2348 - Biology-Guided Radiotherapy for Lung and Bone Tumors: Early Insights into Local Control Outcomes from the Prospective Premier Registry
Presenter(s)
T. Dan1, S. N. Badiyan1, K. D. Westover1, A. Garant1, A. Gul1, D. de Jong2, K. A. Al Feghali2, S. M. Shirvani2, A. Amini3, W. T. Watkins3, C. Han3, H. S. M. Park4, K. L. Johung4, L. Vitzhum5, M. Surucu6, A. Danish7, B. E. Lewis7, H. D. Skinner8, C. T. Wilke8, and N. S. McCall8; 1Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 2RefleXion Medical, Inc., Hayward, CA, 3Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA, 4Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, 5Department of Radiation Oncology, Stanford University, Palo Alto, CA, 6Department of Radiation Oncology, Stanford University, Stanford, CA, 7John Theurer Cancer Center, Hackensack University Medical Center, Hackensack, NJ, 8Department of Radiation Oncology, UPMC Hillman Cancer Center, Pittsburgh, PA
Purpose/Objective(s): Biology-Guided Radiotherapy (BgRT) is a novel technology introduced into clinical practice in 2023 following FDA approval for the treatment of primary and metastatic lung and bone tumors. BgRT is delivered by a positron emission tomography/computed tomography (PET/CT) Linac, that directs the radiation beam during treatment using positron emissions from tumors after a fluorodeoxyglucose injection. We sought to evaluate the early clinical experience with this technology involving new planning and delivery methods by collecting initial local control (LC) outcomes for patients treated with at least one fraction of BgRT across multiple institutions, all of which consented to participate in the PREMIER Registry study.
Materials/Methods: Five institutions participated in the PREMIER Registry study to collect their BgRT patients' demographics, treatment information, oncologic outcomes, and adverse events (AEs). By February 25th, 2025, 58 patients were treated with BgRT, of whom 45 patients (78%) had consented to the PREMIER registry and received at least one fraction of BgRT. 21/45 patients (46.7%) were treated for bone tumors and 24/45 (53.3%) for lung tumors. When available, LC outcomes - assessed by local investigators or multidisciplinary tumor boards as complete response (CR), partial response (PR), stable disease (SD) or progressive disease (PD) - were collected from follow-up imaging (CT or PET/CT). Cumulative LC was calculated.
Results: Among the 45 patients, 31 patients (69%) had follow-up imaging data available. Of these, 48% (15/31) had bone metastases and 52% (16/31) had primary or metastatic lung tumors. The median age of the 31 patients was 68 (range 52-82), 42% were female. Doses and fractionation were at investigator discretion and ranged from 12 Gy in 1 fraction for metastatic tumors to 60 Gy in 5 fractions for primary tumors. At 9 months (up to 270 days) post-treatment, 42 follow-up scans had been performed (14 between 0-90 days, 19 between 91-180 days, and 9 between 181-270 days). The local control rate at 9 months was 100% for patients with follow-up imaging available (9.5% CR, 38.1% PR, 52.4% SD, 0% PD). No patients had local recurrence prior to the 9-month imaging timepoint. No Grade 2 or above AEs related to BgRT were reported.
Conclusion: Preliminary clinical results suggest that BgRT provides LC outcomes comparable to those reported for SBRT. However, longer follow-up and a larger sample size are needed for robust comparisons. Further investigation into correlations with dose/fractionation and physics-based metrics may identify novel biomarkers intrinsic to this new promising radiotherapy treatment option. Clinical Trial number: NCT05406167.