Teniposide is primarily used in the treatment of certain types of cancer, particularly acute lymphoblastic leukemia (ALL) in children who have not responded to other treatments. It works by inhibiting the enzyme topoisomerase II, which is essential for DNA replication and cell division, thereby preventing the growth and proliferation of cancer cells.

In clinical settings, teniposide is often administered intravenously as part of combination chemotherapy regimens. It is particularly effective in cases where patients have relapsed or are refractory to standard therapies. Additionally, teniposide has shown activity against other malignancies, such as neuroblastoma, non-Hodgkin lymphoma, and brain tumors, though its use in these conditions is less common.

Due to its mechanism of action, teniposide is particularly useful in targeting rapidly dividing cancer cells, but it can also affect normal cells, leading to potential side effects such as myelosuppression, alopecia, and gastrointestinal disturbances. Careful monitoring and supportive care are essential during treatment to manage these adverse effects and optimize therapeutic outcomes.