Recruiting
Phase 1
Phase 2

GVV858 & Fulvestrant

Sponsor:

Novartis Pharmaceuticals

Code:

NCT07288359

Conditions

Advanced HR+/HER2- Breast Cancer

Advanced CCNE1-amplified Solid Tumors

Metastatic Castration-resistant Prostate Cancer

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

GVV858

Fulvestrant

Letrozole

Study Details

Brief summary:

Phase I: Characterize safety and tolerability of GVV858 as a single agent and in combination with fulvestrant or letrozole. Identify dose range for optimization/recommended dose for further clinical evaluation.

Phase II: Further characterize the safety and tolerability of GVV858 in combination with fulvestrant in patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced breast cancer.

Conditions

Advanced HR+/HER2- Breast Cancer

Advanced CCNE1-amplified Solid Tumors

Metastatic Castration-resistant Prostate Cancer

Study ID

NCT07288359

Start date

Dec 29, 2025

Status verified date

Jul, 2026

Completion date

May 9, 2031

Anticipated

Primary completion date

May 9, 2031

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • Age ≥ 18 years old.
  • Patients with one of the following histologically or cytologically confirmed advanced cancers:

Phase I (patients with one of the following cancers, from whom no standard therapy is available or appropriate in the judgment of the investigator):

  • HR+/HER2- advanced breast cancer (aBC) with disease progression on or following at least one line of hormone-based therapy in combination with a CDK4/6i and at least one additional line of systemic therapy for metastatic disease.
  • Locally advanced or metastatic cancer with a CCNE1 amplification. For dose expansion only: no more than 3 prior lines of therapy for advanced or metastatic disease.
  • Metastatic castration-resistant prostate adenocarcinoma, with no documented neuroendocrine component, castrate level of testosterone, and no more than 3 prior lines of systemic therapy for metastatic disease.

Phase II:

  • HR+/HER2- aBC with disease progression on or after an endocrine therapy in combination, with a CDK4/6 inhibitor for advanced disease with no more than 2 lines of endocrine therapy and no prior cytotoxic chemotherapy or antibody-drug-conjugate for advanced disease.

\- Measurable disease as determined by RECIST v1.1.
  • BC only: If no measurable disease is present, then at least one predominantly lytic bone lesion must be present that can be accurately assessed at baseline and is suitable for repeated assessment.
  • metastatic Castration-Resistant Prostate Cancer (mCRPC) only: If no measurable disease is present per PCWG3 modified RECIST, then at least 1 metastatic lesion must be present on bone scan imaging.

Exclusion Criteria:

  • Patients with inadequate bone marrow and/or organ functions with out-of-range laboratory values.
  • Clinically significant, uncontrolled heart disease and/or cardiac repolarization abnormality including myocardial infarction (MI), coronary artery bypass graft (CABG), long QT syndrome, or risk factors for Torsades de Pointes (TdP).
  • Presence of symptomatic central nervous system (CNS) metastases or CNS metastases that require local therapy or increasing doses of corticosteroids within 2 weeks prior to study entry.
  • Patients with symptomatic visceral disease, including visceral crisis.
  • For patients with BC: Patient is concurrently using hormone replacement therapy.
  • Women of childbearing potential who are unwilling to use highly effective contraception methods, pregnant or nursing women.

Other protocol-defined inclusion/exclusion criteria may apply.

Study Design

Enrollment

205 participants

Anticipated

Allocation

Randomized

Intervention Model

Sequential

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: GVV858 Single Agent (Arm A)

Phase I

experimental: GVV858 in combination with fulvestrant (Arm B)

Phase I

experimental: GVV858 in combination with letrozole (Arm C)

Phase I

experimental: GVV858 in combination with fulvestrant (Arm D)

Phase II, recommended dose regimen 1

experimental: GVV858 in combination with fulvestrant (Arm E)

Phase II, recommended dose regimen 2, optional dose optimization

Interventions

GVV858

Experimental

Fulvestrant

Approved medication

Letrozole

Approved medication

Primary outcome measure

  • Phase I: Incidence and severity of dose-limiting toxicities (DLTs) [ Time Frame: 28 days ]
  • Phase I and phase II: Incidence and severity of adverse events (AEs) and serious adverse events (SAEs) [ Time Frame: Up to approximately 2 years ]
  • Phase I and phase II: Frequency of dose interruptions, reductions and discontinuations [ Time Frame: Up to approximately 2 years ]
  • Phase I and phase II: Dose intensity [ Time Frame: Up to approximately 2 years ]

Central Contacts and Locations

Central contacts

Novartis Pharmaceuticals

1-888-669-6682novartis.email@novartis.com

Novartis Pharmaceuticals

+41613241111

Locations

Emory University

Recruiting

Atlanta, Georgia, United States, 30322

Contacts

Kelsey Gates

kelsey.gates@emoryhealthcare.org

Principal Investigator:

Elizabeth Sakach

Tennessee Oncology PLLC

Recruiting

Nashville, Tennessee, United States, 37203

Contacts

Caitlin J Pecknold

cpecknold@tnonc.com

Principal Investigator:

Jeffery Russell

START

Recruiting

San Antonio, Texas, United States, 78229

Contacts

Edwin Blanco-Cepeda

+1 210 593 5250edwin.blancocepeda@startresearch.com

Principal Investigator:

Amita Patnaik

More Information

Sponsor

Novartis Pharmaceuticals

Last update posted

Jul 30, 2026

Last verified

Jul, 2026

Keywords

  • GVV858
  • Fulvestrant
  • Letrozole
  • Breast Cancer
  • CCNE1 amplification
  • Prostate Cancer

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by Novartis Pharmaceuticals on 2026-07-30.