Enzalutamide vs. Abiraterone in Chemotherapy-naïve Metastatic Castration-resistant Prostate Cancer (mCRPC)

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 the 100% Medicare Fee-For-Service (FFS) Data (2009-2020)

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

Study Overview

• Status: Completed
• Conditions: Prostatic Neoplasms, Castration-Resistant
• Intervention / Treatment: Drug: Enzalutamide; Drug: Abiraterone acetate

• Study Type: Observational
• Enrollment (Actual): 5506

Contacts and Locations

Study Locations

• United States
  • New York
    • New York, New York, United States, 10017
      • Pfizer Inc

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients 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 100% Fee-For-Service Medicare claims data.

Description

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

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Retrospective

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	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 76 months

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 76 months
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 observed administration plus day of supply associated with last administration, or 3) day before the start of next line of therapy.	Up to approximately 76 months
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 76 months

Collaborators and Investigators

• Sponsor: Pfizer
• 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): August 29, 2022
• Primary Completion (Actual): June 30, 2023
• Study Completion (Actual): June 30, 2023

Study Registration Dates

• First Submitted: August 26, 2022
• First Submitted That Met QC Criteria: August 26, 2022
• First Posted (Actual): August 29, 2022

Study Record Updates

• Last Update Posted (Actual): August 14, 2023
• Last Update Submitted That Met QC Criteria: August 9, 2023
• Last Verified: August 1, 2023

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: C3431046; Enza vs Abi rwOS in Medicare (Other Identifier: Alias Study Number)

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.