Abstract 1410P
Background
Pts with nmCRPC are at high risk of developing metastases if they have a prostate-specific antigen (PSA) doubling time (PSADT) of ≤10 months (mo) or Gleason score (GS) ≥8. Combining androgen deprivation therapy (ADT) with novel hormone therapies (NHTs; apalutamide/darolutamide/enzalutamide) prolongs metastasis-free survival (MFS) and overall survival (OS) in nmCRPC, but data on use of these therapies in real-world settings are minimal. We assessed the real-world use of NHTs in men with high-risk nmCRPC in the United States.
Methods
This retrospective study used the Optum electronic health records database from 2007–2020. Eligible pts were adult men (≥18 years) with nonmetastatic prostate cancer (PC) from 2007–2019 who had surgical castration or use of ADT for ≥6 mo post-PC diagnosis. The nmCRPC index date was defined as the date of the first PSA value ≥2 ng/mL and ≥25% above the nadir that occurred during ADT or after surgical castration. Pts with metastasis within 12 mo pre-index were excluded. High-risk pts had a PSADT of ≤10 mo or GS ≥8. 1L treatment included agents received within 90 days post index. Pt characteristics and 1L treatment distributions were analyzed descriptively.
Results
Of 1572 pts with high-risk nmCRPC, 48.2% received ADT only; 32.9%, ADT + first-generation nonsteroidal antiandrogens (NSAAs); 8.8%, ADT + NHT (including abiraterone); and 10.1% other regimens as 1L treatment. Pt characteristics were generally similar across treatment groups (Table). By 2018–2020, use of ADT + NHT increased but remained <25% of 1L treatment regimens. Importantly in 2018–2020 after approvals of NHTs, most pts received ADT ± NSAA, including those with a PSADT ≤4 mo. Table: 1410P
Patient demographics and clinical characteristics by 1L regimens
| ADT only | ADT + NSAA | ADT + NHT | |
| Sample size, n (%) | 757 (48.2) | 517 (32.9) | 139 (8.8) |
| Age, mean (SD) | 76.3 (6.7) | 75.3 (7.3) | 75.4 (8.0) |
| CCI, mean (SD) | 0.8 (1.4) | 0.8 (1.5) | 0.8 (1.5) |
| Index PSA value, median (IQR) | 5.1 (3.2–10.6) | 6.2 (3.6–15.1) | 6.0 (3.0–18.6) |
| PSADT, mean (SD) | 4.4 (2.8) | 4.3 (2.8) | 4.1 (2.7) |
| Treatment by index year, % | |||
| 2008–2013 (n=772) | 50.4 | 34.5 | 3.1 |
| 2014–2017 (n=571) | 46.6 | 33.5 | 11.7 |
| 2018–2020 (n=229) | 44.5 | 26.2 | 21.0 |
| PSADT ≤4 mo (2018–2020; n=119), % | 40.3 | 28.6 | 21.0 |
159 pts receiving “other treatments” are not included in the table.CCI=Charlson Comorbidity Index; IQR=interquartile range; SD=standard deviation.
Conclusions
Despite Level 1 evidence showing improved MFS and OS with ADT + NHT, these regimens were underutilized in pts with high-risk nmCRPC, even in those with a PSADT ≤4 mo and as recently as 2018–2020. Further studies are needed to evaluate why intensified treatments are underused.
Clinical trial identification
Editorial acknowledgement
Editorial assistance was provided by Alice Xue, MS, Jane Beck, MA, and Nick Strange, BA, from Complete HealthVizion, funded by the study sponsors.
Legal entity responsible for the study
Astellas Pharma Inc.; Pfizer Inc.
Funding
This study was funded by Astellas Pharma Inc. and Pfizer Inc., the co-developers of enzalutamide.
