ERLEADA®
(apalutamide)
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ERLEADA® (apalutamide)
Medical Information
Poster Summary: Bilen et al 2024 – Real-World OS Comparison with Enzalutamide in Patients with mCSPC
Last Updated: 11/26/2024
Real-world STUDY
Bilen et al (2024)1
Study Design/Methods
- Real-world, retrospective, head-to-head, longitudinal study
- Clinical data from Precision Point Specialty (PPS) Analytics collected as part of routine clinical care from community-based urology practices in the United States (US) were linked with administrative claims data from the Komodo Research Database (KRD) obtained from December 16, 2018 to December 31, 2023. Patients were assigned to mutually exclusive treatment cohorts based on the first dispensation or paid pharmacy claim (index date) for ERLEADA or enzalutamide.
- ARPI-naïve patients with mCSPC were required to have a diagnosis code or clinical indicator for bone, nodal, or visceral metastasis without castration resistance prior to or on the index date. Concomitant use of androgen deprivation therapy (ADT) was not required for inclusion.
- Baseline patient characteristics were evaluated 12 months preceding the index date.
- Treatment patterns were assessed from the index date up to 24 months.
- Inverse probability of treatment weighting (IPTW) based on propensity score was used to account for differences in baseline characteristics between the ERLEADA and enzalutamide cohorts.
- Each patient was attributed an inverse probability of treatment weight, defined as 1/(propensity score) for the ERLEADA cohort and 1/(1-propensity score) for the enzalutamide cohort.
- A weighted Kaplan-Meier analysis was used to assess the proportion of patients surviving by 24 months postindex and weighted Cox proportional hazards models were used to evaluate the causal relationship between the index treatment and OS.
- HR <1 indicates a lower rate of death for the ERLEADA cohort compared with the enzalutamide cohort.
- Primary outcome: Proportion of patients who survived by 24 months postindex ARPI initiation
- This study was not designed to assess differences in safety between cohorts.
Results
Patient Characteristics
- Concomitant ADT use was observed in 79.2% of patients in the ERLEADA weighted cohort and 77.8% in the enzalutamide weighted cohort.
- Baseline patient characteristics were well-balanced between weighted cohorts, with standardized differences <10%.
- Patient demographics and baseline characteristics in the weighted population are included in Table: Demographics and Baseline Disease Characteristics.
| Characteristic | Weighted Populationa | |||
|---|---|---|---|---|
| ERLEADA (n=1810) | Enzalutamide (n=1909) | Standardized difference, % | ||
| Mean age, years (SD) | 73.0 (9.2) | 73.0 (9.3) | 0.1 | |
| Race, n (%) | ||||
| White | 1083 (59.8) | 1135 (59.4) | 0.8 | |
| Black or African American | 407 (22.5) | 432 (22.7) | 0.3 | |
| Hispanic or Latino | 135 (7.5) | 146 (7.6) | 0.6 | |
| Other | 79 (4.4) | 88 (4.6) | 1.2 | |
| Unknown | 105 (5.8) | 108 (5.7) | 0.7 | |
| Geographic region, n (%) | ||||
| South | 986 (54.5) | 1021 (53.5) | 2.0 | |
| Midwest | 429 (23.7) | 458 (24.0) | 0.6 | |
| Northeast | 225 (12.4) | 250 (13.1) | 1.9 | |
| West | 170 (9.4) | 181 (9.5) | 0.3 | |
| Index year, n (%) | ||||
| 2019-2020 | 391 (21.6) | 434 (22.7) | 2.7 | |
| 2021 | 488 (27.0) | 524 (27.5) | 1.2 | |
| 2022 | 493 (27.3) | 511 (26.7) | 1.2 | |
| 2023 | 438 (24.2) | 440 (23.1) | 2.7 | |
| Mean time between metastasis and index date, months (SD) | 10.1 (18.2) | 10.6 (18.0) | 2.7 | |
| Mean time between PC diagnosis and index date, months (SD) | 39.4 (46.6) | 39.8 (46.8) | 1.0 | |
| Metastasis type,b | ||||
| Bone | 1301 (71.9) | 1390 (72.8) | 2.1 | |
| Nodal | 887 (49.0) | 918 (48.1) | 1.8 | |
| Visceral | 356 (19.7) | 398 (20.8) | 2.9 | |
| Metastasis in multiple sites | 485 (26.8) | 498 (26.1) | 1.6 | |
