A Study of Taselisib + Fulvestrant Versus Placebo + Fulvestrant in Participants With Advanced or Metastatic Breast Cancer Who Have Disease Recurrence or Progression During or After Aromatase Inhibitor Therapy

Breast Cancer Clinical Trial

— SANDPIPER  

Official title:

A Phase III, Double-Blind, Placebo-Controlled, Randomized Study of Taselisib Plus Fulvestrant Versus Placebo Plus Fulvestrant in Postmenopausal Women With Estrogen Receptor-Positive and HER2-Negative Locally Advanced or Metastatic Breast Cancer Who Have Disease Recurrence or Progression During or After Aromatase Inhibitor Therapy

Clinical Trial Details — Status: Terminated

Administrative data

• NCT number: NCT02340221
• Other study ID #: GO29058
• Secondary ID: 2014-003185-25
• Status: Terminated
• Phase: Phase 3
• Start date: April 9, 2015
• Est. completion date: June 29, 2021

Study information

• Verified date: July 2022
• Source: Hoffmann-La Roche
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

This international, multicenter, randomized, double-blinded, placebo-controlled study is designed to compare the efficacy and safety of taselisib + fulvestrant with that of placebo + fulvestrant in postmenopausal women with estrogen receptor (ER)-positive, human epidermal growth factor receptor-2 (HER2)-negative, oncogene that encodes for phosphatidylinositol-4,5-bisphosphate 3-kinase (PIK3CA)-mutant, unresectable, locally advanced or metastatic breast cancer after recurrence or progression during or after an aromatase inhibitor (AI) therapy. There will be a 2:1 randomization to the taselisib arm versus the placebo arm. Enrollment will be enriched for participants with PIK3CA mutant tumors via central testing. The anticipated duration of the study is approximately 3.5 years.

Recruitment information / eligibility

• Status: Terminated
• Enrollment: 631
• Est. completion date: June 29, 2021
• Est. primary completion date: June 29, 2021
• Accepts healthy volunteers: No
• Gender: Female
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• Postmenopausal women with histologically or cytologically confirmed locally advanced or metastatic estrogen receptor (ER) positive breast cancer

• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

• Participants for whom endocrine therapy (example [e.g.], fulvestrant) is recommended and treatment with cytotoxic chemotherapy is not indicated at time of entry into the study

• Radiologic/objective evidence of recurrence or progression to the most recent systemic therapy for breast cancer

• Radiologic/objective evidence of breast cancer recurrence or progression while on or within 12 months of the end of adjuvant treatment with an aromatase inhibitor (AI), or progression while on or within 1 month of the end of prior AI treatment for locally advanced or metastatic breast cancer

• Measurable disease via Response Evaluation Criteria in Solid Tumors (RECIST) Version 1.1 (v1.1) or non-measurable, evaluable disease with at least one evaluable bone lesion via RECIST v1.1

• Consent to provide a formalin-fixed, paraffin-embedded (FFPE) tumor tissue block (preferred) or a minimum of 20 (25 preferred) freshly cut unstained tumor slides from the most recently collected, available tumor tissue for oncogene that encodes for phosphatidylinositol-4,5-bisphosphate 3-kinase (PIK3CA)-mutation testing

• A valid cobas PIK3CA mutation result by central testing is required

• Adequate hematologic and end-organ function within 28 days prior to treatment initiation

Exclusion Criteria:

• Human epidermal growth factor receptor 2 (HER2)-positive disease by local laboratory testing (immunohistochemistry 3 positive [IHC 3+] staining or in situ hybridization positive)

• Prior treatment with fulvestrant

• Prior treatment with a phosphatidylinositol 3-kinase (PI3K) inhibitor, mammalian target of rapamycin (mTOR) inhibitor (e.g. everolimus), or protein kinase B (AKT) inhibitor

• Prior anti-cancer therapy within 2 weeks prior to Day 1 of Cycle 1

• Prior radiation therapy within 2 weeks prior to Day 1 of Cycle 1

• All acute treatment-related toxicity must have resolved to Grade less than or equal to (</=) 1 or be deemed stable by the Investigator

• Prior treatment with greater than (>) 1 cytotoxic chemotherapy regimen for metastatic breast cancer

