This study has two groups. In the first group, people take a usual cancer medicine called zanubrutinib. It is taken as a pill by mouth two times each day, and the treatment is given in cycles that last 28 days.

In the second group, people take zanubrutinib first for a few cycles. After that, they also start taking a new study medicine called sonrotoclax. This medicine is added slowly, starting at a low dose and increasing step by step each week until the full dose is reached. This is done to help keep people safe and lower the risk of side effects.

The study compares these two treatment plans to see if adding the new medicine works better than the usual treatment alone.

This study is for people who have a blood cancer called chronic lymphocytic leukemia or small lymphocytic lymphoma. These people have not received treatment for this cancer before, but their disease has now gotten worse to the point where treatment is needed. Researchers want to learn more about how to treat this cancer in people who are starting therapy for the first time.

People can join this study if they have a blood cancer called chronic lymphocytic leukemia and meet medical rules that show they need treatment. They must not have been treated for this cancer before.

Participants must be 65 years old or older and healthy enough to take part in the study and do most daily activities. They cannot have had recent surgery or be taking certain blood thinning medicines like warfarin. They must also be able to swallow pills. Some treatments for complications must be finished before joining the study.

This study is trying to learn if adding a new medicine called sonrotoclax to a usual treatment called zanubrutinib can help people with this blood cancer. Researchers want to see if using both medicines together can keep the cancer from getting worse for a longer time compared to using the usual treatment alone.

The study will also look at a blood test that checks for very small amounts of cancer left in the body. Doctors want to learn if this test can help decide how long people should stay on treatment and help control the cancer better.

The goal of the study is to find out if this new approach works better than the usual care and can help people stay healthier for a longer time without their cancer getting worse.