Treating Prostate Cancer That Has Come Back After Surgery With Apalutamide and Targeted Radiation Based on PET Imaging

Study Overview
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Brief Summary
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This phase III trial tests two questions by two separate comparisons of therapies. The first question is whether enhanced therapy (apalutamide in combination with abiraterone + prednisone) added to standard of care (prostate radiation therapy and short term androgen deprivation) is more effective compared to standard of care alone in patients with prostate cancer who experience biochemical recurrence (a rise in the blood level of prostate specific antigen [PSA] after surgical removal of the prostate cancer). A second question tests treatment in patients with biochemical recurrence who show prostate cancer spreading outside the pelvis (metastasis) by positron emission tomography (PET) imaging. In these patients, the benefit of adding metastasis-directed radiation to enhanced therapy (apalutamide in combination with abiraterone + prednisone) is tested. Diagnostic procedures, such as PET, may help doctors look for cancer that has spread to the pelvis. Androgens are hormones that may cause the growth of prostate cancer cells. Apalutamide may help fight prostate cancer by blocking the use of androgens by the tumor cells. Metastasis-directed targeted radiation therapy uses high energy rays to kill tumor cells and shrink tumors that have spread. This trial may help doctors determine if using PET results to deliver more tailored treatment (i.e., adding apalutamide, with or without targeted radiation therapy, to standard of care treatment) works better than standard of care treatment alone in patients with biochemical recurrence of prostate cancer.

