Prostatic Neoplasms, Castration-Resistant
Conditions
Keywords
metastatic castration-resistant prostate cancer, mCRPC, enzalutamide, abiraterone, overall survival, OS, treatment duration
Brief summary
This study will be a retrospective data analysis to compare outcomes between patients with chemotherapy-naïve metastatic castration-resistant prostate cancer (mCRPC) who initiated enzalutamide and those who initiated abiraterone using the 100% Fee-For-Service Medicare claims data. The study will address the following objectives: Primary objective: To compare overall survival (OS) in patients with chemotherapy-naïve mCRPC who initiated enzalutamide vs. abiraterone Secondary objectives: * To compare OS in patients with chemotherapy-naïve mCRPC who received only enzalutamide without any subsequent therapy vs. abiraterone without any subsequent therapy * To compare treatment duration and time to subsequent therapy in chemotherapy-naïve mCRPC patients initiating enzalutamide vs. abiraterone
Interventions
DRUGEnzalutamide
As provided in real-world setting
DRUGAbiraterone acetate
As provided in real-world setting
Sponsors
Pfizer
Study design
Observational model
COHORT
Time perspective
RETROSPECTIVE
Eligibility
Sex/Gender
MALE
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Male with ≥ 1 diagnosis claim for prostate cancer * Have documented secondary metastasis code on or after the initial prostate cancer diagnosis * Have initiated enzalutamide or abiraterone within 90 days prior to the metastasis date or on or after the metastasis date. The initiation date of enzalutamide or abiraterone will be defined as the index date. * Have evidence of surgical or medical castration before the index date * At least 18 years old at the index date * Continuous eligibility for ≥ 12 months prior to the index date
Exclusion criteria
* Received chemotherapy, novel hormonal therapy, radium-223, or immunotherapy prior to the index date * Had a prior history of other cancers
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Overall Survival (OS): Inverse Probability Treatment Weighting (IPTW) | From index date to date of death or censoring date, whichever occurred first (from 10-Sep-2014 to 31-Dec-2020, approximately 76 months); retrospective data extracted and evaluated from study start date and until study completion (approximately 10 months) | OS (time to death) was defined as the time from the initiation of enzalutamide or abiraterone (i.e., index date) to the date of death. Participants who did not die were censored at their last available follow-up, which was defined as the earlier of disenrollment from Medicare or end of data availability. Kaplan-Meier method was used for analysis. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| OS Among Participants Without Any Subsequent Therapy: IPTW | From index date to date of death or censoring date, whichever occurred first (from 10-Sep-2014 to 31-Dec-2020, approximately 76 months); retrospective data extracted and evaluated from study start date and until study completion (approximately 10 months) | OS (time to death) was defined as the time from the initiation of enzalutamide or abiraterone (i.e., index date) to the date of death. Participants who did not die were censored at their last available follow-up, which was defined as the earlier of disenrollment from Medicare or end of data availability. Kaplan-Meier method was used for analysis. |
| Treatment Duration: IPTW | From index date to date of discontinuation event or censoring date, whichever occurred first(from 10-Sep-2014 to 31-Dec-2020, approximately 76months); retrospective data extracted and evaluated from start date and until completion(approximately 10months) | Treatment duration of the index treatment was defined as the time from the initiation of enzalutamide or abiraterone (i.e., index date) to the discontinuation date. Discontinuation was defined as the earliest of 1) death, 2) last observed administration plus day of supply associated with last administration, or 3) day before the start of next line of therapy. Death, a gap of 90 days or more after the last observed prescription date + day of supply, and initiation of next line of therapy was considered as discontinuation events. Participants who did not discontinue were censored at their last available follow-up, which was defined as the earlier of disenrollment from Medicare or end of data availability. |
| Time to Subsequent Therapy: IPTW | From index date to start of next line of therapy (from 10-Sep-2014 to 31-Dec-2020, approximately 76 months); retrospective data extracted and evaluated from study start date and until study completion (approximately 10 months) | Time to subsequent therapy was defined as the time from the initiation of enzalutamide or abiraterone (i.e., index date) to the start of next line of therapy. Participants who did not start a new line of therapy were censored at their last available follow-up, which was defined as the earliest of 1) death, 2) disenrollment from Medicare, and 3) end of data availability. |
Countries
United States
Participant flow
Recruitment details
Data of participants- with chemotherapy naive metastatic castration-resistant prostate cancer (mCRPC), who initiated abiraterone or enzalutamide during the index period of 10 September 2014 to 31 May 2017 (approximately 33 months)- were included in this study. Data was retrieved from 100% Medicare Fee-For-Service (FFS). Retrospective data extracted and evaluated from study start date and until study completion (approximately 10 months) of this retrospective observational study.
