Genetic and Molecular Mechanisms in Assessing Response in Patients With Prostate Cancer Receiving Enzalutamide Therapy

• Sponsor: OHSU Knight Cancer Institute (Other)
• Overall Status: Active, not recruiting
• CT.gov ID: NCT02099864
• Collaborator: Astellas Pharma US, Inc. (Industry), Oregon Health and Science University (Other)
• Enrollment: 36
• Locations: 2
• Arm: 1
• Anticipated Duration (Months): 111.8
• Patients Per Site: 18
• Patients Per Site Per Month: 0.2

Study Details

Study Description

Brief Summary

This phase II trial studies genetic and molecular mechanisms in assessing response in patients with prostate cancer receiving enzalutamide therapy. Androgens can cause the growth of prostate cancer cells. Antihormone therapy, such as enzalutamide, may lessen the amount of androgens made by the body. Studying samples of tissue and blood in the laboratory from patients with prostate cancer may help doctors better understand castration-resistant prostate cancer. It may also help doctors make improvements in prostate cancer treatment.

Condition or Disease	Intervention/Treatment	Phase
Castration-Resistant Prostate Carcinoma; Metastatic Malignant Neoplasm in the Bone; Metastatic Malignant Neoplasm in the Soft Tissues; Metastatic Prostate Adenocarcinoma; Recurrent Prostate Carcinoma; Stage III Prostate Adenocarcinoma AJCC v7; Stage IV Prostate Adenocarcinoma AJCC v7	Drug: Enzalutamide	Phase 2

Detailed Description

PRIMARY OBJECTIVE:

1. To assess the correlations between baseline molecular features and pathways and prostate-specific antigen (PSA) change (</>= 50% decline) at 12 weeks versus (vs.) baseline.

SECONDARY OBJECTIVES:

1. To measure PSA change at 12 weeks and at each study visit vs. baseline after enzalutamide treatment.

2. To measure objective response after enzalutamide treatment. III. To assess the correlations between the baseline molecular features and pathways and progression-free survival, disease-specific survival, and overall survival.

3. To assess the correlations between the baseline molecular features and pathways and time to PSA progression.

4. To identify molecular features and cellular pathways present in tumors from men with metastatic castrate-resistant prostate cancer (CRPC) that are progressing despite enzalutamide treatment.

5. To explore correlation between baseline molecular features and pathways and changes in circulating tumor cells (CTCs) counts.

6. To explore correlation between baseline molecular features and pathways and objective response.

7. To assess the correlations between the baseline molecular features and pathways and degree of PSA decline at 12 weeks and maximal PSA decline observed while on study.

8. To assess the correlations between the baseline molecular features and time on treatment.

EXPLORATORY OBJECTIVES:

1. To assess correlations between cell-free deoxyribonucleic acid (DNA) (cfDNA) molecular features from blood and molecular features and pathways from the biopsy samples.

2. To assess correlations between cfDNA molecular features and endpoints in the primary and secondary objectives listed above.

3. To assess correlations between cell-free DNA and tumor molecular features and changes in PSA after discontinuing enzalutamide.

4. To explore correlations with baseline molecular features and tissue histology.

5. To explore correlations with baseline tissue histology and PSA change, time to PSA progression, time on treatment, progression-free survival, and overall survival.

OUTLINE:

Patients receive enzalutamide orally (PO) once daily (QD) in the absence of disease progression or unacceptable toxicity. Patients undergo a tumor biopsy of a metastatic site at study entry (prior to initiation of enzalutamide) and after the time of progression. Patients may continue treatment beyond progression at the investigator's discretion.

After completion of study treatment, patients are followed up at 2-3 or 6 weeks and then every 12 weeks thereafter.

Study Design

• Study Type: Interventional
• Actual Enrollment: 36 participants
• Allocation: N/A
• Intervention Model: Single Group Assignment
• Masking: None (Open Label)
• Primary Purpose: Treatment
• Official Title: Molecular Mechanisms Underlying Tumor Progression Despite Enzalutamide Treatment
• Actual Study Start Date: Feb 5, 2014
• Actual Primary Completion Date: Oct 1, 2019
• Anticipated Study Completion Date: Jun 1, 2023

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Treatment (Enzalutamide) Patients receive enzalutamide PO QD in the absence of disease progression or unacceptable toxicity. Patients undergo a tumor biopsy of a metastatic site at study entry (prior to initiation of enzalutamide) and after the time of progression. Per the investigator, patients may continue treatment beyond progression.	Drug: Enzalutamide; Given PO; Other Names: ASP9785 MDV3100 Xtandi

Outcome Measures

Primary Outcome Measures

1. Percentage of Participants With a >= 50% Decline in Prostate-specific Antigen (PSA) Value [Baseline to 12 weeks]

   The percentage of participants with a >= 50% decline in PSA values will be reported with 95% exact confidence interval. For each participant, percentage decline in PSA values are calculated as 100% times the difference between PSA values taken at baseline and 12 weeks divided by PSA values at baseline. Percentage of participants determined as 100% times the number of participants with >= 50% decline divided by overall number of participants.

2. Percentage of Participants With Tumor Protein 53 Gene (TP53) Copy Number Alterations and Mutations [Baseline to 12 weeks]

   Evaluate the association between PSA response at 12 weeks after initiating therapy, and TP53 copy number alterations and mutations at baseline. Simple Logistic regression was planned but due to sample size we used Fisher's Exact test. Percentage of patients in each arm with TP53 copy number alterations and mutations will be reported and odds ratio with two-sided 95% confidence interval will be calculated.

