A Study of Atezolizumab Plus Nab-Paclitaxel in the Treatment of Unresectable Locally Advanced or Metastatic PD-L1-Positive Triple-Negative Breast Cancer (EL1SSAR)

An Open-Label, Phase IIIb, Single Arm, Multicenter Safety Study of Atezolizumab (Tecentriq) Plus Nab-Paclitaxel in the Treatment of Unresectable Locally Advanced or Metastatic Triple-Negative Breast Cancer

Study MO39874 is an open-label, Phase IIIb, single arm, global study conducted in participants with unresectable locally advanced or metastatic PD-L1-positive Triple-Negative Breast Cancer (TNBC) who have not received chemotherapy for their unresectable locally advanced or metastatic disease.

Study Overview

• Status: Completed
• Conditions: Triple-Negative Breast Cancer
• Intervention / Treatment: Drug: Atezolizumab; Drug: Nab-Paclitaxel

• Study Type: Interventional
• Enrollment (Actual): 184
• Phase: Phase 3

Contacts and Locations

Study Locations

• Argentina
  • Buenos Aires, Argentina, C1431FWN
    • CEMIC
  • Rosario, Argentina, S2000ORE
    • Sanatorio de la Mujer
  • San Nicolás, Argentina, C1015ABO
    • Organizacion Medica de Investigacion
• Chile
  • Santiago, Chile
    • Pontificia Universidad Catolica de Chile
  • Santiago, Chile, 7630370
    • Instituto de Radiomedicina, IRAM
• Czechia
  • Nový Jičín, Czechia, 741 01
    • Nemocnice AGEL Nový Jičín a.s.
  • Prague, Czechia, 128 08
    • Fakultni Poliklinika Vseobecne Fakultni Niemocnice
  • Prague, Czechia, 180 81
    • Nemocnice Na Bulovce
• France
  • Dijon, France, 21000
    • Institut de Cancérologie de Bourgogne
  • Levallois-Perret, France, 92300
    • Hôpital Franco-Britannique- Fondation Cognacq-Jay
  • Lyon, France, 69373
    • Centre Léon Bérard
  • Nîmes, France, 30029
    • Institut de Cancérologie du Gard
  • Valenciennes, France, 59300
    • Clinique Onco Des Dentellieres
  • Villejuif, France, 94805
    • Departement Medecine
• Hungary
  • Debrecen, Hungary, 4032
    • Debreceni Egyetem Klinikai Kozpont
  • Kecskemét, Hungary, 6000
    • Bács-Kiskun Vármegyei Oktatókórház
  • Miskolc, Hungary, 3526
    • B-A-Z Vármegyei Központi Kórház és Egyetemi Oktatókórház
  • Tatabánya, Hungary, 2800
    • Komarom-Eszergom Varmegyei Szent Borbala Korhaz
  • Zalaegerszeg, Hungary, 8900
    • Zala Varmegyei Szent Rafael Korhaz
• Italy
  • Calabria
    • Catanzaro, Calabria, Italy, 88100
      • Azienda Universitaria Magna Grecia
  • Campania
    • Avellino, Campania, Italy, 83100
      • Azienda Ospedaliera San Giuseppe Moscati
  • Lazio
    • Rome, Lazio, Italy, 00168
      • Policlinico Universitario Agostino Gemelli
  • Lombardy
    • Milan, Lombardy, Italy, 20132
      • IRCCS Ospedale San Raffaele
    • Milan, Lombardy, Italy, 20141
      • Istituto Europeo di Oncologia
    • Monza, Lombardy, Italy, 20900
      • Ospedale San Gerardo
    • Pavia, Lombardy, Italy, 27100
      • Fondazione IRCCS Policlinico San Matteo, Oncologia
  • Sardinia
    • Sassari, Sardinia, Italy, 07100
      • Ospedale Civile
  • Sicily
    • Catania, Sicily, Italy, 95126
      • Ospedale Cannizzaro, Oncologia
  • Trentino-Alto Adige
    • Candiolo, Trentino-Alto Adige, Italy, 10060
      • Fondazione del Piemonte per l?Oncologia (IRCCS)
