Prostate CancerPhase 1NCT05276492

Decreasing Dosing Regimens of Abiraterone 500 mg in Men With Prostate Cancer to Find Lowest Recommended Dose.

A Phase 1 study testing Abiraterone Oral Tablet, Prednisone tablet and Drug Dairy/Log in people with Prostate Cancer and Prostate Adenocarcinoma, run by University of Chicago at 1 site in United States.

Terminated

Stopped early. The study ended before it was planned to and will not resume.

Official record

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Trial summary

Doctors leading this study plan to collect new information about the lowest effective dose of abiraterone acetate in study participants with prostate cancer who are taking abiraterone in combination with prednisone for the first time. The duration of this study will be about 3 months (12 weeks). Read more about this study

Who is it for?: Ages 18 years and older
Conditions the study is for: Prostate Cancer, Prostate Adenocarcinoma, Prostate Neoplasm
What is being tested?: Abiraterone Oral Tablet, Prednisone tablet and Drug Dairy/Log
Type of treatment: Pill or oral medicine
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 50 participants
Where: 1 siteUnited States
Study dates: 24 Jan 2023to 16 Nov 2024
Phase: Phase 1
Are there results?: None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 years and older
All sexes
No healthy volunteers
Adult, Older adult

Who may be able to join

Histologically or cytologically confirmed prostate cancer with plans to initiate abiraterone acetate
Have never received prior abiraterone or other androgen receptor modulators, including enzalutamide, apalutamide, or darolutamide.
Must have a baseline DHEA-S level of >20 mg/dL (in order to adequately assess DHEA-S response)
A minimum washout of 28 days for any other anticancer therapy other than medical or surgical castration, prior to first dose of study drug is required.
Any other radiotherapy or radionuclide require 28-day washout prior to first dose of study drug.
Denosumab or zoledronic acid are allowed.

Show all 9Show fewer

Eastern Cooperative Oncology Group performance status ≤ 2 (Appendix A).
Participants must have normal hepatic function as defined by clinical lab values set by the study doctor/research team.
Ability to understand and the willingness to sign a written informed consent document.

Who cannot join

Therapy with other hormonal therapy, including any dose of megestrol acetate (Megace), finasteride (Proscar), dutasteride (Avodart), or any herbal product known to decrease Prostate-Specific Antigen levels or any systemic corticosteroid (other than prednisone ≤10mg/day) within 4 weeks prior to first dose of study drug.
Inability to swallow capsules or known gastrointestinal malabsorption.
Blood pressure that is not controlled despite > 2 oral agents (SBP >160 and DBP >90 documented during the screening period with no subsequent blood pressure readings <160/100).
Serum K+ < 3.5 mmoL/L. Patients with a K+ < 3.5 mmoL/L are required to have a documented subsequent K+ >3.5 prior to enrollment to be eligible.
Serious intercurrent infections or non-malignant medical illnesses that are uncontrolled.
Active psychiatric illness/social situations that would limit compliance with protocol requirements.
Serious heart issues/congestive heart failure as assessed by New York Heart Association's definition of class II, class III, or IV congestive heart failure.
Taking other medications or drugs with strong inhibitors or inducers of CYP3A4 (See Section 8.12 below for list of strong inhibitor or inducers) due to concerning possible drug-drug interactions with abiraterone.

Trial locations and contacts

1 site in 1 country.

United States1 site

University of Chicago Medicine Comprehensive Cancer Center
Chicago, Illinois, 60637

Other trials in United States

About this study

Official title: Abiraterone Dose De-Escalation Study: A Prospective Study Evaluating Decreasing Dosing Regimens of Abiraterone 500 mg in Men With Prostate Cancer to Find Lowest Recommended Dose.

Read the detailed description

Therefore, this study will evaluate if alternative dosing strategies with 500 mg pills may be equally effective as taking abiraterone 1000 mg daily. This study will specifically assess whether taking 500 mg of abiraterone every other day with a low-fat meal, or 500 mg with a low-fat meal at less frequent intervals (fewer times per week), is equally effective in treating prostate cancer as the 1000 mg/day dose.

