Recruiting
A Study of GB491 in Combination With Letrozole in Patients With HR Positive and HER2 Negative Advanced Breast Cancer
The main purpose of this study is to evaluate the efficacy and safety of GB491 combined with Letrozole versus placebo combined with Letrozole in the treatment of HR+/HER2- locally advanced or metastatic breast cancer without prior systemic antitumor therapy
ClinicalTrials.gov IDNCT05851014
PhasePHASE3
Enrollment350
SponsorGenor Biopharma Co., Ltd.
Age18 Years
SexALL
Conditions studied
Breast Cancer
About this study
The main purpose of this study is to evaluate the efficacy and safety of GB491 combined with Letrozole versus placebo combined with Letrozole in the treatment of HR+/HER2- locally advanced or metastatic breast cancer without prior systemic antitumor therapy
Interventions
- Drug: GB491 combined with Letrozole — Patients were randomized to receive GB491 150 mg orally twice daily, depending on their assignment. Letrozole 2.5 mg orally once a day from the first day of cycle 1 (one cycle every 28 days)
- Drug: Placebo combined with Letrozole — Patients were randomized to receive placebo orally twice daily, depending on their assignment. Letrozole 2.5 mg orally once a day from the first day of cycle 1 (one cycle every 28 days)
Primary outcomes
- Investigator-assessed PFS based on RECIST v1.1 (Approximately 60 months)
Eligibility information
Inclusion Criteria:
* 1\. Age: 18-75 years old;
* Have a pathologically-confirmed diagnosis of hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) breast cancer;
* No previous systematic antitumor therapy for locally advanced or metastatic breast cancer;
* Eastern Cooperative Oncology Group \[ECOG\] 0-1;
* Have adequate organ and marrow function;
* Agree to sign the informed consent;
Exclusion Criteria:
* Systematic treatment with any other CDK4/6 inhibitor；
* Subjects with known allergy to GB491 or any component of Letrozole；
* Confirmed diagnosis of HER2 positive disease;
* Known uncontrolled, or symptomatic central nervous system metastases;
* Had major surgery (or is expected to require major surgery during the study period), chemotherapy, radiation, any investigational drug, or other antitumor therapy within 4 weeks prior to randomization;
* Have previously received chemotherapy for locoregionally recurrent or metastatic breast cancer;
* Clinically significant cardiovascular and cerebrovascular diseases, including but not limited to severe acute myocardial infarction within 6 months before enrollment, unstable or severe angina, Congestive heart failure, or ventricular arrhythmia which need medical intervention；
* Known history of HIV infection or HIV seropositivity (including HIV antibody positive at the time of screening)
Study locations
- The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233004 China
- The First Hospital of Anhui Medical University, Hefei, Anhui 230022 China
- Anhui Cancer Hospital, Hefei, Anhui 230031 China
- The Second Hosptial of Anhui Medical University, Hefei, Anhui 230601 China
- Betjing Tiantan Hosptial，Capital Medical University, Beijing, Beijing Municipality 100070 China
- Chinese PLA General Hospial, Beijing, Beijing Municipality 100853 China
- The First Affiliated Hospital of Chongqing Medical University, Chongqing, Chongqing Municipality 400016 China
- Chongqing University Cancer Hospital, Chongqing, Chongqing Municipality 400030 China
- Fujian Medical University Union Hospital, Fuzhou, Fujian 350001 China
- The First Hospital of Wenzhou Medical University, Wenzhou, Fujian 325000 China
Showing 10 of 52 reported sites. See the official listing for all locations.
Before you participate: Varda Clinical is an independent discovery tool, not the study sponsor or a medical provider. Eligibility can only be determined by the official study team. Discuss potential risks and benefits with a qualified healthcare professional.
Source: ClinicalTrials.gov. Record last refreshed by Varda Clinical: 2026-09-27.