Participants by arm
| Arm | Count |
|---|---|
| Abiraterone Participants with mCRPC who initiated abiraterone during the index period in real-world setting and whose data were observed in the study, were included in this reporting group. | 2,911 |
| Enzalutamide Participants with mCRPC who initiated enzalutamide during the index period in real-world setting and whose data were observed in the study, were included in this reporting group. | 2,595 |
| Total | 5,506 |
Baseline characteristics
| Characteristic | Abiraterone | Enzalutamide | Total |
|---|---|---|---|
| Age, Continuous | 78.4 Years STANDARD_DEVIATION 7.9 | 78.6 Years STANDARD_DEVIATION 8.2 | 78.5 Years STANDARD_DEVIATION 8 |
| Race/Ethnicity, Customized Black | 364 Participants | 336 Participants | 700 Participants |
| Race/Ethnicity, Customized Hispanic | 148 Participants | 134 Participants | 282 Participants |
| Race/Ethnicity, Customized Unknown or Others | 126 Participants | 113 Participants | 239 Participants |
| Race/Ethnicity, Customized White, non-Hispanic | 2273 Participants | 2012 Participants | 4285 Participants |
| Sex: Female, Male Female | 0 Participants | 0 Participants | 0 Participants |
| Sex: Female, Male Male | 2911 Participants | 2595 Participants | 5506 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 2,523 / 2,911 | 2,176 / 2,595 |
| other Total, other adverse events | 0 / 0 | 0 / 0 |
| serious Total, serious adverse events | 0 / 0 | 0 / 0 |
Outcome results
Primary
Overall Survival (OS): Inverse Probability Treatment Weighting (IPTW)
OS (time to death) was defined as the time from the initiation of enzalutamide or abiraterone (i.e., index date) to the date of death. Participants who did not die were censored at their last available follow-up, which was defined as the earlier of disenrollment from Medicare or end of data availability. Kaplan-Meier method was used for analysis.
Time frame: From index date to date of death or censoring date, whichever occurred first (from 10-Sep-2014 to 31-Dec-2020, approximately 76 months); retrospective data extracted and evaluated from study start date and until study completion (approximately 10 months)
Population: Analysis population included all eligible participants whose medical records were retrieved and observed in this study. Here, ''Number of Participants Analyzed'' signifies number of participants evaluable for this outcome measure after adjusting for baseline confounders (demographics, clinical characteristics, prior treatments, comorbidities, medical resource use) using IPTW. Hence, numbers are different here from those presented in participant and baseline section.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Abiraterone | Overall Survival (OS): Inverse Probability Treatment Weighting (IPTW) | 20.6 Months |
| Enzalutamide | Overall Survival (OS): Inverse Probability Treatment Weighting (IPTW) | 22.5 Months |
95% CI: [1.04, 1.16]
Secondary
OS Among Participants Without Any Subsequent Therapy: IPTW
OS (time to death) was defined as the time from the initiation of enzalutamide or abiraterone (i.e., index date) to the date of death. Participants who did not die were censored at their last available follow-up, which was defined as the earlier of disenrollment from Medicare or end of data availability. Kaplan-Meier method was used for analysis.
Time frame: From index date to date of death or censoring date, whichever occurred first (from 10-Sep-2014 to 31-Dec-2020, approximately 76 months); retrospective data extracted and evaluated from study start date and until study completion (approximately 10 months)
Population: Analysis population included all eligible participants whose medical records were retrieved and observed in this study. Here, ''Number of Participants Analyzed'' signifies number of participants evaluable for this outcome measure after adjusting for baseline confounders (demographics, clinical characteristics, prior treatments, comorbidities, medical resource use) using IPTW. Hence, numbers are different here from those presented in participant and baseline section.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Abiraterone | OS Among Participants Without Any Subsequent Therapy: IPTW | 10.6 Months |
| Enzalutamide | OS Among Participants Without Any Subsequent Therapy: IPTW | 13.6 Months |
95% CI: [1.06, 1.27]
Secondary
Time to Subsequent Therapy: IPTW
Time to subsequent therapy was defined as the time from the initiation of enzalutamide or abiraterone (i.e., index date) to the start of next line of therapy. Participants who did not start a new line of therapy were censored at their last available follow-up, which was defined as the earliest of 1) death, 2) disenrollment from Medicare, and 3) end of data availability.
Time frame: From index date to start of next line of therapy (from 10-Sep-2014 to 31-Dec-2020, approximately 76 months); retrospective data extracted and evaluated from study start date and until study completion (approximately 10 months)
Population: Analysis population included all eligible participants whose medical records were retrieved and observed in this study. Here ''Number of Participants Analyzed'' signifies number of participants evaluable for this outcome measure after adjusting for baseline confounders (demographics, clinical characteristics, prior treatments, comorbidities, medical resource use) using IPTW. Hence, numbers are different here from those presented in participant and baseline section.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Abiraterone | Time to Subsequent Therapy: IPTW | 14.5 Months |
| Enzalutamide | Time to Subsequent Therapy: IPTW | 16.7 Months |
95% CI: [1.06, 1.22]
Secondary
Treatment Duration: IPTW
Treatment duration of the index treatment was defined as the time from the initiation of enzalutamide or abiraterone (i.e., index date) to the discontinuation date. Discontinuation was defined as the earliest of 1) death, 2) last observed administration plus day of supply associated with last administration, or 3) day before the start of next line of therapy. Death, a gap of 90 days or more after the last observed prescription date + day of supply, and initiation of next line of therapy was considered as discontinuation events. Participants who did not discontinue were censored at their last available follow-up, which was defined as the earlier of disenrollment from Medicare or end of data availability.
Time frame: From index date to date of discontinuation event or censoring date, whichever occurred first(from 10-Sep-2014 to 31-Dec-2020, approximately 76months); retrospective data extracted and evaluated from start date and until completion(approximately 10months)
Population: Analysis population included all eligible participants whose medical records were retrieved and observed in this study. Here ''Number of Participants Analyzed'' signifies number of participants evaluable for this outcome measure after adjusting for baseline confounders (demographics, clinical characteristics, prior treatments, comorbidities, medical resource use) using IPTW. Hence, numbers are different here from those presented in participant and baseline section.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Abiraterone | Treatment Duration: IPTW | 6.7 Months |
| Enzalutamide | Treatment Duration: IPTW | 7.4 Months |
95% CI: [0.99, 1.1]