Addressing Prospective Data Gaps for Radiotherapy Use in Multiple Myeloma

In a lesion-level PET/CT analysis of 102 patients with relapsed/refractory multiple myeloma treated with ciltacabtagene autoleucel (Carvykti), Alexandra Dreyfuss, MD, MS, and colleagues found that extramedullary and paramedullary disease before CAR T-cell infusion was independently associated with markedly inferior progression-free survival (HR, 7.1 and 20.4, respectively) and overall survival (HR, 3.9 and 5.4, respectively). At progression, disease distribution shifted away from bone-only involvement toward extramedullary and paramedullary compartments, suggesting these sites may be rational targets for bridging or consolidative radiation.

Dreyfuss, an assistant professor in the Department of Radiation Oncology at the University of Miami Sylvester Comprehensive Cancer Center, who presented these findings at the 2026 American Society for Radiation Oncology (ASTRO) Annual Meeting, spoke with CancerNetwork^® about the biggest gaps in prospective radiotherapy data in multiple myeloma and where she would prioritize studying this area further.

Transcript:

CancerNetwork: What do you see as the biggest gap in prospective data for radiotherapy integration in multiple myeloma, and what would you prioritize studying first?

Dreyfuss: I think there’s a gap in general in prospective studies of radiation use in [multiple] myeloma. There have probably only been a handful of studies ever done on any question related to radiation in [multiple] myeloma. We have an ongoing study looking at a dose question for radiation in [multiple] myeloma, and dose has always been a big question in [multiple] myeloma; there’s a huge range of doses used, from some of the lowest doses we use for any cancer to some of the highest doses we use for very radioresistant cancers.

But looking toward the future, I’d say I would probably start with prospective studies in either the CAR T or bispecific space because those therapies are becoming increasingly common and have had very good response rates. Some of the ideas for those studies are alluded to in some of my presentations at ASTRO, whether that’s using radiation in the pre-CAR T bridging setting or the early post-CAR T setting. I’m not presenting on this specifically, but in relation to bispecifics, using radiation to target what we think are higher-risk sites for failure is another aspect. I think there’s definitely an opportunity in those 2 populations to translate what we’re seeing on a retrospective basis into prospective work.

Reference

Dreyfuss A, Yahalom J, Nemorovsky D, et al. Patterns of progression after BCMA CAR T-cell therapy in relapsed/refractory multiple myeloma: a lesion-level PET/CT analysis. Presented at: 2026 ASTRO Annual Meeting; September 26-30, 2026; Boston, MA. Abstract 207.