Summary
This new study will check how safe and helpful a powerful anticancer drug called BGB-21447 (Bcl-2i) is. This drug will be tested in combination with the hormone therapy Fulvestrant, with or without another targeted drug called BGB-43395 (a CDK4 inhibitor) in adults with metastatic breast cancer.
While CDK4/6 inhibitors combined with hormone (also called endocrine) therapy have improved outcomes for people with HR+/HER2- metastatic breast cancer, people may eventually develop a progressive disease on these therapies and require new treatments.
BGB-21447 is an oral drug that is highly potent and selectively stops a protein called B-cell lymphoma-2 (Bcl-2). Bcl-2 proteins are often overexpressed in some cancers (like HR+ breast cancer) by keeping the cancer cells from dying. By disrupting this pathway, anti-tumour effects can be achieved.
BGB-43395 is an oral drug that selectively stops a protein called cyclin-dependent kinase 4 (CDK4). CDK4 is a type of protein that regulates cell growth and division in your body. CDK4 inhibition is believed to have anti-tumour effects.
Fulvestrant is a treatment that blocks oestrogen receptors and reduces oestrogen production. Fulvestrant has been approved to treat hormone receptor positive (HR+) metastatic breast cancer to help stop the cancer cells from growing.
This combination might be a good way to fight cancer, aiming to give people the best possible treatment. The study is designed to see if this combination is safe and works well.
The study has two parts. In Part A, sequential cohorts of increasing dose levels of oral BGB-21447 will be evaluated in combination with Fulvestrant (given as an injection into the muscle). In Part B, sequential cohorts of increasing dose levels of oral BGB-21447 will be evaluated in combination with Fulvestrant and oral BGB-43395.