This study is for people with a type of bone cancer called chondrosarcoma. Chondrosarcoma is a cancer that forms in the cartilage, a tough but flexible tissue that covers the ends of bones. The study is testing a medicine called ivosidenib, which is taken as a pill every day. Some people will get ivosidenib, and others will get a placebo (a pill that looks like the medicine but doesn't have any medicine in it). The study will help doctors see if ivosidenib helps stop the cancer from growing. To join, you must have a specific change in your genes called an IDH1 mutation and have either not been treated or only had one previous treatment for your cancer.

• The study requires regular visits to the hospital for tests and check-ups.
• Participants will be randomly assigned to receive either the study drug or a placebo.
• There may be risks, such as side effects from the medication.