Leflunomide in Previously Treated Metastatic Triple Negative Cancers

March 17, 2026 updated by: Joseph Sparano

A Phase I/II Trial of Leflunomide in Women With Previously Treated Metastatic Triple Negative Cancers

Triple negative breast cancer (TNBC) represents about 15% of breast cancers and is characterized by the lack of expression of estrogen receptor (ER), progesterone receptor (PR), and HER-2 non-amplification. Women with TNBC tend to be younger, African American, and BRCA-1 germline carriers. The hallmark of this subtype is early metastatic recurrences with a peak frequency 1-2 years. Prognosis for metastatic TNBC is especially poor with median survival of about 1 year as compared to about 2-4 years with other types of metastatic breast cancer.

The primary objective of the phase I part of this study is to determine the safety, tolerability and maximum tolerated dose of leflunomide in women with previously treated TNBC (or ER+ , HER2-neg MBC in Phase I). The primary objective of the phase 2 part of this study is to determine the efficacy of leflunomide in patients with TNBC.

Leflunomide, which will be taken daily by mouth, is an inhibitor of dihydroorotate dehydrogenase (DHODH). This proposal will test if DHODH is a novel target for a particular subset of women with metastatic TNBC.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
17

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • New York
      • New York, New York, United States, 10029
        • Icahn School of Medicine at Mount Sinai
      • New York, New York, United States, 10011
        • Mt Sinai Chelesa
      • New York, New York, United States, 10019
        • Mt Sinai West

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Women with histologically confirmed HER2-negative metastatic and/or locally advanced, inoperable breast cancer on a prior biopsy performed as a component of standard of care. The biopsy site may include the primary tumor, regional lymph node, or metastatic site if accessible to biopsy.
  • Age ≥ 18.
  • Prior treatment for metastatic breast cancer:
  • ≤ 3 prior chemotherapies for metastatic disease and up to 2 prior antibody drug conjugate regimens (eg, sacitizumab govitecan, trastuzumab deruxtecan). Patients with ER-positive breast cancer (ER>10%) must have had progressive disease after at least 1 prior line of CKD4/6 inhibitor, and also a PIK3CA inhibitor if known to have a somatic PIK3CA activating mutation (by tumor or ctDNA assay) sensitive to the PIK3CA inhibitor alpelisib.
  • Prior immunotherapy is permitted and does not count as chemotherapy.
  • The use denosumab or zoledronic is permitted.
  • History of previously treated brain metastases with ≥ 4 weeks after definitive surgery and gamma knife/whole brain radiation and not taking steroids.
  • ≥ 4 weeks from last oral or IV chemotherapy, small molecule inhibitor, a biologic agent, surgery or radiation.
  • Performance status 0-2.

  • Adequate organ and marrow function as defined below:

    • leukocytes ≥ 3,000/mcL
    • Absolute neutrophil count ≥ 1,000/mcL
    • platelets ≥ 100,000/mcl
    • total bilirubin within institutional upper limit of normal. (≤ ULN)
    • AST (SGOT)/ALT (SPGT) ≤ 3 x ULN (3xULN if liver mets)
    • Creatinine ≤ ULN
    • A negative serum or urine pregnancy test within 3 days of receiving Day 1 Cycle 1 of leflunomide.
  • Women of child-bearing potential and men must agree to use adequate contraception before study entry, for the duration of study participation and for 90 days following completion of therapy. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately.
  • Recommended methods of birth control are: The consistent use of an approved hormonal contraception such as an intrauterine device (IUD), Double barrier methods (Diaphragm with spermicidal gel or condoms with contraceptive foam), Sexual abstinence (no sexual intercourse) or Sterilization. The use of hormonal forms of birth control is controversial in TNBC and as such women enrolled in the trial are permitted to use birth control pills or depot Provera, only after a documented discussion by the treating physician as too the uncertain risks of hormonal birth control methods in the TNBC population. A female of child-bearing potential is any woman (regardless of sexual orientation, having undergone a tubal ligation, or remaining celibate by choice) who meets the following criteria: Has not undergone a hysterectomy or bilateral oophorectomy; or Has not been naturally postmenopausal for at least 12 consecutive months (i.e., has had menses at any time in the preceding 12 months).
  • Ability to understand and the willingness to sign a written informed consent.

Exclusion Criteria:

  • Patients who have had chemotherapy or radiotherapy within ≥ 2 weeks before entering the study or those who have not recovered from adverse events due to agents administered more than ≥ 4 weeks earlier.
  • Patients may not be receiving any other investigational agents.
  • The known history human immunodeficiency virus, acute and chronic Hepatitis B or C, or acute or previously treated tuberculosis.
  • Patients with untreated brain metastases should be excluded from this clinical trial because of their poor prognosis and because they often develop progressive neurologic dysfunction that would confound the evaluation of neurologic and other adverse events.
  • History of allergic reactions attributed to compounds of similar chemical or biologic composition to leflunomide or teriflunomide.
  • Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.
  • Patients must not be pregnant or nursing due to the potential for congenital abnormalities and the potential of this regimen to harm nursing infants.

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: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Leflunomide

Women with HER2-negative metastatic and/or locally advanced, inoperable breast cancer.

Leflunomide tablet orally daily
Drug: Leflunomide
Single agent leflunomide
Other Names:
  • Arava

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Clinical Benefit Rate (CBR)
Time Frame: 6 months
Response and progression to be evaluated using the Response Evaluation Criteria in Solid Tumors (RECIST). CBR = Complete Response (CR) + Partial Response (PR) + Stable Disease (SD) for at least 6 months duration
6 months
Maximum Tolerated Dose (MTD)
Time Frame: 3 months
3+3 escalation schema. Patients will be enrolled in escalating cohorts of 3 patients per dose level until Dose-limiting Toxicity (DLT) (defined as any grade 3 or higher toxicity seen during the first 3-week cycle of leflunomide). If 0 of 3 patients are observed to have a DLT, the next 3 patients will be enrolled in the next higher dose level cohort. If 2/3 patients experience a DLT, escalation will stop and the previous dose will be defined as the MTD. If 1/3 experiences a DLT, three additional patients will be enrolled at the same dose level. If ≤ 2/6 patients experience a DLT, the next cohort of three patients will be treated at the next dose level. If ≥ 3/6 experience a DLT, the next lower dose level will define the MTD. If at the 50 mg dose/day if 0/3 or ≤ 2/6 patients experience a DLT, then that dose will define the MTD
3 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Number of side effects
Time Frame: 6 years
Number of side effects associated with oral leflunomide using NCI CTCAE v.4.03
6 years
Objective Response Rate
Time Frame: 6 years
Objective Response Rate (proportion of patients with the best overall response of CR or PR) in those who have measurable disease by RECIST
6 years
Progression-free survival (PFS)
Time Frame: 6 years
PFS of women with phosphatase and tensin homolog (PTEN) wild-type and PTEN null expression breast cancers. PFS is defined as the duration of time from the start of treatment to the first occurrence of disease progression or death from any cause, whichever occurs first.
6 years

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Joseph Sparano

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Joseph Sparano, MD, Icahn School of Medicine at Mount Sinai

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
April 16, 2019

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 27, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 27, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 14, 2018

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 14, 2018

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 17, 2018

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 19, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 17, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • GCO 18-1832

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

product manufactured in and exported from the U.S.

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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