• Concurrent hormone replacement therapy

• Known untreated or active central nervous system (CNS) metastases

• Type 1 or Type 2 diabetes mellitus requiring anti-hyperglycemic medications

• History of inflammatory bowel disease or active bowel inflammation

• Clinically significant cardiac or pulmonary dysfunction

• Clinically significant history of liver disease, including cirrhosis, current alcohol abuse, or current known active infection with human immunodeficiency virus (HIV), hepatitis B or C virus

Related Conditions & MeSH terms

• Breast Cancer
• Breast Neoplasms
• Recurrence

Intervention

Drug:
• Taselisib
Taselisib 4 mg was administered as two tablets of 2 mg each as per the schedule specified in the respective arm.
• Placebo
Placebo matching to taselisib was administered as per the schedule specified in the respective arm.
• Fulvestrant
Fulvestrant 500 mg was administered as two IM injections of 250 mg each as per the schedule specified in the respective arms.

Locations

Country	Name	City	State
Australia	Mater Hospital; Oncology	Brisbane	Queensland
Australia	Austin Hospital; Medical Oncology	Heidelberg	Victoria
Australia	Liverpool Hospital; Cancer Therapy Centre	Liverpool	New South Wales
Australia	Macquarie University Hospital	Macquarie Park	New South Wales
Australia	St John of God Murdoch Hospital; Oncology West	Murdoch	Western Australia
Australia	Sunshine Hospital; Oncology Research	St Albans	Victoria
Australia	Newcastle Mater Misericordiae Hospital; Oncology	Waratah	New South Wales
Austria	Lkh-Univ. Klinikum Graz; Klinik Für Innere Medizin I	Graz
Austria	Tiroler Landeskrankenanstalten Ges.M.B.H.; Abt. Für Gynäkologie	Innsbruck
Austria	Ordensklinikum Linz Barmherzige Schwestern; Abt. fur Innere Medizin 1	Linz
Austria	Medizinische Universität Wien; Univ.Klinik für Innere Medizin I	Wien
Bosnia and Herzegovina	University Clinical Center of the Republic of Srpska	Banja Luka
Bosnia and Herzegovina	Clinic of Oncology, University Clinical Center Sarajevo	Sarajevo
Bulgaria	Complex Oncological Center - Plovdiv, EOOD	Plovdiv
Bulgaria	MHAT Nadezhda	Sofia
Bulgaria	SHATO - Sofia	Sofia
Bulgaria	SHATOD Dr. Marko Antonov Markov-Varna, EOOD	Varna
Canada	Cross Cancer Institute	Edmonton	Alberta
Canada	Grand River Hospital	Kitchener	Ontario
Canada	McGill University; Sir Mortimer B Davis Jewish General Hospital; Oncology	Montreal	Quebec
Canada	The Ottawa Hospital Cancer Centre; Oncology	Ottawa	Ontario
Canada	Hospital Du Saint-Sacrement	Quebec City	Quebec
Canada	Sunnybrook Health Science Centre	Toronto	Ontario
Canada	British Columbia Cancer Agency (Bcca) - Vancouver Cancer Centre	Vancouver	British Columbia
China	Jilin Cancer Hospital	Changchun
China	the First Hospital of Jilin University	Changchun
China	Jiangsu Cancer Hospital	Nanjing City
China	Fudan University Shanghai Cancer Center	Shanghai City
China	Zhejiang Cancer Hospital	Zhejiang
Colombia	Clinica del Country	Bogota
Colombia	Oncomedica S.A.	Monteria
Czechia	University Hospital; Oncology and Radiotherapy	Hradec Kralove