3. Percentage of Participants With Phosphatase and Tensin Homologue Gene (PTEN) Copy Number Alterations and Mutations [Baseline to 12 weeks]

   Evaluate the association between PSA response at 12 weeks after initiating therapy, and PTEN copy number alterations and mutations at baseline. Simple Logistic regression was planned but due to sample size we used Fisher's Exact test. Percentage of patients in each arm with PTEN copy number alterations and mutations will be reported and odds ratio with two-sided 95% confidence interval will be calculated.

4. Percentage of Participants With Retinoblastoma Gene (RB1) Copy Number Alterations and Mutations [Baseline to 12 weeks]

   Evaluate the association between PSA response at 12 weeks after initiating therapy, and RB1 copy number alterations and mutations at baseline. Simple Logistic regression was planned but due to sample size we used Fisher's Exact test. Percentage of patients in each arm with RB1 copy number alterations and mutations will be reported and odds ratio with two-sided 95% confidence interval will be calculated.

5. Androgen Receptor (AR) Messenger RNA (mRNA) Expression [Baseline to 12 weeks]

   Median AR mRNA expression between responders and non-responders.

6. Androgen Receptor Variant 7 (AR-V7) Expression [Baseline to 12 weeks]

   Median AR-V7 expression between responders and non-responders.

7. Percentage of Participants With Androgen Receptor (AR) Copy Number Alterations and Mutations [Baseline to 12 weeks]

   Evaluate the association between PSA response at 12 weeks after initiating therapy, and AR copy number alterations and mutations at baseline. Simple Logistic regression was planned but due to sample size we used Fisher's Exact test. Percentage of patients in each arm with AR copy number alterations and mutations will be reported and odds ratio with two-sided 95% confidence interval will be calculated.

8. Number of Participants With Protein Expression of AR [Baseline to 12 weeks]

   The number of participants, responders and non-responders, that were found to have protein expression of AR.

9. Androgen Receptor (AR) Activity Level [Baseline to 12 weeks]

   Median Normalized Enrichment Score (NES) AR activity levels of responders and non-responders. Gene Set Enrichment Analysis (GSEA) is used to interpret gene expression data. GSEA enrichment score (ES) reflects the degree to which a gene set (GS) is overrepresented at the top or bottom of a ranked list of genes. ES is calculated by walking down the list, increasing a running-sum statistic when a gene is in the GS and decreasing when it's not. Magnitude of increment depends on correlation of the gene with the phenotype. ES is the max deviation from zero encountered in walking the list. Positive ES indicates GS enrichment at the top of the list; negative indicates GS enrichment at the bottom. GSEA calculates NES as actual ES divided by mean (ESs against all permutations of the dataset). Low AR activity has been linked to stemness and lineage plasticity that are recognized as a cause of acquired resistance to AR-targeting therapies.

Secondary Outcome Measures

1. Prostate-specific Antigen (PSA) Changes [Baseline to up to 5 years]

   Will be evaluated.

2. Percentage of Participants With an Objective Response [Baseline to date of first documented radiographic objective response, assessed up to 1 year]

   The percentage of participants with an objective response will be reported with 95% exact confidence interval. Objective radiographic response is evaluated using the new international criteria proposed by the revised Response Evaluation Criteria in Solid Tumors (RECIST) guideline (version 1.1). Changes in the largest diameter (unidimensional measurement) of the tumor lesions and the shortest diameter in the case of malignant lymph nodes are used in the RECIST criteria. For each participant, objective response is calculated as 100% times the difference between the sum of measurable target lesions at baseline and the smallest sum of measurable target lesions achieved after the initiation of therapy, divided by the sum of target lesions at baseline.

3. Progression-free Survival (PFS) [Time from day 1 of study drug treatment to date of first documented radiographic progression or clinical progression, assessed up to 5 years]

   Correlations between baseline molecular features and pathways and PFS will be assessed using cox regression model. In addition, Kaplan-Meier plots will be used to graphically illustrate the survival distributions across the strata of categorical molecular predictors.

4. Disease-specific Survival (DSS) [Time from day 1 of study drug treatment to date of death from prostate cancer, assessed up to 5 years]

   Correlations between baseline molecular features and pathways and DSS will be assessed using cox regression model. In addition, Kaplan-Meier plots will be used to graphically illustrate the survival distributions across the strata of categorical molecular predictors.

5. Overall Survival (OS) [Time from day 1 of study drug treatment to date of death from any cause, assessed up to 5 years]

   Correlations between baseline molecular features and pathways and OS will be assessed using cox regression model. In addition, Kaplan-Meier plots will be used to graphically illustrate the survival distributions across the strata of categorical molecular predictors.

6. Time to Prostate-specific Antigen (PSA) Progression [Up to 5 years]

   Correlations between baseline molecular features and pathways and time to PSA progression will be assessed.

7. Molecular Features and Cellular Pathways Present in Tumors That Are Progressing Despite Treatment With Enzalutamide [Up to 5 years]

   Random Forests classification will be used to identify molecular features and pathways present in patients with disease progression or who discontinue Enzalutamide treatment.

8. Changes in Circulating Tumor Cell (CTC) Counts [Baseline to up to 5 years]

   Linear regression model will be used to assess the association for changes in CTC counts from baseline and maximal prostate-specific antigen (PSA) observed while on study.

