of Novel Combination (New) of Low Dose Oral CyclophoSphamide (s) to Potentiate Axatilimab (A) + Retifanlimab (R) in Treating Metastatic Triple Negative Breast Cancer (TNBC)

A Phase 1 study testing Cyclophosphamide, Axatilimab (SNDX-6352) and Retifanlimab in people with Breast Cancer, run by M.D. Anderson Cancer Center at 1 site in United States.

Suspended

Paused. Enrolment is on hold for now and may resume.

Official record
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Trial summary

The goal of this clinical research study is to find the best dose of the drugs cyclophosphamide and axatilimab that can be given in combination with the standard dose of retifanlimab to patients with metastatic TNBC. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Breast Cancer
What is being tested?
Cyclophosphamide, Axatilimab (SNDX-6352) and Retifanlimab
Could I receive a placebo?
No, everyone receives an active treatment
How many people
24 participants
Where
1 siteUnited States
Study dates
13 Aug 2025to 31 Jan 2029
Phase
Phase 1
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Patients must have histologically confirmed malignancy that is metastatic or locally recurrent unresectable and for which standard curative or palliative measures do not exist or are no longer effective.
  • Patients must have histologically or cytologically confirmed non-IBC triple negative breast cancers, defined here as ER<1%, PR<1% and HER2 negative per ASCO CAP 2018 guideline. OR
  • Inflammatory breast cancer (IBC) confirmed according to international consensus criteria that is ER<20% and PR<20%.
  • At least 1 week since prior chemotherapy or radiation therapy
  • Age .18 years.
  • Has at least one measurable lesion per RECIST 1.1
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  • ECOG performance status . 2 (Karnofsky . 60%,).
  • Patients must have adequate organ and marrow function as defined below:
  • absolute neutrophil count . 1,000/mcL
  • hemoglobin >9 mg/dL
  • platelets . 100,000/mcL
  • total bilirubin . institutional upper limit of normal (ULN)
  • AST(SGOT)/ALT(SGPT) . 3 ~ institutional ULN; . 5 ~ institutional ULN if confirmed liver metastasis and elevation is deemed to be directly due to metastasis.
  • Creatinine clearance .30 mL/min (measured by the Cockcroft-Gault equation*).
  • Ability to understand and the willingness to sign a written informed consent
  • . Cognitively impaired subjects will not be enrolled in this study.
  • Negative serum pregnancy test within 72 hours of receiving the first dose of the study medication for women of childbearing potential as per institutional guidelines.
  • Subjects of childbearing potential must be willing to use highly effective birth control methods or be surgically sterile or abstain from heterosexual activity for the course of the study. Women must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. This includes all female patients, between the onset of menses (as early as 8 years of age) and 55 years unless the patient presents with an applicable exclusionary factor which may be one of the following:
  • Postmenopausal (no menses in greater than or equal to 12 consecutive months).
  • History of hysterectomy or bilateral salpingo-oophorectomy.
  • Ovarian failure (Follicle Stimulating Hormone and Estradiol in menopausal range, who have received Whole Pelvic Radiation Therapy).
  • History of bilateral tubal ligation or another surgical sterilization procedure.
  • Approved methods of birth control are as follows: Hormonal contraception (i.e., birth control pills, injection, implant, transdermal patch, vaginal ring), Intrauterine device (IUD), Tubal Ligation or hysterectomy, Subject/Partner post vasectomy, Implantable or injectable contraceptives, and condoms plus spermicide. Not engaging in sexual activity for the total duration of the trial and the drug washout period is an acceptable practice; however periodic abstinence, the rhythm method, and the withdrawal method are not acceptable methods of birth control.
  • Men treated or enrolled on this protocol must also agree to use adequate contraception prior to the study, for the duration of study participation, and 4 months after completion of all study drug administration.