Czechia	Fakultni nemocnice Olomouc; Onkologicka klinika	Olomouc
Czechia	Vseobecna fakultni nemocnice v Praze	Praha 2
Finland	KYS Sadesairaala; Syopatautien poliklinikka	Kuopio
Finland	Turku Uni Central Hospital; Oncology Clinics	Turku
France	Centre Jean Perrin; Hopital De Semaine	Clermont-Ferrand
France	Centre Georges François Leclerc; Service Pharmacie, Bp 77980	Dijon
France	Hopital Prive Drome Ardeche; Chir 2A 2B	Guilherand Granges
France	CHD Vendée	La Roche Sur Yon
France	Hopital Dupuytren; Oncologie Medicale	Limoges
France	Institut régional du Cancer Montpellier	Montpellier
France	Institut Curie; Oncologie Medicale	Paris
France	Ch Lyon Sud; Onco Secteur Jules Courmont	Pierre Benite
France	Pole de Cancerologie Prive Strasbourgeois	Strasbourg
France	Centre Alexis Vautrin; Oncologie Medicale	Vandoeuvre-les-nancy
Germany	Hochwaldkrankenhaus; Abt.Gynäkologie Geburtshilfe u.Senologie	Bad Nauheim
Germany	Onkologische Schwerpunktpraxis Kurfürstendamm	Berlin
Germany	Praxisklinik Krebsheilkunde für Frauen / Brustzentrum (Dres. Kittel/Klare)	Berlin
Germany	Universitätsklinikum Essen; Zentrum Für Frauenheilkunde	Essen
Germany	Kooperatives Mammazentrum Hamburg Krankenhaus Jerusalem	Hamburg
Germany	Klinikum der Universität München; Frauenklinik - Onkologie II	München
Germany	Klinikum Mutterhaus der Borromäerinnen, Innere Medizin I	Trier
Greece	Alexandras General Hospital of Athens; Oncology Department	Athens
Greece	IASO General Hospital of Athens	Athens
Greece	Univ General Hosp Heraklion; Medical Oncology	Heraklion
Greece	University Hospital of Patras Medical Oncology	Patras
Greece	Euromedical General Clinic of Thessaloniki; Oncology Department	Thessaloniki
Greece	Papageorgiou General Hospital; Medical Oncology	Thessaloniki
Italy	Centro Catanese Di Oncologia; Oncologia Medica	Catania	Sicilia
Italy	Azienda Ospedaliero-Universitaria Careggi; SOD Radioterapia	Firenze	Toscana
Italy	IRCCS Istituto Nazionale Per La Ricerca Sul Cancro (IST); Oncologia Medica A	Genova	Liguria
Italy	Azienda USL 9 Grosseto; Dipartimento Politiche del Farmaco	Grosseto	Toscana
Italy	AZ. Usll12 Veneziana-Ospedale Dell'angelo;Oncologia Medica	Mestre	Veneto
Italy	Istituto Europeo Di Oncologia	Milano	Lombardia
Italy	Istituto Nazionale Tumori Irccs Fondazione g. PASCALE;U.O.C. Oncologia Medica Senologica	Napoli	Campania
Italy	Azienda usl 5 Di Pisa-Ospedale Di Pontedera;U.O. Oncologia	Pontedera	Toscana
Italy	ARCISPEDALE S. MARIA NUOVA - REGGIO EMILIA; Struttura Semplice Coordinamento Breast Unit Integrata	Reggio Emilia	Emilia-Romagna
Italy	A.O. Universitaria S. Maria Della Misericordia Di Udine; Oncologia	Udine	Friuli-Venezia Giulia
Korea, Republic of	Inje university Haeundae Paik Hospital	Busan
Korea, Republic of	Chungbuk National University Hospital	Cheongju-si
Korea, Republic of	National Cancer Center	Goyang-si
Korea, Republic of	Asan Medical Center	Seoul
Korea, Republic of	Korea University Anam Hospital	Seoul
Korea, Republic of	Samsung Medical Center	Seoul
Korea, Republic of	Seoul National University Hospital	Seoul