Conditions: Prostate Cancer, Prostate Adenocarcinoma, Prostate Neoplasm, Prostate Cancer Metastatic
Being tested: Abiraterone Oral Tablet, Prednisone tablet, Drug Dairy/Log, Low-fat meal
Keywords: prostate cancer, prostate adenocarcinoma
Medical subject headings: Prostatic Neoplasms

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Abiraterone Oral TabletDrug
Also called Yonsa, Zytiga
Abiraterone is used in combination with prednisone to treat a certain type of prostate cancer that has spread to other parts of the body. Abiraterone is in a class of medications called androgen biosynthesis inhibitors. It works by decreasing the amount of certain hormones in the body.
Prednisone tabletDrug
Also called Deltasone, Prednicot, Rayos, Sterapred
Prednisone is a corticosteroid (cortisone-like medicine or steroid). It works on the immune system to help relieve swelling, redness, itching, and allergic reactions.
Drug Dairy/LogOther
A drug dairy/log that will the study team will give for you to document information about the study drugs and meals you take during the study.
Low-fat mealDrug
A low-fat meal that will be taken with abiraterone. If you have questions about what is considered "a low-fat" meal during the study, ask the study doctor or research staff.

Study groups in NCT05276492
Study group	Role	What they receive
Group 1: Dose Regimen 1	Experimental	You will be enrolled in the study based on the study group that is open at that particular time. If you are enrolled in this group, you will receive: - Abiraterone 500 mg and prednisone 5mg with a low-fat meal every other day. You will take 2 pills (500 mg total) of abiraterone acetate, first thing in the morning with breakfast. The tablets should be swallowed whole and not crushed, chewed, or dissolved in water. This breakfast should be a low-fat meal (avoid high calorie foods with a high percentage of fat, such as bacon or sausage). You will be asked to document the details of the meal/taking abiraterone in a daily log. You will also take prednisone 5 mg daily in the form of tablets taken by mouth with approximately 8 ounces of water with food. You do not have to take prednisone and abiraterone at the same time of day. If you inadvertently miss a dose of the study drug, you should take the dose the next day and record this on your Drug Diary. Receives: Drug: Abiraterone Oral Tablet; Drug: Prednisone tablet; Other: Drug Dairy/Log; Drug: Low-fat meal
Group 2: Dose Regimen 2	Experimental	You will be enrolled in the study based on the study group that is open at that particular time. If you are enrolled in this group, you will receive: - Abiraterone 500 mg and prednisone 5mg with a low-fat meal on day 1, day 3, day 5 of every week You will take 2 pills (500 mg total) of abiraterone acetate, first thing in the morning with breakfast. The tablets should be swallowed whole and not crushed, chewed, or dissolved in water. This breakfast should be a low-fat meal (avoid high calorie foods with a high percentage of fat, such as bacon or sausage). You will be asked to document the details of the meal/taking abiraterone in a daily log. You will also take prednisone 5 mg daily in the form of tablets taken by mouth with approximately 8 ounces of water with food. You do not have to take prednisone and abiraterone at the same time of day. If you inadvertently miss a dose of the study drug, you should take the dose the next day and record this on your Drug Diary. Receives: Drug: Abiraterone Oral Tablet; Drug: Prednisone tablet; Other: Drug Dairy/Log; Drug: Low-fat meal
Group 3: Dose Regimen 3	Experimental	You will be enrolled in the study based on the study group that is open at that particular time. If you are enrolled in this group, you will receive: - Abiraterone 500 mg and prednisone 5mg with a low-fat meal on day 1 and day 4 of every week You will take 2 pills (500 mg total) of abiraterone acetate, first thing in the morning with breakfast. The tablets should be swallowed whole and not crushed, chewed, or dissolved in water. This breakfast should be a low-fat meal (avoid high calorie foods with a high percentage of fat, such as bacon or sausage). You will be asked to document the details of the meal/taking abiraterone in a daily log. You will also take prednisone 5 mg daily in the form of tablets taken by mouth with approximately 8 ounces of water with food. You do not have to take prednisone and abiraterone at the same time of day. If you inadvertently miss a dose of the study drug, you should take the dose the next day and record this on your Drug Diary. Receives: Drug: Abiraterone Oral Tablet; Drug: Prednisone tablet; Other: Drug Dairy/Log; Drug: Low-fat meal
Group 4: Dose Regimen 4	Experimental	You will be enrolled in the study based on the study group that is open at that particular time. If you are enrolled in this group, you will receive: - Abiraterone 500 mg and prednisone 5mg with a low-fat meal on day 1 of every week You will take 2 pills (500 mg total) of abiraterone acetate, first thing in the morning with breakfast. The tablets should be swallowed whole and not crushed, chewed, or dissolved in water. This breakfast should be a low-fat meal (avoid high calorie foods with a high percentage of fat, such as bacon or sausage). You will be asked to document the details of the meal/taking abiraterone in a daily log. You will also take prednisone 5 mg daily in the form of tablets taken by mouth with approximately 8 ounces of water with food. You do not have to take prednisone and abiraterone at the same time of day. If you inadvertently miss a dose of the study drug, you should take the dose the next day and record this on your Drug Diary. Receives: Drug: Abiraterone Oral Tablet; Drug: Prednisone tablet; Other: Drug Dairy/Log; Drug: Low-fat meal

