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Pembrolizumab and Enobosarm in Treating Patients With Androgen Receptor Positive Metastatic Triple Negative Breast Cancer

A Phase 2 Clinical Trial of the Combination of Pembrolizumab and Selective Androgen Receptor Modulator (SARM) GTX-024 in Patients With Metastatic Androgen Receptor (AR) Positive Triple Negative Breast Cancer (TNBC)

Status
Completed
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT02971761
Enrollment
18
Registered
2016-11-23
Start date
2017-06-01
Completion date
2022-08-16
Last updated
2024-02-20

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Androgen Receptor Positive, Estrogen Receptor Negative, HER2/Neu Negative, Metastatic Triple-Negative Breast Carcinoma, Progesterone Receptor Negative, Stage IV Breast Cancer AJCC v6 and v7

Brief summary

This phase II trial studies the side effects and how well pembrolizumab and enobosarm work in treating patients with androgen receptor positive triple negative breast cancer that has spread to other places in the body (metastatic). Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Androgen can cause the growth of breast cancer cells. Hormone therapy using enobosarm may fight breast cancer by blocking the use of androgen by the tumor cells. Giving pembrolizumab and enobosarm may work better than pembrolizumab alone in treating patients with androgen receptor positive triple negative breast cancer.

Detailed description

PRIMARY OBJECTIVES: I. To evaluate the safety/tolerability of the combination regimen. II. To determine the response rate (complete response \[CR\] or partial response \[PR\] via Response Evaluation Criteria in Solid Tumors \[RECIST\] 1.1) of the combination of pembrolizumab with enobosarm (GTx-024) in patients with advanced androgen receptor (AR) positive (+) triple negative breast cancer (TNBC). SECONDARY OBJECTIVES: I. To evaluate clinical outcomes by RECIST 1.1 including clinical benefit rate (CBR) at 24 weeks, progression free-survival (PFS), duration of response (DOR), event free survival (EFS), time-to-treatment failure (TTF); and overall survival (OS). II. To evaluate the role of immune-related response criteria (irRECIST). III. To evaluate the association of AR by immunohistochemistry (IHC) and clinical response. EXPLORATORY OBJECTIVES: I. To evaluate the association of an AR gene expression signature and clinical response. II. To evaluate genomic and phenotypic status of breast tumor. III. To evaluate the effect of the combination therapy on peripheral blood circulating tumor cells (CTCs) and circulating tumor deoxyribonucleic acid (DNA) (ctDNA). IV. To evaluate the effect of combination therapy on tumor-derived exosomes (TEX) and TEX associated immune biomarkers. V. Immune correlatives: Va. To evaluate pre-treatment programmed death ligand 1 (PD-L1) and tumor infiltrating lymphocytes (TILs) as a predictor of response to combination therapy. Vb. To evaluate specific TIL subsets (e.g. CD4, CD8, regulatory T cell \[Treg\] distribution) and other immunological correlatives (e.g. T cell receptor \[TCR\] repertoire analysis) as possible predictors of response. Vc. To evaluate change in TILs as a result of the combination therapy. Vd. To evaluate peripheral blood, immune biomarkers. OUTLINE: Patients receive pembrolizumab intravenously (IV) over 30 minutes on day 1 and enobosarm orally (PO) once daily (QD) on days 1-21. Treatment repeats every 21 days for up to 35 cycles in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up at 30 and 90 days, every 3 months, and bi-annually.

