RECIP 1.0 Predicts Progression-Free Survival After [<sup>177</sup>Lu]Lu-PSMA Radiopharmaceutical Therapy in Patients with Metastatic Castration-Resistant Prostate Cancer
Andrei Gafita, Loïc Djaileb, Isabel Rauscher, Wolfgang P. Fendler, Boris Hadaschik, Steven P. Rowe, Ken Herrmann, Lilja B. Sólnes, Jérémie Calais, Matthew B. Rettig, Manuel Weber, Andrea Farolfi, Matthias Benz, Matthias Eiber
Abstract
Response Evaluation Criteria in Prostate-Specific Membrane Antigen Imaging (RECIP) 1.0 is an evidence-based framework to evaluate therapeutic efficacy in metastatic prostate cancer using prostate-specific membrane antigen (PSMA) PET/CT. This study aimed to evaluate the associations of interim PSMA PET/CT by RECIP 1.0 with short-term outcome after radiopharmaceutical treatment. <b>Methods:</b> This multicenter retrospective study included patients with metastatic castration-resistant prostate cancer who underwent [<sup>177</sup>Lu]Lu-PSMA radiopharmaceutical therapy at 3 academic centers and received PSMA PET/CT at baseline and at 12 wk. Pairs of PSMA PET/CT images were assessed by 5 readers for visual RECIP 1.0. The primary outcome was the association of RECIP with prostate-specific antigen progression-free survival (PSA-PFS) by Kaplan–Meier analysis. <b>Results:</b> In total, 124 of 287 screened patients met the inclusion criteria, with 0 (0%), 29 (23%), 54 (44%), and 41 (33%) of those 124 patients having complete response, partial response, stable disease, or progressive disease (PD) by visual RECIP 1.0, respectively. Patients with visual RECIP PD had a significantly shorter PSA-PFS than those with RECIP stable disease or with RECIP partial response (2.6 vs. 6.4 vs. 8.4 mo; <i>P</i> < 0.001). The median PSA-PFS among patients with RECIP PD versus those with non-RECIP PD was 2.6 versus 7.2 mo (hazard ratio, 13.0; 95% CI, 7.0–24.1; <i>P</i> < 0.001). <b>Conclusion:</b> PSMA PET/CT by RECIP 1.0 after 2 cycles of [<sup>177</sup>Lu]Lu-PSMA is prognostic for PSA-PFS. PSMA PET/CT by RECIP 1.0 may be used in earlier stages of prostate cancer to evaluate drug efficacy and to predict progression-free survival.