In this study, people will take a special medicine called PLX-61639 one time each day. Before starting, there will be a time called the screening period that can last up to 28 days. During this time, doctors will check to see if you can join the study. After that, you will take the medicine in 28-day cycles.

You will go to the clinic often for check-ups. These visits will include blood tests, heart tests, and scans. Some visits might take the whole day. You will also write in a diary to keep track of when you take the medicine. The amount of medicine you get may be different depending on when you join the study. You can stay in the study as long as the doctor thinks the medicine is helping you.

This study is for people who have a serious kind of cancer. The cancer has spread or gotten worse, and it was caused by a change in a gene called SMARCA4.

To join this study, people must have cancer that was caused by a change in the SMARCA4 gene. Their cancer must have come back or not gotten better with other treatments. They must be adults who are 18 years old or older. They cannot be pregnant or breastfeeding. If they or their partner could become pregnant, they must agree to follow rules to help prevent pregnancy during the study.

This study is trying out a new medicine called PLX-61639. The goal is to find out if the medicine is safe and if it can help treat a certain kind of cancer. The medicine works by breaking down a protein that is found in cancer cells. Scientists hope this study will lead to better ways to treat people who have this type of cancer.