A Study of BGB-16673 Compared to Investigator's Choice in Participants With Chronic Lymphocytic Leukemia or Small Lymphocytic Lymphoma Previously Exposed to Both Bruton Tyrosine Kinase (BTK) and B-cell Leukemia/Lymphoma 2 Protein (BCL2) Inhibitors

To join this study, doctors will first check if you have a confirmed diagnosis of CLL or SLL and if your condition requires treatment. It's important that you have already received treatment for your CLL or SLL using specific medicines known as BTK inhibitors and BCL2 inhibitors. If you have SLL, your doctors need to be able to see and measure your cancer using scans like CT or MRI.

Other important checks include your general health and how well your body is working. Your doctor will assess your overall physical condition, and they'll also check your liver and blood clotting functions to make sure they are healthy enough to take part in the study. You must be at least 18 years old.

However, there are reasons why you might not be able to join. For example, if you have another more aggressive type of leukemia or if your cancer has spread to your brain or spinal cord. Also, if you've recently had certain types of transplants or cell therapy, or if you have a serious infection, or certain heart problems, you might not be eligible. Your study doctor will review all these details carefully with you.

If you decide to join this study, you will be randomly assigned to receive either the new drug, BGB-16673, or one of several existing treatments. Neither you nor your doctor will get to choose which treatment you receive; this is done by chance, like flipping a coin, to make the study fair. The treatments will be given according to a set schedule, which might involve taking medicine by mouth or through an infusion (drip).

Throughout the study, you will have regular visits to the clinic. These visits will involve various tests, such as blood tests, physical examinations, and scans (like CT or MRI) to monitor your health and how your cancer is responding to the treatment. These checks are important for your safety and to see if the treatment is working. The study team will explain how often these visits will be and what they will involve.

The duration of your participation will depend on how you respond to the treatment. You will continue treatment as long as it is helping you and you are not experiencing severe side effects. Even after you stop receiving the study drug, there will be follow-up appointments to continue monitoring your health. The total duration of your involvement could be several years, including follow-up.