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

NCT05968599 | Completed Results

• 2 other identifiers: C3431047NCT05968599
• Study Type: observational
• Target: 2,731
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Prostatic Neoplasms, Castration-Resistant

Keywords

metastatic castration-resistant prostate cancer; mCRPC; enzalutamide; abiraterone; overall survival; OS; treatment duration

Outcome Measures

Primary Outcomes (1)

• Overall Survival (OS): Adjusted Using Inverse Probability Treatment Weighting (IPTW)

  OS 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 during this period were censored at their last available follow-up, which was defined as the earlier of end of data availability or last participant contact. Index date was defined as the date of initiation of enzalutamide or abiraterone and their index date was required to occur during the index period. Kaplan-Meier (weighted) method was used for analysis.

  From index date to date of death or censoring date, whichever occurred first (approximately 104.7 months); retrospective data retrieved and evaluated during approximately 18.7 months

Secondary Outcomes (3)

• OS Without Subsequent Therapy: Adjusted Using IPTW

  From index date to date of death or censoring date, whichever occurred first (approximately 104.7 months); retrospective data retrieved and evaluated during approximately 18.7 months

• Time to Treatment Discontinuation (TTD): Adjusted Using IPTW

  From index date to date of treatment discontinuation or censoring date, whichever occurred first (approximately 104.7 months); retrospective data retrieved and evaluated during approximately 18.7 months

• Time to Subsequent Therapy (TTST): Adjusted Using IPTW

  From index date to date of start of next LOT or censoring date, whichever occurred first (approximately 104.7 months); retrospective data retrieved and evaluated during approximately 18.7 months

Study Arms (2)

Enzalutamide cohort

Patients with mCRPC initiating enzalutamide

Drug: Enzalutamide

Abiraterone cohort

Patients with mCRPC initiating abiraterone acetate

Drug: Abiraterone acetate

Interventions

Enzalutamide DRUG

As provided in real-world setting

Also known as: Xtandi

Enzalutamide cohort

Abiraterone acetate DRUG

As provided in real-world setting

Also known as: Yonsa, Zytiga

Abiraterone cohort

Eligibility Criteria

• Age: 18 Years+
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• 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.

You may qualify if:

• 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

You may not qualify if:

• Received chemotherapy, novel hormonal therapy, radium-223, olaparib/rucaparib, or immunotherapy prior to the index date
• Had a prior history of other cancers

Sponsors & Collaborators

• Pfizer: lead
• Astellas Pharma Inc: collaborator

Study Sites (1)

Pfizer Inc

New York, New York, 10001, United States

Location

Related Links

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

MeSH Terms

Conditions

Prostatic Neoplasms, Castration-Resistant

Interventions

enzalutamide; Abiraterone Acetate

Condition Hierarchy (Ancestors)

Prostatic Neoplasms; Genital Neoplasms, Male; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Genital Diseases, Male; Genital Diseases; Urogenital Diseases; Prostatic Diseases; Male Urogenital Diseases

Intervention Hierarchy (Ancestors)

Androstenes; Androstanes; Steroids; Fused-Ring Compounds; Polycyclic Compounds

Results Point of Contact

• Title: Pfizer ClinicalTrials.gov Call Center
• Organization: Pfizer Inc.

ClinicalTrials.gov_Inquiries@pfizer.com

1-800-718-1021

Study Officials

• Pfizer CT.gov Call Center

  Pfizer

  STUDY DIRECTOR

Publication Agreements

• PI is Sponsor Employee: No
• Restriction Type: OTHER
• Restrictive Agreement: Yes

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: RETROSPECTIVE
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 21, 2023
• First Posted: August 1, 2023
• Study Start: July 24, 2023
• Primary Completion: February 14, 2025
• Study Completion: February 14, 2025
• Last Updated: February 25, 2026
• Results First Posted: February 25, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)