Radium 223 without androgen deprivation therapy (ADT) in patients (Pts) with biochemically recurrent prostate cancer (BCR) and PET findings in the bones.

• DOI: 10.1200/jco.2025.43.5_suppl.180
• Publication Date: 2025-02-18T14:32:56Z
• Authors: Melissa Lauren Abel; Fatima Karzai; Philip M. Arlen; Clara Chen; Esther Mena; Liza Lindenberg; Jeanny B. Aragon-...; Lisa M. Cordes; Katherine Lee-Wisdom; Amy Hankin; Monique Williams; Yolanda L McKinney; James L Gulley; William Douglas Figg; Peter Choyke; Ravi Amrit Madan
• Keywords: Radium-223; Recurrent prostate cancer; breakpoint cluster region; Biochemical recurrence

180 Background: BCR pts have a rising PSA after definitive surgery or radiation, but negative CT/Tc99 scans. While ADT-based strategies are commonly used, they can be associated with life-altering toxicities and not been shown to improve survival. Radium 223 is an alpha-emitting radiopharmaceutical that accumulates in areas of high bone turnover has demonstrated survival benefit metastatic prostate cancer, its benefits as monotherapy without ADT explored prior this study. This strategy may important metastasis drives morbidity/mortality cancer. Methods: Eligible study (NCT04206319) following therapy, testosterone (T) >100ng/dL, normal organ marrow function, imaging. Pts must findings on NaF PSMA PET suspicious for disease seen Tc99. treated at the approved dosing 55 kBq/kg 6 cycles. declines were defined 2 more confirmed from intra-study apex (ISAP; Madan ASCO GU 2018). All pre- post-treatment Immune responses (primary endpoint) evaluated completion. Results: 18 enrolled 16 currently evaluable response, median age 67 yrs (58-80) 1.75 ng/ml (0.2-49.5). 14/16 had PSMA+ 13/16 NaF+ There no missed cycles toxicity grade >3 toxicities. Grade rare 1 changes hemoglobin platelets occurred. rapid doubling times came off progression follow up Five (31%) ISAP 14%, 21%, 24%, 33%, 57% lasting 84, 173, 292, 246+, 661+ days, respectively. 8/11 evidence decreased standard uptake value (SUV) imaging treatment. Two resolution multiple findings, one them remains 2+ years stable PSA. Conclusions: safe 1/2 Decreases SUV most scans suggest targeting lesions. Substantial improvements observed. Delayed 31% pts. therapeutic activity further studies needed define potential role PET+ BCR. Clinical trial information: NCT04206319 .