PD-1 Antibody is being studied for its use in treating metastatic solid tumors with leptomeningeal disease. This medication is administered directly into the spinal fluid, a method known as intrathecal administration. The trial aims to determine the highest dose that can be given safely and to evaluate the safety of this treatment approach. The PD-1 antibody works by blocking a specific pathway that cancer cells use to avoid being attacked by the immune system, potentially allowing the body’s natural defenses to better target and destroy cancer cells.

Leptomeningeal Disease – This condition involves the spread of cancer to the membranes surrounding the brain and spinal cord, known as the leptomeninges. It occurs when cancer cells infiltrate the cerebrospinal fluid, leading to inflammation and irritation of these protective layers. Symptoms can vary widely, including headaches, nausea, vomiting, and neurological deficits such as weakness or sensory changes. As the disease progresses, it can cause more severe neurological impairments, including difficulties with coordination, balance, and cognitive functions. The progression of symptoms often depends on the type and location of the primary cancer, as well as the extent of leptomeningeal involvement.