Disclosure
S. Gupta: Non-Financial Interests, Institutional, Funding, Study funding and support for Medical Writing/editing: Astellas Pharma Inc.; Non-Financial Interests, Institutional, Funding, Medical writing support: OPTUM; Non-Financial Interests, Institutional, Funding, Editing support: Complete HealthVizion; Financial Interests, Institutional, Principal Investigator: Pfizer, BMS, Rexahn, Novartis, LSK/Elevar, Seattle Genetics, Debiopharm, Merck, AstraZeneca, Acrotech, Clovis; Non-Financial Interests, Institutional, Advisory Board: Seagen, Astellas; Financial Interests, Personal, Stocks/Shares: Salarius; Non-Financial Interests, Institutional, Other, research collaboration: Oncocyte, Caris. A. Hong: Non-Financial Interests, Personal and Institutional, Funding, Study funding and support for medical writing/editing: Astellas Pharma Inc.; Financial Interests, Personal, Stocks/Shares: Revance, Veru, Insmed, Intercept, CRISPR; Financial Interests, Institutional, Funding, Medical writing support: OPTUM; Financial Interests, Institutional, Funding, Editing support: Complete HealthVizion. N.N. El-Chaar: Non-Financial Interests, Institutional, Funding, Study funding and support for Medical Writing/editing: Astellas Pharma Inc.; Non-Financial Interests, Institutional, Funding, Medical writing support: OPUM; Non-Financial Interests, Institutional, Funding, Editing support: Complete HealthVizion; Financial Interests, Personal, Stocks/Shares: TNXP, SNGX, BNGO, SESN; Financial Interests, Personal, Stocks/Shares, Astellas Pharma Inc: RXRX; Financial Interests, Personal and Institutional, Full or part-time Employment: Astellas Pharma Inc. C. Young: Non-Financial Interests, Institutional, Funding, Study funding and support for Medical Writing/editing: Astellas Pharma Inc.; Non-Financial Interests, Institutional, Funding, Medical writing support: OPTUM; Non-Financial Interests, Institutional, Funding, Editing support: Complete HealthVizion. K. Ramaswamy: Non-Financial Interests, Institutional, Funding, Study funding and support for Medical Writing/editing: Astellas Pharma Inc.; Non-Financial Interests, Institutional, Funding, Medical writing support: OPTUM; Non-Financial Interests, Institutional, Funding, Editing support: Complete HealthVizion; Financial Interests, Personal, Stocks/Shares: Pfizer; Financial Interests, Personal and Institutional, Full or part-time Employment: Pfizer. B. Xie: Non-Financial Interests, Personal and Institutional, Funding, Study funding and support for Medical Writing/editing: Astellas Pharma Inc.; Non-Financial Interests, Institutional, Funding, Medical writing support: OPTUM; Non-Financial Interests, Institutional, Funding, Editing support: Complete HealthVizion. S. Bunner: Non-Financial Interests, Institutional, Funding, Study funding and support for Medical Writing/editing: Astellas Pharma Inc.; Non-Financial Interests, Personal and Institutional, Funding, Medical writing support: OPTUM; Non-Financial Interests, Institutional, Funding, Editing support: Complete HealthVizion. B. Diessner: Non-Financial Interests, Institutional, Funding, Study funding and support for Medical Writing/editing: Astellas Pharma Inc.; Non-Financial Interests, Personal and Institutional, Funding, Medical writing support: OPTUM; Non-Financial Interests, Institutional, Funding, Editing support: Complete HealthVizion; Financial Interests, Personal and Institutional, Full or part-time Employment: Optum/UnitedHealth Group. U. Swami: Non-Financial Interests, Institutional, Funding, Study funding and support for Medical Writing/editing: Astellas Pharma Inc.; Non-Financial Interests, Institutional, Funding, Medical writing support: OPUM; Non-Financial Interests, Institutional, Funding, Editing support: Complete HealthVizion; Non-Financial Interests, Personal, Advisory Role: Seattle Genetics, Astellas Pharma Inc., Exelixis; Non-Financial Interests, Personal, Research Grant: Janssen, Seattle Genetics/Astellas, Exelixis.