    • Trento, Trentino-Alto Adige, Italy, 38100
      • Ospedale Santa Chiara
  • Tuscany
    • Florence, Tuscany, Italy, 50134
      • Azienda ospedaliero-universitaria careggi, Sezione di radioterapia del dipartimento di fisiopatolo
    • Pisa, Tuscany, Italy, 56126
      • Azienda Ospedaliero - Universitaria Pisana U.O. Oncologia Medica 2 Universitaria ? Polo Oncologico
    • Prato, Tuscany, Italy, 59100
      • Nuovo Ospedale di Prato S. Stefano - Azienda USL Toscana Centro
    • Torrette, Tuscany, Italy, 60020
      • Clinica Oncologica-Ospedali Riuniti Ancona
  • Umbria
    • Città Di Castello (PG), Umbria, Italy, 06012
      • USL Umbria 1 - Osp. Città di Castello
  • Veneto
    • Mirano (VE), Veneto, Italy, 30035
      • AULSS3 - Presidio di Mirano
• Mexico
  • Distrito Federal, Mexico, 14080
    • Instituto Nacional de Cancerologia
  • Mexico CITY (federal District)
    • Mexico City, Mexico CITY (federal District), Mexico, 06720
      • Hospital de Oncología Siglo XXI
• Peru
  • Lima, Peru, 31
    • Hospital Nacional Cayetano Heredia
  • Lima, Peru, 15038
    • Instituto Nacional de Enfermedades Neoplasicas
• Poland
  • Brzozów, Poland, 36-200
    • Szpital Specjalistyczny Podkarpacki O?rodek Onkologiczny
  • Koszalin, Poland, 75-581
    • Szpital Wojewódzki im. Miko?aja Kopernika
  • Pi?a, Poland, 64-920
    • Ars Medical Sp. z o. o.
  • Rzeszów, Poland, 35-021
    • MRUKMED Lekarz Beata Madej-Mruk i Partner Spolka Partnerska Oddzial nr 1 w Rzeszowie
• Portugal
  • Almada, Portugal, 2801-951
    • Hospital Garcia de Orta
  • Coimbra, Portugal, 3000-075
    • IPO de Coimbra
  • Lisbon, Portugal, 1998-018
    • Hospital CUF Descobertas
  • Lisbon, Portugal, 1495-005
    • Hospital de S. Francisco Xavier
  • Lisbon, Portugal, 1099-023
    • IPO de Lisboa
  • Porto, Portugal, 4200-072
    • IPO do Porto
• Romania
  • Cluj-Napoca, Romania, 400015
    • Prof. Dr. I. Chiricuta Institute of Oncology
  • Craiova, Romania, 200542
    • Centrul de Oncologie Sfantul Nectarie
  • Floreşti, Romania, 407280
    • Centrul de Radioterapie Amethyst
• Slovenia
  • Ljubljana, Slovenia, 1000
    • Institute of Oncology Ljubljana
  • Maribor, Slovenia, 2000
    • Univerzitetni klini?ni center Maribor
• Spain
  • Granada, Spain, 18003
    • Hospital Universitario San Cecilio
  • Lleida, Spain, 25198
    • Hospital Universitari Arnau de Vilanova de Lleida
  • Lugo, Spain, 27003
    • Hospital Lucus Augusti
  • Madrid, Spain, 28041
    • Hospital Universitario 12 de Octubre
  • Murcia, Spain, 30008
    • Hospital General Universitario J.M Morales Meseguer
  • Málaga, Spain, 29010
    • Hospital Clínico Universitario Virgen de la Victoria
  • Salamanca, Spain, 37007
    • Hospital Clínico Universitario de Salamanca
  • Alicante
    • Elche, Alicante, Spain, 03203
      • Hospital General Universitario de Elche
  • Barcelona
    • Sabadell, Barcelona, Spain, 08208
      • Corporacio Sanitaria Parc Tauli
  • Pontevedra
    • Vigo, Pontevedra, Spain, 36312
      • Hospital Alvaro Cunqueiro
  • Principality of Asturias
    • Oviedo, Principality of Asturias, Spain, 33011
      • Hospital Univ. Central de Asturias
  • Vizcaya
    • Bilbao, Vizcaya, Spain, 48013
      • Hospital de Basurto