9. Degree of Prostate-specific Antigen (PSA) Decline [At 12 weeks]

   Degree of prostate-specific antigen (PSA) change from baseline to 12 weeks. PSA at week 12 minus PSA at baseline divided by PSA at baseline and multiplied by 100%. Decline shown as negative percent and incline shown as positive percent.

10. Maximal Prostate-specific Antigen (PSA) Decline Observed [Up to 5 years]

    Correlations between baseline molecular features and pathways and maximal PSA decline observed will be assessed. Linear regression model will be used to assess the association for changes in circulating tumor cells (CTC) counts from baseline and maximal PSA observed while on study.

11. Time on Treatment [Up to 5 years]

    The association between molecular predictors and survival outcomes (e.g., progression-free survival [PFS], disease-free survival [DSS] and overall survival [OS]) and time on treatment will be assessed using cox regression model.

Eligibility Criteria

Criteria

• Ages Eligible for Study: 18 Years and Older
• Sexes Eligible for Study: Male
• Accepts Healthy Volunteers: No

Inclusion Criteria:

• Histologically or cytologically confirmed adenocarcinoma of the prostate without pure small cell carcinoma; patients without histologically confirmed adenocarcinoma may be eligible if both the treating physician and the study principal investigator (PI) agree that the patient's history is unambiguously indicative of advanced adenocarcinoma

• Ongoing androgen deprivation therapy with a gonadotropin-releasing hormone (GnRH) analogue or orchiectomy (i.e., surgical or medical castration); patients who have not had an orchiectomy must maintain effective GnRH-analogue therapy for the duration of the trial

• Radiographic evidence of regional or distant metastases with suspected tumor in an area that is safe to biopsy

• Willingness to undergo a tumor biopsy at baseline and at disease progression

• Serum testosterone level < 50 ng/dL at screening

• Progressive disease by PSA or imaging in the setting of medical or surgical castration; disease progression for study entry is defined as one or more of the following three criteria:

• PSA evidence for progressive prostate cancer which consists of a PSA level of at least 2 ng/ml which has risen on at least 2 successive occasions, at least 1 week apart; if the confirmatory PSA value is less than the screening value, then an additional PSA value greater than #2 will be required to document progression of

= 1 week

• PSA values to be obtained >= 1 week apart

• Soft tissue disease progression defined by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1

• Bone disease progression defined by two or more new lesions on bone scan

• Patient's physician has already recommended enzalutamide for treatment of progression

• Eastern Cooperative Oncology Group (ECOG) performance status of 0-2

• Willing and able to give informed consent

• Estimated life expectancy >= 6 months

• Subjects who have partners of childbearing potential must be willing to use a method of birth control with adequate barrier protection as determined to be acceptable by the principal investigator and sponsor during the study and for 1 week after last study drug administration

• A minimum of 4 weeks elapsed off of anti-androgen therapy prior to enrollment for flutamide and 6 weeks for bicalutamide and nilutamide without evidence of an anti-androgen withdrawal response; patients who NEVER HAD A PSA decline with the most recent anti-androgen therapy or in whom the response to the most recent anti-androgen was for < 3 months require only a 2 week washout period prior to first dose of study drug

• A minimum of 4 weeks from prior systemic anti-cancer therapies or 3 weeks for radiation treatment prior to enrollment is required

Exclusion Criteria:

• Severe, concurrent disease, infection, or co-morbidity that, in the judgment of the investigator, would make the patient inappropriate for enrollment

• Previous treatment with docetaxel for metastatic prostate cancer

• Known metastases in the brain or active epidural disease (NOTE: patients with treated epidural disease are allowed)

• Absolute neutrophil count < 1,000/uL

• Platelet count < 75,000/uL

• Hemoglobin < 9 g/dL at the screening visit; (NOTE: subject may not have received any growth factors or blood transfusions within seven days of the hematologic laboratory values obtained at the screening visit)

• Total bilirubin (TBL) > 2.5 times the upper limit of normal at the screening visit

• Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) > 2.5 times the upper limit of normal at the screening visit

• Creatinine (Cr) > 2 mg/dL at the screening visit

• Prothrombin time (PT) or international normalized ratio (INR) and a partial thromboplastin time (PTT) > 1.5 times the upper limit of normal

• Previous treatment with an agent that blocks adrenal androgen synthesis (e.g. abiraterone acetate, TAK-700, TOK-001, ketoconazole) or second generation androgen receptor (AR) antagonists (e.g., BMS 641988, ARN-509,TOK-001)

• Systemic corticosteroids greater than the equivalent of 10 mg of prednisone per day within 4 weeks of study drug administration are prohibited

• Structurally unstable bone lesions suggesting impending fracture

• Previous treatment with enzalutamide (MDV3100)

• Medical contraindications to stopping aspirin, Coumadin or other anticoagulants prior to image-guided tumor biopsies; follow institutional guidelines when determining drugs to avoid and length of washout

• Plans to initiate treatment with an investigational agent during the study

• History of seizure or condition that may predispose to seizure; also, history of loss of consciousness or transient ischemic attack within 12 months of (day 1 visit)

• Concomitant use of the strong CYP2C8 inhibitors gemfibrozil or trimethoprim (Bactrim)

• History of known malabsorption syndrome or prior surgery(ies) that may lead to malabsorption

• Use of herbal products that may have hormonal anti-prostate cancer activity and/or are known to decrease PSA levels (e.g., saw palmetto) within 4 weeks of study drug administration (day 1)

• Use of the following drugs within 4 weeks of study drug administration: 5 alpha-reductase inhibitors (finasteride, dutasteride), estrogens, Cyproterone acetate, biologic, or other agents with anti-tumor activity against prostate cancer, and androgens (testosterone, dihydroepiandrosterone [DHEA], etc.)

