Abstract 609P
Background
Androgen deprivation therapy (ADT) remains the backbone of therapy for mCSPC. While earlier studies (before 2012) adding first-generation nonsteroidal antiandrogens (NSAA) to ADT failed to show consistent OS improvement, clinical trials since 2014 combining docetaxel (DOC) or novel hormonal therapies (NHT) to ADT have shown improved OS over ADT alone in this population, with even greater benefit seen than in metastatic castration-resistant prostate cancer (mCRPC). Real-world data on outcomes in mCSPC are limited.
Methods
Veterans Health Administration data were used to retrospectively study patient characteristics, practice patterns, and OS in men with mCSPC who initiated either ADT alone or ADT with NSAA, DOC, or NHT from 2006 to 2019. Kaplan-Meier and Cox models were used to estimate OS in 3 cohorts representing the periods before (2006-2011) and after (2012-2014) NHT introduction in mCRPC and NHT/DOC in mCSPC (2015-2019), respectively.
Results
Of 7,340 men with mCSPC, 4,420 (60%) received ADT alone, 2,092 (29%) ADT + NSAA, 261 (4%) ADT + DOC, and 567 (8%) ADT + NHT. Over time the use of ADT alone and ADT + NSAA declined, and the use of ADT + DOC and ADT + NHT increased, though they remained low. As of 2019, less than one third of the men with mCSPC received first-line ADT + DOC or ADT + NHT. Patient characteristics were similar over time, albeit with increasing prevalence of node metastases. OS improved over time: compared to 2006-2011, the risk of death was reduced by 14% (p<0.001) and 25% (p<0.001) in 2012-2014 and 2015-2019, respectively (Table). Multivariable analysis to compare time to mCRPC and OS over time and across treatment cohorts is ongoing.
Conclusions
OS improvement in men with mCSPC coincided with the introduction of NHT in mCRPC and DOC and NHT in mCSPC. However, there is room for significant OS improvement in this population. Table: 609P
Treatment allocation and OS by treatment initiation year
| 2006-2011 | 2012-2014 | 2015-2019 | |
| N | 1,989 | 1,505 | 3,846 |
| Age at the index date, mean ± SD | 72.9 ± 10.6 | 72.5 ± 10.1 | 73.2 ± 9.5 |
| Baseline PSA (ng/mL), median [IQR] | 32.2 [7.7-178.6] | 31.2 [7.2-163.2] | 28.2 [6.1-140.2] |
| Node metastases only, n (%) | 235 (11.8) | 224 (14.9) | 743 (19.3) |
| Any visceral metastases, n (%) | 209 (10.5) | 154 (10.2) | 385 (10.0) |
| ADT alone, n (%) | 1,252 (62.9) | 945 (62.8) | 2,223 (57.8) |
| ADT + NSAA, n (%) | 723 (36.3) | 510 (33.9) | 859 (22.3) |
| ADT + DOC, n (%) | 12 (0.6) | 24 (1.6) | 225 (5.9) |
| ADT + NHT, n (%) | 2 (0.1) | 26 (1.7) | 539 (14.0) |
| OS: Unadjusted HR (95% CI) (vs 2006-2011) | - | 0.86 (0.79, 0.93)* | 0.75 (0.70, 0.81)* |
* p <0.001. CI, confidence interval; HR, hazard ratio; IQR, interquartile range; PSA, prostate-specific antigen.
Clinical trial identification
Editorial acknowledgement
Medical writing assistance funded by both sponsor companies was provided by Kirstie Anderson and Matthieu Larochelle, MD, of Onyx (a Prime Global agency).
Legal entity responsible for the study
Pfizer, Inc. and Astellas Pharma, Inc.
Funding
Pfizer, Inc. and Astellas Pharma, Inc.