| Mean Quan-CCI (SD) | 8.6 (3.0) | 8.6 (3.1) | 1.1 | |
| De novo PC,c | 1017 (56.2) | 1072 (56.2) | 0.1 | |
| Concurrent use of ADT with index ARPI,d | 1434 (79.2) | 1486 (77.8) | 3.3 | |
| Mean duration of ADT episode overlapping with index date, months (SD) | 4.5 (8.6) | 5.5 (9.3) | 9.6 | |
| Prior use of first-generation ARPI,e | 350 (19.4) | 393 (20.6) | 3.0 | |
| Prior use of chemotherapy,f | 41 (2.3) | 49 (2.6) | 2.0 | |
| Most recent PSA level, ng/mL, n (%) | ||||
| ≤0.2 | 281 (15.5) | 283 (14.8) | 2.0 | |
| >0.2 to ≤2 | 291 (16.1) | 302 (15.8) | 0.8 | |
| >2 to ≤5 | 180 (9.9) | 181 (9.5) | 1.5 | |
| >5 to ≤10 | 165 (9.1) | 165 (8.6) | 1.6 | |
| >10 | 541 (29.9) | 563 (29.5) | 0.8 | |
| Unknown | 352 (19.5) | 415 (21.7) | 5.6 | |
| Initial Gleason score,g | ||||
| ≤6 | 101 (5.6) | 108 (5.7) | 0.3 | |
| 7 | 323 (17.8) | 326 (17.1) | 2.1 | |
| 8 | 256 (14.2) | 267 (14.0) | 0.4 | |
| 9 | 383 (21.1) | 405 (21.2) | 0.1 | |
| 10 | 60 (3.3) | 64 (3.3) | 0.1 | |
| Unknown | 687 (37.9) | 739 (38.7) | 1.6 | |
| Abbreviations: ADT, androgen deprivation therapy; ARPI, androgen receptor pathway inhibitor; CCI, Charlson Comorbidity Index; PC, prostate cancer; PSA, prostate-specific antigen; SD, standard deviation. aThe number of patients reported in this weighted population represents the sum of weights for the corresponding nonweighted patients, rounded to the nearest integer. The proportions displayed were calculated before rounding and may be slightly different than if they were calculated based on rounded numbers. bTypes of metastases were defined at any time prior to (and including) the index date. The types of metastases were not mutually exclusive. cDe novo PC was defined as ≤180 days between the first PC diagnosis and date of metastasis. dConcurrent ADT use was defined as an episode of continuous ADT use overlapping with the index date (using a 60-day gap to define discontinuation). ePrior use of first-generation ARPI was defined as any prescription for bicalutamide, nilutamide, or flutamide in the 12 months preceding the index date. fPrior chemotherapy use was defined as administration at any time prior to (and excluding) the index date. gThe Gleason score was evaluated at any time prior to and including the index date. | ||||
24 Months Postindex
- By 24 months postindex, patients initiated on ERLEADA had a statistically significant 23% reduction in the risk of death when compared with patients initiated on enzalutamide (hazard ratio [HR], 0.77; 95% confidence interval [CI], 0.62-0.96; P=0.019).
The proportion of patients surviving at 24 months postindex was 87.6% in the ERLEADA cohort and 84.6% in the enzalutamide cohort.
48 Months Postindex
- When evaluating OS using all available follow-up at 48 months postindex, results were consistent with OS at 24 months postindex (HR, 0.77; 95% CI, 0.64-0.93; nominal P=0.008). This endpoint was not adjusted for multiple comparisons. Therefore, the p-value displayed is nominal, and statistical significance has not been established.
- The proportion of patients surviving at 48 months postindex was 75.6% in the ERLEADA cohort and 68.1% in the enzalutamide cohort.
Treatment Patterns
- The mean (median) follow-up duration was 17.2 (20.1) months for the ERLEADA cohort and 17.2 (20.1) months for the enzalutamide cohort.
- The mean (median) duration of continuous index ARPI use (using a 90-day gap in treatment to define discontinuation) was 9.6 (6.9) months for the ERLEADA cohort and 8.6 (6.4) months for the enzalutamide cohort.
Safety results were not reported.
References
| 1 | Bilen MA, Lowentritt B, Khilfeh I, et al. Real-world head-to-head analysis of overall survival in patients with metastatic castration-sensitive prostate cancer initiated on apalutamide versus enzalutamide in the United States. Poster presented at: European Conference of Oncology Pharmacy (ECOP); October 2-4, 2024; Lisbon, Portugal. |