In short
BGB-43395 fumarate is an investigational oral substance being studied for previously untreated advanced or metastatic HR+/HER2- breast cancer. The clinical data currently consist of one Phase 3 trial (NCT07492641) with 1,056 planned participants, comparing BGB-43395 plus letrozole against CDK4/6 inhibitors plus letrozole. The trial is authorised, and its main measure is progression-free survival.
Key points
- Phase 3 trial in advanced or metastatic HR+/HER2- breast cancer
- 1,056 participants planned
- Compares BGB-43395 plus letrozole with CDK4/6 inhibitor plus letrozole
- Main measure: progression-free survival by blinded independent central review
- Trial status: Authorised
- Given orally, in combination with letrozole
What is BGB-43395 fumarate?
BGB-43395 fumarate is an investigational substance being studied in oncology. The available registry data do not state its exact chemical class, but the trial in which it is being investigated uses it in combination with letrozole for patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) breast cancer. The substance is given orally, and the registry record lists its dose as not reported (0 mg in the intervention description).
How does BGB-43395 fumarate work?
The available clinical trial record does not describe the mechanism of action of BGB-43395 fumarate. The trial compares BGB-43395 plus letrozole with three different CDK4/6 inhibitors (abemaciclib, palbociclib, and ribociclib) plus letrozole. This comparison suggests that BGB-43395 may act in a related pathway, but no mechanism is stated in the registry data, so no further statement can be made.
Which conditions is BGB-43395 fumarate studied for?
- Advanced or metastatic HR+/HER2- breast cancer — breast cancer that is hormone receptor-positive and HER2-negative, and has spread beyond the breast or is locally advanced.
How is BGB-43395 fumarate given?
BGB-43395 fumarate is given orally in the trial. The registry record does not specify a dose for BGB-43395 (listed as 0 mg), while the comparator CDK4/6 inhibitors are listed with their oral doses: abemaciclib 300 mg, palbociclib 125 mg, and ribociclib 600 mg. Letrozole is given at 2.5 mg orally in all arms.
What do the clinical trials show?
There is one registered clinical trial for BGB-43395 fumarate: a Phase 3 interventional study with 1,056 planned participants. The trial is authorised, meaning it has received approval to begin, but no results are yet available in the registry.
What is the trial measuring?
The primary outcome is progression-free survival (PFS), defined as the time from randomisation to the first documentation of disease progression or death, whichever occurs first, as determined by blinded independent central review (BICR) using RECIST v1.1 criteria. RECIST v1.1 is a standard way of measuring tumour response to treatment.
Who can take part?
The trial enrols patients with advanced or metastatic HR+/HER2- breast cancer who have not received prior systemic treatment for advanced or metastatic disease. The trial compares two treatment approaches: BGB-43395 plus letrozole (Arm A) versus a CDK4/6 inhibitor plus letrozole (Arm B).
What side effects are known?
The registry record for this trial does not list side effects for BGB-43395 fumarate. No supplementary sources with side effect information were provided, so no side effect profile can be described.