What is being measured

The primary outcome is the main question the study is designed to answer.

Change in DHEA-S Levels Among Participants at 4 Weeks
Efficacy of different dosing regimens of abiraterone 500 mg as assessed by decrease/reduction in serum dihydroepiadrosterone sulfate (DHEA-S) levels among participants at 4 weeks.
Measured: 4 weeks

Secondary outcomes (2)

Change in Prostate-Specific Antigen (PSA) Levels of Participants at 12 Weeks
The effects of different dosing regimens of abiraterone 500 mg on serum as assessed by a reduction/decline in Prostate-Specific Antigen (PSA) levels (a 50% decline in PSA from baseline) at 12 weeks.
Measured: 12 weeks
Rate of Adverse Events Reported Among Participants in Different Abiraterone Dosing Regimen Groups
Rate of adverse events reported among participants taking abiraterone 500 mg in different dosing groups as assessed by the Common Terminology Criteria for Adverse Events version 5.
Measured: 12 weeks

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

24 Jan 202316 Nov 2024

First posted11 Mar 2022
Study start24 Jan 2023
Primary completion16 Nov 2024
Study completion16 Nov 2024

Why it stopped: Closed by PI due to not meeting primary endpoint

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Other trials for Prostate CancerStudies of the same condition, open and under way.
More trials run by University of ChicagoThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 1
Primary purpose: Treatment
Allocation: Randomised
Intervention model: Sequential
Masking: None (open label)
Enrolment: 50 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT05276492
Sponsor's protocol ID: IRB21-1869
Status last verified: Sep 2025
First submitted: 2 Mar 2022
Last updated: 3 Oct 2025
Results posted: No
Data monitoring committee: No
FDA-regulated drug: Yes
FDA-regulated device: No

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

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Study at a glance

From the registry record, last updated by the sponsor on 3 Oct 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Abiraterone Dose De-Escalation Study: A Prospective Study Evaluating Decreasing Dosing Regimens of Abiraterone 500 mg in Men With Prostate Cancer to Find Lowest Recommended Dose.
ClinicalTrials.gov ID: NCT05276492
Acronym / sponsor ID: IRB21-1869
Conditions: Prostate Cancer, Prostate Adenocarcinoma, Prostate Neoplasm, Prostate Cancer Metastatic
Keywords: prostate cancer, prostate adenocarcinoma
Phase: Phase 1
Study type: Interventional
Recruitment status: TerminatedReason stopped: Closed by PI due to not meeting primary endpoint
Enrolment: 50 participants (actual)
Lead sponsor: University of ChicagoUniversity, hospital or other
Study start: 24 Jan 2023 (actual)
Primary completion: 16 Nov 2024 (actual)
Study completion: 16 Nov 2024 (actual)
First posted: 11 Mar 2022 (actual)
Results: Not posted in the source record

