Breast CancerPhase 2BYLieveNCT03056755
Study Assessing the Efficacy and Safety of Alpelisib Plus Fulvestrant or Letrozole, Based on Prior Endocrine Therapy, in Patients With PIK3CA Mutant, HR+, HER2- Advanced Breast Cancer Who Have Progressed on or After Prior Treatments
A Phase 2 study testing Alpelisib, Fulvestrant and Letrozole in people with Breast Cancer, run by Novartis Pharmaceuticals at 94 sites in 19 countries.
Trial summary
This was a Phase II, multicenter, open-label, three-cohort, non-comparative study of alpelisib plus endocrine therapy (either fulvestrant or letrozole) in subjects (pre- and post-menopausal women and men) with HR-positive, HER2-negative aBC harboring PIK3CA mutation(s) in the tumor, whose disease had progressed on or… Read more about this study
- Who is it for?
- Ages 18 to 99 years
- Conditions the study is for
- Breast Cancer
- What is being tested?
- Alpelisib, Fulvestrant and Letrozole
- Type of treatment
- Pill or oral medicine, Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 383 participants
- Where
- 94 sitesin 19 countries
- Study dates
- 29 Aug 2017to 12 Nov 2024
- Phase
- Phase 2
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 to 99 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
None listed.
Who cannot join
- Subjects with a known hypersensitivity to alpelisib, fulvestrant, letrozole, goserelin, or leuprolide or to any of their excipients.
- Subjects with prior treatment with any PI3K inhibitor (PI3Ki).
- Subjects with central nervous system (CNS) involvement unless they met all of the following criteria:
- At least 4 weeks from prior therapy completion (including radiation and/or surgery) to starting the study treatment, ii. Clinically stable CNS tumor at the time of screening untreated or without evidence of progressions for at least 4 weeks after treatment as determined by clinical examination and brain imaging (magnetic resonance imaging (MRI) or computed tomography (CT) during screening period and stable low dose of steroids for 2 weeks prior to initiating study treatment.
- Subjects with an established diagnosis of diabetes mellitus type I or uncontrolled type II.
- Any concurrent severe and/or uncontrolled medical conditions that would, in the investigator's judgment, contraindicate subject participation in the study (e.g., chronic active hepatitis, severe hepatic impairment, etc.).
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- Subjects with a history of noncompliance to medical regimens.
- Subjects with impairment of gastrointestinal (GI) function or GI disease that could significantly alter the absorption of the study drugs based on investigator discretion.
- Subjects with documented pneumonitis/interstitial lung disease which was active and requiring treatment.
- Subjects concurrently using other anticancer therapy. All anticancer therapy had to be discontinued prior to Day 1 of study treatment.
- Subjects who had major surgery within 14 days prior to starting treatment with alpelisib, or did not recover from major side effects.
- Subjects with significant cardiac abnormalities.
- History of acute pancreatitis within 1 year of screening or past medical history of chronic pancreatitis.
- Subjects who did not use highly effective contraception while on alpelisib and through the duration after the final dose of alpelisib (not applicable to postmenopausal women).
- Subjects with unresolved osteonecrosis of the jaw.
- Other inclusion/exclusion criteria may apply
Trial locations and contacts
94 sites in 19 countries.