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Unresectable locally advanced or metastatic, histologically documented TNBC (negative for HER2 and ER and PgR)
• At least one specimen positive for PD-L1 status as determined by VENTANA PD-L1 SP142 IHC Assay
• No prior chemotherapy, experimental or targeted systemic therapy for unresectable locally advanced or metastatic TNBC
• Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1 or 2
• Life expectancy ≥ 12 weeks
• Measurable disease, as defined by RECIST v1.1
• Adequate haematologic and end-organ function, defined by the following laboratory results obtained within 14 days prior to the initiation of study treatment
• Negative hepatitis B surface antigen (HBsAg) test at screening
• Negative total hepatitis B core antibody (HBcAb) test at screening, or positive HBcAb test followed by a negative hepatitis B virus (HBV) deoxyribonucleic acid (DNA) test at screening
• Negative hepatitis C virus (HCV) antibody test at screening, or positive HCV antibody test followed by a negative HCV ribonucleic acid (RNA) test at screening
• Patients with treated asymptomatic central nervous system (CNS) metastases are eligible, provided that all the following criteria are met: (a) The metastases are limited to the supratentorial region or cerebellum (b) No ongoing requirement for corticosteroids as therapy for CNS disease (c) No stereotactic radiation within 7 days or whole-brain radiation or neurosurgical resection within 2 weeks before the start of study treatment (d) Radiographic demonstration of interim stability between the completion of CNS-directed therapy and the screening imaging study.
• Patients with a history of autoimmune disease (Appendix 2) are allowed if controlled and on stable treatment (i.e., same treatment, same dose) for the last 12 weeks
• For women of childbearing potential: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive methods that result in a failure rate of < 1% per year, during the treatment period and for at least 5 months after the last dose of atezolizumab or 6 months after the last dose of nab-paclitaxel/paclitaxel, whichever is later. In addition, women must refrain from donating eggs during the same time period
• For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive measures and agreement to refrain from donating sperm
• Women who are not postmenopausal (≥ 12 months of non-therapy-induced amenorrhea) or surgically sterile must have a negative serum pregnancy test result within 14 days prior to initiation of study drug

Exclusion Criteria:

Cancer- Specific Exclusion Criteria:

• Spinal cord compression not definitively treated with surgery and/or radiation, or previously diagnosed and treated spinal cord compression without evidence that disease has been clinically stable for > 2 weeks prior to the first dose of study treatment (Cycle 1, Day 1).
• Leptomeningeal carcinomatosis or any symptomatic CNS metastases
• Uncontrolled symptomatic pleural effusion, pericardial effusion, or ascites
• Uncontrolled tumour-related pain
• Uncontrolled hypercalcemia (> 1.5 mmol/L ionized calcium or calcium > 12 mg/dL or corrected serum calcium > ULN) or symptomatic hypercalcemia requiring continued use of bisphosphonate therapy.
• Malignancies other than breast cancer within 5 years prior to the first dose of study treatment (Cycle 1, Day 1), with the exception of those with a negligible risk of metastasis or death and treated with expected curative outcome

General Medical Exclusion Criteria:

• Pregnancy or lactation
• Evidence of significant uncontrolled concomitant disease that could affect compliance with the protocol or interpretation of results, including significant liver disease
• Significant cardiovascular disease such as New York Heart Association (NYHA) cardiac disease (Class II or greater), myocardial infarction within 3 months prior to the first dose of study treatment (Cycle 1, Day 1), unstable arrhythmias, or unstable angina
• Severe infection within 4 weeks prior to the first dose of study treatment (Cycle 1, Day 1), including but not limited to hospitalization for complications of infection, bacteraemia, or severe pneumonia, or any active infection, that in the opinion of the investigator, could impact patient safety.
• Treatment with oral or IV antibiotics within 2 weeks prior to initiation of study treatment (Cycle 1, Day 1)
• Major surgical procedure within 28 days prior to the first dose of study treatment (Cycle 1, Day 1), or anticipation of the need for a major surgical procedure during the course of the study (other than diagnostic procedures)
• Treatment with investigational therapy within 4 weeks prior to Cycle 1, Day 1
• Known hypersensitivity to nab-paclitaxel or any of the excipients, when nab-paclitaxel is used as a backbone taxane
• Known hypersensitivity to paclitaxel or any of the excipients, when paclitaxel is used as a backbone taxane
• Positive human immunodeficiency virus (HIV) test at screening, unless the patient meets all of the following conditions: stable on anti-retroviral therapy, CD4 count ≥200/mL, undetectable viral load
• Any other disease, metabolic dysfunction, physical examination finding, or clinical laboratory finding that contraindicates the use of an investigational drug, may affect the interpretation of the results, or may render the patient at high risk from treatment complications

