The US Food and Drug Administration (FDA) has announced an investigation into cases where patients who received CAR-T cell therapy, a groundbreaking cancer treatment, later developed new cancers. CAR-T cell therapy involves genetically modifying T cells to target and attack cancer cells. While this therapy has shown remarkable results in treating blood cancers, reports of patients developing secondary cancers after treatment have raised concerns.

Since 2017, the FDA has approved six commercial CAR-T cell therapies for blood cancers such as leukemias and lymphomas. These therapies have been considered a last-line option when traditional treatments like chemotherapy and radiation fail. With up to two-thirds or more of patients experiencing remission, CAR-T cell therapies have been hailed as a significant medical innovation.

However, the FDA has recently received reports of T cells becoming cancerous following CAR-T cell therapy. Some patients have been hospitalized or even died after treatment, prompting the agency to evaluate the need for regulatory action. The FDA suspects that the use of harmless viruses to insert genetic material into patients' T cells may have played a role in the development of secondary cancers.

The potential risk arises from the random integration of the genetic material into a person's genome, which could activate nearby cancer genes. The FDA's notice emphasized the need to monitor patients receiving CAR-T cell therapy for new malignancies for their lifetimes. This requirement is already in place for 15 years post-treatment due to the theoretical risk associated with these therapies.

Experts and manufacturers are responding to the FDA's investigation. David Porter, an oncologist and blood cancer expert at the University of Pennsylvania School of Medicine, where CAR-T cell therapy was pioneered, stated that they have not encountered cases of T cell cancers developing after treatment at their institution. Novartis, the manufacturer of Kymriah, one of the approved CAR-T cell therapies, affirmed that they have seen no evidence to suggest a causal relationship between their product and secondary malignancies.

While the investigation is ongoing, it is crucial to note that the FDA still considers the benefits of CAR-T cell therapies to outweigh potential risks. The FDA's announcement has sparked concerns and calls for more information, but experts believe that these occurrences are likely to be rare. As the investigation progresses, ensuring patient safety and continuous monitoring of the long-term effects of CAR-T cell therapies remains a top priority.