This study is for adults with **relapsed or refractory multiple myeloma (RRMM)**, a type of blood cancer that comes back or doesn’t respond to treatment. The research looks at **KTX-1001**, a new medicine taken by mouth to see if it’s safe and how well it works. It stops certain proteins that help cancer grow. The study has two parts. In the first part, they test different doses to find the best one. In the second part, they use this best dose to see how safe it is and how it works with other treatments, like dexamethasone. Patients need to have tried at least three different treatments before, including certain drugs like **carfilzomib** and **pomalidomide**. They must be 18 or older and have specific health conditions checked, like protein levels in their body. Some people can’t join, especially if they have other serious diseases, ongoing infections, or other cancers that need treatment.

• Study lasts about 28 days for the first cycle, with more cycles if continued.
• Regular check-ups and tests are needed during the study.
• Risks include common side effects of cancer drugs, like tiredness or nausea.