• A second active malignancy except adequately treated non-melanoma skin cancer or other non-invasive or in situ neoplasm

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	UCSF Medical Center-Mount Zion	San Francisco	California	United States	94115
2	OHSU Knight Cancer Institute	Portland	Oregon	United States	97239

Sponsors and Collaborators

• OHSU Knight Cancer Institute
• Astellas Pharma US, Inc.
• Oregon Health and Science University

Investigators

• Principal Investigator: Tom Beer, MD, OHSU Knight Cancer Institute

Study Documents (Full-Text)

• Study Protocol and Statistical Analysis Plan - Mar 2, 2020

More Information

Publications

None provided.

• Responsible Party: Tom Beer, Principal Investigator, OHSU Knight Cancer Institute
• ClinicalTrials.gov Identifier: NCT02099864
• Other Study ID Numbers: IRB00010241; NCI-2014-00417; IIT000800; MR00045569; IRB00010241
• First Posted: Mar 31, 2014
• Last Update Posted: Jul 12, 2022
• Last Verified: Jun 1, 2022

• Studies a U.S. FDA-regulated Drug Product: Yes
• Studies a U.S. FDA-regulated Device Product: No
• Additional relevant MeSH terms: Carcinoma; Neoplasms; Adenocarcinoma; Prostatic Neoplasms; Neoplasms, Second Primary

Study Results

Participant Flow

Arm/Group Title	Treatment (Enzalutamide)
Arm/Group Description	Patients receive enzalutamide PO QD in the absence of disease progression or unacceptable toxicity. Patients undergo a tumor biopsy of a metastatic site at study entry (prior to initiation of enzalutamide) and after the time of progression. Per the investigator, patients may continue treatment beyond progression. Enzalutamide: Given PO
Period Title: Overall Study
STARTED	36
COMPLETED	36
NOT COMPLETED	0

Baseline Characteristics

Arm/Group Title	Treatment (Enzalutamide)
Arm/Group Description	Patients receive enzalutamide PO QD in the absence of disease progression or unacceptable toxicity. Patients undergo a tumor biopsy of a metastatic site at study entry (prior to initiation of enzalutamide) and after the time of progression. Per the investigator, patients may continue treatment beyond progression. Enzalutamide: Given PO
Overall Participants	36
Age (Count of Participants)
<=18 years	0 0%
Between 18 and 65 years	7 19.4%
>=65 years	29 80.6%
Age (years) [Median (Full Range) ]
Median (Full Range) [years]	71.9
Sex: Female, Male (Count of Participants)
Female	0 0%
Male	36 100%
Ethnicity (NIH/OMB) (Count of Participants)
Hispanic or Latino	1 2.8%
Not Hispanic or Latino	34 94.4%
Unknown or Not Reported	1 2.8%
Race (NIH/OMB) (Count of Participants)
American Indian or Alaska Native	1 2.8%
Asian	1 2.8%
Native Hawaiian or Other Pacific Islander	0 0%
Black or African American	1 2.8%
White	31 86.1%
More than one race	0 0%
Unknown or Not Reported	2 5.6%
Region of Enrollment (participants) [Number]
United States	36 100%

Outcome Measures

1. Primary Outcome

Title	Percentage of Participants With a >= 50% Decline in Prostate-specific Antigen (PSA) Value
Description	The percentage of participants with a >= 50% decline in PSA values will be reported with 95% exact confidence interval. For each participant, percentage decline in PSA values are calculated as 100% times the difference between PSA values taken at baseline and 12 weeks divided by PSA values at baseline. Percentage of participants determined as 100% times the number of participants with >= 50% decline divided by overall number of participants.
Time Frame	Baseline to 12 weeks

Outcome Measure Data

Analysis Population Description

Evaluable patients will include those patients for whom data from genomic studies and IHC tests are available from the pre-treatment biopsy samples and who have completed at least 12 weeks of therapy or who have confirmed disease progression prior to 12 weeks of therapy, and for whom baseline and 12 week PSA data were available. 36 subjects shown in participant flow. 2 subjects were excluded from this PSA analysis: 1 had missing PSA data, 1 had falling PSA in setting of rapid disease progression

Arm/Group Title	Treatment (Enzalutamide)
Arm/Group Description	Patients receive enzalutamide PO QD in the absence of disease progression or unacceptable toxicity. Patients undergo a tumor biopsy of a metastatic site at study entry (prior to initiation of enzalutamide) and after the time of progression. Per the investigator, patients may continue treatment beyond progression. Enzalutamide: Given PO
Measure Participants	34
Number (95% Confidence Interval) [percentage of subjects]	73.5

2. Primary Outcome

Title	Percentage of Participants With Tumor Protein 53 Gene (TP53) Copy Number Alterations and Mutations
Description	Evaluate the association between PSA response at 12 weeks after initiating therapy, and TP53 copy number alterations and mutations at baseline. Simple Logistic regression was planned but due to sample size we used Fisher's Exact test. Percentage of patients in each arm with TP53 copy number alterations and mutations will be reported and odds ratio with two-sided 95% confidence interval will be calculated.
Time Frame	Baseline to 12 weeks

Outcome Measure Data

Analysis Population Description

For the primary endpoint, evaluable patients will include those patients for whom data from genomic studies and IHC tests are available from the pre-treatment biopsy samples and who have completed at least 12 weeks of therapy or who have confirmed disease progression prior to 12 weeks of therapy. Targeted DNA sequencing was performed on 26 of 36 biopsies that contained sufficient material.

