A Study to Learn About Two Medicines (Apalutamide and Enzalutamide) in People With Metastatic Castration-sensitive Prostate Cancer (mCSPC)

NCT07086651 | Completed FDA Drug

• 1 other identifier: C3431053
• Study Type: observational
• Target: 1,300
• Locations: 1 country
• Sites: 1

Brief Summary

The purpose of this study is to learn about how long apalutamide and enzalutamide are taken by men to treat mCSPC. Prostate cancer is one of the most common cancers in men. The prostate is a gland in the male body that helps make semen. Metastatic cancer is a cancer that has spread to other parts of the body. Castration-sensitive prostate cancer means the cancer is being controlled by keeping the testosterone levels as low as would be expected if the testicles were removed by surgery. This is a real-world study, not a clinical study. 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 cancer clinics (Flatiron Health electronic health records). The study will include patients' information from the database for men who:

• Were identified to have mCSPC.
• Started treatment with apalutamide or enzalutamide (index date) for mCSPC.
• Were 18 years of age or older on the index date. Men in this study will be taking apalutamide or enzalutamide for treatment of their mCSPC. The study will compare how long men take apalutamide or enzalutamide. This study will use patient information from cancer clinics. Information from start of apalutamide or enzalutamide treatment until information is available in the database will be used to describe how long patients receive treatment.

Conditions

Metastatic Castration Sensitive Prostate Cancer (mCSPC); Cancer of the Prostate; Prostate Neoplasms; Prostate Cancer

Keywords

enzalutamide; Xtandi; apalutamide; Erleada; mCSPC; metastatic castration-sensitive prostate cancer; treatment duration; metastatic hormone-sensitive prostate cancer; mHSPC

Outcome Measures

Primary Outcomes (1)

• Treatment duration

  Treatment duration will be defined as the time from index date to the discontinuation (i.e., addition of subsequent treatment, treatment gap of 90 days, death) of the index treatment for any reason. Patients without an event will be censored on the date of last confirmed clinical activity.

  Up to approximately 65 months

Study Arms (2)

Enzalutamide cohort

Patients initiating enzalutamide for mCSPC

Drug: Enzalutamide

Apalutamide cohort

Patients initiating apalutamide for mCSPC

Drug: Apalutamide

Interventions

Enzalutamide DRUG

As provided in real-world setting

Also known as: XTANDI

Enzalutamide cohort

Apalutamide DRUG

As provided in real-world setting

Also known as: ERLEADA

Apalutamide cohort

Eligibility Criteria

• Age: 18 Years+
• Gender Eligibility Details: Male
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Men with metastatic castration-sensitive prostate cancer who initiated apalutamide or enzalutamide and met eligibility criteria will be included in the study. Patients will be identified from the Flatiron Health electronic health records database.

You may qualify if:

• Male patients diagnosed with metastatic prostate cancer
• Initiated apalutamide or enzalutamide for the first-line treatment of metastatic castration-sensitive prostate cancer (mCSPC). Initiation date of first treatment defines the index date.
• Index date on or after 1 January 2020
• Evidence of androgen deprivation therapy (ADT) use between 90 days prior to the index date and 6 months following the index date
• Age ≥18 years on the index date -≥6 months of clinical activity following the index date, unless the patient died

You may not qualify if:

• Evidence of castration-resistance prior to the index date
• Received chemotherapy, androgen receptor pathway inhibitor, radiopharmaceuticals, immunotherapy, PARP inhibitor, or estrogens prior to the index date
• Evidence of ADT use between 1 year and 91 days 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

Interventions

enzalutamide; apalutamide

Condition Hierarchy (Ancestors)

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

Study Officials

• Pfizer CT.gov Call Center

  Pfizer

  STUDY DIRECTOR

Study Design

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

Study Record Dates

• First Submitted: July 18, 2025
• First Posted: July 25, 2025
• Study Start: July 21, 2025
• Primary Completion: October 31, 2025
• Study Completion: October 31, 2025
• Last Updated: December 8, 2025

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)