Interventions

Given PO

OTHERLaboratory Biomarker Analysis

Correlative studies

BIOLOGICALPembrolizumab

Given IV

Sponsors

National Cancer Institute (NCI)
CollaboratorNIH
City of Hope Medical Center
Lead SponsorOTHER

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* Documented informed consent * Willing to provide a sample from a recently obtained (within 42 days prior to initiation of day 1) biopsy of a tumor lesion * If recently-obtained samples are unavailable an archived metastatic specimen not previously irradiated may be submitted upon agreement from the study principal investigator (PI) * Eastern Cooperative Oncology Group (ECOG) performance status of =\< 1 * Life expectancy of \> 3 months * Metastatic triple negative breast cancer (TNBC) * Measurable disease per RECIST version (v)1.1 criteria: at least 1 lesion of \> 10 mm in long axis diameter for non-lymph nodes or \> 15 mm in short axis diameter for lymph nodes that is serially measurable according to RECIST 1.1 using computerized tomography, magnetic resonance imaging, or panoramic and close-up color photography * Histologically proven diagnosis of TNBC per current American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guideline * Estrogen receptor (ER) negative (ER expression =\< 10% positive tumor nuclei), progesterone receptor (PR) negative (PR expression =\< 10% positive tumor nuclei) and HER2 negative breast cancer by IHC and /or fluorescence in situ hybridization (FISH) * Androgen receptor positive (AR+) * Defined as \>= 50% nuclear AR staining by immunohistochemistry (IHC) in either the primary or metastatic lesion * NOTE: research testing of AR status is available at City of Hope (COH) Pathology * Resolution of grade 2 and above toxicities of most recent therapy except for stable sensory neuropathy (=\< grade 2) and alopecia * Female (childbearing potential): use an adequate method of birth control (except hormonal contraception) or be surgically sterile, or abstain from heterosexual activity for the course of the study through 120 days after the last dose of study medication * Childbearing potential defined as not being surgically sterilized or have not been free from menses for \> 1 year * Male: use and adequate method of contraception with the first dose of study therapy through 120 days after the last dose of study therapy * Note: abstinence is acceptable if this is the usual lifestyle and preferred contraception for the subject * Absolute neutrophil count (ANC) \>= 1500/mm\^3 (within 14 days prior to day 1 of protocol therapy) * Platelets \>= 100,000/mm\^3 (within 14 days prior to day 1 of protocol therapy) * Hemoglobin \>= 9 g/dL or \>= 5.6 mmol/L without transfusion or erythropoietin (EPO) dependency (within 7 days of assessment) (within 14 days prior to day 1 of protocol therapy) * Serum total bilirubin =\< 1.5 x upper limit of normal (ULN) OR direct bilirubin =\< ULN if total bilirubin levels \> 1.5 x ULN (within 14 days prior to day 1 of protocol therapy) * Albumin \>= 2.5 mg/dL (within 14 days prior to day 1 of protocol therapy) * Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) =\< 2.5 x ULN OR =\< 5.0 x ULN if liver metastases present (within 14 days prior to day 1 of protocol therapy) * Serum creatinine =\< 1.5 x ULN OR creatinine clearance (if measured or calculated per institutional standard; glomerular filtration rate \[GFR\] can also be used in place of creatinine or creatinine clearance \[CrCl\]) \>= 60 mL/min if creatinine levels \> 1.5 x ULN (within 14 days prior to day 1 of protocol therapy) * Female of childbearing potential only: negative urine or serum pregnancy test; if the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required (within 14 days prior to day 1 of protocol therapy)

