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Taking people in ItalyPhase 1/2

Tests GDC-4198 with or without giredestrant in advanced breast cancer

Tests GDC-4198 with giredestrant in adults whose breast cancer grew after CDK4/6 treatment.

Key facts

Who runs it
Genentech Inc.
Where
Bergamo, Bologna, Brescia, Meldola, and Milan, ItalySee the 5 sitesAlso in 3 other countries, 18 sites
Registry title
To compare the Safety and activity of GDC-4198 Alone and in Combination with Giredestrant against Abemaciclib and Giredestrant in Participants with Breast Cancer
Status
Recruiting
Phase
Phase 1/2
People taking part
73 people, planned
Started
18 Dec 2025
Expected to end
31 Aug 2028
Type of study
Interventional
Record updated
12 October 2026

Who can take part

AI summary

From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.

The trial is looking for adults with locally advanced or metastatic breast cancer that is estrogen receptor-positive and HER2-negative, whose disease got worse during or after a CDK4/6 inhibitor.

Age
18 years or older
Sex
All sexes can join
Disease stage
Breast cancer that has spread locally or to other parts of the body, confirmed by tissue or cell tests. Surgery or radiation to remove all of the disease is not possible. The disease must be measurable or at least evaluable by scans (RECIST v1.1).
Earlier treatment
The disease must have got worse during or after an approved CDK4/6 inhibitor and approved hormone (endocrine) therapy. No more than one line of therapy for advanced or metastatic disease. No earlier chemotherapy for metastatic breast cancer.
Biomarker or test result
Estrogen receptor-positive (ER+) tumor and HER2-negative tumor, documented earlier.

Main reasons for not taking part

  • Advanced, symptomatic spread to organs with a short-term risk of life-threatening complications
  • More than one line of therapy for advanced or metastatic disease
  • Earlier chemotherapy for metastatic breast cancer
  • Oral hormone therapy within 7 days before the study drug
  • Fulvestrant or a CDK4/6 inhibitor within 21 days before the study drug

The registry criteria, word for word

Show all 10 criteriaShow less

Who can take part

  • Histologically and/or cytologically confirmed adenocarcinoma of the breast that is locally advanced (not amenable to surgical or radiation therapy with curative intent) or metastatic
  • Previously documented ER+ tumor according to American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP; Allison et al. 2020) or European Society of Medical Oncology (ESMO) guidelines or any national guidelines with criteria conforming to ASCO/CAP or ESMO guidelines
  • Previously documented HER2– tumor according to ASCO/CAP (Wolff et al. 2023) or ESMO guidelines or any national guidelines with criteria conforming to ASCO/CAP or ESMO guidelines
  • Disease progression during or after treatment with an approved CDK4/6 inhibitor (e.g., abemaciclib, palbociclib, ribociclib, etc.) and approved endocrine therapy (ET) in the locally advanced or metastatic setting
  • Measurable or non-measurable evaluable disease per Response Evaluation Criteria in Solid Tumors (RECIST v1.1)
  • Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1

Who cannot take part

  • Advanced, symptomatic, visceral spread that is at risk of life-threatening complications in the short term (including massive uncontrolled effusions [pleural, pericardial, peritoneal] or pulmonary lymphangitis) appropriate for treatment with cytotoxic chemotherapy at time of entry into the study, as per national or local treatment guidelines
  • Have received more than one-line of therapy for locally advanced or metastatic disease
  • Have received prior chemotherapy for metastatic breast cancer
  • Treatment with an approved oral ET within 7 days prior to initiation of study drug; treatment with fulvestrant or an approved CDK4/6 inhibitor within 21 days prior to initiation of study drug

Where in Italy

Also in 3 other countries, 18 sites

  • Azienda Socio Sanitaria Territoriale Papa Giovanni XXIIIBergamo, ItalyTaking people
  • Azienda Ospedaliero-Universitaria Di Bologna IRCCS Istituto Di Ricerca E Di Cura A Carattere ScientificoBologna, ItalyTaking people
  • Azienda Socio Sanitaria Territoriale degli Spedali Civili di BresciaBrescia, ItalyTaking people
  • Istituto Romagnolo per lo Studio dei Tumori "Dino Amadori" - IRST S.r.lMeldola, ItalyTaking people
  • Ospedale San Raffaele S.r.l.Milan, ItalyTaking people

About the trial

What the trial wants to find out

Phase Ib Stage: To evaluate the safety of GDC-4198 alone and in combination with giredestrant Phase II Stage: To compare the efficacy of two dose levels of GDC-4198 in combination with giredestrant to the efficacy of abemaciclib in combination with giredestrant

Questions to ask the study team

  1. How often do I need to come in, and for how long each time?
  2. Are travel costs paid?
  3. Can I keep my own doctor?
  4. What happens if I want to stop?

Contact the study team: see the registry record

Print a page for my doctor

Data and sources

Registry record
Listed on the EU's official list of trials (CTIS).
Official title
A Phase Ib/ II Multicenter, Open-Label, Randomized Study Evaluating the Safety, Pharmacokinetics, and Activity of GDC-4198 Alone and in Combination with Giredestrant in Comparison with Abemaciclib and Giredestrant in Participants with Locally Advanced or Metastatic Estrogen Receptor-Positive, HER2-Negative Breast Cancer who Have Previously Progressed During or After a CDK4/6 Inhibitor
Plain-language title
Tests GDC-4198 with or without giredestrant in advanced breast cancerGenerated from the registry record. The registry title is the official one.
AI summary
From the trial's eligibility criteria. Read by machine on 9 November 2026.
Record updated
12 October 2026