Arm/Group Title	Responders	PSA Non-responders
Arm/Group Description	PSA Responder: A ≥ 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.	PSA Non-Responder: A less than 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.
Measure Participants	21	5
Number [percentage of subjects]	28.6	80.0

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Treatment (Enzalutamide), PSA Non-responders
	Comments
	Type of Statistical Test	Other
	Comments
Statistical Test of Hypothesis	p-Value	0.055
	Comments
	Method	Fisher Exact
	Comments	Due to sample size, Fisher's exact test was used rather than simple logistic regression.
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	10.0
	Confidence Interval	(2-Sided) 95%; 0.9 to 108.8
	Parameter Dispersion	Type: Value:
	Estimation Comments

3. Primary Outcome

Title	Percentage of Participants With Phosphatase and Tensin Homologue Gene (PTEN) Copy Number Alterations and Mutations
Description	Evaluate the association between PSA response at 12 weeks after initiating therapy, and PTEN copy number alterations and mutations at baseline. Simple Logistic regression was planned but due to sample size we used Fisher's Exact test. Percentage of patients in each arm with PTEN copy number alterations and mutations will be reported and odds ratio with two-sided 95% confidence interval will be calculated.
Time Frame	Baseline to 12 weeks

Outcome Measure Data

Analysis Population Description

For the primary endpoint, evaluable patients will include those patients for whom data from genomic studies and IHC tests are available from the pre-treatment biopsy samples and who have completed at least 12 weeks of therapy or who have confirmed disease progression prior to 12 weeks of therapy. Targeted DNA sequencing was performed on 26 of 36 biopsies that contained sufficient material.

Arm/Group Title	Responders	PSA Non-responders
Arm/Group Description	PSA Responder: A ≥ 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.	PSA Non-Responder: A less than 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.
Measure Participants	21	5
Number [percentage of subjects]	47.6	40.0

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Treatment (Enzalutamide), PSA Non-responders
	Comments
	Type of Statistical Test	Other
	Comments
Statistical Test of Hypothesis	p-Value	1.000
	Comments
	Method	Fisher Exact
	Comments	Due to sample size, Fisher's exact was used rather than regression.
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	0.7
	Confidence Interval	(2-Sided) 95%; 0.1 to 5.3
	Parameter Dispersion	Type: Value:
	Estimation Comments

4. Primary Outcome

Title	Percentage of Participants With Retinoblastoma Gene (RB1) Copy Number Alterations and Mutations
Description	Evaluate the association between PSA response at 12 weeks after initiating therapy, and RB1 copy number alterations and mutations at baseline. Simple Logistic regression was planned but due to sample size we used Fisher's Exact test. Percentage of patients in each arm with RB1 copy number alterations and mutations will be reported and odds ratio with two-sided 95% confidence interval will be calculated.
Time Frame	Baseline to 12 weeks

Outcome Measure Data

Analysis Population Description

For the primary endpoint, evaluable patients will include those patients for whom data from genomic studies and IHC tests are available from the pre-treatment biopsy samples and who have completed at least 12 weeks of therapy or who have confirmed disease progression prior to 12 weeks of therapy. Targeted DNA sequencing was performed on 26 of 36 biopsies that contained sufficient material.

Arm/Group Title	Responders	PSA Non-responders
Arm/Group Description	PSA Responder: A ≥ 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.	PSA Non-Responder: A less than 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.
Measure Participants	21	5
Number [percentage of subjects]	9.5	0.0

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Treatment (Enzalutamide), PSA Non-responders
	Comments
	Type of Statistical Test	Other
	Comments
Statistical Test of Hypothesis	p-Value	1.000
	Comments
	Method	Fisher Exact
	Comments
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	0.7
	Confidence Interval	(2-Sided) 95%; 0.0 to 17.0
	Parameter Dispersion	Type: Value:
	Estimation Comments

5. Primary Outcome

Title	Androgen Receptor (AR) Messenger RNA (mRNA) Expression
Description	Median AR mRNA expression between responders and non-responders.
Time Frame	Baseline to 12 weeks

Outcome Measure Data

Analysis Population Description

Evaluable patients will include those patients for whom data from genomic studies and IHC tests are available from the pre-treatment biopsy samples and who have completed at least 12 weeks of therapy or who have confirmed disease progression prior to 12 weeks of therapy, and for whom baseline and 12 week PSA data were available. RNA sequencing was performed on 25 of 36 biopsies that contained sufficient material.

Arm/Group Title	Responders	Non-responders
Arm/Group Description	PSA Responder: A ≥ 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.	PSA Non-Responder: A less than 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.
Measure Participants	18	7
Median (Standard Deviation) [TPM]	224.9 (133.2)	201.7 (201.7)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Treatment (Enzalutamide), PSA Non-responders
	Comments
	Type of Statistical Test	Other
	Comments
Statistical Test of Hypothesis	p-Value	0.84
	Comments
	Method	Wilcoxon (Mann-Whitney)
	Comments
Method of Estimation	Estimation Parameter	Median Difference (Final Values)
	Estimated Value	23.2
	Confidence Interval	(2-Sided) %; to
	Parameter Dispersion	Type: Value:
	Estimation Comments	Difference is the median for responders minus the median for non-responders.

