New hope for advanced breast cancer: experimental drug combo enters human trials

NCT ID NCT07100106

Recruiting now Disease control Sponsor: Genentech, Inc. Source: ClinicalTrials.gov ↗

First seen Nov 01, 2025 · Last updated Jun 22, 2026 · Updated 33 times

Summary

This study tests a new drug called GDC-4198, alone or combined with another drug (giredestrant), against a standard treatment (abemaciclib plus giredestrant) in people with advanced ER+/HER2- breast cancer that has worsened after prior CDK4/6 inhibitor therapy. The trial has two phases: first to check safety and dosing, then to compare how well the new combination controls the cancer. About 285 participants will be enrolled.

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This is a summary of the original study . Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.

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Contacts and locations

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Study contacts

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Locations

ASST degli Spedali Civili di Brescia - Spedali Civili di Brescia
RECRUITING

Brescia, Lombardy, 25123, Italy
Asan Medical Center.
RECRUITING

Seoul, 05505, South Korea
Barbara Ann Karmanos Cancer Institute
RECRUITING

Detroit, Maine, 48201-2013, United States
Cancer Research SA
RECRUITING

Adelaide, South Australia, 5000, Australia
Centre Eugene Marquis
RECRUITING

Rennes, 35042, France
Centre Francois Baclesse
RECRUITING

Caen, 14076, France
Centre Oscar Lambret
RECRUITING

Lille, 59020, France
City of Hope
RECRUITING

Duarte, California, 91010, United States
City of Hope - Orange County Lennar Foundation Cancer Center
RECRUITING

Irvine, California, 92618, United States
City of Hope® Cancer Center Chicago
RECRUITING

Zion, Illinois, 60099, United States
Fudan University Shanghai Cancer Center - Pudong Campus
RECRUITING

Shanghai, Shanghai Municipality, 201321, China
Gangnam Severance Hospital, Yonsei University Health System
RECRUITING

Seoul, Seoul Teugbyeolsi, 6273, South Korea
Gustave Roussy
RECRUITING

Villejuif, Val-de-Marne, 94805, France
Hospital Beata Maria Ana
RECRUITING

Madrid, 28007, Spain
Hospital Clinico Universitario de Valencia
RECRUITING

Valencia, 46010, Spain
Hospital General Universitario Gregorio Maranon
RECRUITING

Madrid, 28007, Spain
Hospital Universitario 12 de Octubre
RECRUITING

Madrid, 28041, Spain
Hospital de Clinicas de Porto Alegre (HCPA) - PPDS
RECRUITING

Porto Alegre, Rio Grande do Sul, 90560-030, Brazil
Hospital do Cancer de Pernambuco - HCP
RECRUITING

Recife, Pernambuco, 50040-000, Brazil
Institut Jean Godinot
RECRUITING

Reims, Champagne-Ardenne, 51100, France
Instituto Do Câncer Do Estado de São Paulo Octávio Frias de Oliveira - ICESP
RECRUITING

São Paulo, 01246-000, Brazil
Instituto de Investigacion Oncologica Vall dHebron (VHIO) - EPON
RECRUITING

Barcelona, 08035, Spain
Irmandade Da Santa Casa de Misericordia de Porto Alegre
RECRUITING

Porto Alegre, Rio Grande do Sul, 90035-074, Brazil
Istituto Romagnolo per lo Studio dei Tumori Dino Amadori - IRST S.r.l - PPDS
RECRUITING

Meldola, Emilia-Romagna, 47014, Italy
KEM - Evang. Huyssens-Stiftung Essen-Huttrop
RECRUITING

Essen, North Rhine-Westphalia, 45136, Germany
Levine Cancer Institute
RECRUITING

Charlotte, North Carolina, 28204, United States
Moffitt Cancer Center
RECRUITING

Tampa, Florida, 33612, United States
New York Cancer & Blood Specialists
RECRUITING

East Patchogue, New York, 11772, United States
ONCOSITE Centro de Pesquisa Clínica Em Oncologia
RECRUITING

Ijuí, Rio Grande do Sul, 98700-000, Brazil
Princess Margaret Hospital
RECRUITING

Toronto, Ontario, M5G 2M9, Canada
Rutgers Cancer Institute of New Jersey
RECRUITING

New Brunswick, New Jersey, 08901-1914, United States
Seoul National University Bundang Hospital
RECRUITING

Seongnam-si, 13620, South Korea
Seoul National University Hospital
RECRUITING

Seoul, 03080, South Korea
Severance Hospital, Yonsei University Health System
RECRUITING

Seoul, 3722, South Korea
St Vincent's Hospital Sydney
RECRUITING

Darlinghurst, New South Wales, 2010, Australia
Texas Oncology (Worth) - USOR
RECRUITING

Dallas, Texas, 75246-2003, United States
The Catholic University of Korea, Seoul St. Mary's Hospital
RECRUITING

Seoul, 06591, South Korea
UC San Diego Moores Cancer Center
RECRUITING

La Jolla, California, 92093-1503, United States
UCSF Helen Diller Family CCC
RECRUITING

San Francisco, California, 94158, United States
UPMC - Hillman Cancer Center
RECRUITING

Pittsburgh, Pennsylvania, 15213-3108, United States
University of Pennsylvania - Abramson Cancer Center
RECRUITING

Philadelphia, Pennsylvania, 19104, United States
Vanderbilt Breast Center at One Hundred Oaks
RECRUITING

Nashville, Tennessee, 37204-3609, United States
Virginia Oncology Associates (Norfolk) - USOR
RECRUITING

Norfolk, Virginia, 23502-2800, United States
Washington University Siteman Cancer Center
RECRUITING

St Louis, Missouri, 63110-1010, United States
Winship Cancer Institute of Emory University
RECRUITING

Atlanta, Georgia, 30322-1013, United States

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance

GDC-4198 (also known as RGT-419B) and giredestrant (also known as GDC-9545)

What this could lead to

If successful, this could offer a new treatment option for people with advanced ER+/HER2- breast cancer whose disease has worsened after standard CDK4/6 inhibitor therapy.

What could go wrong

This is an early-phase (Ib/II) trial with only 285 participants, so results may not confirm benefit or safety. The new drug combination might not work better than existing treatments and could have unexpected side effects.

Conditions

The condition(s) this trial relates to.

breast cancer breast neoplasm estrogen-receptor positive breast cancer

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

BREAST CANCER