Abstract 661P
Background
Therapeutic options for mCRPC pts are continually advancing. We described the US tx patterns of pts diagnosed with mCRPC from 01/2013 to 03/2019.
Methods
mCRPC pts with a confirmed adenocarcinoma mCRPC diagnosis (dx) were identified in the US Flatiron Health EHR-derived de-identified database, which primarily covers community-based clinical practices (91% of pts vs 9% in academic settings). Pts were followed from the mCRPC dx until the end of clinical activity, end of data availability (03/2019), or death. Tx patterns (incl. tx per lines of therapies [LOTs], LOT sequences and time on tx) were described.
Results
Of 5,213 pts (mean age: 73 yrs; mean follow-up post-mCRPC: 1.5 yrs), 4,374 (84%) were treated with ≥ 1 LOT (2,419 [46%] with ≥ 2 LOTs; 1,292 [25%] with ≥ 3 LOTs; 645 [12%] with ≥ 4 LOTs; and 292 [6%] with ≥ 5 LOTs) during the follow-up. The most commonly chosen first line (1L) tx regimens were abiraterone (35% pts with 1L; observed median tx duration: 5.1 mo), enzalutamide (30%; 5.6 mo), docetaxel (14%; 3.3 mo); for 2L they were enzalutamide (29% of pts with 2L; 4.4 mo), abiraterone (22%; 4.1 mo), docetaxel (16%; 3.0 mo); for 3L they were docetaxel (23% of pts with 3L; 2.9 mo), enzalutamide (16%; 3.3 mo), abiraterone (13%; 3.3 mo). In tx class analyses, the main tx class used in 1L was new hormonal agent (NHA; 65%; Table). In LOT sequence analyses by tx class (Table), 25 distinct 1L → 2L LOT sequences were observed in pts with ≥ 2 LOTs and 97 distinct 1L → 2L → 3L LOT sequences were observed in pts with ≥ 3 LOTs. The most common 1L → 2L and 1L → 2L → 3L LOT sequences were NHA → NHA (30% pts; median time from 1L start to 2L end: 13.4 mo) and NHA → NHA→ Chemo (17%; median time from 1L start to 3L end: 17.4 mo), respectively. Table: 661P
LOT sequences by Tx class
| % pts | Median months on tx | |
| Pts with ≥ 1 LOT (N = 4,374) | On 1L | |
| 1L class | ||
| NHA | 65 | 5.2 |
| Chemo | 16 | 2.8 |
| I/O | 7 | 3.3 |
| Other | 5 | 3.7 |
| Combinations of classes | 7 | 5.1 |
| NHA-based | 6 | 5.1 |
| Pts with ≥ 2 LOTs (N = 2,419) | From 1L start to 2L end | |
| 1L → 2L (by frequency) | ||
| NHA → NHA | 30 | 13.4 |
| NHA → Chemo | 16 | 8.6 |
| Chemo → NHA | 9 | 10.7 |
| Remaining 22 sequences | 45 | 10.5 |
| Pts with ≥ 3 LOTs (N = 1,292) | From 1L start to 3L end | |
| 1L → 2L → 3L (by frequency) | ||
| NHA → NHA → Chemo | 17 | 17.4 |
| NHA → Chemo → Chemo | 7 | 13.1 |
| I/O → NHA → NHA | 5 | 19.4 |
| Remaining 94 sequences | 71 | 16.1 |
I/O , immunotherapy (excl. pembrolizumab); NHA , new hormonal agents (e.g., abiraterone, enzalutamide); Other , incl. pembrolizumab, targeted tx, radium-223, androgren-deprivation tx, clinical trial tx.
Conclusions
While 1L NHA was widely used in pts newly diagnosed with mCRPC from 2013 to 2019, the 1L NHA duration was relatively short. A plethora of LOT sequences were observed beyond 1L, reflecting a need for clearer guidance on optimal sequencing.
Clinical trial identification
Editorial acknowledgement
Editorial assistance was provided by Mona Lisa Chanda, and employee at Analysis Group, Inc. in Montréal, Quebec, Canada.
Legal entity responsible for the study
Merck & Co., Inc. and Analysis Group, Inc.
Funding
This study was funded by Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA and by AstraZeneca.
Disclosure
N. Shore: Advisory/Consultancy: Amgen, Astellas, AstraZeneca, Bayer, BMS, Dendreon, Fergene, Ferring, Janssen, Merck, Myovant, Nymox, Pfizer, Sanofi, Tolmar; Honoraria (self): Amgen, Astellas, AstraZeneca, Bayer, BMS, Dendreon, Fergene, Ferring, Janssen, Merck, Myovant, Nymox, Pfizer, Sanofi, Tolmar; Speaker Bureau/Expert testimony: Astellas, Bayer, Janssen; Leadership role: LUGPA, BCAN Boards; Research grant/Funding (institution): Astellas, Bayer, Tolmar; Travel/Accommodation/Expenses: Amgen, Astellas, AstraZeneca, Bayer, BMS, Dendreon, Fergene, Ferring, Janssen, Merck, Myovant, Nymox, Pfizer, Sanofi, Tolmar. F. Laliberté: Research grant/Funding (institution), I am an employee at Analysis Group, a company that has received funding from Merck: Merck & Co, Inc.; Full/Part-time employment, Analysis Group has provided paid consulting services to various clients in the bio medical arena: Analysis Group, Inc.. R. Ionescu-Ittu: Research grant/Funding (institution), I am an employee at Analysis Group, a company that has received funding from Merck: Merck & Co, Inc.; Full/Part-time employment, Analysis Group has provided paid consulting services to various clients in the bio medical arena: Analysis Group, Inc.. A. Gayle: Full/Part-time employment: AstraZeneca. S. Amin: Shareholder/Stockholder/Stock options, Full/Part-time employment: AstraZeneca. L. Yang: Honoraria (self), Honoraria (institution), Travel/Accommodation/Expenses, Shareholder/Stockholder/Stock options, Full/Part-time employment: Merck & Co, Inc. S. Payne: Full/Part-time employment, Full-time employee: AstraZeneca. M. Mahendran: Research grant/Funding (institution), I work for Analysis Group, a company that has received funding from Merck: Merck & Co, Inc.; Full/Part-time employment, Analysis Group has provided paid consulting services to various clients in the bio medical arena: Analysis Group, Inc.. D. Lejeune: Research grant/Funding (institution), I am an employee of Analysis Group, a consulting company which has received funding from Merck: Merck & Co, Inc.; Full/Part-time employment, Analysis Group has provided paid consulting services to various clients in the bio medical arena: Analysis Group, Inc. L. Yu: Research grant/Funding (institution), I am an employee of Analysis Group, a consulting company which has received funding from Merck: Merck & Co, Inc.; Full/Part-time employment, Analysis Group has provided paid consulting services to various clients in the bio medical arena: Analysis Group, Inc. J. Burgents: Shareholder/Stockholder/Stock options, Full/Part-time employment, Spouse/Financial dependant, Stocks and Spouse: Merck & Co, Inc. M.S. Duh: Research grant/Funding (institution), I am an employee of Analysis Group, a consulting company which has received funding from Merck: Merck & Co, Inc.; Full/Part-time employment, Analysis Group has provided paid consulting services to various clients in the bio medical arena: Analysis Group, Inc. S. Ghate: Shareholder/Stockholder/Stock options, Full/Part-time employment: Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.