This clinical trial is focused on studying a rare type of blood cancer called Waldenstrom Macroglobulinemia (WM), which is a condition where the body produces too many abnormal white blood cells. The study is testing a treatment called brexucabtagene autoleucel, also known by its code name KTE-X19. This treatment involves using a patient’s own immune cells, which are modified in a lab to better fight cancer cells. The purpose of the study is to evaluate how effective this treatment is in patients with WM.

Participants in the study will receive the treatment through an intravenous infusion, which means it is given directly into the bloodstream. The study will also involve other medications, including ibrutinib, a drug that helps block certain proteins that cancer cells need to grow, and cyclophosphamide, a type of chemotherapy. Additionally, supportive medications like mesna to protect the bladder, methylprednisolone and dexamethasone as corticosteroids to reduce inflammation, and fludarabine, another chemotherapy drug, may be used. Some participants may receive a placebo instead of certain medications to compare the effects.

The study will take place over several months, with regular check-ups to monitor the participants’ health and the effectiveness of the treatment. The goal is to see how well the treatment works in reducing the cancer and improving the patients’ condition. Participants will be closely monitored by healthcare professionals throughout the study to ensure their safety and well-being.