Abstract 5529
Background
The treatment of mCRPC is a major medical challenge. The beta-emitting Lu-177-PSMA radioligand therapy (RLT) is a new option but its antitumor effect can decrease over time. The aim of this retrospective analysis was to investigate safety and efficacy of the alpha emitting Ac-225-PSMA-617 RLT in mCRPC after Lu-177-PSMA failure.
Methods
At data analysis 03/19 18 patients (pts) underwent Ac-225-PSMA-617 RLT between 10/17 and 12/18. All pts had previously received second line antihormonal treatment and 17/18 pts taxane based chemotherapy. All pts had shown progression after Lu-177-PSMA therapy (median 2 cycles). High PSMA-expression of the tumor lesions in PSMA-PET/CT before Ac-225-PSMA-617 was mandatory. Pts were treated at 8 weekly intervals until progression or intolerable side effects. Prostate-specific antigen (PSA) and blood cell count were measured every 2-3 weeks. We report updated data of hematological and non-hematological side effects, biochemical response and a subgroupanalysis.
Results
A total of 36 cycles of Ac-225-PSMA-617 (median dose 8 MBq, range 4,4–12.8) were applied. 7 pts received only 1 cycle, 5 pts 2 cycles, 5 pts 3 cycles and 1 patient 4 cycles. Baseline PSA was 822 ng/ml (range 49–4073). ECOG score was grade 0, 1 and 2 in 3, 13 and 2 pts. 15/18 pts showed any PSA-decline, 5/18 a PSA-decline of more than 50% and 3 pts no PSA-decline at any time. 6 weeks after treatment 12/18 showed any PSA decline and 4/18 a PSA-decline of > 50%. Grade 1 xerostomia occurred in 17 and grade 2 in 1 patient. 6/18 pts (33%) requested to stop treatment due to xerostomia. 2 pts developed grade 2 renal insufficiency, 5 pts grade 3-4 anemia, 2 pts grade 3-4 thrombocytopenia and 2 pts 3-4 leucopenia. 7/18 pts died during the observation period (median overall survival 9,6 months). The PSA-progression free survival was 1,3 months. In a subgroupanalysis of 9 pts with a rapid progression under a previous Lu-177-PSMA treatment 7 pts achieved any PSA-decline and 4 pts a decline of more than 50%.
Conclusions
In this small cohort Ac-225-PSMA-617 RLT showed antitumor effect in mCRPC after Lu-177-PSMA failure even after rapid tumour progression. However, treatment had to be stopped in one third of the pts due to xerostomia.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
5043 - Comprehensive results of a Phase Ib study with a HER2/neu B-cell peptide vaccine administered with cisplatin and 5-fluorouracil or capecitabine chemotherapy show safety, immunogenicity and clinical response in patients with HER2/Neu overexpressing advanced gastric cancer
Presenter: Ursula Wiedermann
Session: Poster Display session 3
Resources:
Abstract
4506 - Single intravenous preoperative administration of the oncolytic virus Pexa-Vec to prime anti-tumor immunity
Presenter: Adel Samson
Session: Poster Display session 3
Resources:
Abstract
1631 - Randomized phase 2 clinical trial of NY-ESO-1 protein vaccine combined with cholesteryl pullulan (CHP-NY-ESO-1) in resected esophageal cancer patients
Presenter: Shinichi Kageyama
Session: Poster Display session 3
Resources:
Abstract
4244 - T cell repertoire sequencing reveals dynamics of response to dendritic cell vaccine plus dasatinib for checkpoint blockade resistant metastatic melanoma
Presenter: Luca Quagliata
Session: Poster Display session 3
Resources:
Abstract
5791 - Ixovex, a novel oncolytic E1B-mutated adenovirus
Presenter: Mohiemen Anwar
Session: Poster Display session 3
Resources:
Abstract
4170 - Anti-CSPG4 DNA vaccination as a promising strategy for the treatment of CSPG4+ tumors: a comparative oncology trial
Presenter: Federica Riccardo
Session: Poster Display session 3
Resources:
Abstract
5780 - Antitumor activity, immunogenicity and safety of a novel PD-1 vaccine in combination with two chimeric HER-2 peptide vaccine in syngeneic Balb/c, C57Bl/6 models and in beagle dogs
Presenter: Pravin Kaumaya
Session: Poster Display session 3
Resources:
Abstract
5860 - Maternal immunization against ALK as a weapon to fight neuroblastoma
Presenter: Giuseppina Barutello
Session: Poster Display session 3
Resources:
Abstract
4720 - Phase 1 study evaluating safety, pharmacokinetics (PK), pharmacodynamics, and preliminary efficacy of ABBV-428, first-in-class mesothelin (MSLN)-CD40 bispecific, in patients (pts) with advanced solid tumors
Presenter: Jason Luke
Session: Poster Display session 3
Resources:
Abstract
5717 - Anti-PD-L1/IL-15 fusion protein generates robust adaptive immune gene signatures in tumors leading to tumor inhibition and memory responses
Presenter: Stella Martomo
Session: Poster Display session 3
Resources:
Abstract