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
1500 - Retrospective evaluation of neutropenic admission events in metastatic or high-risk hormone-sensitive prostate cancer (HSPC) patients having docetaxel chemotherapy upfront or for castrate-resistant prostate cancer (CRPC) in STAMPEDE
Presenter: Harriet Mintz
Session: Poster Display session 3
Resources:
Abstract
3524 - Cabazitaxel For Octogenarian Patients With Metastatic Castration-Resistant Prostate Cancer (MCRPC).
Presenter: Paolo Tralongo
Session: Poster Display session 3
Resources:
Abstract
5637 - External Validation of a Prognostic Score in First-Line Metastastic Castration-Resistant Prostate Cancer (mCRPC)
Presenter: David Lorente
Session: Poster Display session 3
Resources:
Abstract
3228 - Treatment outcomes of 3rd treatment in a real-world metastatic castration resistant prostate cancer (mCRPC) population: results from the Dutch CAPRI-registry
Presenter: Jessica Notohardjo
Session: Poster Display session 3
Resources:
Abstract
4695 - Pelvic lymph node dissection and its extent on survival benefit in prostate cancer patients with a risk of lymph node invasion>5%: a propensity score matching analysis from SEER database
Presenter: Junru Chen
Session: Poster Display session 3
Resources:
Abstract
4438 - Multi-institutional evaluation of therapeutic management for oligometastatic cancer prostate recurrence with choline-PET/CT
Presenter: Morgane Guibert-broudic
Session: Poster Display session 3
Resources:
Abstract
4574 - Safety of new androgen receptor inhibitors (ARi) in patients with nonmetastatic castration-resistant prostate cancer (nmCRPC): a network meta-analysis of randomized controlled trials (RCT)
Presenter: Amelia Altavilla
Session: Poster Display session 3
Resources:
Abstract
3816 - Real-world use of radium-223 for treatment of metastatic castration resistant-prostate cancer (mCRPC): results from the Dutch CAPRI registry
Presenter: Malou Kuppen
Session: Poster Display session 3
Resources:
Abstract
5180 - A phase 2a study of radium-223 dichloride (Ra-223) alone or in combination with abiraterone acetate or enzalutamide in metastatic castration-resistant prostate cancer (mCRPC)
Presenter: Daniel Petrylak
Session: Poster Display session 3
Resources:
Abstract
1067 - Adding ADT to PSMA-PET/CT-guided SBRT for oligometastatic prostate cancer improves distant progression-free survival
Presenter: Carole Mercier
Session: Poster Display session 3
Resources:
Abstract