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Study design

Primary purpose: Treatment
Allocation: Randomised
Intervention model: Sequential
Masking: None (open label)
Number of arms: 4

Arm	Type	Receives
Group 1: Dose Regimen 1	Experimental	Drug: Abiraterone Oral Tablet, Drug: Prednisone tablet, Other: Drug Dairy/Log, Drug: Low-fat mealYou will be enrolled in the study based on the study group that is open at that particular time. If you are enrolled in this group, you will receive: - Abiraterone 500 mg and prednisone 5mg with a low-fat meal every other day. You will take 2 pills (500 mg total) of abiraterone acetate, first thing in the morning with breakfast. The tablets should be swallowed whole and not crushed, chewed, or dissolved in water. This breakfast should be a low-fat meal (avoid high calorie foods with a high percentage of fat, such as bacon or sausage). You will be asked to document the details of the meal/taking abiraterone in a daily log. You will also take prednisone 5 mg daily in the form of tablets taken by mouth with approximately 8 ounces of water with food. You do not have to take prednisone and abiraterone at the same time of day. If you inadvertently miss a dose of the study drug, you should take the dose the next day and record this on your Drug Diary.
Group 2: Dose Regimen 2	Experimental	Drug: Abiraterone Oral Tablet, Drug: Prednisone tablet, Other: Drug Dairy/Log, Drug: Low-fat mealYou will be enrolled in the study based on the study group that is open at that particular time. If you are enrolled in this group, you will receive: - Abiraterone 500 mg and prednisone 5mg with a low-fat meal on day 1, day 3, day 5 of every week You will take 2 pills (500 mg total) of abiraterone acetate, first thing in the morning with breakfast. The tablets should be swallowed whole and not crushed, chewed, or dissolved in water. This breakfast should be a low-fat meal (avoid high calorie foods with a high percentage of fat, such as bacon or sausage). You will be asked to document the details of the meal/taking abiraterone in a daily log. You will also take prednisone 5 mg daily in the form of tablets taken by mouth with approximately 8 ounces of water with food. You do not have to take prednisone and abiraterone at the same time of day. If you inadvertently miss a dose of the study drug, you should take the dose the next day and record this on your Drug Diary.
Group 3: Dose Regimen 3	Experimental	Drug: Abiraterone Oral Tablet, Drug: Prednisone tablet, Other: Drug Dairy/Log, Drug: Low-fat mealYou will be enrolled in the study based on the study group that is open at that particular time. If you are enrolled in this group, you will receive: - Abiraterone 500 mg and prednisone 5mg with a low-fat meal on day 1 and day 4 of every week You will take 2 pills (500 mg total) of abiraterone acetate, first thing in the morning with breakfast. The tablets should be swallowed whole and not crushed, chewed, or dissolved in water. This breakfast should be a low-fat meal (avoid high calorie foods with a high percentage of fat, such as bacon or sausage). You will be asked to document the details of the meal/taking abiraterone in a daily log. You will also take prednisone 5 mg daily in the form of tablets taken by mouth with approximately 8 ounces of water with food. You do not have to take prednisone and abiraterone at the same time of day. If you inadvertently miss a dose of the study drug, you should take the dose the next day and record this on your Drug Diary.
Group 4: Dose Regimen 4	Experimental	Drug: Abiraterone Oral Tablet, Drug: Prednisone tablet, Other: Drug Dairy/Log, Drug: Low-fat mealYou will be enrolled in the study based on the study group that is open at that particular time. If you are enrolled in this group, you will receive: - Abiraterone 500 mg and prednisone 5mg with a low-fat meal on day 1 of every week You will take 2 pills (500 mg total) of abiraterone acetate, first thing in the morning with breakfast. The tablets should be swallowed whole and not crushed, chewed, or dissolved in water. This breakfast should be a low-fat meal (avoid high calorie foods with a high percentage of fat, such as bacon or sausage). You will be asked to document the details of the meal/taking abiraterone in a daily log. You will also take prednisone 5 mg daily in the form of tablets taken by mouth with approximately 8 ounces of water with food. You do not have to take prednisone and abiraterone at the same time of day. If you inadvertently miss a dose of the study drug, you should take the dose the next day and record this on your Drug Diary.