Korea, Republic of	Severance Hospital, Yonsei University Health System	Seoul
Korea, Republic of	Ulsan University Hosiptal	Ulsan
Mexico	Iem-Fucam	D.f.
Mexico	Instituto Nacional De Cancerologia; Oncology; Tumores Mamarios	Distrito Federal
Mexico	Consultorio de Medicina Especializada; Dentro de Condominio San Francisco	Mexico City
Mexico	Hospital San Jose Del Tec. de Monterrey; Oncology	Monterrey
Mexico	Oaxaca Site Management Organization	Oaxaca
Netherlands	Medisch Centrum Alkmaar	Alkmaar
Netherlands	Ziekenhuis Rijnstate	Arnhem
Peru	Clinica Internacional, Sede San Borja; Unidad de Investigacion de Clínica Internacional	Lima
Peru	Instituto Nacional de Enfermedades Neoplasicas	Lima
Peru	Oncocenter Peru S.A.C.; Oncosalud	Lima
Peru	Instituto Regional de Enfermedades Neoplasicas - IREN Norte	Trujillo
Poland	Bialostockie Centrum Onkologii; Oddzial Onkologii Klinicznej	Bialystok
Poland	Centrum Onkologii w Bydgoszczy; Oddzial Kliniczny Onkologii	Bydgoszcz
Poland	Uniwersyteckie Centrum Kliniczne, Klinika Onkologii i Radioterapii	Gdansk
Poland	Przychodnia Lekarska KOMED, Roman Karaszewski	Konin
Poland	Szpital Uniwersytecki w Krakowie, Oddzial Kliniczny Kliniki Onkologii	Kraków
Poland	Woj.Wielospecjalistyczne Centrum Onkologii i Traumatologii; Oddz.Hematologii Pododz.Chemioterapii	Lodz
Poland	Centrum Onkologii Ziemi LUBELSKIEJ im. Sw Jana z Dukli, I oddz. Chemioterapii	Lublin
Poland	Zachodniopomorskie Centrum Onkologii, Osrodek Innowacyjnosci, Rozwoju i Badan Klinicznych	Szczecin
Poland	Centrum Onkologii - Instytut im. Marii Sklodowskiej-Curie Klinika Nowotworów Piersi i Chirurgii	Warszawa
Poland	Wojewodzki Szpital Specjalistyczny; Osrodek Badawczo-Rozwojowy, Oddzial Chemioterapii	Wroclaw
Portugal	Hospital Garcia de Orta; Servico de Oncologia Medica	Almada
Portugal	Hospital da Luz; Departamento de Oncologia Medica	Lisboa
Portugal	Hospital de Santa Maria; Servico de Oncologia Medica	Lisboa
Portugal	IPO de Lisboa; Servico de Oncologia Medica	Lisboa
Portugal	IPO do Porto; Servico de Oncologia Medica	Porto
Romania	Institut of Oncology Al. Trestioreanu Bucharest; Oncology Department	Bucuresti
Romania	Prof. Dr. I. Chiricuta Institute of Oncology	Cluj Napoca
Romania	Oncology Center Sf. Nectarie	Craiova
Romania	Euroclinic Center of Oncology SRL	Iasi
Russian Federation	Regional Clinical Oncology Dispensary; Surgery Dept, Thoracic	Arkhangelsk
Russian Federation	Ivanovo Regional Oncology Dispensary	Ivanovo
Russian Federation	Clinical Oncology Dispensary of Ministry of Health of Tatarstan	Kazan
Russian Federation	Moscow City Oncology Hospital #62	Moscovskaya Oblast	Moskovskaja Oblast
Russian Federation	State Inst. Of Healthcare Orenburg Regional Clinical Oncology Dis	Orenburg
Russian Federation	S-Pb clinical scientific practical center of specialized kinds of medical care (oncological)	Saint-Petersburg
Serbia	Institute for Onc/Rad Serbia	Belgrade
Spain	Hospital Clínic i Provincial; Servicio de Hematología y Oncología	Barcelona
Spain	Hospital Universitari Vall d'Hebron	Barcelona
