Impact of gadopiclenol on decision making in patients with brain metastases: A post-hoc study.

Frank Anton Giordano Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany info_outline Frank Anton Giordano, Jens Fleckenstein, Miriam Eckl, Florian Stieler, Martin Bendszus, Marco Essig, Frederik Wenz, Gustavo R. Sarria

Authors Frank Anton Giordano Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany info_outline Frank Anton Giordano, Jens Fleckenstein, Miriam Eckl, Florian Stieler, Martin Bendszus, Marco Essig, Frederik Wenz, Gustavo R. Sarria Organizations Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany, Neuroradiology, UKHD, Heidelberg, Germany, Department of Radiology, University of Manitoba, Manitoba, MB, Canada, Freiburg University Medical Center, Freiburg, Germany, Department of Radiation Oncology, University Hospital Bonn, University of Bonn, Bonn, Germany Abstract Disclosures Research Funding Guerbet SA Background: Gadopiclenol (Elucirem, Guerbet, France) is a new high relaxivity macrocyclic gadolinium-based contrast agent (GBCA), recently approved by the FDA and EMA at the dose of 0.05 mmol/kg. The aim of this post-hoc analysis was to evaluate the impact of contrast-enhanced MRI with gadopiclenol at 0.1 mmol/kg on decision making and radiotherapy (RT) treatment planning of brain metastases (BM). Methods: This is a post-hoc analysis of data from a phase IIb study where patients underwent two separate MRI examinations, one with gadopiclenol at 0.025, 0.05, 0.1 or 0.2 mmol/kg and one with gadobenate dimeglumine at 0.1 mmol/kg. MR images of patients who received both GBCAs at 0.1 mmol/kg, with ≥1 BM detected in either of the scans, were subjected to a blinded reader analysis and contouring by two radiation oncology experts. For each patient, treatment plans (stereotactic radiosurgery [SRS] or whole-brain radiotherapy [WBRT]) were determined for both MRIs, with the gross target volume (GTV) indicating the contrast-enhancing aspects of the tumor. Mean GTVs and normal tissue volumes receiving 12 Gy (V 12 ), as well as the Dice similarity coefficient (DSC) were obtained for the paired contours. The Spearman´s rank (ρ) correlation was additionally calculated. Furthermore, three experts blindly evaluated the contrast enhancement of each lesion for contouring purposes and subjectively qualified them as “better”, in detriment of the counterpart, or “equal”. Results: In total, images from 13 adult patients were analyzed. MRI with gadopiclenol depicted additional BM as compared with gadobenate dimeglumine in 7 patients (54%). The treatment plan was changed in 2 patients (15%), from no treatment to SRS and from SRS to WBRT. Gadopiclenol depicted additional BM in these 2 patients (from 0 and 10 BM with gadobenate dimeglumine to 1 and 15 BM with gadopiclenol). The mean GTVs and V 12 were comparable between gadopiclenol and gadobenate dimeglumine (p=0.694, p=1.974). The mean DSC was 0.70 (SD: 0.14, ρ0.82). From a total of 36 answers, contrast enhancement was qualified as better with gadopiclenol in 21 (58.3%) evaluations, better with gadobenate dimeglumine in 8 (22.2%) evaluations, while no difference was observed in 7 (19.4%) evaluations. Conclusions: Gadopiclenol at 0.1 mmol/kg improved BM detection and contrast enhancement with potential impact on RT treatment decisions.