6. Primary Outcome

Title	Androgen Receptor Variant 7 (AR-V7) Expression
Description	Median AR-V7 expression between responders and non-responders.
Time Frame	Baseline to 12 weeks

Outcome Measure Data

Analysis Population Description

Evaluable patients will include those patients for whom data from genomic studies and IHC tests are available from the pre-treatment biopsy samples and who have completed at least 12 weeks of therapy or who have confirmed disease progression prior to 12 weeks of therapy, and for whom baseline and 12 week PSA data were available. RNA sequencing was performed on 25 of 36 biopsies that contained sufficient material.

Arm/Group Title	Responders	Non-responders
Arm/Group Description	PSA Responder: A ≥ 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.	PSA Non-Responder: A less than 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.
Measure Participants	18	7
Median (Standard Deviation) [TPM]	10.4 (7.2)	12.3 (11.8)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Treatment (Enzalutamide), PSA Non-responders
	Comments
	Type of Statistical Test	Other
	Comments
Statistical Test of Hypothesis	p-Value	0.14
	Comments
	Method	Wilcoxon (Mann-Whitney)
	Comments
Method of Estimation	Estimation Parameter	Median Difference (Final Values)
	Estimated Value	-1.9
	Confidence Interval	(2-Sided) %; to
	Parameter Dispersion	Type: Value:
	Estimation Comments	Difference is the median for responders minus the median for non-responders.

7. Primary Outcome

Title	Percentage of Participants With Androgen Receptor (AR) Copy Number Alterations and Mutations
Description	Evaluate the association between PSA response at 12 weeks after initiating therapy, and AR copy number alterations and mutations at baseline. Simple Logistic regression was planned but due to sample size we used Fisher's Exact test. Percentage of patients in each arm with AR copy number alterations and mutations will be reported and odds ratio with two-sided 95% confidence interval will be calculated.
Time Frame	Baseline to 12 weeks

Outcome Measure Data

Analysis Population Description

For the primary endpoint, evaluable patients will include those patients for whom data from genomic studies and IHC tests are available from the pre-treatment biopsy samples and who have completed at least 12 weeks of therapy or who have confirmed disease progression prior to 12 weeks of therapy. AR immunohistochemistry was available in 22 patients with sufficient samples.

Arm/Group Title	Responders	PSA Non-responders
Arm/Group Description	PSA Responder: A ≥ 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.	PSA non-responders: A less than 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.
Measure Participants	19	3
Number [percentage of subjects]	73.7	100.0

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Treatment (Enzalutamide), PSA Non-responders
	Comments
	Type of Statistical Test	Other
	Comments
Statistical Test of Hypothesis	p-Value	1.00
	Comments
	Method	Fisher Exact
	Comments
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	2.7
	Confidence Interval	(2-Sided) 95%; 0.1 to 60.2
	Parameter Dispersion	Type: Value:
	Estimation Comments

8. Primary Outcome

Title	Number of Participants With Protein Expression of AR
Description	The number of participants, responders and non-responders, that were found to have protein expression of AR.
Time Frame	Baseline to 12 weeks

Outcome Measure Data

Analysis Population Description

For the primary endpoint, evaluable patients will include those patients for whom data from genomic studies and IHC tests are available from the pre-treatment biopsy samples and who have completed at least 12 weeks of therapy or who have confirmed disease progression prior to 12 weeks of therapy. AR protein expression was analyzed using immunohistochemical analysis from 21 patients with sufficient samples.

Arm/Group Title	Responders	PSA Non-responders
Arm/Group Description	PSA Responder: A ≥ 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.	PSA Non-Responder: A less than 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.
Measure Participants	15	6
Number [participants]	15 41.7%	6 NaN

9. Primary Outcome

Title	Androgen Receptor (AR) Activity Level
Description	Median Normalized Enrichment Score (NES) AR activity levels of responders and non-responders. Gene Set Enrichment Analysis (GSEA) is used to interpret gene expression data. GSEA enrichment score (ES) reflects the degree to which a gene set (GS) is overrepresented at the top or bottom of a ranked list of genes. ES is calculated by walking down the list, increasing a running-sum statistic when a gene is in the GS and decreasing when it's not. Magnitude of increment depends on correlation of the gene with the phenotype. ES is the max deviation from zero encountered in walking the list. Positive ES indicates GS enrichment at the top of the list; negative indicates GS enrichment at the bottom. GSEA calculates NES as actual ES divided by mean (ESs against all permutations of the dataset). Low AR activity has been linked to stemness and lineage plasticity that are recognized as a cause of acquired resistance to AR-targeting therapies.
Time Frame	Baseline to 12 weeks

Outcome Measure Data

Analysis Population Description

Evaluable patients will include those patients for whom data from genomic studies and IHC tests are available from the pre-treatment biopsy samples and who have completed at least 12 weeks of therapy or who have confirmed disease progression prior to 12 weeks of therapy, and for whom baseline and 12 week PSA data were available. RNA sequencing was performed on 25 of 36 biopsies that contained sufficient material.