Spain	Hospital de Cruces; Servicio de Oncologia	Bilbao	Vizcaya
Spain	Hospital Universitario de Canarias;servicio de Oncologia	La Laguna	Tenerife
Spain	Centro Oncologico MD Anderson Internacional; Servicio de Oncologia	Madrid
Spain	HOSPITAL DE MADRID NORTE SANCHINARRO- CENTRO INTEGRAL ONCOLOGICO CLARA CAMPAL; Servicio de Oncologia	Madrid
Spain	Hospital Ramon y Cajal; Servicio de Oncologia	Madrid
Spain	Hospital Universitario Puerta de Hierro; Servicio de Oncologia	Majadahonda	Madrid
Spain	Complejo Hospitalario Universitario de Santiago (CHUS) ; Servicio de Oncologia	Santiago de Compostela	LA Coruña
Spain	Fundación IVO	Valencia
Spain	Hospital Universitario Miguel Servet; Servicio Oncologia	Zaragoza
Sweden	Uni Hospital Linkoeping; Dept. of Oncology	Linköping
Sweden	Sodersjukhuset; Onkologkliniken	Stockholm
Sweden	Akademiska sjukhuset, Onkologkliniken	Uppsala
Taiwan	Mackay Memorial Hospital; Dept of Surgery	Taipei
Taiwan	National Taiwan Uni Hospital; General Surgery	Taipei
Taiwan	VETERANS GENERAL HOSPITAL; Department of General Surgery	Taipei
Taiwan	Koo Foundation Sun Yat-Sen Cancer Center; Hemato-Oncology	Taipei City
Thailand	Department of Surgery, King Chulalongkorn Memorial Hospital	Bangkok
Thailand	Ramathibodi Hospital; Dept of Med.-Div. of Med. Onc	Bangkok
Thailand	Maharaj Nakorn Chiang Mai Hospital; Department of Surgery/Head Neck and Breast Unit; Clinical Trial	Chiang Mai
Turkey	Baskent University Adana Dr. Turgut Noyan Practice and Research Hospital; Medical Oncology	Adana
Turkey	Trakya University Medical Faculty Research And Practice Hospital Medical Oncology Department	Edirne
Turkey	Istanbul Uni Cerrahpasa Medical Faculty Hospital; Medical Oncology	Istanbul
Turkey	Ege Uni Medical Faculty; Oncology Dept	Izmir
Turkey	Hacettepe Uni Medical Faculty Hospital; Oncology Dept	Sihhiye/Ankara
United States	Georgia Cancer Specialists - Northside	Atlanta	Georgia
United States	MSKCC at Basking Ridge	Basking Ridge	New Jersey
United States	Oregon Health & Science University; Knight Cancer Institute, Community Hematology Oncology	Beaverton	Oregon
United States	Dana Farber Can Ins	Boston	Massachusetts
United States	Memorial Sloan-Kettering; Cancer Center	Commack	New York
United States	John Theurer Cancer Ctr at Hackensack Univ Medical Ctr	Hackensack	New Jersey
United States	Pinnacle Health	Harrisburg	Pennsylvania
United States	Memorial Sloan Kettering Cancer Center; Memorial Sloan Kettering; at Westchester	Harrison	New York
United States	Ingalls Hospital	Harvey	Illinois
United States	Northwest Georgia Oncology Centers, a Service of WellStar Cobb Hospital	Marietta	Georgia
United States	Memorial Sloan Kettering Cancer Center	New York	New York
United States	Maryland Oncology Hematology	Rochville	Maryland
United States	Mercy Hospitals East Communities d/b/a Mercy Hospital St. Louis	Saint Louis	Missouri
United States	Arizona Oncology	Tucson	Arizona
United States	Arizona Oncology Associates, P.C.	Tucson	Arizona
United States	Memorial Sloan Kettering Nassau	Uniondale	New York