Who may qualify

Ages: 18 years and older
Sex: All
Healthy volunteers: Not accepted
Age groups: Adult, Older adult

Key inclusion criteria (9 listed)

Histologically or cytologically confirmed prostate cancer with plans to initiate abiraterone acetate
Have never received prior abiraterone or other androgen receptor modulators, including enzalutamide, apalutamide, or darolutamide.
Must have a baseline DHEA-S level of >20 mg/dL (in order to adequately assess DHEA-S response)
A minimum washout of 28 days for any other anticancer therapy other than medical or surgical castration, prior to first dose of study drug is required.
Any other radiotherapy or radionuclide require 28-day washout prior to first dose of study drug.

Key exclusion criteria (8 listed)

Therapy with other hormonal therapy, including any dose of megestrol acetate (Megace), finasteride (Proscar), dutasteride (Avodart), or any herbal product known to decrease Prostate-Specific Antigen levels or any systemic corticosteroid (other than prednisone ≤10mg/day) within 4 weeks prior to first dose of study drug.
Inability to swallow capsules or known gastrointestinal malabsorption.
Blood pressure that is not controlled despite > 2 oral agents (SBP >160 and DBP >90 documented during the screening period with no subsequent blood pressure readings <160/100).
Serum K+ < 3.5 mmoL/L. Patients with a K+ < 3.5 mmoL/L are required to have a documented subsequent K+ >3.5 prior to enrollment to be eligible.
Serious intercurrent infections or non-malignant medical illnesses that are uncontrolled.

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Abiraterone Oral TabletAlso: Yonsa, ZytigaAbiraterone is used in combination with prednisone to treat a certain type of prostate cancer that has spread to other parts of the body. Abiraterone is in a class of medications called androgen biosynthesis inhibitors. It works by decreasing the amount of certain hormones in the body.	Drug	Group 1: Dose Regimen 1, Group 2: Dose Regimen 2, Group 3: Dose Regimen 3, Group 4: Dose Regimen 4
Prednisone tabletAlso: Deltasone, Prednicot, Rayos, SterapredPrednisone is a corticosteroid (cortisone-like medicine or steroid). It works on the immune system to help relieve swelling, redness, itching, and allergic reactions.	Drug	Group 1: Dose Regimen 1, Group 2: Dose Regimen 2, Group 3: Dose Regimen 3, Group 4: Dose Regimen 4
Drug Dairy/LogA drug dairy/log that will the study team will give for you to document information about the study drugs and meals you take during the study.	Other	Group 1: Dose Regimen 1, Group 2: Dose Regimen 2, Group 3: Dose Regimen 3, Group 4: Dose Regimen 4
Low-fat mealA low-fat meal that will be taken with abiraterone. If you have questions about what is considered "a low-fat" meal during the study, ask the study doctor or research staff.	Drug	Group 1: Dose Regimen 1, Group 2: Dose Regimen 2, Group 3: Dose Regimen 3, Group 4: Dose Regimen 4

Primary outcome

Change in DHEA-S Levels Among Participants at 4 Weeks
Time frame: 4 weeks
Efficacy of different dosing regimens of abiraterone 500 mg as assessed by decrease/reduction in serum dihydroepiadrosterone sulfate (DHEA-S) levels among participants at 4 weeks.

2 secondary outcomes

Change in Prostate-Specific Antigen (PSA) Levels of Participants at 12 Weeks
Time frame: 12 weeks
Rate of Adverse Events Reported Among Participants in Different Abiraterone Dosing Regimen Groups
Time frame: 12 weeks

Results and safety

The study was stopped early (reason given: Closed by PI due to not meeting primary endpoint). Results are not available in the source record.

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 3 Oct 2025.

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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Russell Szmulewitz, MD principal investigator

University of Chicago

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 9 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: stopped early, as of the sponsor's last update on 3 Oct 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study was stopped early (reason given: Closed by PI due to not meeting primary endpoint). Results are not available in the source record.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in DHEA-S Levels Among Participants at 4 Weeks (time frame: 4 weeks). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05276492.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Oct 2025.