94 sites in 19 countries
United States25 sites
New Mexico Cancer Care Alliance
Albuquerque, New Mexico, 87106
Kaiser Permanente Medical Group
Anaheim, California, 92807
Mercy Medical Center
Baltimore, Maryland, 21202
Greater Baltimore Med Center Cancer Center
Baltimore, Maryland, 21204
Beverly Hills Cancer Center
Beverly Hills, California, 90211
St Vincent Frontier Cancer Center
Billings, Montana, 59102
Massachusetts General Hospital
Boston, Massachusetts, 02114
Lahey Clinic
Burlington, Massachusetts, 01805
Uni Hosp of Cleveland Cancer Center
Cleveland, Ohio, 44106
Texas Oncology
Dallas, Texas, 75246
Josephine Ford Cancer Center
Detroit, Michigan, 48202
Banner MD Anderson Cancer Center
Gilbert, Arizona, 85234
University of Calif Irvine Med Cntr
Irvine, California, 92660
University of Kansas Cancer Center
Kansas City, Kansas, 66205
University of Louisville James Graham Brown Cancer Center
Louisville, Kentucky, 40202
Yale University Yale Cancer Center
New Haven, Connecticut, 06511
Memorial Sloane Ketterin Cancer Ctr
New York, New York, 10065
Virginia Oncology Associates
Norfolk, Virginia, 23502
Advent Health Cancer Institute
Orlando, Florida, 32804
Mayo Clinic Arizona
Phoenix, Arizona, 85054
Cancer Care Centers of South Texas HOAST
San Antonio, Texas, 78229
UT Health San Antonio
San Antonio, Texas, 78229
Kaiser Permanent Southern Californi
San Diego, California, 92120
UCSF
San Francisco, California, 94115
Northwest Medical Specialists
Tacoma, Washington, 98405
France10 sites
Novartis Investigative Site
Bordeaux, 33076
Novartis Investigative Site
Caen, 14021
Novartis Investigative Site
Lille, 59020
Novartis Investigative Site
Lyon, 69373
Novartis Investigative Site
Montpellier, 34298
Novartis Investigative Site
Nice, Alpes Maritimes, 06189
Novartis Investigative Site
Saint-Cloud, Hauts De Seine, 92210
Novartis Investigative Site
Saint-Herblain, 44805
Novartis Investigative Site
Strasbourg, 67000
Novartis Investigative Site
Toulouse, 31059
Italy8 sites
Novartis Investigative Site
Ancona, AN, 60126
Novartis Investigative Site
Bergamo, BG, 24127
Novartis Investigative Site
Bologna, BO, 40138
Novartis Investigative Site
Genova, GE, 16132
Novartis Investigative Site
Milan, MI, 20133
Novartis Investigative Site
Milan, MI, 20141
Novartis Investigative Site
Naples, 80131
Novartis Investigative Site
Roma, RM, 00168
Germany7 sites
Novartis Investigative Site
Augsburg, 86150
Novartis Investigative Site
Berlin, 14169
Novartis Investigative Site
Dresden, Saxony, 01307
Novartis Investigative Site
Erlangen, 91054
Novartis Investigative Site
Essen, 45136
Novartis Investigative Site
Heidelberg, 69120
Novartis Investigative Site
Ulm, 89081
Spain7 sites
Novartis Investigative Site
Barcelona, Catalonia, 08035
Novartis Investigative Site
Barcelona, 08036
Novartis Investigative Site
Castellon, 12002
Novartis Investigative Site
L'Hospitalet de Llobregat, Barcelona, 08907
Novartis Investigative Site
Madrid, 28041
Novartis Investigative Site
Salamanca, Castille and León, 37007
Novartis Investigative Site
Seville, 41013
Argentina6 sites
Novartis Investigative Site
CABA, Buenos Aires, C1118AAT
Novartis Investigative Site
CABA, Buenos Aires, C1125ABD
Novartis Investigative Site
CABA, Buenos Aires, C1426ANZ
Novartis Investigative Site
La Rioja, 5300
Novartis Investigative Site
Rosario, Santa Fe Province, S2000DSV
Novartis Investigative Site
Rosario, Sante Fe, S200KZE
United Kingdom5 sites
Novartis Investigative Site
Edinburgh, Scotland, EH4 2XU
Novartis Investigative Site
Leicester, LE2 7LG
Novartis Investigative Site
London, SW3 6JJ
Novartis Investigative Site
Nottingham, NG5 1PB
Novartis Investigative Site
Sutton, Surrey, SM2 5PT
Canada4 sites
Novartis Investigative Site
Halifax, Nova Scotia, B3H 2Y9
Novartis Investigative Site
Kitchener, Ontario, N2G 1G3
Novartis Investigative Site
Toronto, Ontario, M5B 1N9
Novartis Investigative Site
Vancouver, British Columbia, V5Z 4E6
Israel4 sites
Novartis Investigative Site
Petah Tikva, 4941492
Novartis Investigative Site
Ramat Gan, 5265601
Novartis Investigative Site
Rehovot, 7661041
Novartis Investigative Site
Tel Aviv, 6423906
Chile3 sites
Novartis Investigative Site
Santiago, 7500921
Novartis Investigative Site
Santiago, 8420383
Novartis Investigative Site
Temuco, Araucania, 4810469
Taiwan3 sites
Novartis Investigative Site
Tainan, 70403
Novartis Investigative Site
Taipei, 10002
Novartis Investigative Site
Taipei, 103616
Belgium2 sites
Novartis Investigative Site
Leuven, 3000
Novartis Investigative Site
Liège, 4000