Who cannot join

  • Patients who have not recovered from adverse events due to prior anti-cancer therapy (i.e., have residual toxicities > Grade 1) except for alopecia. Note: Subjects may be enrolled with chronic, stable Grade 2 toxicities (defined as no worsening to > Grade 2 for at least 3 months prior to [enrollment/Cycle 1 Day 1] and managed with standard of care treatment) that the investigator deems related to previous anticancer therapy, including: Chemotherapyinduced neuropathy, Fatigue, Residual toxicities from prior IO treatment: Grade 1 or Grade 2 endocrinopathies which may include: Hypothyroidism/hyperthyroidism, Type I diabetes, Hyperglycemia, Adrenal insufficiency, Adrenalitis and Skin hypopigmentation (vitiligo)
  • Patients with a history of interstitial lung disease (past or current) or active, non-infectious pneumonitis.
  • Patients with active autoimmune disease requiring systemic immunosuppression with corticosteroids (> 10 mg/day of prednisone or equivalent) or immunosuppressive drugs within 2 years before the first dose of study treatment.
  • History of allergic reactions attributed to compounds of similar chemical or biologic composition to cyclophosphamide, axatilimab, retifanlimab used in study.
  • Patients with uncontrolled intercurrent illness. Medical history or complication considered inappropriate for participation in the study, or a serious physical or psychiatric disease, the risk of which may be increased by participation in the study in the investigator's opinion.
  • Patients with active infections requiring systemic antibiotics or antifungal or antiviral treatment within 14 days of C1D1 study treatment.
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  • Patients with known active Hepatitis B or Hepatitis C infection. Testing is required to establish eligibility. Active Hepatitis B infection is defined as a positive Hepatitis B surface antigen and positive Hepatitis B core antibody test. Active Hepatitis C infection is defined assay.
  • For patients with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral load must be undetectable on suppressive therapy, if indicated.
  • Patients with a history of hepatitis C virus (HCV) infection must have been treated and cured.
  • For patients with HCV infection who are currently on treatment, they are eligible if they have an undetectable HCV viral load.
  • Patients with known HIV infection, defined as positive for HIV1/2 antibodies. Human immunodeficiency virus (HIV)-infected patients on effective anti-retroviral therapy with undetectable viral load within 6 months are eligible for this trial.
  • Patients with psychiatric illness/social situations that would limit compliance with study requirements.
  • Pregnant women are excluded from this study due to potential for teratogenic or abortifacient effects.
  • Patients who are cancer survivors other than cured non-melanomatous skin cancer or cured cervical carcinoma in situ and thyroid cancer will be excluded from the study as other cancers can recur.
  • Patients with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial.
  • Patients with active brain metastasis if treatment is warranted. Patients with treated brain metastases are eligible if follow-up brain imaging after central nervous system (CNS)- directed therapy shows no evidence of progression.
  • Patients with known leptomeningeal disease, defined as unequivocal imaging or cytologyproven disease.
  • Patients with known history or current symptoms of cardiac disease, or history of treatment with cardiotoxic agents, should have a clinical risk assessment of cardiac function using the New York Heart Association Functional Classification. To be eligible for this trial, patients should be class 2B or better, and EF greater than 45% despite best supportive cae.
  • Patients with a history or presence of screening ECG test that is clinically significantly abnormal in the investigator's opinion. Patients with a prolonged Qtc interval > 480 milliseconds (corrected by Fridericia or Bazett formula are excluded, but medically controlled arrhythmias are allowed.
  • Patients with a history of significant cardiac event within 6 months of C1D1. Significant cardiac events include baseline NYHA class III/IV cardiac disease, acute myocardial infarction, severe/unstable angina, cardiomyopathy, coronary/peripheral artery bypass graft, symptomatic congestive heart failure, critical conduction delay, transient ischemic attack or pulmonary embolism.
  • Patients who are receiving any other investigational agents.

Trial locations and contacts

1 site in 1 country.

United States1 site

  • The University of Texas M. D. Anderson Cancer Center

    Houston, Texas, 77030

Other trials in United States

About this study

The goal of this clinical research study is to find the best dose of the drugs cyclophosphamide and axatilimab that can be given in combination with the standard dose of retifanlimab to patients with metastatic TNBC.

Read the detailed description

Primary Objective:

The goal of this clinical research study is to find the best dose of the drugs cyclophosphamide and axatilimab that can be given in combination with the standard dose of retifanlimab to patients with metastatic TNBC.

Secondary Objectives:

The goal of this clinical research study is to find the best dose of the drugs cyclophosphamide and axatilimab that can be given in combination with the standard dose of retifanlimab to patients with metastatic TNBC.

Conditions
Breast Cancer
Being tested
Cyclophosphamide, Axatilimab (SNDX-6352), Retifanlimab
Medical subject headings
Breast Neoplasms

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • CyclophosphamideDrug

    Given by mouth

  • Axatilimab (SNDX-6352)Drug

    Given by IV

  • RetifanlimabDrug

    Given by IV

Study groups in NCT06959537
Study groupRoleWhat they receive
Treatment with Cyclophosphamide + Axatilimab + RetifanlimabExperimentalParticipants will be requestd to maintain a medication diary of each dose of medication while taking oral cyclophosphamide. The medication diary will be returned to clinic staff at the end of each course.
Receives: Drug: Cyclophosphamide; Drug: Axatilimab (SNDX-6352); Drug: Retifanlimab

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Safety and Adverse Events (AEs)

    Incidence of Adverse Events, Graded According to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) Version (v) 5.0

    Measured: Through study completion; an average of 1 year

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted6 May 2025
  2. Study start13 Aug 2025
  3. Primary completion31 Jan 2027 (estimated)
  4. Study completion31 Jan 2029 (estimated)

Why it stopped: PI Request

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 1
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
24 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06959537
Sponsor's protocol ID
2025-0016
Other IDs
NCI-2025-03170
Status last verified
Sep 2026
First submitted
28 Apr 2025
Last updated
5 Oct 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No

Questions about this trial

What is this clinical trial studying?

A Phase 1 study testing Cyclophosphamide, Axatilimab (SNDX-6352) and Retifanlimab in people with Breast Cancer, run by M.D. Anderson Cancer Center at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 24 inclusion and 21 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: paused, as of the sponsor's last update on 5 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Results are not available in the source record.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Safety and Adverse Events (AEs) (time frame: Through study completion; an average of 1 year). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06959537.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Oct 2026.

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