Disclosure
S.J. Freedland: Financial Interests, Personal and Institutional, Other, Consultant: Pfizer; Financial Interests, Personal and Institutional, Other, Consultant: Astellas; Financial Interests, Personal and Institutional, Other, Consultant: Janssen; Financial Interests, Personal and Institutional, Other, Consultant: Bayer; Financial Interests, Personal and Institutional, Other, Consultant: Sanofi; Financial Interests, Personal and Institutional, Other, Consultant: Clovis; Financial Interests, Personal and Institutional, Other, Consultant: Merck; Financial Interests, Personal and Institutional, Other, Consultant: AstraZeneca; Financial Interests, Personal and Institutional, Other, Consultant: Myovant; Financial Interests, Personal and Institutional, Other, Consultant: Exact Sciences; Financial Interests, Personal and Institutional, Invited Speaker: Sanofi; Financial Interests, Personal and Institutional, Invited Speaker: AstraZeneca. R. Sandin: Financial Interests, Personal, Stocks/Shares: Pfizer; Financial Interests, Personal, Other, Employee: Pfizer. S.T. Tagawa: Financial Interests, Personal, Advisory Role: Sanofi; Financial Interests, Personal, Advisory Role: Medivation/Astellas; Financial Interests, Personal, Advisory Role: Dendreon; Financial Interests, Personal, Advisory Role: Janssen; Financial Interests, Personal, Advisory Role: Genentech; Financial Interests, Personal, Advisory Role: Bayer; Financial Interests, Personal, Advisory Role: Endocyte; Financial Interests, Personal, Advisory Role: Eisai; Financial Interests, Personal, Advisory Role: Immunomedics; Financial Interests, Personal, Advisory Role: Karyopharm; Financial Interests, Personal, Advisory Role: Abbvie; Financial Interests, Personal, Advisory Role: Tolmar; Financial Interests, Personal, Advisory Role: Seattle Generics; Financial Interests, Personal, Advisory Role: Amgen; Financial Interests, Personal, Advisory Role: Clovis; Financial Interests, Personal, Advisory Role: QED; Financial Interests, Personal, Advisory Role: Pfizer; Financial Interests, Personal, Advisory Role: AAA/Novartis; Financial Interests, Personal, Advisory Role: Clarity; Financial Interests, Personal, Advisory Role: Genomic Health; Financial Interests, Personal, Advisory Role: POINT Biopharma; Financial Interests, Personal, Advisory Role: Blue Earth Diagnostics; Financial Interests, Personal, Advisory Role: Aikido Pharma; Financial Interests, Personal, Advisory Role: Gilead Sciences; Financial Interests, Institutional, Research Grant: Sanofi; Financial Interests, Institutional, Research Grant: Medivation; Financial Interests, Institutional, Research Grant: Astellas; Financial Interests, Institutional, Research Grant: Janssen; Financial Interests, Institutional, Research Grant: Amgen; Financial Interests, Institutional, Research Grant: Progenics; Financial Interests, Institutional, Research Grant: Dendreon; Financial Interests, Institutional, Research Grant: Lilly; Financial Interests, Institutional, Research Grant: Genentech; Financial Interests, Institutional, Research Grant: Newlink; Financial Interests, Institutional, Research Grant: BMS; Financial Interests, Institutional, Research Grant: Inovio; Financial Interests, Institutional, Research Grant: AstraZeneca; Financial Interests, Institutional, Research Grant: Immunomedics; Financial Interests, Institutional, Research Grant: Aveo; Financial Interests, Institutional, Research Grant: Rexahn; Financial Interests, Institutional, Research Grant: Atlab; Financial Interests, Institutional, Research Grant: Boehringer Ingelheim; Financial Interests, Institutional, Research Grant: Millennium; Financial Interests, Institutional, Research Grant: Bayer; Financial Interests, Institutional, Research Grant: Merck; Financial Interests, Institutional, Research Grant: Abbvie; Financial Interests, Institutional, Research Grant: Karyopharm; Financial Interests, Institutional, Research Grant: Endocyte; Financial Interests, Institutional, Research Grant: Clovis; Financial Interests, Institutional, Research Grant: Seattle Genetics; Financial Interests, Institutional, Research Grant: AAA/Novartis; Financial Interests, Institutional, Research Grant: POINT Biopharma; Financial Interests, Institutional, Research Grant: Gilead Sciences. Z. Klaassen: Financial Interests, Personal, Advisory Board: Bayer; Financial Interests, Personal, Advisory Board: Astellas-Pfizer; Financial Interests, Personal, Other, Consulting: Sesen, Bio. K. Ramaswamy: Financial Interests, Personal, Other, Employee: Pfizer. B. Emir: Financial Interests, Personal, Other, Employee: Pfizer. C. Bland: Financial Interests, Personal, Other, Employee: Pfizer. A. Hong: Financial Interests, Personal, Other, Employee: Astellas. H. Yang: Financial Interests, Personal, Other, Employee: