Outcomes of combined bispecific antibody and radiation therapy in relapsed/refractory hematologic malignancies

Bispecific antibodies (BsAbs) are an emerging treatment avenue offering promising outcomes for patients with relapsed or refractory hematologic malignancies, yet little is known about their use in combination with radiation therapy (RT). Therefore, we sought to report early experience combining RT with BsAbs in 26 heavily pretreated patients (LBCL, n = 7; MM, n = 19). A total of 45 irradiated sites were analyzed, including pre-BsAb (n = 15), peri-BsAb (n = 19), and post-BsAb (n = 11), with median follow-up after each RT course of 6.0 months (range, 0.4-21 months). The median dose/fractionation were 20 Gy (range, 4-41.6 Gy) and 5 fractions (range, 1-26 fractions). Eighteen irradiated sites were bulky (≥5 cm). The overall in-field response rate was 95%, and no grade 3-4 RT-related toxicities were reported. These findings suggest that RT can be safely integrated with BsAbs, achieving effective local control and symptom relief, even in bulky disease, and underscore the need for further investigation into their combined therapeutic potential.