Radiation Prior to CAR-T Therapy for Multiple Myeloma Does Not Increase Toxicity

Treatment with radiation prior to chimeric antigen receptor (CAR) T-cell therapy was found to be safe and did not increase toxicity for patients with multiple myeloma (MM), according to new findings presented at the American Society for Radiation Oncology (ASTRO) 2020 Annual Meeting.

CAR-T therapy is an immunotherapy which uses genetically modified T-cells from the patient to reprogram their immune system to attack cancer cells. Radiation therapy is often used for patients with MM to alleviate bone pain, though the impact this treatment on patients receiving CAR-T cell therapy is still being studied.

This new study found patients who received radiation 34 days or fewer before CAR-T infusions did not have higher rates severe of cytokine syndrome (CRS) or neurotoxicity than patients who did not receive the radiation bridging care, suggesting radiation is a safe option for patients prior to the cell therapy.

Researchers from Penn Medicine conducted a retrospective analysis using medical records of 25 patients with MM who received CART-BCMA (B cell maturation antigen) cell therapy. Patients were categorized into three groups: those who received radiation t 34 days or less prior to CAR-T infusion, those who received radiation within one year of infusion, and a third group who received no radiation within at least one year preceding the cellular therapy.

None of the four patients who underwent radiation within 34 days of CAR-T infusion experienced levels of CRS or other toxicities higher than grade 3. These patients also had lower rates of grade 4 hematologic toxicities. Three of eight patients who received radiation within one year of cellular therapy experienced grade 3 or higher CRS. Out of the 13 patients who did not receive any radiation therapy, five experienced grade 3 or higher CRS. Administration of radiation therapy was not associated with a decrease in overall survival or progression free survival.

“Our work is hypothesis generating, hinting at a potential synergism between radiation and CART-BCMA therapy, which has been reported by others in the literature,” said lead author Shwetha Manjunath, MD, Radiation Oncology Resident at Penn’s Perelman School of Medicine, in a press release. “Future prospective trials that combine radiation with CART-BCMA may further optimize safety and long-term efficacy of this novel cell therapy.”