Sponsors (1)

Lead Sponsor	Collaborator
Hoffmann-La Roche

Countries where clinical trial is conducted

United States,  Australia,  Austria,  Bosnia and Herzegovina,  Bulgaria,  Canada,  China,  Colombia,  Czechia,  Finland,  France,  Germany,  Greece,  Italy,  Korea, Republic of,  Mexico,  Netherlands,  Peru,  Poland,  Portugal,  Romania,  Russian Federation,  Serbia,  Spain,  Sweden,  Taiwan,  Thailand,  Turkey, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Progression-Free Survival (PFS) as Assessed by Investigator Using Response Evaluation Criteria in Solid Tumors (RECIST) Version 1.1 (v1.1) at Primary Analysis	PFS was defined as the time from randomization to disease progression as determined by the investigator with the use of RECIST v1.1 or death due to any cause, whichever occurred earlier. Disease progression was defined as at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study, including baseline. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 millimeters (mm). For non-target lesions, disease progression was defined as unequivocal progression of existing lesions. The appearance of one or more new lesions was also considered progression.	From randomization until the first occurrence of disease progression or death from any cause, whichever occurs earlier (up to the 15 Oct 2017 data cutoff, approximately 2.5 years)
Primary	PFS as Assessed by Investigator Using RECIST v1.1 at Final Analysis	PFS was defined as the time from randomization to disease progression as determined by the investigator with the use of RECIST v1.1 or death due to any cause, whichever occurred earlier. Disease progression was defined as at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study, including baseline. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. For non-target lesions, disease progression was defined as unequivocal progression of existing lesions. The appearance of one or more new lesions was also considered progression.	From randomization until the first occurrence of disease progression or death from any cause, whichever occurs earlier (up to approximately 6.2 years)
Secondary	Percentage of Participants With Objective Response (Partial Response [PR] Plus Complete Response [CR]), as Assessed Using RECIST v.1.1 at Primary Analysis	PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum of diameters. CR was defined as disappearance of all target and non-target lesions and normalization of tumor marker levels (as applicable to non-target lesions).	From randomization until the first occurrence of disease progression or death from any cause, whichever occurs earlier (up to the 15 Oct 2017 data cutoff, approximately 2.5 years)
Secondary	Percentage of Participants With Objective Response (PR Plus CR), as Assessed Using RECIST v.1.1 at Final Analysis	PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum of diameters. CR was defined as disappearance of all target and non-target lesions and normalization of tumor marker levels (as applicable to non-target lesions).	From randomization until the first occurrence of disease progression or death from any cause, whichever occurs earlier (up to approximately 6.2 years)
Secondary	Overall Survival (OS) at Primary Analysis	OS was defined as the time from the date of randomization to the date of death due to any cause.	From randomization up to death from any cause (up to the 15 Oct 2017 data cutoff, approximately 2.5 years)
Secondary	OS at Final Analysis	OS was defined as the time from the date of randomization to the date of death due to any cause.	From randomization up to death from any cause (up to approximately 6.2 years)
Secondary	Percentage of Participants With Clinical Benefit, as Assessed According to RECIST v1.1 at Primary Analysis	Clinical benefit was defined as objective response (PR+CR), or no disease progression lasting for more than or equal to (>/=) 24 weeks since randomization. PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum of diameters. CR was defined as disappearance of all target and non-target lesions and normalization of tumor marker levels (as applicable to non-target lesions). Disease progression was defined as at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study, including baseline. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. For non-target lesions, disease progression was defined as unequivocal progression of existing lesions. The appearance of one or more new lesions was also considered progression.	From randomization until the first occurrence of disease progression or death from any cause, whichever occurs earlier (up to the 15 Oct 2017 data cutoff, approximately 2.5 years)
Secondary	Percentage of Participants With Clinical Benefit, as Assessed According to RECIST v1.1 at Final Analysis	Clinical benefit was defined as objective response (PR+CR), or no disease progression lasting for more than or equal to (>/=) 24 weeks since randomization. PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum of diameters. CR was defined as disappearance of all target and non-target lesions and normalization of tumor marker levels (as applicable to non-target lesions). Disease progression was defined as at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study, including baseline. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. For non-target lesions, disease progression was defined as unequivocal progression of existing lesions. The appearance of one or more new lesions was also considered progression.	From randomization until the first occurrence of disease progression or death from any cause, whichever occurs earlier (up to approximately 6.2 years)