Exclusion Criteria Related to Atezolizumab:

• History of severe allergic, anaphylactic, or other hypersensitivity reactions to chimeric or humanized antibodies or fusion proteins
• Known hypersensitivity or allergy to biopharmaceuticals produced in Chinese hamster ovary cells or any component of the atezolizumab formulation
• Prior allogenic stem cell or solid organ transplantation
• History of idiopathic pulmonary fibrosis (including pneumonitis), drug-induced pneumonitis, organizing pneumonia (i.e., bronchiolitis obliterans, cryptogenic organizing pneumonia), or evidence of active pneumonitis on screening chest CT scan
• Current treatment with anti-viral therapy for HBV
• Active tuberculosis
• Receipt of a live, attenuated vaccine within 4 weeks prior to the first dose of study treatment (Cycle 1, Day 1), or anticipation that such a live, attenuated vaccine will be required during atezolizumab treatment or within 5 months following the final dose of atezolizumab
• Prior treatment with CD137 agonists or immune checkpoint blockade therapies (including anti-CTLA4 antibodies), except for anti-PD-1 or anti-PD-L1 antibodies.
• Treatment with systemic immunostimulatory agents (including but not limited to interferons or IL-2) within 4 weeks or five half-lives of the drug (whichever is longer) prior to the first dose of study treatment (Cycle 1, Day 1)
• Only in patients without autoimmune disease: Treatment with systemic corticosteroids or other systemic immunosuppressive medications (including but not limited to prednisone, dexamethasone, cyclophosphamide, azathioprine, methotrexate, thalidomide, and antitumour necrosis factor [TNF] agents) within 2 weeks prior to the first dose of study treatment (Cycle 1, Day 1), or anticipated requirement for systemic immunosuppressive medications during the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Atezolizumab plus Nab-Paclitaxel; Participants will receive Atezolizumab via intravenous (IV) infusion on Days 1 and 15 of every 28-day cycle in combination with Nab-Paclitaxel on Days 1, 8, and 15 (individually selected by the investigator) until disease progression, or unacceptable toxicity, additionally until loss of clinical benefit as determined by the investigator or participant decision to discontinue treatment.

Drug: Atezolizumab; Atezolizumab will be administered at a dose of 840 mg via IV infusion on Days 1 and 15 of every 28-day cycle. Day 15: Atezolizumab may be administered on Days 15-18 of each cycle.; Other Names: Tecentriq; Drug: Nab-Paclitaxel; Nab-Paclitaxel will be administered at the 100 mg/m2 dose via IV infusion on Days 1, 8, and 15 of every 28-day cycle. Day 8: Nab-paclitaxel may be administered on Days 8-11 of each cycle. Day 15: Nab-paclitaxel may be administered on Days 15-18 of each cycle, on the same day with the atezolizumab infusion.; Other Names: Abraxane