Denmark2 sites
Novartis Investigative Site
Odense C, 5000
Novartis Investigative Site
Vejle, DK-7100
Singapore2 sites
Novartis Investigative Site
Singapore, 168583
Novartis Investigative Site
Singapore, 217562
South Korea2 sites
Novartis Investigative Site
Seoul, Korea, 03080
Novartis Investigative Site
Seoul, 06351
Netherlands1 site
Novartis Investigative Site
Maastricht, Limburg, 6229 HX
About this study
Official title: BYLieve: A Phase II, Multicenter, Open-label, Three-cohort, Non- Comparative Study to Assess the Efficacy and Safety of Alpelisib Plus Fulvestrant or Letrozole in Patients With PIK3CA Mutant, Hormone Receptor (HR) Positive, HER2-negative Advanced Breast Cancer (aBC), Who Have Progressed on or After Prior Treatments
This was a Phase II, multicenter, open-label, three-cohort, non-comparative study of alpelisib plus endocrine therapy (either fulvestrant or letrozole) in subjects (pre- and post-menopausal women and men) with HR-positive, HER2-negative aBC harboring PIK3CA mutation(s) in the tumor, whose disease had progressed on or after prior treatments.
Read the detailed description
The study comprised two phases:
- Core Phase: included a treatment phase for all subjects from first subject first treatment (FSFT) until disease progression, unacceptable toxicity, or death until 18 months post last subject first treatment (LSFT) + 1 month safety follow-up (total 19 months post LSFT), discontinuation from the study treatment for any other reason, or sponsor terminates the study. At the start of the Core Phase, subjects were assigned to Cohort A, Cohort B, or Cohort C based on previous therapy as follows:
- Cohort A: alpelisib (300 mg oral QD) + fulvestrant (500 mg intramuscular (IM)) to subjects whose last prior treatment was a CDK4/6i plus any AI;
- Cohort B: alpelisib (300 mg oral QD) + letrozole (2.5 mg oral QD) to subjects whose last prior treatment was a CDK4/6i plus fulvestrant;
- Cohort C: alpelisib (300 mg oral QD)+ fulvestrant (500 mg IM) to subjects who failed prior AI based therapy and whose last prior treatment was systemic chemotherapy or endocrine therapy (as monotherapy or in combination with targeted treatment except CDK 4/6i + AI). Endocrine therapy included letrozole, fulvestrant and CDK 4/6 inhibitor plus fulvestrant.
- Extension Phase: included a treatment phase starting at the end of the treatment Core Phase until last subject last visit(LSLV) (up to 36 months). Following the end of the Core Phase, subjects continuing to derive benefit from study treatment who were not eligible for Post-Study Drug Supply (PSDS) in their country based on local regulations were re-consented and transitioned to the Extension Phase. Subjects continued on their existing study treatment assigned in the Core Phase until disease progression/lack of clinical benefit or any other reason for which the subject may have been discontinued from study treatment. If PSDS became available for a subject, the subject was to be discontinued from the study and to access treatment via PSDS. When subjects discontinued treatment for any reason, the end of treatment visit was performed after discontinuation of the medication , followed by safety follow-up 30 days after last dose.
A total of 340 subjects were planned to be enrolled, with approximately 112 subjects in each cohort. In the Core Phase, 379 subjects were analyzed, with 127 subjects in Cohort A, 126 subjects in Cohort B, and 126 subjects in Cohort C. In the Extension Phase, 11 subjects were analyzed, with 1 subject in Cohort A and 10 subjects in Cohort C.
- Conditions
- Breast Cancer
- Being tested
- Alpelisib, Fulvestrant, Letrozole, Goserelin, Leuprolide
- Keywords
- advanced breast cancer, PIK3CA, CDK 4/6 inhibitor, fulvestrant, letrozole, HR+, HER2-negative, post menopausal, pre-menopausal, aromatase inhibitor, endocrine treatment, AI, ET
- Medical subject headings
- Breast Neoplasms, Hereditary Sensory and Autonomic Neuropathies
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
AlpelisibDrug
Also called BYL719
300 mg of alpelisib film-coated tablets administered orally once daily
FulvestrantDrug
500 mg of fulvestrant via intramuscular injection administered on Days 1, 15 on Cycle 1 and Day 1 at each cycle thereafter. Cycle=28 days
LetrozoleDrug
2.5 mg of letrozole film-coated tablets administered orally once daily
GoserelinDrug
3.6 mg of goserelin via injectable subcutaneous implant administered every 28 days. Only for men in Cohort B and premenopausal women.
