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GDC-4198

Phase 1

Breast Cancer | Small molecule | Oncology |Roche Holding AG|Last Updated: Aug 10, 2026

Success Probability

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Market & Valuation

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Trial Design

RandomizedCONTROLLED
Total Trials1
Total Enrollment285

FDA Designations

No designations recorded

Clinical trial landscape

GDC-4198 · 1 trial · 1 indication

Phase 1 1
NCT07100106A Study to Evaluate the Effect of GDC-4198 Alone and in Combination With Giredestrant Versus Abemaciclib and Giredestrant in Participants With Locally Advanced or Metastatic Estrogen Receptor-Positive (ER+), Human Epidermal Growth Factor Receptor-Negative (HER2-) Breast CancerBreast Cancer
RECRUITING285 Analytics
PHASE1RECRUITING
A Study to Evaluate the Effect of GDC-4198 Alone and in Combination With Giredestrant Versus Abemaciclib and Giredestrant in Participants With Locally Advanced or Metastatic Estrogen Receptor-Positive (ER+), Human Epidermal Growth Factor Receptor-Negative (HER2-) Breast Cancer
Breast CancerUnlock trial analytics

Study Endpoints

Primary Endpoints

Phase Ib: Incidence and Severity of Adverse Events (AEs)
Up to 36 months

Severity of AEs determined according to the CTCAE v5.0 grading scale

Phase Ib: Number of Participants With Dose-Limiting Toxicity (DLTs)
From Day 1 to Day 28 of Cycle 1 (1 cycle=28 days)
Phase II: Progression-free Survival (PFS)
Up to 36 months

Secondary Endpoints

Phase Ib: Objective Response Rate (ORR)
Up to 36 months
Phase Ib: Clinical Benefit Rate (CBR)
Up to 36 months
Phase II: ORR
Up to 36 months
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Study Design & Arms

AllocationRANDOMIZED
MaskingNONE
ModelSEQUENTIAL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Phase Ib: Dose-Finding StageEXPERIMENTALParticipants will receive GDC-4198 as monotherapy and in combination with giredestrant, 30 milligrams (mg), orally, daily, as per a pre-defined dosing regimen during each cycle until unacceptable toxicity or disease progression and/or loss of clinical benefit. (1 cycle=28 days).
Phase II: Arm AEXPERIMENTALParticipants will receive GDC-4198, higher dose, in combination with giredestrant, 30 mg, orally, daily, as per a pre-defined dosing regimen during each cycle until unacceptable toxicity or disease progression and/or loss of clinical benefit. (1 cycle=28 days).
Phase II: Arm BEXPERIMENTALParticipants will receive GDC-4198, lower dose, in combination with giredestrant, 30 mg, orally, daily, as per a pre-defined dosing regimen during each cycle until unacceptable toxicity or disease progression and/or loss of clinical benefit. (1 cycle=28 days).
Phase II: Arm CEXPERIMENTALParticipants will receive abemaciclib, 150 mg twice daily, in combination with giredestrant, 30 mg, orally, daily, as per a pre-defined dosing regimen during each cycle until unacceptable toxicity or disease progression and/or loss of clinical benefit. (1 cycle=28 days).

Interventions

NameTypeDescription
GDC-4198DRUGGDC-4198 will be administered orally.
GiredestrantDRUGGiredestrant will be administered orally.
AbemaciclibDRUGAbemaciclib will be administered orally.
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites61

Inclusion Criteria: * Histologically and/or cytologically confirmed adenocarcinoma of the breast that is locally advanced or metastatic. * Previously documented ER+ and HER2- tumor according to American Society of Clinical Oncology (ASCO)/ College of American Pathologists (CAP) or European Society ...

Countries:United StatesAustraliaBrazilCanadaChinaFranceGermanyItalySouth KoreaSpain
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Competitive Landscape -Breast Cancer 402 trials