Arm/Group Title	Responders	Non-responders
Arm/Group Description	PSA Responder: A ≥ 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.	PSA Non-Responder: A less than 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.
Measure Participants	18	7
Median (Standard Deviation) [score on a scale]	2.2 (3.3)	-2.6 (1.4)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Treatment (Enzalutamide), PSA Non-responders
	Comments
	Type of Statistical Test	Other
	Comments
Statistical Test of Hypothesis	p-Value	0.01
	Comments
	Method	Wilcoxon (Mann-Whitney)
	Comments
Method of Estimation	Estimation Parameter	Median Difference (Final Values)
	Estimated Value	4.8
	Confidence Interval	(2-Sided) %; to
	Parameter Dispersion	Type: Value:
	Estimation Comments	Difference is the median for the responders minus the median for the non-responders.

10. Secondary Outcome

Title	Prostate-specific Antigen (PSA) Changes
Description	Will be evaluated.
Time Frame	Baseline to up to 5 years

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title

Arm/Group Description

11. Secondary Outcome

Title	Percentage of Participants With an Objective Response
Description	The percentage of participants with an objective response will be reported with 95% exact confidence interval. Objective radiographic response is evaluated using the new international criteria proposed by the revised Response Evaluation Criteria in Solid Tumors (RECIST) guideline (version 1.1). Changes in the largest diameter (unidimensional measurement) of the tumor lesions and the shortest diameter in the case of malignant lymph nodes are used in the RECIST criteria. For each participant, objective response is calculated as 100% times the difference between the sum of measurable target lesions at baseline and the smallest sum of measurable target lesions achieved after the initiation of therapy, divided by the sum of target lesions at baseline.
Time Frame	Baseline to date of first documented radiographic objective response, assessed up to 1 year

Outcome Measure Data

Analysis Population Description

Only those subjects who have measurable disease present at baseline, have received at least one cycle of therapy, and have had their disease re-evaluated will be considered evaluable for objective response.

Arm/Group Title	Treatment (Enzalutamide)
Arm/Group Description	Patients receive enzalutamide PO QD in the absence of disease progression or unacceptable toxicity. Patients undergo a tumor biopsy of a metastatic site at study entry (prior to initiation of enzalutamide) and after the time of progression. Per the investigator, patients may continue treatment beyond progression. Enzalutamide: Given PO
Measure Participants	22
Number (95% Confidence Interval) [percentage of subjects]	63.6

12. Secondary Outcome

Title	Progression-free Survival (PFS)
Description	Correlations between baseline molecular features and pathways and PFS will be assessed using cox regression model. In addition, Kaplan-Meier plots will be used to graphically illustrate the survival distributions across the strata of categorical molecular predictors.
Time Frame	Time from day 1 of study drug treatment to date of first documented radiographic progression or clinical progression, assessed up to 5 years

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title

Arm/Group Description

13. Secondary Outcome

Title	Disease-specific Survival (DSS)
Description	Correlations between baseline molecular features and pathways and DSS will be assessed using cox regression model. In addition, Kaplan-Meier plots will be used to graphically illustrate the survival distributions across the strata of categorical molecular predictors.
Time Frame	Time from day 1 of study drug treatment to date of death from prostate cancer, assessed up to 5 years

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title

Arm/Group Description

14. Secondary Outcome

Title	Overall Survival (OS)
Description	Correlations between baseline molecular features and pathways and OS will be assessed using cox regression model. In addition, Kaplan-Meier plots will be used to graphically illustrate the survival distributions across the strata of categorical molecular predictors.
Time Frame	Time from day 1 of study drug treatment to date of death from any cause, assessed up to 5 years

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title

Arm/Group Description

15. Secondary Outcome

Title	Time to Prostate-specific Antigen (PSA) Progression
Description	Correlations between baseline molecular features and pathways and time to PSA progression will be assessed.
Time Frame	Up to 5 years

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title

Arm/Group Description

16. Secondary Outcome

Title	Molecular Features and Cellular Pathways Present in Tumors That Are Progressing Despite Treatment With Enzalutamide
Description	Random Forests classification will be used to identify molecular features and pathways present in patients with disease progression or who discontinue Enzalutamide treatment.
Time Frame	Up to 5 years

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title

Arm/Group Description

17. Secondary Outcome

Title	Changes in Circulating Tumor Cell (CTC) Counts
Description	Linear regression model will be used to assess the association for changes in CTC counts from baseline and maximal prostate-specific antigen (PSA) observed while on study.
Time Frame	Baseline to up to 5 years

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title

Arm/Group Description

18. Secondary Outcome

Title	Degree of Prostate-specific Antigen (PSA) Decline
Description	Degree of prostate-specific antigen (PSA) change from baseline to 12 weeks. PSA at week 12 minus PSA at baseline divided by PSA at baseline and multiplied by 100%. Decline shown as negative percent and incline shown as positive percent.
Time Frame	At 12 weeks

Outcome Measure Data

Analysis Population Description

Evaluable patients will include those patients for whom data from genomic studies and IHC tests are available from the pre-treatment biopsy samples and who have completed at least 12 weeks of therapy or who have confirmed disease progression prior to 12 weeks of therapy, and for whom baseline and 12 week PSA data were available. 36 subjects shown in participant flow. 2 subjects were excluded from this PSA analysis: 1 had missing PSA data, 1 had falling PSA in setting of rapid disease progression

Arm/Group Title	Responders	PSA Non-responders
Arm/Group Description	PSA Responder: A ≥ 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.	PSA Non-Responder: A less than 50% reduction at 12 weeks after the initiation of therapy vs. baseline. Baseline PSA will be defined as the measurement obtained immediately prior to initiation of Enzalutamide on Day 1 of study.
Measure Participants	25	9
Mean (Standard Deviation) [percentage of PSA at baseline]	-86.7 (13.5)	101.8 (140.2)

19. Secondary Outcome

Title	Maximal Prostate-specific Antigen (PSA) Decline Observed
Description	Correlations between baseline molecular features and pathways and maximal PSA decline observed will be assessed. Linear regression model will be used to assess the association for changes in circulating tumor cells (CTC) counts from baseline and maximal PSA observed while on study.
Time Frame	Up to 5 years

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title

Arm/Group Description

20. Secondary Outcome

Title	Time on Treatment
Description	The association between molecular predictors and survival outcomes (e.g., progression-free survival [PFS], disease-free survival [DSS] and overall survival [OS]) and time on treatment will be assessed using cox regression model.
Time Frame	Up to 5 years

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title

Arm/Group Description

Adverse Events

Time Frame	Median time period 14 months (range 2 months to 53 months).
Adverse Event Reporting Description	Adverse events are collected from the start date of treatment with enzalutamide to the last date of treatment with enzalutamide. Adverse events are collected for any untoward clinical experience with the exception of lab abnormalities which are only reported if the test result is deemed Clinically Significant by the responsible or treating physician. Clinical significance is based on clinical judgement and individual patient situation, at the discretion of the physician.
Arm/Group Title	Treatment (Enzalutamide)
Arm/Group Description	Patients receive enzalutamide PO QD in the absence of disease progression or unacceptable toxicity. Patients undergo a tumor biopsy of a metastatic site at study entry (prior to initiation of enzalutamide) and after the time of progression. Per the investigator, patients may continue treatment beyond progression. Enzalutamide: Given PO
All Cause Mortality
	Treatment (Enzalutamide)
	Affected / at Risk (%)	# Events
Total	2/36 (5.6%)
Serious Adverse Events
	Treatment (Enzalutamide)
	Affected / at Risk (%)	# Events
Total	6/36 (16.7%)
Blood and lymphatic system disorders
Anemia	1/36 (2.8%)
Cardiac disorders
Atrial fibrillation	1/36 (2.8%)
Heart failure	1/36 (2.8%)
General disorders
Disease progression	1/36 (2.8%)
Infections and infestations
Sepsis	1/36 (2.8%)
Soft tissue infection	1/36 (2.8%)
Urinary tract infection	2/36 (5.6%)
Injury, poisoning and procedural complications
fracture	1/36 (2.8%)
Neoplasms benign, malignant and unspecified (incl cysts and polyps)
Myelodysplastic syndrome	1/36 (2.8%)
Nervous system disorders
Intracranial hemorrhage	1/36 (2.8%)
Encephalopathy	1/36 (2.8%)
Renal and urinary disorders
Acute kidney injury	1/36 (2.8%)
Hematuria	1/36 (2.8%)
Renal and urinary disorders - other, kidney cancer	1/36 (2.8%)
Vascular disorders
Hypotension	1/36 (2.8%)
Other (Not Including Serious) Adverse Events
	Treatment (Enzalutamide)
	Affected / at Risk (%)	# Events
Total	36/36 (100%)
Gastrointestinal disorders
diarrhea	3/36 (8.3%)
Nausea	5/36 (13.9%)
Abdominal pain	2/36 (5.6%)
General disorders
edema limbs	4/36 (11.1%)
pain	8/36 (22.2%)
fatigue	17/36 (47.2%)
Infections and infestations
Skin infection	2/36 (5.6%)
Upper respiratory infection	5/36 (13.9%)
Urinary tract infection	4/36 (11.1%)
Injury, poisoning and procedural complications
fall	12/36 (33.3%)
fracture	9/36 (25%)
Investigations
Weight loss	2/36 (5.6%)
Metabolism and nutrition disorders
Hypokalemia	3/36 (8.3%)
Musculoskeletal and connective tissue disorders
Myalgia	2/36 (5.6%)
Pain in extremity	2/36 (5.6%)
back pain	3/36 (8.3%)
Musculoskeletal and connective tissue disorder - Other, hip pain	8/36 (22.2%)
Musculoskeletal and connective tissue disorder - Other, shoulder pain	2/36 (5.6%)
Nervous system disorders
dizziness	4/36 (11.1%)
Dysgeusia	3/36 (8.3%)
Nervous system disorders - Other, neuropathy	3/36 (8.3%)
Paresthesia	3/36 (8.3%)
Presyncope	2/36 (5.6%)
Stroke	4/36 (11.1%)
Psychiatric disorders
depression	3/36 (8.3%)
Insomnia	3/36 (8.3%)
Renal and urinary disorders
Hematuria	3/36 (8.3%)
Urinary incontinence	2/36 (5.6%)
Urinary retention	2/36 (5.6%)
Reproductive system and breast disorders
Gynecomastia	3/36 (8.3%)
Respiratory, thoracic and mediastinal disorders
dyspnea	4/36 (11.1%)
Skin and subcutaneous tissue disorders
Pruritus	2/36 (5.6%)
Vascular disorders
Hot flashes	4/36 (11.1%)
Hypertension	3/36 (8.3%)

Limitations/Caveats

[Not Specified]

More Information

Certain Agreements

All Principal Investigators ARE employed by the organization sponsoring the study.

There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.