Dr Danish on Post-CAR T-Cell Bridging Radiation Therapy Eligibility in High-Risk NHL

Adnan F. Danish, MD, chief, Division of Radiation Oncology, St. Joseph’s Health; radiation oncologist, John Theurer Cancer Center, Hackensack University Medical Center, discusses findings from a study evaluating the prevalence of patients with high-risk non-Hodgkin lymphoma (NHL) who were eligible for bridging radiation therapy prior to receiving CAR T-cell therapy, as well as the outcomes of these patients following CAR T-cell therapy.

This single-center, retrospective study included 81 patients with relapsed/refractory NHL who received CAR T-cell therapy between the years of 2018 and 2022. The CAR T-cell products that patients received included axicabtagene ciloleucel (Yescarta; 62%), lisocabtagene maraleucel (Breyanzi; 16%), tisagenlecleucel (Kymriah; 15%), and brexucabtagene autoleucel (Tecartus; 7%).

Patients were deemed eligible for bridging radiation therapy if they had less than 5 malignant lesions according to pre-apheresis radiological study results. Patients were classified as having high-risk disease if they had bulky disease of at least 10 cm, at least 1 extranodal site, lactate dehydrogenase levels above normal, or at least 1 lesion with an SUVmax of at least 10. Investigators found that 40 patients (49%) included in this study would have been eligible for bridging radiation therapy. Among these patients, 29 had disease with high-risk features, including 4 with bulky disease, 6 with 1 or more lesions with an SUVmax of at least 10, and 2 with at least 1 extranodal site. Of the 40 eligible patients, 9 received bridging radiation therapy, 2 of whom had high-risk disease.

Among patients with a high risk of disease relapse after CAR T-cell therapy, 44% experienced either a partial response, stable disease, or progressive disease at 3 months post–CAR T-cell therapy. Moreover, 1 patient with transformed diffuse large B-cell lymphoma (DLBCL) had persistent disease in the nasopharynx following 3 cycles of R-CHOP (rituximab [Rituxan], cyclophosphamide, doxorubicin, vincristine, and prednisone) and R-HyperCVAD (rituximab, cyclophosphamide, vincristine, doxorubicin, methotrexate, cytarabine, and dexamethasone). This patient received radiation therapy as a bridge to CAR T-cell therapy, which led to a continued complete response (CR) at 23 months of follow-up. Another notable patient with non–double-hit, germinal center B–like DLBCL achieved a CR with 6 cycles of R-CHOP, and experienced disease relapse less than 1 year later. This patient then received bridging radiation therapy, and experienced disease relapse 6 months after CAR T-cell therapy.