Kymriah is a groundbreaking immunotherapy treatment that has shown promising results in the treatment of certain types of cancer. It is a CAR-T cell therapy that involves modifying a patient's own T cells to recognize and attack cancer cells. The persistence of Kymriah in the body is an important factor to consider in terms of its effectiveness and potential side effects.

According to the sources provided, there is limited information available specifically about the duration of persistence of Kymriah in the body. The drug patent information [1] does not provide specific details about the persistence of Kymriah. However, the FDA document [2] and the research article [3] shed some light on the topic.

The FDA document [2] states that the persistence of Kymriah in patients can vary and may depend on factors such as the disease being treated, the individual patient, and the specific characteristics of the CAR-T cells used. It mentions that Kymriah has been detected in patients for up to 20 months after infusion, but the duration of persistence beyond that timeframe is not well established.

The research article [3] discusses the persistence of CAR-T cells in general and provides some insights into the potential duration of Kymriah's presence in the body. It explains that CAR-T cells can persist in patients for months to years, and in some cases, they may become long-term memory cells. However, the article also highlights that the persistence of CAR-T cells can vary between patients and depends on various factors, including the type of cancer being treated and the characteristics of the CAR-T cells.

It is important to note that the persistence of Kymriah in the body is not necessarily indicative of its effectiveness. The response to Kymriah treatment can vary between patients, and the duration of response may depend on several factors, including the type and stage of cancer being treated.

In conclusion, the available sources do not provide specific information about the exact duration of Kymriah's persistence in the body. However, it is known that CAR-T cells, including Kymriah, can persist in patients for months to years. Further research and clinical studies are needed to better understand the persistence of Kymriah and its implications for cancer treatment.

Sources:
[1] Drug Patent Watch. Kymriah Trademark Details. Retrieved from: https://www.drugpatentwatch.com/p/biologics/tradename/KYMRIAH
[2] U.S. Food and Drug Administration (FDA). Kymriah Prescribing Information. Retrieved from: https://www.fda.gov/media/107296/download
[3] Turtle CJ. et al. (2019). CD19 CAR-T cells of defined CD4+:CD8+ composition in adult B cell ALL patients. Journal of Clinical Investigation, 129(6), 2123-2138. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10056741/