In a recent report published in the New England Journal of Medicine, researchers have alerted physicians about the potential risk of developing secondary cancers in some patients undergoing CAR-T therapy, a lifesaving cancer treatment. The study emphasizes the importance of monitoring patients for unusual symptoms following the therapy.

CAR-T therapy, or chimeric antigen receptor T-cell therapy, approved in 2017, involves extracting immune cells from the patient's body, engineering them to target tumors, and infusing them back into the bloodstream. While this breakthrough treatment has saved countless lives, there is a small risk associated with gene therapies, including CAR-T, potentially disrupting cell DNA and leading to the development of other cancers.

According to the researchers, out of approximately 30,000 patients who have received CAR-T therapy in the US, 25 individuals have been diagnosed with secondary cancers afterward. While the occurrence of this side effect is rare, accounting for less than 1% of CAR-T patients, a separate study conducted by oncologists at Stanford found that up to 6.5% of patients developed secondary cancers within three years of receiving CAR-T therapy.

Despite the risks, both studies highlight that CAR-T therapy has been immensely beneficial in treating patients who have not responded to other therapies and would otherwise face a grim prognosis. However, the authors stress the importance of raising awareness among oncologists to be vigilant about monitoring their patients for new cancer developments.

Dr. Metin Ozdemirli, a co-author of the study and a professor of pathology at Georgetown University, explains that early detection becomes easier when physicians are aware of the potential problems to look out for. As CAR-T therapy becomes more widely adopted, it is essential to remain cautious and attentive to any signs of secondary cancer.

In November 2023, the FDA announced a review of CAR-T therapy, specifically investigating these 19 reported cases of secondary cancer. The review aims to gain a deeper understanding of the association between CAR-T therapy and the development of secondary cancers.

The report published by oncologists and pathologists from Georgetown University Hospital presented a case study of a 71-year-old woman who had been battling cancer for eight years. After receiving CAR-T therapy for myeloma, a type of cancer affecting white blood cells in the bone marrow, the patient initially showed no signs of cancer. However, four months later, she experienced weight loss and persistent diarrhea, leading to further investigations.

Doctors initially diagnosed her with an autoimmune disease and treated her with steroids, but when her condition did not improve, a biopsy revealed the reappearance of cancer. The patient had developed lymphoma, a cancer affecting the immune system, approximately nine months after CAR-T treatment. Analysis of the tumor's DNA suggested that it may have originated from the immune cells used for CAR-T therapy.

Scientists are still not entirely certain about the mechanisms behind these occurrences. They hypothesize that the cells collected from patients for therapy could possess cancerous mutations, or mutations could occur during the manufacturing or reintroduction process.

While the patient in question is currently undergoing treatment for the new cancer, her symptoms have shown slight improvement as of April 2024, according to the report.

In conclusion, the recent studies highlight the necessity of closely monitoring patients who undergo CAR-T therapy for the potential development of secondary cancers. While the incidence remains rare, it is crucial for oncologists to remain vigilant and consider this rare side effect of the treatment. As research progresses, further understanding of the underlying mechanisms will help improve the safety and effectiveness of CAR-T therapy, allowing more patients to benefit from this groundbreaking treatment.