LeuprolideDrug
7.5 mg of leuprolide via injectable intramuscular depot administered every 28 days. Only for men in cohort B and premenopausal women.
| Study group | Role | What they receive |
|---|---|---|
| Cohort A: Pre-treated with CDK 4/6i + AI | Experimental | Participants who received any Cyclin-Dependent Kinases 4 and 6 inhibitor (CDK 4/6i) plus aromatase inhibitor (AI) as immediate prior treatment will receive alpelisib + fulvestrant Receives: Drug: Alpelisib; Drug: Fulvestrant; Drug: Goserelin; Drug: Leuprolide |
| Cohort B: Pre-treated with CDK 4/6i + fulvestrant | Experimental | Patients who received any CDK 4/6i plus fulvestrant as immediate prior treatment will receive alpelisib + letrozole Receives: Drug: Alpelisib; Drug: Letrozole; Drug: Goserelin; Drug: Leuprolide |
| Cohort C: Pre-treated with systemic chemotherapy or ET | Experimental | Participants who received systemic chemotherapy or endocrine therapy (ET) (as monotherapy or in combination with targeted treatment except CDK 4/6i + AI) as immediate prior treatment will receive alpelisib + fulvestrant. Receives: Drug: Alpelisib; Drug: Fulvestrant; Drug: Goserelin; Drug: Leuprolide |
What is being measured
The primary outcome is the main question the study is designed to answer.
Core Phase: Percentage of Participants Who Were Alive Without Disease Progression at 6 Months
Percentage of participants who were alive without disease progression at 6-month follow-up based on local investigator assessment per RECIST v1.1 in Cohort A, Cohort B and Cohort C. Participants who progressed, died, or discontinued study before 6 months were counted as a failure.
Measured: At 6 months
Secondary outcomes (7)
Core Phase: Progression Free Survival (PFS)
PFS is defined as the time from the date of first dose of study medication to the date of the first documented progression or death due to any cause occurring in the study. PFS was assessed based on local investigator's assessment according to RECIST v1.1. PFS was censored if no PFS event was observed before the cut-off date. The censoring date was the date of last adequate tumor assessment before the cut-off date. If a PFS event was observed after two or more missing or non-adequate tumor assessments, then PFS was censored at the last adequate tumor assessment. PFS was estimated using the Kaplan-Meier method.
Measured: From date of first dose to date of first documented progression or death, up to 46 months
Core Phase: Progression Free Survival on Next Line Treatment (PFS2)
PFS2 is defined as time from the date of first dose of study medication to the date of first documented progression on next-line therapy or death from any cause. The first documented progression on next-line treatment is based on investigator assessment of progressive disease. PFS2 was estimated using the Kaplan-Meier method.
Measured: From date of first dose to date of first documented progression on next-line therapy or death, up to approximately 55 months
Core Phase: Overall Response Rate (ORR)
ORR is defined as the percentage of participants with best overall response (BOR) of complete response (CR) or partial response (PR) based on local investigator's assessment according to RECIST v1.1 in each cohort. CR: Disappearance of all non-nodal target lesions and all non-target lesions. In addition, any pathological lymph nodes assigned as target lesions must have a reduction in short axis to < 10 mm and all lymph nodes assigned as non-target lesions must be non-pathological in size (<10 mm short axis) PR: At least a 30% decrease in the sum of diameter of all target lesions, taking as reference the baseline sum of diameters.
Measured: Up to 46 months
Core Phase: Clinical Benefit Rate (CBR)
CBR is defined as the percentage of participants with a BOR of CR or PR or an overall lesion response of stable disease (SD) or Non-CR/ Non-PD lasting ≥ 24 weeks based on local investigator's assessment according to RECIST v1.1. CR: Disappearance of all non-nodal target lesions and all non-target lesions. In addition, any pathological lymph nodes assigned as target lesions must have a reduction in short axis to < 10 mm and all lymph nodes assigned as non-target lesions must be non-pathological in size (<10 mm short axis) PR: At least a 30% decrease in the sum of diameter of all target lesions, taking as reference the baseline sum of diameters. SD: Neither sufficient shrinkage to qualify for PR or CR nor an increase in lesions which would qualify for progressive disease.
