The Cancer Institute at St. Francis Hospital Oyster bay, NY
E. Obedian1, J. Tabaco1, J. Mathew1, S. Jacob-Perez1, S. Solito1, H. Wong1, R. Radigan2, A. Finkelstein2, S. Saed3, L. Salichos4, and B. Mehrotra1; 1The Cancer Institute at St. Francis Hospital, East Hills, NY, 2New York Institute of Technology, Old Westbury, NY, 3The CUNY School of Medicine, New York, NY, 4New York Institute of Technology, Dept of Biological and Chemical Sciences, Biomedical Data Science Center, and Center of Cancer Research, Old Westbury, NY
Purpose/Objective(s): PSMA targeted radioligand therapy with Lu-177-PSMA-617 (Lu-P) represents a new SOC for metastatic CRPC. This study tests the hypothesis that safety and efficacy can be achieved using Lu-P in a community cancer center, to assess reasons for Rx discontinuation, and to evaluate factors associated with improved outcomes. Materials/
Methods: After IRB approval, retrospective chart review was performed for all consecutive pts between 4/2022 and 2/2024 who received Lu-P therapy. All pts had PSMA PET avid disease and failed prior ADT, second generation ADT and taxane based chemotherapy. All pts had CMP, CBC, and PSA levels measured prior to each dose. Information re: age, Gleason grade, prior Rx regimen(s), initial staging at presentation, genomic information (if available), PSMA PET results, comorbidities and symptom score were obtained. Adverse events were graded by CTCAE. OS, PFS (by imaging and/or PSA), number of doses received, and Rx related toxicity were reviewed. Univariate and multivariate Cox proportional hazard regression analysis were performed to determine predictors for survival. Results: 52 pts were treated with Lu-P at our cancer center during this period. Med age:76 yrs (range 55–97). Pre-Rx PSA ranged from 0 to 2693 ng/ml (med 89.9 ng/ml). Pts with prior Ra-223 (n=10, 19%); immunotherapy (n=13, 25%). 17/52 pts are still undergoing Rx. 186 doses of Lu-P have been delivered to these 52 pts. Avg number of doses administered per pt=4 (rounded); 17 pts received >4 doses;12 pts received =6 doses. 3 pts received repeat Lu-P (1-3 doses) for recurrent disease despite initial response to 6 doses. PSA levels declined by >50% in 16 pts (31%) and >90% in 11 pts (21%) which correlated with improvement in OS (p=0.05). Dose was reduced from 200 to 160 mCi in only 2 pts (4%). 25 pts (48%) discontinued Lu-P most frequently due to progression of disease (84%, n=21) and less commonly due to Rx related toxicity (16%, n=4). Grade 1 or 2 toxicities were hematologic- anemia (n=37, 71%), thrombocytopenia (n=36, 69%), leukopenia (n=40, 79%), GI (nausea, diarrhea, constipation and/or abdominal pain, n=33, 63%), fatigue (n=24, 46%), and xerostomia (n=22, 42%). Grade 3 toxicity was uncommon- anemia (n=6, 12%), thrombocytopenia (n=5, 10%), GI (n=3, 6%), and/or xerostomia (n=2, 4%). There were no Grade 4 or 5 toxicities related to treatment. Median OS was 6.3 mos.36 pts (69%) are still alive. Med follow up: 7 mo (range 1 - 20). Pre-treatment Hb level, prior immunotherapy and initial M stage at diagnosis were significant predictors of OS outcome by multivariate Cox proportional hazards regression analysis (p=0.001). Conclusion: Lu-177-PSMA-617 can be safely and effectively delivered in a community cancer center. One third of our patient population had significant serological responses to Lu-P which correlated with improved OS. The most common reason for discontinuation of treatment was progression of disease. Pre-Rx hemoglobin level, prior immunotherapy, and initial M0 stage at Dx were strong predictors of survival.
