Study of Vimseltinib for Tenosynovial Giant Cell Tumor

To join this study, you need to be at least 18 years old and have Tenosynovial Giant Cell Tumor (TGCT) that your doctor has confirmed through a biopsy, especially if you don't have previous results. Importantly, your TGCT must be in a situation where surgery isn't a suitable treatment option for you. You should also be experiencing symptoms like at least moderate pain or stiffness from your TGCT.

Your existing pain medication should be stable for at least two weeks before starting the study. The tumor must be a certain size (at least 2cm) and visible on scans for doctors to measure any changes. You'll also need to be well enough overall, with healthy organ and bone marrow function. If you're a woman who could become pregnant, you'll need to have a negative pregnancy test and agree to use effective contraception during the study.

There are also reasons why you might not be able to join. For example, if you've already had certain types of targeted drug treatments for TGCT (like those affecting CSF1 or CSF1R), or if you've recently taken part in another drug study. Serious heart rhythm problems, known widespread TGCT (outside the local area), or other active cancers that need immediate treatment might also mean you can't participate. Your study doctor will review all your health information to confirm if this study is right for you.

If you decide to take part, the study involves two main stages. For the first 24 weeks, you'll be randomly assigned to receive either the study drug, vimseltinib, or a placebo (a dummy drug). Neither you nor your study doctor will know which one you're receiving during this time. Throughout these 24 weeks, you'll have regular visits to the clinic for various checks. These will include physical examinations, blood tests, and heart tracings (ECGs). You'll also have MRI scans to measure your tumor and complete questionnaires about your symptoms and how you're feeling on an electronic device.

After 24 weeks, if you were initially on the placebo, you'll have the option to switch to receiving vimseltinib. Everyone who continues in the study from this point onwards, including those who started on vimseltinib, will receive the active drug. This second part of the study is a long-term treatment phase, and you'll continue to have regular check-ups and assessments similar to the first part. The total duration of your participation in the study will depend on how long the study continues and your individual health journey, but it generally involves regular visits over an extended period.