Top 20 of 92 competitors

CompanyTickerTrialsLead PhaseDrugs
AstraZeneca PLCAZN47PHASE3Fulvestrant, Capivasertib
Merck & Co., Inc.MRK12PHASE3Pembrolizumab, Paclitaxel, Doxorubicin, Epirubicin, Cyclophosphamide
Eli Lilly and CompanyLLY27PHASE3Abemaciclib, Standard Adjuvant Endocrine Therapy
BioNTech SE Sponsored ADRBNTX7PHASE3DB-1303/BNT323, T-DM1
Gilead Sciences, Inc.GILD13PHASE3Sacituzumab Govitecan-hziy, Eribulin, Capecitabine Product, Gemcitabine, Vinorelbine
Novartis AG Sponsored ADRNVS30PHASE3Ribociclib
Pfizer Inc.PFE34PHASE3ARV-471, Fulvestrant
BeOne Medicines Ltd. Sponsored ADRONC5PHASE3BGB-43395, Letrozole, Abemaciclib, Palbociclib, Ribociclib
Olema Pharmaceuticals, Inc.OLMA5PHASE3Palazestrant, Fulvestrant, Anastrozole, Letrozole, Exemestane
Jazz Pharmaceuticals Public Limited CompanyJAZZ3PHASE3Zanidatamab, Trastuzumab, Eribulin, Vinorelbine, Gemcitabine
Celcuity Inc.CELC3PHASE3Gedatolisib, Palbociclib, Fulvestrant, Alpelisib
Relay Therapeutics, Inc.RLAY2PHASE3Zovegalisib, Capivasertib, Fulvestrant
GSK plc Sponsored ADRGSK2PHASE3Niraparib
Greenwich LifeSciences, Inc.GLSI1PHASE3GLSI-100
Bristol-Myers Squibb CompanyBMY5PHASE2Iza-bren, Nab-paclitaxel, Paclitaxel, Capecitabine, Carboplatin
BriaCell Therapeutics CorpBCTX2PHASE3SV-BR-1-GM, Cyclophosphamide, Interferon infiltration of the inoculation site, Retifanlimab, Treatment of Physician's Choice
Incyte CorporationINCY4PHASE2Ruxolitinib, Capecitabine, Regorafenib
Natera, Inc.NTRA3PHASE2Discontinuation of the anti-HER2 maintenance therapy
Puma Biotechnology, Inc.PBYI3PHASE2Neratinib, Loperamide, Colesevelam
Atossa Therapeutics, Inc.ATOS1PHASE2endoxifen, goserelin
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Recent Changes (Last 90 Days)

LOWAug 11, 2026NCT07100106lastUpdatePostDate: changed
LOWAug 11, 2026NCT07100106lastUpdatePostDate: changed
LOWAug 11, 2026NCT07100106lastUpdatePostDate: changed
LOWJul 13, 2026NCT07100106lastUpdatePostDate: changed
LOWJul 13, 2026NCT07100106lastUpdatePostDate: changed
LOWJul 5, 2026NCT07100106primaryCompletionDate: changed
LOWJul 5, 2026NCT07100106primaryCompletionDate: changed
LOWJul 5, 2026NCT07100106primaryCompletionDate: changed

Frequently asked questions about GDC-4198

What is GDC-4198 used for in breast cancer?

GDC-4198 is an investigational small molecule being studied for the treatment of locally advanced or metastatic estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2-) breast cancer. It is currently in Phase 1 clinical development and is not yet approved by regulatory authorities.

What does GDC-4198 target?

GDC-4198 is a small molecule being evaluated in combination with giredestrant for ER+ HER2- breast cancer. Its specific molecular target has not been disclosed in the available clinical trial information, so its mechanism of action is not described here.

Who makes GDC-4198?

GDC-4198 is being developed by Roche Holding AG, which trades under the ticker RHHBY. The company is conducting a Phase 1 clinical trial of the drug in patients with ER+ HER2- breast cancer.

What phase is GDC-4198 in?

GDC-4198 is in Phase 1 clinical development. It is an investigational drug and has not been approved by the FDA or any other regulatory agency. The ongoing trial is actively recruiting participants.

What clinical trials is GDC-4198 in?

GDC-4198 is being studied in a single Phase 1 clinical trial, NCT07100106. This trial evaluates GDC-4198 alone and in combination with giredestrant versus abemaciclib and giredestrant in participants with ER+ HER2- breast cancer. The trial is recruiting in the United States, Australia, Brazil, Canada, China, France, Germany, Italy, South Korea, and Spain.

Is GDC-4198 the same as giredestrant?

No, GDC-4198 is not the same as giredestrant. GDC-4198 is the investigational drug being studied, while giredestrant is a separate agent used in combination with GDC-4198 in the clinical trial. The trial compares GDC-4198 plus giredestrant against abemaciclib plus giredestrant.