As scientists find innovative ways to harness the body’s own immune system to fight cancer, the FDA is working fast to review and recommend treatments with the most life-saving potential. Just months after the FDA fast-tracked approval of a novel method of treatment for cancers based on specific biomarkers instead of the location of the body where the cancer originated, the agency is now closer to approving cancer treatment that utilizes genetically engineered cells from the patient’s own immune system.

This form of immunotherapy treatment is named adoptive cell transfer (ACT) and involves modifying the body’s T cells (cells produced by the thymus gland which play a key role in immunity) in a lab before reintroducing them back into the patient. This method is known among the medical community as using a “living drug” because it involves using the patient’s own body to recognize and re-produce the new cells.

When the patient’s T cells are collected, they are genetically modified to produce protein receptors on their surface called chimeric antigen receptors (CARs). These proteins help the T cells recognize another protein specific to the tumor cells. The cells are multiplied in the lab before being reinserted into the patient where they are multiplied again by the body as they destroy the cancerous cells. Although costly at about $500,000 per infusion and requiring specific and thorough training to administer, this method of treatment has been promising, producing remission in 83% of patients.