A Study to Learn About the Study Medicines Called Enzalutamide and Abiraterone in People With Metastatic Castration-resistant Prostate Cancer

Study Overview
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Brief Summary
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The purpose of this real-world study is to learn about the effects of 2 study medicines called enzalutamide and abiraterone used to treat metastatic castration-resistant prostate cancer (mCRPC). Prostate cancer is one of the most common cancers in men. The prostate is a gland in the male body that helps make semen. Most prostate cancers need male sex hormones, such as testosterone, to grow. Prostate cancer that keeps growing even when the amount of testosterone in the body is reduced to very low levels is known as castration-resistant. Metastatic cancer is a cancer that has spread to other parts of the body. This is a real-world study, not a clinical trial. This means that researchers will look at what happens when men receive the treatments prescribed by their own doctor as part of their usual healthcare treatment. In this study, researchers will use information from the Flatiron Electronic Health Record (EHR) database. The study will include patients' information from the database for men who: Were confirmed by medical tests to have mCRPC Started first-line treatment with enzalutamide or abiraterone (index date) for mCRPC Had not received chemotherapy treatment before index date Were 18 years of age or older on index date Men who are part of this study will receive enzalutamide or abiraterone as part of their usual treatment for mCRPC. We will compare the following between men receiving enzalutamide and men receiving abiraterone: time from treatment start until death, treatment duration, and time to next treatment. This study will use patient information from the database until the end of information that is available.

Official Title
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A Real-World Comparison of Clinical Outcomes in Chemotherapy-naive Metastatic Castration-resistant Prostate Cancer(mCRPC) Patients Who Initiated Enzalutamide vs. Abiraterone Acetate (Abiraterone) in Flatiron Electronic Health Record (EHR)Database

Conditions
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Prostatic Neoplasms, Castration-Resistant

Intervention / Treatment
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* Drug: Enzalutamide
* Drug: Abiraterone acetate


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male with metastatic prostate cancer diagnosis and abstracted castration-resistant prostate cancer diagnosis Initiated enzalutamide or abiraterone within 14 days prior to or after the metastatic castration-resistant prostate cancer diagnosis. The initiation date of enzalutamide or abiraterone will be defined as the index date. At least 18 years old at the index date Exclusion Criteria: Received chemotherapy, novel hormonal therapy, radium-223, olaparib/rucaparib, or immunotherapy prior to the index date Had a prior history of other cancers

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Enzalutamide cohort<br>Patients with mCRPC initiating enzalutamide | Drug: Enzalutamide<br>* As provided in real-world setting<br>* Other names: Xtandi;|
| Abiraterone cohort<br>Patients with mCRPC initiating abiraterone acetate | Drug: Abiraterone acetate<br>* As provided in real-world setting<br>* Other names: Yonsa, Zytiga;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Overall Survival | Overall survival (OS) will be defined as the time from the initiation of enzalutamide or abiraterone to the date of death. | Up to approximately 8 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Overall survival among patients without subsequent therapy | Overall survival (OS) among the subgroup of patients who received only enzalutamide without any subsequent therapy or received only abiraterone without any subsequent therapy. OS will be defined as the time from the initiation of enzalutamide or abiraterone (i.e., index date) to the date of death. | Up to approximately 8 years | 
| Treatment duration | Treatment duration will be defined as the time from the initiation of enzalutamide or abiraterone to the discontinuation date. Discontinuation will be defined as the earliest of 1) death, 2) last abstracted end date for enzalutamide or abiraterone, or 3) day before the start of next line of therapy. | Up to approximately 8 years | 
| Time to subsequent therapy | Time to subsequent therapy will be defined as the time from the initiation of enzalutamide or abiraterone to the start of next line of therapy. | Up to approximately 8 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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metastatic castration-resistant prostate cancer, mCRPC, enzalutamide, abiraterone, overall survival, OS, treatment duration