Detailed Description
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PRIMARY OBJECTIVES: I. For patients without PET-evidence of extrapelvic metastases, to evaluate whether the addition of enhanced systemic therapy to standard of care (SOC) salvage radiation therapy (RT) could prolong progression-free survival (PFS). II. For patients with PET-evidence of extrapelvic metastases, to evaluate whether the addition of metastasis-directed RT to enhanced systemic therapy and SOC salvage RT could prolong PFS. III. To compare overall quality of life, measured by Functional Assessment of Cancer Therapy - Prostate (FACT-P) total score, at 6 months between the two sets of treatment arms (A with B and C with D). (QUALITY OF LIFE [QOL] OBJECTIVE) SECONDARY OBJECTIVES: I. To evaluate overall survival in each arm. II. To evaluate event-free survival in each arm. III. To evaluate time to prostate-specific antigen (PSA) progression in each arm. IV. To assess the incidence of adverse events with the addition of enhanced systemic therapy in patients without PET-evidence of extrapelvic metastases. V. To assess the incidence of adverse events with local ablative metastasis-directed RT for PET-positive metastatic disease in patients with PET-evidence of extrapelvic metastases. VI. To estimate the detection rate of PET at the patient and regional level, and to evaluate its concordance with the follow-up Food and Drug Administration (FDA)-approved conventional imaging modalities (CIM) (as available) considered standard-of-care per institution, including computed tomography (CT), bone scintigraphy, magnetic resonance imaging (MRI) and PET imaging. VII. To determine the distribution of PET-positive lesions among anatomic sites (prostate fossa, intrapelvic soft tissue/lymph node, extrapelvic soft tissue/lymph node, and bone metastases) in patients with post-radical prostatectomy (RP) biochemical recurrence (BCR), correlated with PSA (level, doubling time, velocity) and other relevant clinical parameters. VIII. To compare the change in overall QOL, measured by FACT-P total score, from baseline to 6 months between the two sets of treatment arms (A with B and C with D). (QOL OBJECTIVE) IX. To compare patient-reported fatigue (Functional Assessment of Chronic Illness Therapy [FACIT]-Fatigue scores) at 6 months between the two sets of treatment arms (A with B and C with D). (QOL OBJECTIVE) X. To compare patient-reported overall QOL (FACT-P scores), fatigue (FACIT-Fatigue scores) and pain interference (patient reported outcomes measurement information system [PROMIS] Pain Interference Short Form 4a) between the two sets of treatment arms (A with B and C with D) at the time of disease progression. (QOL OBJECTIVE) EXPLORATORY OBJECTIVES: I.To determine the value of repeat PET (PET2) at time of second PSA progression, clinical concern for progression, or 12 months after completion of enhanced systemic therapy, whichever comes first to assess response to therapy (enhanced systemic therapy +/- focal RT and/or androgen deprivation therapy [ADT]) compared to available standard response assessments (PSA and conventional imaging modalities [CIM]). II. To compare cognitive function, measured by FACT - cognitive function (Cog) peritoneal cancer index (PCI) and total scores, between the three treatment arms receiving enhanced systemic treatment with ADT and apalutamide (Arms B, C, and D) and antiandrogen therapy (ADT) alone (Arm A) at 6 and 12 month. (QOL OBJECTIVE) III. To compare the change in cognitive function, measured by change in FACT-Cog PCI and total scores, from baseline to 6 and baseline to 12 months, between the three treatment arms receiving enhanced systemic treatment with ADT and apalutamide (Arms B, C, and D) and ADT alone (Arm A) at 6 and 12 months. (QOL OBJECTIVE) IV. To characterize longitudinal change in cognitive function between baseline and 24 months in patients with prostate cancer receiving treatment for biochemical recurrence (BCR) and define clinical and disease related characteristics associated with greater cognitive change by the FACT-Cog PCI and total scores. (QOL OBJECTIVE) OUTLINE: STEP 0: Patients undergo SOC PET/CT or PET/MR scan at baseline. Patients randomized to Arms C or D and receiving fluciclovine F18 intravenously (IV) undergo a repeat PET2 at time of PSA progression or clinical concerns for progression or 12 months after completion of enhanced systemic therapy, whichever occurs first. Patients in Arm C or D using another tracer for PET1 do not undergo PET2. STEP 1: Patients are randomized to 1 of 4 arms based on results of fluciclovine F18 PET/CT or PET/MR in Step 0. ARM A (PET NEGATIVE FOR EXTRA PELVIC-METASTASES): Patients undergo SOC external beam radiation therapy (EBRT) for 6 months. Patients also receive goserelin acetate subcutaneously (SC), leuprolide acetate intramuscularly (IM), triptorelin IM, relugolix orally (PO), or degarelix SC for 6 months starting up to 3 months prior to EBRT but no later than 7 days after start of EBRT. All treatment continues for 6 months in the absence of disease progression or unacceptable toxicity. ARM B (PET NEGATIVE FOR EXTRA PELVIC-METASTASES): Patients undergo SOC EBRT and receive goserelin acetate SC, leuprolide acetate IM, triptorelin IM, relugolix PO, or degarelix SC as in Arm A. Patients also receive apalutamide PO once daily (QD) for 6 months in the absence of disease progression or unacceptable toxicity. ARM C: (PET POSITIVE FOR EXTRA PELVIC-METASTASES): Patients undergo SOC EBRT and receive goserelin acetate SC, leuprolide acetate IM, triptorelin IM, relugolix PO, or degarelix SC as in Arm A. Patients also receive apalutamide PO QD as in Arm B. ARM D (PET POSITIVE FOR EXTRA PELVIC-METASTASES): Patients undergo SOC EBRT and receive goserelin acetate SC, leuprolide acetate IM, triptorelin IM, relugolix PO, or degarelix SC as in Arm A and apalutamide PO QD as in Arm B. Patients also undergo stereotactic body radiation therapy (SBRT) or 3-dimensional (3D) conformal radiation therapy (CRT), intensity-modulated radiation therapy (IMRT) (including volume modulated arc therapy [VMAT]), and intensity-modulated proton therapy (IMPT) over 3-10 fractions in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up every 3 months for the first 2 years, every 6 months for years 3-5, and then annually for years 6-10.