Measured: Up to 46 months
Core Phase: Duration of Response (DOR)
DOR is the time from the date of first documented response (confirmed CR or PR based on local investigator's assessment according to RECIST v1.1) to the date of first documented progression or death due to underlying cancer. Subjects continuing without progression or death due to underlying cancer were censored at the date of their last adequate tumor assessment. DOR was estimated using the Kaplan-Meier method.
Measured: From date of first documented response to first documented progression or death, up to 33.3 months
Core Phase: Overall Survival (OS)
OS is defined as the time of start of treatment to date of death or lost to follow-up. If a subject was not known to have died, then the OS data was censored at the date of the last known alive status for the patient.
Measured: From date of first dose and up to approximately 55 months
Extension Phase: Percentage of Participants With Clinical Benefit as Assessed by the Investigator During the Extension Phase
Clinical Benefit Rate, as assessed by the Investigator during the Extension Phase, was defined as the proportion of patients with a best overall response of Complete Response (CR) or Partial Response (PR), or an overall lesion response of Stable Disease (SD) or non-complete response/non-progressive disease that lasted at least 24 weeks, based on the local investigator's assessment according to Response Evaluation Criteria in Solid Tumors version 1.1.
Measured: Day 1 of each extension cycle up to Cycle 29 (each cycle lasting 28 days); median duration of exposure to study treatment (alpelisib or fulvestrant) = 41 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Feb 2017
- Study start29 Aug 2017
- Primary completion14 Jun 2021
- Study completion12 Nov 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for Breast CancerStudies of the same condition, open and under way.
- More trials run by Novartis PharmaceuticalsThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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 2
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 383 participants (actual)
Sponsor and investigators
- Lead sponsor
- Novartis Pharmaceuticals
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Novartis Pharmaceuticals, Study director, Novartis Pharmaceuticals
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03056755
- Sponsor's protocol ID
- CBYL719X2402
- Other IDs
- 2023-509167-24-00, 2023
- Acronym
- BYLieve
- Status last verified
- Dec 2025
- First submitted
- 15 Feb 2017
- Last updated
- 13 Jan 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Novartis is committed to sharing with qualified external researchers, access to patient-level data and supporting clinical documents from eligible studies. These requests are reviewed and approved by an independent review panel on the basis of scientific merit. All data provided is anonymized to respect the privacy of patients who have participated in the trial in line with applicable laws and regulations. This trial data availability is according to the criteria and process described on www.clinicalstudydatarequest.com
Publications
Rugo HS, Lerebours F, Ciruelos E, Drullinsky P, Ruiz-Borrego M, Neven P, Park YH, Prat A, Bachelot T, Juric D, Turner N, Sophos N, Zarate JP, Arce C, Shen YM, Turner S, Kanakamedala H, Hsu WC, Chia S. Alpelisib plus fulvestrant in PIK3CA-mutated, hormone receptor-positive advanced breast cancer after a CDK4/6 inhibitor (BYLieve): one cohort of a phase 2, multicentre, open-label, non-comparative study. Lancet Oncol. 2024 Dec;25(12):e629-e638. doi: 10.1016/S1470-2045(24)00673-9.
PubMed 39637900Borrego MR, Lu YS, Reyes-Cosmelli F, Park YH, Yamashita T, Chiu J, Airoldi M, Turner N, Fein L, Ghaznawi F, Singh J, Pantoja K, Schnell C, Akdere M, Chia S. SGLT2 inhibition improves PI3Kalpha inhibitor-induced hyperglycemia: findings from preclinical animal models and from patients in the BYLieve and SOLAR-1 trials. Breast Cancer Res Treat. 2024 Nov;208(1):111-121. doi: 10.1007/s10549-024-07405-8. Epub 2024 Aug 23.
PubMed 39177931Rodon J, Demanse D, Rugo HS, Burris HA, Simo R, Farooki A, Wellons MF, Andre F, Hu H, Vuina D, Quadt C, Juric D. A risk analysis of alpelisib-induced hyperglycemia in patients with advanced solid tumors and breast cancer. Breast Cancer Res. 2024 Mar 4;26(1):36. doi: 10.1186/s13058-024-01773-1.