Exclusion criteria

* Anti-programmed cell death protein-1 (anti-PD-1), PD ligand-1 (PD-L1), PD ligand-2 (PD-L2) agent, an antibody targeting other immuno-regulatory receptors or mechanisms * Radiotherapy within 14 days prior to day 1 of protocol therapy * AR targeted agents (including GTx-024, enzalutamide or other AR targeted therapies) * Investigational agent within 21 days prior to day 1 of protocol therapy * Hormone replacement therapies (estrogens, megestrol acetate) within 14 days prior to day 1 of protocol therapy * Live-virus vaccination within 30 days prior to day 1 of protocol therapy * Systemic cytotoxic chemotherapy, antineoplastic biologic therapy, or major surgery within 21 days of the first dose of trial medication * Testosterone or testosterone-like agents (methyltestosterone, oxandrolone, oxymetholone, danazol, fluoxymesterone, dehydroepiandrosterone, androstenedione) other androgenic compounds or anti-androgens within 30 days prior to day 1 of protocol therapy * Chronic systemic steroid therapy or on any other form of immunosuppressive medication * Unstable or untreated brain/leptomeningeal metastasis * Clinically active diverticulitis, intra-abdominal abscess, gastrointestinal (GI) obstruction, or abdominal carcinomatosis (known risks factors for bowel perforation) * Active central nervous system metastases and/or carcinomatous meningitis * Severe hypersensitivity reaction to treatment with another monoclonal antibody * Active autoimmune disease that has required systemic treatment in the past 2 years (replacement therapies for hormone deficiencies are allowed) * Known history of human immunodeficiency virus (HIV), hepatitis B or hepatitis C * History of pneumonitis (non-infectious) that required steroids or current pneumonitis * Diagnosed with or treated for cancer within the previous two years, other than breast cancer or non-melanoma carcinoma of the skin * Unable to swallow capsules * Currently on bisphosphonate or denosumab with elevated serum calcium levels corrected for albumin/ionized calcium levels outside of institutional normal limits * Female: pregnant or lactating * Concomitant medical condition that precludes adequate study treatment compliance or assessment, or increases subject risk, in the opinion of the investigator, such as but not limited to: * Myocardial infarction or arterial thromboembolic events within 6 months prior to baseline or severe or unstable angina, New York Heart Association (NYHA) class III or IV disease, or a QTCB (corrected according to Bazett's formula) interval \> 470 msec; serious uncontrolled cardiac arrhythmia grade II or higher according to NYHA; uncontrolled hypertension (systolic \> 150 and/or diastolic \> 100 mm Hg) * Acute and chronic active infectious disorders and non-malignant medical illnesses that are uncontrolled or whose control may be jeopardized by the complications of this study therapy * Impairment of gastrointestinal function or gastrointestinal disease that may significantly alter the absorption of study drugs (e.g., ulcerative disease, uncontrolled nausea, vomiting, diarrhea, malabsorption syndrome) * Prospective participants who, in the opinion of the investigator, may not be able to comply with all study procedures (including compliance issues related to feasibility/logistics)

Design outcomes

Primary

MeasureTime frameDescription
Response Rate (Complete Response or Partial Response)Up to 36 monthsResponse rate (complete response or partial response) assessed using Response Evaluation Criteria in Solid Tumors version 1.1.

Secondary

MeasureTime frameDescription
Progression-free SurvivalTime to disease progression/relapse or death as a result of any cause, assessed up to 36 monthsProgression-free survival assessed using Response Evaluation Criteria in Solid Tumors version 1.1. Kaplan-Meier estimates will be generated.
Clinical Benefit RateAt 16 weeksClinical benefit rate assessed by immune-related Response Evaluation Criteria in Solid Tumors version 1.1.
Overall SurvivalTime to death as a result of any cause, assessed up to 36 monthsOverall survival assessed by Response Evaluation Criteria in Solid Tumors version 1.1. Kaplan-Meier estimates will be generated.

Countries

United States

Participant flow

Recruitment details

Patients seen at the City of Hope main campus and its surrounding affiliated community clinics.

Pre-assignment details

Study was conducted from June 1, 2017 to October 28, 2019.

Participants by arm

ArmCount
Treatment (Pembrolizumab, Enobosarm)
Patients receive pembrolizumab IV over 30 minutes on day 1 and enobosarm PO QD on days 1-21. Courses repeat every 21 days for up to 35 cycles in the absence of disease progression or unacceptable toxicity. Enobosarm: Given PO Laboratory Biomarker Analysis: Correlative studies Pembrolizumab: Given IV
16
Total16

Withdrawals & dropouts

PeriodReasonFG000
Overall StudyGTx-024 drug supply was withdrawn2

Baseline characteristics

CharacteristicTreatment (Pembrolizumab, Enobosarm)
Age, Continuous64 years
Initial tumor stage
Stage I
6 Participants
Initial tumor stage
Stage II
8 Participants
Initial tumor stage
Stage III
2 Participants
Nottingham Histological grade
Grade 1
2 Participants
Nottingham Histological grade
Grade 2
5 Participants
Nottingham Histological grade
Grade 3
9 Participants
Number of previous lines of therapy
Received 0-1 previous lines of therapy
9 Participants
Number of previous lines of therapy
Received >=2 previous lines of therapy
7 Participants
Performance Status (ECOG)
ECOG stage 0
7 Participants
Performance Status (ECOG)
ECOG stage 1
9 Participants
Prior radiation
No
1 Participants
Prior radiation
Yes, received prior radiation
15 Participants
Prior surgery
Lumpectomy
7 Participants
Prior surgery
Mastectomy
9 Participants
Race/Ethnicity, Customized
African American
1 Participants
Race/Ethnicity, Customized
Asian
2 Participants
Race/Ethnicity, Customized
Hispanic
5 Participants
Race/Ethnicity, Customized
non-Hispanic White
8 Participants
Region of Enrollment
United States
16 participants
Sex: Female, Male
Female
16 Participants
Sex: Female, Male
Male
0 Participants

Adverse events

Event typeEG000
affected / at risk
deaths
Total, all-cause mortality
8 / 18
other
Total, other adverse events
18 / 18
serious
Total, serious adverse events
4 / 18

Outcome results

Primary

Response Rate (Complete Response or Partial Response)

Response rate (complete response or partial response) assessed using Response Evaluation Criteria in Solid Tumors version 1.1.

Time frame: Up to 36 months

ArmMeasureCategoryValue (COUNT_OF_PARTICIPANTS)
Treatment (Pembrolizumab, Enobosarm)Response Rate (Complete Response or Partial Response)Complete response1 Participants
Treatment (Pembrolizumab, Enobosarm)Response Rate (Complete Response or Partial Response)Partial response1 Participants
Treatment (Pembrolizumab, Enobosarm)Response Rate (Complete Response or Partial Response)Stable disease2 Participants
Treatment (Pembrolizumab, Enobosarm)Response Rate (Complete Response or Partial Response)Progressive disease12 Participants
Secondary

Clinical Benefit Rate

Clinical benefit rate assessed by immune-related Response Evaluation Criteria in Solid Tumors version 1.1.

Time frame: At 16 weeks

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Treatment (Pembrolizumab, Enobosarm)Clinical Benefit Rate4 Participants
Secondary

Overall Survival

Overall survival assessed by Response Evaluation Criteria in Solid Tumors version 1.1. Kaplan-Meier estimates will be generated.

Time frame: Time to death as a result of any cause, assessed up to 36 months

ArmMeasureValue (MEDIAN)
Treatment (Pembrolizumab, Enobosarm)Overall Survival25.5 months
Secondary

Progression-free Survival

Progression-free survival assessed using Response Evaluation Criteria in Solid Tumors version 1.1. Kaplan-Meier estimates will be generated.

Time frame: Time to disease progression/relapse or death as a result of any cause, assessed up to 36 months

ArmMeasureValue (MEDIAN)
Treatment (Pembrolizumab, Enobosarm)Progression-free Survival2.6 months
Secondary

Progression-free Survival

Progression-free survival defined as failure of treatment or death as a result of any cause assessed by Response Evaluation Criteria in Solid Tumors version 1.1. Kaplan-Meier estimates will be generated.

Time frame: Up to 1 year

Population: Two patients were not evaluable for response, and were excluded from progression-free survival.

ArmMeasureValue (MEDIAN)
Treatment (Pembrolizumab, Enobosarm)Progression-free Survival2.6 months

Source: ClinicalTrials.gov · Data processed: Feb 21, 2026