Secondary	Duration of Objective Response, as Assessed by Investigator Using RECIST v1.1 at Primary Analysis	Duration of objective response: the time from the first tumor assessment that supported the participant's objective response (CR or PR, whichever was first recorded) to first documented disease progression or death due to any cause, whichever occurred first. CR was defined as disappearance of all target and non-target lesions and normalization of tumor marker levels (as applicable to non-target lesions). PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum of diameters. Disease progression: at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study, including baseline. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. For non-target lesions, disease progression was defined as unequivocal progression of existing lesions. The appearance of one or more new lesions was also considered progression.	Time from the first occurrence of a documented objective response to the time of the first documented disease progression or death from any cause, whichever occurs earlier (up to the 15 Oct 2017 data cutoff, approximately 2.5 years)
Secondary	Duration of Objective Response, as Assessed by Investigator Using RECIST v1.1 at Final Analysis	Duration of objective response: the time from the first tumor assessment that supported the participant's objective response (CR or PR, whichever was first recorded) to first documented disease progression or death due to any cause, whichever occurred first. CR was defined as disappearance of all target and non-target lesions and normalization of tumor marker levels (as applicable to non-target lesions). PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum of diameters. Disease progression: at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study, including baseline. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. For non-target lesions, disease progression was defined as unequivocal progression of existing lesions. The appearance of one or more new lesions was also considered progression.	Time from the first occurrence of a documented objective response to the time of the first documented disease progression or death from any cause, whichever occurs earlier (up to approximately 6.2 years)
Secondary	PFS as Assessed by Blinded Independent Central Review (BICR) Using RECIST v1.1 at Primary Analysis	PFS was defined as the time from randomization to disease progression as determined by BICR with the use of RECIST v1.1 or death due to any cause, whichever occurred earlier. Disease progression was defined as at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study, including baseline. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. For non-target lesions, disease progression was defined as unequivocal progression of existing lesions. The appearance of one or more new lesions was also considered progression.	From randomization until the first occurrence of disease progression or death from any cause, whichever occurs earlier (up to the 15 Oct 2017 data cutoff, approximately 2.5 years)
Secondary	PFS as Assessed by BICR Using RECIST v1.1 at Final Analysis	PFS was defined as the time from randomization to disease progression as determined by BICR with the use of RECIST v1.1 or death due to any cause, whichever occurred earlier. Disease progression was defined as at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study, including baseline. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. For non-target lesions, disease progression was defined as unequivocal progression of existing lesions. The appearance of one or more new lesions was also considered progression.	From randomization until the first occurrence of disease progression or death from any cause, whichever occurs earlier (up to approximately 6.2 years)
Secondary	Percentage of Participants With Adverse Events at Primary Analysis	An adverse event was any untoward medical occurrence in a clinical investigation participant administered a pharmaceutical product, regardless of causal attribution.	From randomization up to the 15 Oct 2017 data cutoff, approximately 2.5 years.
Secondary	Percentage of Participants With Adverse Events at Final Analysis	An adverse event was any untoward medical occurrence in a clinical investigation participant administered a pharmaceutical product, regardless of causal attribution.	From randomization up to approximately 6.2 years
Secondary	Maximum Observed Plasma Concentration (Cmax) of Taselisib		1 to 4 hours (hrs) post-dose on Cycle (C) 1, Day (D) 1; 0 to 3 hrs pre-dose and 2 to 6 hrs post dose on Cycle 2, Day 1 (each cycle=28 days)
Secondary	Minimum Observed Plasma Concentration (Cmin) of Taselisib		1 to 4 hrs post-dose on Cycle 1, Day 1; 0 to 3 hrs pre-dose and 2 to 6 hrs post dose on Cycle 2, Day 1; 0 to 3 hrs pre-dose on Cycle 6, Day 1 (each cycle=28 days)
Secondary	Change From Baseline in European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 (QLQ-C30) Score	The EORTC QLQ-C30 consists of 30 questions that comprise aspects of participant's functioning assessment (physical, emotional, role, cognitive, and social); symptom scales (fatigue; nausea, vomiting, and pain; the global health/quality of life [QoL]); and single items (dyspnoea, insomnia, appetite loss, constipation, diarrhoea, and financial difficulties), within a recall period of "the past week." Most questions used a 4-point scale (1=Not at all to 4=Very much; two questions used a 7-point scale (1=Very poor to 7=Excellent). Scores were averaged and transformed to a 0-100 scale; a higher score for Global Qol/functional scales=better level of functioning; a higher score for symptom scale=greater degree of symptoms.	Baseline, C2D1 up to C7D1 (each cycle=28 days)
Secondary	Change From Baseline in Modified EORTC Quality of Life Questionnaire Breast Cancer Module 23 (QLQ-BR23) Score	EORTC-QLQ-BR23 is a 23-item breast cancer-specific companion module to the EORTC-QLQ-C30 and consists of functional scales (body image, sexual enjoyment, sexual functioning, future perspective [FP]) and symptom scales (systemic side effects [SE], upset by hair loss, arm symptoms, breast symptoms). Questions used a 4-point scale (1=not at all, 2=a little, 3=quite a bit, 4=very much). Scores were averaged and transformed to a 0-100 scale. Higher scores for the functional scales indicated a higher/better level of functioning/healthy functioning. Higher scores for the symptom scales indicated worse symptoms.	Baseline, C2D1 up to C7D1 (each cycle=28 days)