Abstract
BACKGROUND: We aim to investigate the prognostic value of [(68)Ga]Ga-Pentixafor PET/CT in multiple myeloma (MM) patients. RESULTS: This is a retrospective analysis of a prospective cohort study. Twenty-five patients with treatment-naïve, newly diagnosed MM were included. All participants underwent [(68)Ga]Ga-Pentixafor PET/CT scans at baseline and after first-line chemotherapy. The endpoints included the time to progression (TTP) and the time to next treatment (TTNT). The correlation between PET/CT characteristics and survival was then analyzed. Patients with a decline in SUVmax of bone marrow of less than 40% from baseline demonstrated significantly shorter TTP and TTNT (estimated median TTP, 27.5 months [95% CI, 16.7-38.2] vs. not reached, P = 0.047; estimated median TTNT, 31.8 months [95% CI, 20.8-42.8] vs. not reached, P = 0.012). Patients with visually reduced splenic uptake in the follow-up [(68)Ga]Ga-Pentixafor PET/CT from baseline exhibited significantly shorter TTP and TTNT (estimated median TTP, 24.4 months [95% CI, 7.9-24.4] vs. not reached, P = 0.018; estimated median TTNT, 31.9 months [95% CI, 18.5-31.9] vs. not reached, P = 0.043). A 20% reduction in splenic SUVmax was identified as a predictive indicator for shorter TTP and TTNT (estimated median TTP, 24.4 months [95% CI, 14.5-24.4] vs. not reached, P = 0.025; estimated mean TTNT, 31.9 months [95% CI, 18.5-31.9] vs. not reached, P = 0.048). Patients with splenic SUVmax < 5.0 at follow-up also exhibited significantly shorter TTP and TTNT. However, the splenic SUVmax at baseline PET/CT was not predictive of TTP or TTNT (P > 0.05). CONCLUSION: Reduced splenic uptake of [(68)Ga]Ga-Pentixafor following first-line chemotherapy was predictive for poor prognosis in patients with newly diagnosed MM, while baseline splenic uptake is not associated with prognosis. TRIAL REGISTRATION: ClinicalTrials. NCT03436342 Registered 25 October 2017, https://register. CLINICALTRIALS: gov/prs/app/action/SelectProtocol?sid=S0007IL2&selectaction=Edit&uid=U0001JRW&ts=6&cx=-3sdpwu . CLINICALTRIALS: NCT04504526 Registered 6 August 2020, https://clinicaltrials.gov/study/NCT04504526?cond=NCT04504526&rank=1 .