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Completed

NCT Number: NCT05968599

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

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.

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Key information

Conditions

Prostatic Neoplasms, Castration-Resistant Genital Diseases Genital Diseases, Male Genital Neoplasms, Male Male Urogenital Diseases Neoplasms Neoplasms by Site Prostatic Diseases Prostatic Neoplasms Urogenital Diseases Urogenital Neoplasms

Age range

18 year and older

Sex eligibility

Male

Study type

Observational

Primary location

Pfizer Inc

New York, 10001, United States

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Enzalutamide

Drug

As provided in real-world setting

Other names: Xtandi

Abiraterone Acetate

Drug

As provided in real-world setting

Other names: Yonsa, Zytiga

Primary outcomes

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

    Time frame: 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

    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.

Secondary outcomes

  1. OS Without Subsequent Therapy: Adjusted Using IPTW

    Time frame: 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

    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. OS of only those participants who initiated abiraterone and enzalutamide on the index date and did not receive subsequent systemic anti-neoplastic therapy were reported in this outcome measure. Kaplan-Meier (weighted) method was used for analysis.

  2. Time to Treatment Discontinuation (TTD): Adjusted Using IPTW

    Time frame: 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

    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. 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. Discontinuation was defined as the earliest of 1) death, 2) abstracted end date for last enzalutamide or abiraterone drug episode that started within the index treatment line of therapy (LOT) (drug episodes for abstracted oral therapies from the Flatiron Drug Episode table), or 3) day before the start of next LOT. Participants who did not discontinue were censored at their last available follow-up, which was defined as the earlier of end of data availability or last participant contact. Kaplan-Meier (weighted) method was used for analysis.

  3. Time to Subsequent Therapy (TTST): Adjusted Using IPTW

    Time frame: 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

    TTST was defined as the time from the initiation of enzalutamide or abiraterone (i.e., index date) to the start of next LOT. 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. Participants who did not start a new LOT were censored at their last available follow-up, which was defined as the earliest of 1) death, 2) end of data availability or 3) last participant contact. Kaplan-Meier (weighted) method was used for analysis.

Sponsors and collaborators

Lead sponsor

Pfizer

Industry

Collaborators

  • Astellas Pharma Inc

Registry information

Official study title

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

Important dates

Study start
2023
Primary completion
2025
Study completion
2025
First posted
Aug 1, 2023
Registry last updated
Feb 25, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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