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Participants With Treatment-emergent Grade ≥3 Adverse Events (AEs)	AE=untoward medical occurrence in participant administered a pharmaceutical product, regardless of causal attribution. AE=any unfavorable & unintended sign, symptom/disease temporally associated with the use of pharmaceutical product, whether/not considered related to it. Severity was graded per National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0 (NCI CTCAE v5.0). Grade 1=Mild; asymptomatic/mild symptoms; clinical/diagnostic observations only; or intervention not indicated; Grade 2=Moderate; minimal, local/non-invasive intervention indicated; or limiting age-appropriate instrumental activities of daily living; Grade 3=Severe/medically significant, but not immediately life-threatening; hospitalization/prolongation of hospitalization indicated; disabling; or limiting self-care activities of daily living; Grade 4=Life-threatening consequences/urgent intervention indicated; Grade 5=Death related to AE. Percentages have been rounded off.	Up to 60 months
Percentage of Participants With Treatment-emergent Grade ≥2 Immune-mediated AEs (imAEs)	AE=any untoward medical occurrence in a participant administered a pharmaceutical product, regardless of causal attribution. AE=any unfavorable and unintended sign, symptom/disease temporally associated with the use of a pharmaceutical product, whether/not considered related to it. Severity was graded according to NCI CTCAE v5.0. Grade 1=Mild; asymptomatic/mild symptoms; clinical/diagnostic observations only; or intervention not indicated; Grade 2=Moderate; minimal, local/non-invasive intervention indicated; or limiting age-appropriate instrumental activities of daily living (ADL); Grade 3=Severe/medically significant, but not immediately life-threatening; hospitalization/prolongation of hospitalization indicated; disabling; or limiting self-care ADL; Grade 4=Life-threatening consequences/urgent intervention indicated; Grade 5=Death related to AE. imAEs are events that resemble autoimmune diseases and are known side effects of immune checkpoint inhibitors.	Up to 60 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Participants With All Treatment-emergent AEs	An AE was any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (including abnormal laboratory values or abnormal clinical test results), symptoms, or disease temporally associated with the use of a pharmaceutical product, whether or not considered related to the PP. Percentages have been rounded off.	Up to 60 months
Percentage of Participants With All Treatment-emergent Serious Adverse Events (SAEs)	An AE was any untoward medical occurrence in a participant administered a PP and which does not necessarily have to have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (including abnormal laboratory values or abnormal clinical test results), symptoms, or disease temporally associated with the use of a pharmaceutical product, whether or not considered related to the PP. SAEs were defined as any AE that fulfilled any of the following criteria: fatal (resulted in death), life-threatening, required in-patient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/ birth defect, was medically significant or required intervention to prevent any of the other outcomes listed here. Percentages have been rounded off.	Up to 60 months
Overall Survival (OS) in Safety-evaluable Population	OS was defined as time from initiation of study treatment to death from any cause. OS was estimated using Kaplan-Meier (K-M) method.	Up to 60 months
OS in PD-L1-positive Population	OS was defined as time from initiation of study treatment to death from any cause. OS was estimated using K-M method.	Up to 60 months
Progression Free Survival (PFS) in Safety-evaluable Population	PFS was defined as the time from initiation of study treatment to the first occurrence of PD, as determined by the investigator according to Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1), or death from any cause, whichever occurs first. PD was defined as at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum of diameters at prior timepoints (including baseline), and must also demonstrate an absolute increase of ≥ 5 millimeters (mm). PFS was estimated using K-M method.	Up to 60 months
PFS in PD-L1-positive Population	PFS was defined as the time from initiation of study treatment to the first occurrence of PD, as determined by the investigator according to RECIST v1.1, or death from any cause, whichever occurs first. PD was defined as at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum of diameters at prior timepoints (including baseline), and must also demonstrate an absolute increase of ≥ 5 mm. PFS was estimated using K-M method.	Up to 60 months

Collaborators and Investigators

• Sponsor: Hoffmann-La Roche
• Investigators: Study Director: Clinical Trials, Hoffmann-La Roche

Study record dates

Study Major Dates

• Study Start (Actual): December 10, 2019
• Primary Completion (Actual): December 15, 2024
• Study Completion (Actual): December 15, 2024

Study Registration Dates

• First Submitted: October 31, 2019
• First Submitted That Met QC Criteria: October 31, 2019
• First Posted (Actual): November 4, 2019

Study Record Updates

• Last Update Posted (Actual): December 26, 2025
• Last Update Submitted That Met QC Criteria: December 24, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Breast Neoplasms; Skin and Connective Tissue Diseases; Triple Negative Breast Neoplasms; Amino Acids, Peptides, and Proteins; Proteins; Organic Chemicals; Hydrocarbons; Cycloparaffins; Hydrocarbons, Alicyclic; Hydrocarbons, Cyclic; Terpenes; Taxoids; Cyclodecanes; Diterpenes; Albumins; Paclitaxel; Albumin-Bound Paclitaxel; atezolizumab; 130-nm albumin-bound paclitaxel
• Other Study ID Numbers: MO39874; 2019-002488-91 (EudraCT Number)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: For eligible studies, qualified researchers may request access to individual patient level clinical data. See Roche's commitment to transparency of clinical study information here: https://go.roche.com/data_sharing

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes