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BYL719 and Letrozole in Post-Menopausal Patients With Hormone Receptor-Positive Metastatic Breast Cancer

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
ClinicalTrials.gov Identifier: NCT01791478
Recruitment Status : Active, not recruiting
First Posted : February 15, 2013
Last Update Posted : October 18, 2022
National Cancer Institute (NCI)
Information provided by (Responsible Party):
Laura Kennedy, Vanderbilt-Ingram Cancer Center

Brief Summary:
This phase I trial studies the side effects and best dose of the PI3K inhibitor BYL719 when given together with letrozole in treating patients with hormone receptor-positive metastatic breast cancer. The PI3K inhibitor BYL719 may stop the growth of tumor cells by blocking some of the proteins needed for cell growth. Hormone therapy using letrozole may fight breast cancer by blocking the use of estrogen by the tumor cells. Giving the PI3K inhibitor BYL719 together with letrozole may kill more tumor cells

Condition or disease Intervention/treatment Phase
Estrogen Receptor-positive Breast Cancer HER2-negative Breast Cancer Invasive Ductal Breast Carcinoma Progesterone Receptor-positive Breast Cancer Recurrent Breast Cancer Stage IV Breast Cancer Drug: PI3K inhibitor BYL719 Drug: letrozole Other: laboratory biomarker analysis Other: pharmacological studies Phase 1

Detailed Description:

PRIMARY OBJECTIVE: To determine the safety and tolerability of BYL719 given in combination with endocrine therapy in post-menopausal patients with hormone receptor-positive metastatic breast cancer by determining:

I. Dose limiting toxicities (DLTs) during the first 4 weeks of treatment (cycle 1).

II. Maximum tolerated dose (MTD) of BYL719 (PI3K inhibitor BYL719) given in combination with letrozole.

III. Highest tolerated dose - ability to tolerate BYL719 with letrozole for a total of 8 weeks without development of:

  • Hyperglycemia (fasting glucose > 200 mg/dL) for more than 2 weeks in a row despite optimal medical treatment
  • CTC Grade 3 or > rash for more than 2 weeks in a row despite optimal medical treatment
  • CTC Grade 2 or > GI toxicity for more than 2 weeks in a row despite optimal medical treatment
  • CTC Grade 2 or > serum creatinine, bilirubin, AST, ALT elevation from baseline for more than 2 weeks in a row despite optimal medical treatment

SECONDARY OBJECTIVES: To determine the anti-tumor effect of the combinations of endocrine therapy with BYL719 in post-menopausal patients with hormone receptor-positive metastatic breast cancer by assessing:

I. Progression free survival (PFS). II. Objective response rate (ORR). III. Clinical benefit rate (complete response [CR]+partial response [PR]+stable disease [SD] >= 6 months).


I. Pharmacokinetics of BYL719 in combination with letrozole: Plasma concentration-time profiles and derived basic pharmacokinetic (PK) parameters of BYL719 and letrozole, including but not limited to area under the plasma concentration-time curve from time zero to the last measurable concentration (AUC0-tlast), AUC curve to infinite time (AUC0-inf), maximum observed concentration (Cmax), time to peak concentration (Tmax), clearance over bioavailability (CL/F), apparent volume of distribution (Vz/F) and the terminal half-life (t1/2) and other PK parameters if deemed appropriate.

II. Correlation of response with alterations of the PI3K pathway: Mutational analysis of PIK3CA (exons 9 and 20), phosphatase and tensin homolog (PTEN), and AKT1 in formalin-fixed paraffin blocks (FFPB) from previous surgeries or fresh-frozen biopsies (if available) on all patients enrolled in the trial.

OUTLINE: This is an open-label phase Ib dose-escalation study of the PI3K inhibitor BYL719 in combination with letrozole in post-menopausal patients with ER+ metastatic breast cancer.

Patients receive BYL719 orally (PO) once daily (QD) and letrozole PO QD. Courses repeat every 4 weeks in the absence of disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed up for 4 weeks.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 46 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: A Phase Ib Trial of BYL719 (an α-Specific PI3K Inhibitor) in Combination With Endocrine Therapy in Post-Menopausal Patients With Hormone Receptor-Positive Metastatic Breast Cancer
Study Start Date : April 2013
Actual Primary Completion Date : December 2014
Estimated Study Completion Date : October 2023

Resource links provided by the National Library of Medicine

Drug Information available for: Letrozole

Arm Intervention/treatment
Experimental: Treatment (PI3K inhibitor BYL719, letrozole)
Patients receive PI3K inhibitor BYL719 PO QD and letrozole PO QD. Courses repeat every 4 weeks in the absence of disease progression or unacceptable toxicity.
Drug: PI3K inhibitor BYL719
Given PO
Other Name: BYL719, a-specific phosphoinositide 3-kinase inhibitor BYL719

Drug: letrozole
Given PO
Other Names:
  • 112809-51-5, 4,4'-(1H-1,2,4triazol-1-ylmethylene)dibenzonitrile, 719345, CGS 20267,
  • Femara,LTZ

Other: laboratory biomarker analysis
Correlative studies

Other: pharmacological studies
Correlative studies

Primary Outcome Measures :
  1. Maximum tolerated dose of BYL719 in combination with letrozole [ Time Frame: 4 weeks ]
    Highest dose of BYL719 tested in which a DLT is experienced by 0 out of 3 or 1 of 6 patients, based on the NCI Common Toxicity Criteria for Adverse Events (CTCAE) version 4.0

Secondary Outcome Measures :
  1. Highest tolerated dose of BYL719 in combination with letrozole [ Time Frame: 8 weeks ]
    Highest dose of BYL719 without CTC Grade > 2 hyperglycemia(fasting glucose > 200 mg/dL) for > 2 weeks, Grade > 3 rash for > 2 weeks , Grade > 2 gastrointestinal toxicity for > 2 weeks and Grade > 2 creatinine, bilirubin, AST, ALT for > 2 weeks.

  2. Clinical benefit rate [ Time Frame: At 6 months of study treatment ]
    Per Response Evaluation Criteria In Solid Tumors (RECIST) version 1.1; percentage of patients with complete response (CR) + partial response (PR) + stable disease (SD) for more than 6 months.

  3. Overall progression-free survival [ Time Frame: Up to 4 weeks after interruption of study treatment ]
    Duration from on-study date to date of progressive disease.

  4. Overall response [ Time Frame: Every 8 weeks to interruption of treatment ]
    Per RECIST version 1.1. number of patients each with CR, PR, SD, and progressive disease (PD) as their best response.

  5. Worst grade toxicities [ Time Frame: Up to 4 weeks after interruption of study treatment ]
    Number of patients with worst-grade toxicity at each of five grades (grade 1, least severe; to grade 5, most severe) following NCI Common Toxicity Criteria 4.0.

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   No

Inclusion Criteria

  • Patients must provide informed written consent.
  • Patients must be >/= 18 years of age.
  • ECOG performance status 0 - 1.
  • Clinical stage IV invasive mammary carcinoma, ER-positive and/or PR-positive by immunohistochemistry (IHC) and HER2 negative (by IHC or ISH). Patients may have either measurable or non-measurable disease, both are allowed.
  • A minimum of 10 patients in the trial (~50%) will need to have a PIK3CA mutation in their cancer
  • Patients must have had at least one line of endocrine therapy in the metastatic setting, or be diagnosed with metastatic breast cancer during or within 1 year of adjuvant endocrine therapy. There is no limit on lines of prior treatment in the metastatic setting.
  • Patients must have available tissue (archived formalin-fixed paraffin embedded blocks (FFPB) or fresh frozen tissue from original diagnosis or metastatic setting) for correlative studies. Tissue needs to be located and available at the time of registration (tissue needs to be submitted within 3 weeks of study initiation). Patients will not be able to start study drugs without tissue availability.
  • Life expectancy ≥ 6 months
  • Patients must have adequate hematologic, hepatic, and renal function. All laboratory tests must be obtained less than 1 week from study entry. This includes:

    1. ANC >/= 1,500/mm3
    2. platelet count >/=100,000/mm3
    3. HgB ≥ 9 g/dL
    4. Creatinine ≤ 1.5x ULN
    5. INR ≤ 2
    6. Fasting plasma glucose ≤ 140 mg/dL
    7. HgBA1C ≤ 8%
    8. Total Serum Bilirubin ≤ 1.5 x ULN (Patients with known Gilbert Syndrome, a total bilirubin ≤ 3.0 x ULN, with direct bilirubin ≤ 1.5 x ULN)
    9. SGOT, SGPT ≤ 3 X ULN if no liver metastasis present
    10. SGOT, SGPT ≤ 5 X ULN if liver metastasis present
  • Patients must be able to swallow and retain oral medication.
  • Patients must be post-menopausal. Post-menopausal female subjects should be defined prior to protocol enrollment by any of the following:

    1. Subjects at least 55 years of age; OR
    2. Subjects under 55 years of age and naturally (spontaneous) amenorrhea for at least 12 months or follicle-stimulating hormone (FSH) values ≥ 40 IU/L and estradiol levels </= 20 IU/L; OR
    3. Prior bilateral oophorectomy; OR
    4. Prior radiation castration with amenorrhea for at least 6 months

      NOTE: Treatment with a luteinizing hormone-releasing hormone (LH-RH) agonist (such as goserelin acetate or leuprolide acetate) is not permitted for induction of ovarian suppression.

  • Patients must complete all screening assessments as outlined in the protocol.

Exclusion Criteria

  • Locally recurrent resectable breast cancer.
  • Any kind of malabsorption syndrome significantly affecting gastrointestinal function.
  • Patients with clinically manifest diabetes mellitus (treated and/or clinical signs or with fasting glucose >/= 140 mg/dL / 7.8 mmol/L), history of gestational diabetes mellitus or documented steroid-induced diabetes mellitus.
  • Patients who have received radiation therapy </= 2 weeks prior to study entry. Patients who have received prior radiotherapy must have recovered from toxicity (≤ grade 1) induced by this treatment.
  • Patients who have received systemic anti-cancer therapy such as chemotherapy, immunotherapy and/or biologic therapy </= 4 weeks prior to study entry. Concurrent anti-cancer therapy (chemotherapy, immunotherapy, biologic therapy) other than the ones specified in the protocol is not permitted during study participation. Patients must have discontinued the above cancer therapies for 4 weeks prior to the first dose of study medication, as well as recovered from toxicity (to ≤ than grade 1, except for alopecia) induced by previous treatments. Any investigational drugs should be discontinued 4 weeks prior to the first dose of study medication.
  • Prior hormonal / endocrine therapy </= 2 weeks prior to study entry. Patients must have recovered from toxicity > grade 1, except for alopecia.
  • Prior therapy with a PI3K inhibitor. Prior use of Akt or mTOR inhibitors are allowed.
  • Patients who have received herbal medications </= 2 weeks prior to study entry. Herbal medications include, but are not limited to: St. John's wort, Kava, ephedra (ma huang), gingko biloba, dehydroepiandrosterone (DHEA), yohimbe, saw palmetto, and ginseng.
  • Use of drugs that are CYP3A4 modifiers
  • Patients who are currently receiving medication with a known risk of prolonging the QT interval or inducing Torsades de Pointes (TdP) and the treatment cannot either be discontinued or switched to a different medication prior to starting study drug treatment.
  • Patients with a family history of congenital long QT syndrome
  • Patients with abnormal calcium, potassium, or magnesium levels that cannot be adequately corrected to within normal range prior to initiation of study drugs
  • Uncontrolled intercurrent illness including, but not limited to:

    1. ongoing or active infection requiring parenteral antibiotics
    2. impairment of lung function (COPD > grade 2, lung conditions requiring oxygen therapy)
    3. symptomatic congestive heart failure (class III or IV of the New York Heart Association classification for heart disease)
    4. Left Ventricular Ejection Fraction (LVEF) < 50%
    5. unstable angina pectoris, angioplasty, stenting, or myocardial infarction within 6 months
    6. uncontrolled hypertension within 2 weeks of study initiation (systolic blood pressure > 180 mm Hg or diastolic blood pressure > 110 mm Hg, found on two consecutive measurements separated by a 1 or 2-week period despite adequate medical support)
    7. clinically significant cardiac arrhythmia (multifocal premature ventricular contractions, bigeminy,trigeminy, ventricular tachycardia that is symptomatic or requires treatment [National Cancer Institute -Common Terminology Criteria for Adverse Events, Version 4.0, grade 3]
    8. QTcF ≥ 480 msec on screening EKG
    9. known history of QT/QTc prolongation or Torsades de Pointes (TdP)
    10. ST depression or elevation of ≥ 1.5 mm in 2 or more leads
    11. Diarrhea of any cause ≥ CTCAE grade 2
    12. psychiatric illness/social situations that would compromise patient safety or limit compliance with study requirements including maintenance of a compliance/pill diary
    13. patients with symptomatic brain metastases (patients with a history of brain metastases must be clinically stable for more than 4 weeks from completion of radiation treatment)
    14. patients with known history of chronic liver or renal failure
    15. patients with known history of chronic or acute pancreatitis

Individuals of all races and ethnic groups are eligible for this trial. There is no bias towards age or race in the clinical trial outlined. This trial is open to the accrual of women.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01791478

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United States, Massachusetts
Massachusetts General Hospital, Dana-Farber Cancer Institute
Boston, Massachusetts, United States, 02114
United States, Tennessee
Vanderbilt-Ingram Cancer Center
Nashville, Tennessee, United States, 37232-6838
Sponsors and Collaborators
Vanderbilt-Ingram Cancer Center
National Cancer Institute (NCI)
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Principal Investigator: Ingrid Mayer Vanderbilt-Ingram Cancer Center
Additional Information:
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Responsible Party: Laura Kennedy, Assistant Professor of Medicine, Vanderbilt-Ingram Cancer Center
ClinicalTrials.gov Identifier: NCT01791478    
Other Study ID Numbers: VICC BRE 12101
NCI-2013-00102 ( Registry Identifier: CTRP (Clinical Trial Reporting Program) )
First Posted: February 15, 2013    Key Record Dates
Last Update Posted: October 18, 2022
Last Verified: October 2022
Keywords provided by Laura Kennedy, Vanderbilt-Ingram Cancer Center:
-Metastatic breast cancer, PI3K inhibitor, Endocrine therapy
Additional relevant MeSH terms:
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Breast Neoplasms
Carcinoma, Ductal, Breast
Neoplasms by Site
Breast Diseases
Skin Diseases
Carcinoma, Ductal
Neoplasms, Glandular and Epithelial
Neoplasms by Histologic Type
Neoplasms, Ductal, Lobular, and Medullary
Phosphoinositide-3 Kinase Inhibitors
Antineoplastic Agents
Aromatase Inhibitors
Steroid Synthesis Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Estrogen Antagonists
Hormone Antagonists
Hormones, Hormone Substitutes, and Hormone Antagonists
Physiological Effects of Drugs