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

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

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.

Study Overview

• Status: Active, not recruiting
• Conditions: Prostatic Neoplasms, Castration-Resistant
• Intervention / Treatment: Drug: Enzalutamide; Drug: Abiraterone acetate

• Study Type: Observational
• Enrollment (Estimated): 2800

Contacts and Locations

• Study Contact: Name: Pfizer CT.gov Call Center; Phone Number: 1-800-718-1021; Email: ClinicalTrials.gov_Inquiries@pfizer.com

Study Locations

• United States
  • New York
    • New York, New York, United States, 10001
      • Pfizer Inc

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Men with chemotherapy-naïve mCRPC (aged ≥18 years) who initiated enzalutamide or abiraterone and met eligibility criteria will be included in the study. Patients will be identified from the Flatiron EHR database.

Description

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

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Enzalutamide cohort; Patients with mCRPC initiating enzalutamide	Drug: Enzalutamide; As provided in real-world setting; Other Names: Xtandi
Abiraterone cohort; Patients with mCRPC initiating abiraterone acetate	Drug: Abiraterone acetate; As provided in real-world setting; Other Names: Yonsa, Zytiga

What is the study measuring?

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

Collaborators and Investigators

• Sponsor: Pfizer
• Collaborators: Astellas Pharma Inc
• Investigators: Study Director: Pfizer CT.gov Call Center, Pfizer

Publications and helpful links

Helpful Links

• To obtain contact information for a study center near you, click here.

Study record dates

Study Major Dates

• Study Start (Actual): July 24, 2023
• Primary Completion (Estimated): March 31, 2024
• Study Completion (Estimated): March 31, 2024

Study Registration Dates

• First Submitted: July 21, 2023
• First Submitted That Met QC Criteria: July 21, 2023
• First Posted (Actual): August 1, 2023

Study Record Updates

• Last Update Posted (Estimated): March 5, 2024
• Last Update Submitted That Met QC Criteria: March 1, 2024
• Last Verified: March 1, 2024

More Information

Terms related to this study

• Keywords: enzalutamide; mCRPC; metastatic castration-resistant prostate cancer; abiraterone; overall survival; OS; treatment duration
• Additional Relevant MeSH Terms: Neoplasms; Urogenital Neoplasms; Neoplasms by Site; Genital Neoplasms, Male; Prostatic Diseases; Urogenital Diseases; Male Urogenital Diseases; Genital Diseases, Male; Genital Diseases; Prostatic Neoplasms; Prostatic Neoplasms, Castration-Resistant; Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Enzyme Inhibitors; Antineoplastic Agents; Hormones, Hormone Substitutes, and Hormone Antagonists; Cytochrome P-450 Enzyme Inhibitors; Hormone Antagonists; Steroid Synthesis Inhibitors; Abiraterone Acetate
• Other Study ID Numbers: C3431047

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.