PubMed 38439079Rugo HS, Lerebours F, Ciruelos E, Drullinsky P, Ruiz-Borrego M, Neven P, Park YH, Prat A, Bachelot T, Juric D, Turner N, Sophos N, Zarate JP, Arce C, Shen YM, Turner S, Kanakamedala H, Hsu WC, Chia S. Alpelisib plus fulvestrant in PIK3CA-mutated, hormone receptor-positive advanced breast cancer after a CDK4/6 inhibitor (BYLieve): one cohort of a phase 2, multicentre, open-label, non-comparative study. Lancet Oncol. 2021 Apr;22(4):489-498. doi: 10.1016/S1470-2045(21)00034-6.
PubMed 33794206
Study at a glance
From the registry record, last updated by the sponsor on 13 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- BYLieve: A Phase II, Multicenter, Open-label, Three-cohort, Non- Comparative Study to Assess the Efficacy and Safety of Alpelisib Plus Fulvestrant or Letrozole in Patients With PIK3CA Mutant, Hormone Receptor (HR) Positive, HER2-negative Advanced Breast Cancer (aBC), Who Have Progressed on or After Prior Treatments
- ClinicalTrials.gov ID
- NCT03056755
- Acronym / sponsor ID
- BYLieve / CBYL719X2402
- Conditions
- Breast Cancer
- Keywords
- advanced breast cancer, PIK3CA, CDK 4/6 inhibitor, fulvestrant, letrozole, HR+, HER2-negative, post menopausal
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 383 participants (actual)
- Lead sponsor
- Novartis PharmaceuticalsIndustry (pharma, biotech, devices)
- Study start
- 29 Aug 2017 (actual)
- Primary completion
- 14 Jun 2021 (actual)
- Study completion
- 12 Nov 2024 (actual)
- First posted
- 17 Feb 2017 (actual)
- Results
- Posted 27 Mar 2024
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This was a Phase II, multicenter, open-label, three-cohort, non-comparative study of alpelisib plus endocrine therapy (either fulvestrant or letrozole) in subjects (pre- and post-menopausal women and men) with HR-positive, HER2-negative aBC harboring PIK3CA mutation(s) in the tumor, whose disease had progressed on or after prior treatments.
Detailed description
The study comprised two phases:
- Core Phase: included a treatment phase for all subjects from first subject first treatment (FSFT) until disease progression, unacceptable toxicity, or death until 18 months post last subject first treatment (LSFT) + 1 month safety follow-up (total 19 months post LSFT), discontinuation from the study treatment for any other reason, or sponsor terminates the study. At the start of the Core Phase, subjects were assigned to Cohort A, Cohort B, or Cohort C based on previous therapy as follows:
- Cohort A: alpelisib (300 mg oral QD) + fulvestrant (500 mg intramuscular (IM)) to subjects whose last prior treatment was a CDK4/6i plus any AI;
- Cohort B: alpelisib (300 mg oral QD) + letrozole (2.5 mg oral QD) to subjects whose last prior treatment was a CDK4/6i plus fulvestrant;
- Cohort C: alpelisib (300 mg oral QD)+ fulvestrant (500 mg IM) to subjects who failed prior AI based therapy and whose last prior treatment was systemic chemotherapy or endocrine therapy (as monotherapy or in combination with targeted treatment except CDK 4/6i + AI). Endocrine therapy included letrozole, fulvestrant and CDK 4/6 inhibitor plus fulvestrant.
- Extension Phase: included a treatment phase starting at the end of the treatment Core Phase until last subject last visit(LSLV) (up to 36 months). Following the end of the Core Phase, subjects continuing to derive benefit from study treatment who were not eligible for Post-Study Drug Supply (PSDS) in their country based on local regulations were re-consented and transitioned to the Extension Phase. Subjects continued on their existing study treatment assigned in the Core Phase until disease progression/lack of clinical benefit or any other reason for which the subject may have been discontinued from study treatment. If PSDS became available for a subject, the subject was to be discontinued from the study and to access treatment via PSDS. When subjects discontinued treatment for any reason, the end of treatment visit was performed after discontinuation of the medication , followed by safety follow-up 30 days after last dose.