Analysis Group, Inc; Financial Interests, Institutional, Other, Analysis Group has received funding for this study: Pfizer. W. Gao: Financial Interests, Personal, Other, Employee: Analysis Group, Inc; Other, Institutional, Other, Analysis Group has received funding for this study: Pfizer. W. Song: Financial Interests, Personal, Other, Employee: Analysis Group, Inc; Financial Interests, Institutional, Other, Consulting: Pfizer. D.J. George: Financial Interests, Personal, Other, Senior Editor: American Association for Cancer Research; Financial Interests, Personal and Institutional, Other, Consultant: Astellas; Financial Interests, Personal and Institutional, Other, Research: Astellas; Financial Interests, Personal and Institutional, Advisory Board: Astellas; Financial Interests, Personal and Institutional, Other, Research: AstraZeneca; Financial Interests, Personal and Institutional, Other, Consultant: AstraZeneca; Financial Interests, Personal and Institutional, Advisory Board: AstraZeneca; Financial Interests, Personal and Institutional, Other, CAPI-281 Steering Committee member: AstraZeneca; Financial Interests, Personal, Other, Independent Contractor: Axess Oncology; Financial Interests, Personal, Other, Consultant: Bayer H/C Pharmaceuticals; Financial Interests, Personal, Invited Speaker: Bayer H/C Pharmaceuticals; Financial Interests, Personal, Other, Honorarium: Bayer H/C Pharmaceuticals; Financial Interests, Personal, Other, Travel accommodations: Bayer H/C Pharmaceuticals; Financial Interests, Personal, Other, SC: Bayer H/C Pharmaceuticals; Financial Interests, Personal and Institutional, Other, Consultant: BMS; Financial Interests, Personal and Institutional, Other, Research: BMS; Financial Interests, Personal and Institutional, Other, Steering Committee: BMS; Financial Interests, Institutional, Other, Research: Calithera; Financial Interests, Personal, Advisory Board: Capio Biosciences; Financial Interests, Personal, Other, Consultant: Constellation Pharmaceuticals; Financial Interests, Personal, Other, Honorarium: EMD Serono; Financial Interests, Personal and Institutional, Other, Research: Exelixis, Inc; Financial Interests, Personal and Institutional, Other, Consultant: Exelixis, Inc; Financial Interests, Personal and Institutional, Invited Speaker: Exelixis, Inc; Financial Interests, Personal and Institutional, Other, Honorarium: Exelixis, Inc; Financial Interests, Personal and Institutional, Other, Travel accommodations: Exelixis, Inc; Financial Interests, Personal, Other, Consultant: Flatiron; Financial Interests, Personal, Other, Honorarium: Ipsen; Financial Interests, Personal and Institutional, Other, Research: Janssen Pharmaceuticals; Financial Interests, Personal and Institutional, Other, Consultant: Janssen Pharmaceuticals; Financial Interests, Personal and Institutional, Other, IDMC: Janssen Pharmaceuticals; Financial Interests, Personal, Other, Consultant: MSD; Financial Interests, Personal, Other, Honorarium: Michael J Nehhessey Associates; Financial Interests, Personal, Other, Consultant: Michael J Nehhessey Associates; Financial Interests, Personal, Other, Co-Editor in Chief: Millennium Medical Publishing, Clinical Advances in Hematology and Oncology; Financial Interests, Personal, Advisory Board: Modra Pharmaceuticals BV; Financial Interests, Personal, Other, Consultant: Myovant Sciences, Inc; Financial Interests, Personal, Other, NCI Genitourinary Steering Committee member: Leidos Biomedical Research Inc; Financial Interests, Personal, Other, Steering committee: Nektar Therapeutics; Other, Institutional, Other, Research: Novartis; Financial Interests, Personal, Other, Consultant: Physician Education Resource LLC; Financial Interests, Personal and Institutional, Other, Research: Pfizer; Financial Interests, Personal and Institutional, Other, Consultant: Pfizer; Financial Interests, Personal and Institutional, Other, Steering committee: Pfizer; Financial Interests, Personal and Institutional, Other, Honorarium: Pfizer; Financial Interests, Personal, Other, Consultant: Propella TX (formerly Vizuri); Financial Interests, Personal, Other, Consultant: RevHealth, LLC; Financial Interests, Personal and Institutional, Other, Research: Sanofi; Financial Interests, Personal and Institutional, Other, Consultant: Sanofi; Financial Interests, Personal and Institutional, Invited Speaker: Sanofi; Financial Interests, Personal and Institutional, Other, Honorarium: Sanofi; Financial Interests, Personal and Institutional, Other, Travel accommodations: Sanofi; Financial Interests, Personal, Other, Honorarium: UroGPO; Financial Interests, Personal, Other, Honorarium: UroToday; Financial Interests, Personal, Other, Travel accommodations: UroToday. All other authors have declared no conflicts of interest.