Secondary Cancers Post CAR T Therapy: A Concern?

TOPLINE:

Secondary cancers were flagged in 4.3% of all adverse event reports among patients who received CAR T therapy, with T-cell malignancies comprising only 0.15% of the total reports and 3.54% of all second primary malignancies, according to an analysis of adverse event reports submitted to the US Food and Drug Administration (FDA).

METHODOLOGY:

• In November 2023, the FDA announced its investigation into whether chimeric antigen receptor (CAR) T-cell immunotherapies can cause secondary blood cancers, specifically T-cell malignancies. At the time, the agency said: “Although the overall benefits of these products continue to outweigh their potential risks for their approved uses, FDA is investigating the identified risk of T-cell malignancy with serious outcomes.”
• In January 2024, the FDA issued boxed warnings on the six approved CART cell therapies, citing the possibility of second primary malignancies, including CAR-positive lymphomas, in patients who had received a CAR T agent.
• To evaluate the extent of these secondary cancers, researchers analyzed the FDA Adverse Event Reporting System database for CAR T-cell reports citing second primary malignancies.

TAKEAWAY:

• Overall, the authors identified 12,394 unique adverse events associated with CAR T therapy; of these, 536 adverse events (4.3%) were second primary malignancies.
• Axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tis-cel) accounted for most of the second primary malignancies reports — 51.7% (277 of 536 patients) for axi-cel and 33% (177 of 536 patients) for tis-cel.
• The researchers identified 19 cases of T-cell malignancies, representing only 0.15% of all unique adverse events and 3.54% of all second primary malignancies (19 of 536 patients); 17 of these cases were T-cell non-Hodgkin lymphomas, and two were T-cell large granular lymphocytic leukemia.
• Among the reported 536 second primary malignancies, the most frequent cancers were leukemias (333 reports, or 62%), followed by skin neoplasms (54 reports, or 10.1%), hematopoietic neoplasms excluding leukemias and lymphomas (26 reports, 4.85%), nervous system tumors (21 reports, 3.92%), and respiratory neoplasms (20 reports, 3.73%).

IN PRACTICE:

“We will continue to monitor the data released by the FDA to learn more about CAR T-associated risks. However, it’s crucial to stress that the benefits of CAR T-cell therapies still outweigh the risks for the approved indications,” Magdi Elsallab, MD, the study’s co-lead author, said in a news release.

SOURCE:

This work, led by Dr. Elsallab from Harvard Medical School in Boston, was published online on March 14 in Blood.

LIMITATIONS:

The limitations of the analysis include the presence of duplicate report submissions, incomplete data, difficulty establishing causal relationships, and the potential for both underreporting and overreporting based on the severity of adverse events. Furthermore, without the total number of prescribed products, it was difficult to determine the adverse event frequency.

DISCLOSURES:

The study funding source was not disclosed. Some of the authors reported financial ties with various organizations outside this work, including Bristol Myers Squibb, Janssen Biotech, Johnson & Johnson, Kite Pharma, and Novartis.

A version of this article appeared on Medscape.com.