A total of 340 subjects were planned to be enrolled, with approximately 112 subjects in each cohort. In the Core Phase, 379 subjects were analyzed, with 127 subjects in Cohort A, 126 subjects in Cohort B, and 126 subjects in Cohort C. In the Extension Phase, 11 subjects were analyzed, with 1 subject in Cohort A and 10 subjects in Cohort C.
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Cohort A: Pre-treated with CDK 4/6i + AI | Experimental | Drug: Alpelisib, Drug: Fulvestrant, Drug: Goserelin, Drug: LeuprolideParticipants who received any Cyclin-Dependent Kinases 4 and 6 inhibitor (CDK 4/6i) plus aromatase inhibitor (AI) as immediate prior treatment will receive alpelisib + fulvestrant |
| Cohort B: Pre-treated with CDK 4/6i + fulvestrant | Experimental | Drug: Alpelisib, Drug: Letrozole, Drug: Goserelin, Drug: LeuprolidePatients who received any CDK 4/6i plus fulvestrant as immediate prior treatment will receive alpelisib + letrozole |
| Cohort C: Pre-treated with systemic chemotherapy or ET | Experimental | Drug: Alpelisib, Drug: Fulvestrant, Drug: Goserelin, Drug: LeuprolideParticipants who received systemic chemotherapy or endocrine therapy (ET) (as monotherapy or in combination with targeted treatment except CDK 4/6i + AI) as immediate prior treatment will receive alpelisib + fulvestrant. |
Who may qualify
- Ages
- 18 to 99 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (0 listed)
Key exclusion criteria (16 listed)
- Subjects with a known hypersensitivity to alpelisib, fulvestrant, letrozole, goserelin, or leuprolide or to any of their excipients.
- Subjects with prior treatment with any PI3K inhibitor (PI3Ki).
- Subjects with central nervous system (CNS) involvement unless they met all of the following criteria:
- Subjects with an established diagnosis of diabetes mellitus type I or uncontrolled type II.
- Any concurrent severe and/or uncontrolled medical conditions that would, in the investigator's judgment, contraindicate subject participation in the study (e.g., chronic active hepatitis, severe hepatic impairment, etc.).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| AlpelisibAlso: BYL719300 mg of alpelisib film-coated tablets administered orally once daily | Drug | Cohort A: Pre-treated with CDK 4/6i + AI, Cohort B: Pre-treated with CDK 4/6i + fulvestrant, Cohort C: Pre-treated with systemic chemotherapy or ET |
| Fulvestrant500 mg of fulvestrant via intramuscular injection administered on Days 1, 15 on Cycle 1 and Day 1 at each cycle thereafter. Cycle=28 days | Drug | Cohort A: Pre-treated with CDK 4/6i + AI, Cohort C: Pre-treated with systemic chemotherapy or ET |
| Letrozole2.5 mg of letrozole film-coated tablets administered orally once daily | Drug | Cohort B: Pre-treated with CDK 4/6i + fulvestrant |
| Goserelin3.6 mg of goserelin via injectable subcutaneous implant administered every 28 days. Only for men in Cohort B and premenopausal women. | Drug | Cohort A: Pre-treated with CDK 4/6i + AI, Cohort B: Pre-treated with CDK 4/6i + fulvestrant, Cohort C: Pre-treated with systemic chemotherapy or ET |
| Leuprolide7.5 mg of leuprolide via injectable intramuscular depot administered every 28 days. Only for men in cohort B and premenopausal women. | Drug | Cohort A: Pre-treated with CDK 4/6i + AI, Cohort B: Pre-treated with CDK 4/6i + fulvestrant, Cohort C: Pre-treated with systemic chemotherapy or ET |
Primary outcome
Core Phase: Percentage of Participants Who Were Alive Without Disease Progression at 6 Months
Time frame: At 6 months
Percentage of participants who were alive without disease progression at 6-month follow-up based on local investigator assessment per RECIST v1.1 in Cohort A, Cohort B and Cohort C. Participants who progressed, died, or discontinued study before 6 months were counted as a failure.
