Chemokine Receptor 4-Targeted PET/CT with [68Ga]pentixather in Newly Diagnosed Multiple Myeloma: a Comparative Study with [68Ga]pentixafor PET/CT

Purpose This study aimed to compare the detection rate of [Ga-68]pentixather PET/CT and [Ga-68]pentixafor PET/CT in newly diagnosed multiple myeloma (NDMM) patients, and to explore the value of [Ga-68]pentixather PET/CT for tumor load assessment. Methods Nineteen NDMM Patients were prospectively recruited and underwent both [68Ga]pentixather PET/CT and [Ga-68]pentixafor PET/CT. A positive PET scan was defined as the presence of PET-positive focal bone lesions, paraskeletal disease, extramedullary plasmacytoma, or diffuse bone marrow uptake. Lesion numbers, SUVmax and PET-related tumor burden values were compared. The correlations between PET-related tumor burden and clinical risk stratification were analyzed. Results [Ga-68]pentixather PET/CT showed a tendency of higher positive rate compared with [68Ga]pentixafor PET/CT [94.7% (18/19) vs. 78.9% (15/19), p > 0.05]. Among 14 patients with 151 matched focal bone lesions, [Ga-68]pentixather PET detected more or equal number of lesions in 13 patients, and demonstrated higher uptake value than Ga-68 -pentixafor PET [SUVmax, 16.8 (9.0, 23.8) vs. 13.4 (6.5, 20.4), p < 0.001]. For PET related-tumor burden, positive correlations of total bone marrow uptake (TBmU) (r = 0.9540, p < 0.0001) and SUVmean of total bone marrow (r = 0.9632, p < 0.0001) in two PET scans were observed. Higher TBmU [7864.9 (5549.2, 11,616.2) vs. 5383.4(4102.7, 11,041.8), p < 0.001], SUVmean of total bone marrow [1.4 (1.1, 2.2) vs. 1.1 (0.7, 2.1), p < 0.001] were demonstrated on [Ga-68]pentixather PET than [Ga-68]pentixafor PET. And the level of TBmU in [Ga-68]pentixather PET and [Ga-68]pentixafor PET were both elevated in Durie-Salmon Staging (DSS) III than DSS I (p < 0.01). Conclusions [Ga-68]pentixather PET/CT performed a non-inferior capability for tumor detection compared to [Ga-68]pentixafor PET/CT in NDMM patients. [Ga-68]pentixather PET/CT can assess tumor load in MM patients and depict a significantly higher PET-related total tumor burden than [Ga-68]pentixafor PET/CT.