7 secondary outcomes
Core Phase: Progression Free Survival (PFS)
Time frame: From date of first dose to date of first documented progression or death, up to 46 months
Core Phase: Progression Free Survival on Next Line Treatment (PFS2)
Time frame: From date of first dose to date of first documented progression on next-line therapy or death, up to approximately 55 months
Core Phase: Overall Response Rate (ORR)
Time frame: Up to 46 months
Core Phase: Clinical Benefit Rate (CBR)
Time frame: Up to 46 months
Core Phase: Duration of Response (DOR)
Time frame: From date of first documented response to first documented progression or death, up to 33.3 months
Core Phase: Overall Survival (OS)
Time frame: From date of first dose and up to approximately 55 months
Extension Phase: Percentage of Participants With Clinical Benefit as Assessed by the Investigator During the Extension Phase
Time frame: Day 1 of each extension cycle up to Cycle 29 (each cycle lasting 28 days); median duration of exposure to study treatment (alpelisib or fulvestrant) = 41 months
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Jan 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 39637900Rugo HS, Lerebours F, Ciruelos E, Drullinsky P, Ruiz-Borrego M, Neven P, Park YH, Prat A, Bachelot T, Juric D, Turner N, Sophos N, Zarate JP, Arce C, Shen YM, Turner S, Kanakamedala H, Hsu WC, Chia S. Alpelisib plus fulvestrant in PIK3CA-mutated, hormone receptor-positive advanced breast cancer after a CDK4/6 inhibitor (BYLieve): one cohort of a phase 2, multicentre, open-label, non-comparative study. Lancet Oncol. 2024 Dec;25(12):e629-e638. doi: 10.1016/S1470-2045(24)00673-9.
- Derived from this study: PubMed 39177931Borrego MR, Lu YS, Reyes-Cosmelli F, Park YH, Yamashita T, Chiu J, Airoldi M, Turner N, Fein L, Ghaznawi F, Singh J, Pantoja K, Schnell C, Akdere M, Chia S. SGLT2 inhibition improves PI3Kalpha inhibitor-induced hyperglycemia: findings from preclinical animal models and from patients in the BYLieve and SOLAR-1 trials. Breast Cancer Res Treat. 2024 Nov;208(1):111-121. doi: 10.1007/s10549-024-07405-8. Epub 2024 Aug 23.
- Derived from this study: PubMed 38439079Rodon J, Demanse D, Rugo HS, Burris HA, Simo R, Farooki A, Wellons MF, Andre F, Hu H, Vuina D, Quadt C, Juric D. A risk analysis of alpelisib-induced hyperglycemia in patients with advanced solid tumors and breast cancer. Breast Cancer Res. 2024 Mar 4;26(1):36. doi: 10.1186/s13058-024-01773-1.
- Derived from this study: PubMed 33794206Rugo HS, Lerebours F, Ciruelos E, Drullinsky P, Ruiz-Borrego M, Neven P, Park YH, Prat A, Bachelot T, Juric D, Turner N, Sophos N, Zarate JP, Arce C, Shen YM, Turner S, Kanakamedala H, Hsu WC, Chia S. Alpelisib plus fulvestrant in PIK3CA-mutated, hormone receptor-positive advanced breast cancer after a CDK4/6 inhibitor (BYLieve): one cohort of a phase 2, multicentre, open-label, non-comparative study. Lancet Oncol. 2021 Apr;22(4):489-498. doi: 10.1016/S1470-2045(21)00034-6.
- A Plain Language Trial Summary is available on www.novctrd.comLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. Novartis is committed to sharing with qualified external researchers, access to patient-level data and supporting clinical documents from eligible studies. These requests are reviewed and approved by an independent review panel on the basis of scientific merit. All data provided is anonymized to respect the privacy of patients who have participated in the trial in line with applicable laws and regulations. This trial data availability is according to the criteria and process described on www.clinicalstudydatarequest.com
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Novartis Pharmaceuticals study director
Novartis Pharmaceuticals
94 sites in 19 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Alpelisib, Fulvestrant and Letrozole in people with Breast Cancer, run by Novartis Pharmaceuticals at 94 sites in 19 countries.
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 0 inclusion and 16 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: finished, as of the sponsor's last update on 13 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 94 sites in United States, France, Italy, Germany, Spain and 14 more countries. 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 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 27 Mar 2024). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
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?
Core Phase: Percentage of Participants Who Were Alive Without Disease Progression at 6 Months (time frame: At 6 months). 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 NCT03056755, which also lists 4 linked publications.
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 13 Jan 2026.