Official Title
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Phase III Study of Local or Systemic Therapy INtensification DIrected by PET in Prostate CAncer Patients With Post-ProstaTEctomy Biochemical Recurrence (INDICATE)

Conditions
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Stage IVB Prostate Cancer AJCC v8, Biochemically Recurrent Prostate Carcinoma, Metastatic Prostate Carcinoma, Prostate Adenocarcinoma

Intervention / Treatment
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* Radiation: 3-Dimensional Conformal Radiation Therapy
* Drug: Apalutamide
* Procedure: Computed Tomography
* Drug: Degarelix
* Radiation: External Beam Radiation Therapy
* Other: Fluciclovine F18
* Drug: Goserelin Acetate
* Procedure: Intensity-Modulated Proton Therapy
* Radiation: Intensity-Modulated Radiation Therapy
* Drug: Leuprolide Acetate
* Procedure: Magnetic Resonance Imaging
* Procedure: Positron Emission Tomography
* Other: Quality-of-Life Assessment
* Other: Questionnaire Administration
* Drug: Relugolix
* Radiation: Stereotactic Body Radiation Therapy
* Drug: Triptorelin
* Radiation: Volume Modulated Arc Therapy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: STEP 0: REGISTRATION ELIGIBILITY CRITERIA Patient must be male and >= 18 years of age. Patient must have had a radical prostatectomy (RP) as definitive therapy for histopathologically-proven prostatic adenocarcinoma Patient must have biochemical recurrence (BCR) after RP, defined as follows: If time to BCR, defined as time to first detectable PSA ( > lower limit of normal for assay used) after RP, is < 12 months, a minimum PSA level of >= 0.2 ng/mL and a confirmatory reading of >= 0.2 ng/mL is required, per the American Urological Association (AUA) definition (Note: patients with a persistent PSA reading of at least 0.2 ng/mL are eligible) If time to BCR, defined as time to first detectable PSA (> lower limit of normal for assay used) after RP, is >= 12 months, a minimum absolute PSA of 0.5 ng/mL is required If the patient has a detectable PSA (> lower limit of normal for assay used) at any time after RP AND has an eligible baseline SOC PET (PET1) with at least one positive lesion in any location, then there is no minimum PSA requirement Patients must have no definite evidence for extrapelvic metastatic disease by conventional imaging modalities (CIM) (CT abdomen/pelvis or MRI abdomen/pelvis AND bone scintigraphy, or equivalent), within 26 weeks prior to Step 0 registration. If a patient only has a study-eligible PET/CT or PET/MR (i.e., PET done without prior CIM): if the PET is negative for extrapelvic lesions, then baseline CIM is NOT required. If the PET positive for extrapelvic lesions, then patient should have a baseline CT/MRI for soft tissue lesions and/or a bone scan for osseous lesions Study eligible = PET using FDA-approved radiotracer and performed within 16 weeks prior to study registration Extra-pelvic metastases is defined as any osseous metastases and/or any extrapelvic soft tissue, lymph nodes and organ metastases; extra-pelvic is defined as superior to common iliac bifurcation, outside of standard prostate bed + whole pelvis nodal RT fields. Baseline PET/CT or PET/MR scan (PET1) is eligible for this study if the SOC PET scan is completed with an FDA approved radiotracer for prostate cancer after Step 0 registration and prior to Step 1 randomization OR up to 16 weeks prior to Step 0 registration Patient must be a candidate for SOC post-prostatectomy radiation therapy (RT) to the prostate bed and pelvic nodes with androgen deprivation therapy (ADT) Patient must have the ability to understand and the willingness to sign a written informed consent document. Patients with impaired decision-making capacity (IDMC) who have a legally authorized representative (LAR) or caregiver and/or family member available will also be considered eligible Patient must have an Eastern Cooperative Oncology Group (ECOG) performance status 0-2 Patient must not have started ADT for biochemical recurrence prior to baseline PET (PET1) imaging. A short course of low-dose anti-androgen such as bicalutamide, given after baseline study PET/CT but prior to study registration, is permitted as a brief temporizing measure in advance of starting protocol-approved SOC ADT. Patient must not be enrolled in another therapeutic clinical trial Patient must be able to lie flat and still for approximately 20-30 minutes or otherwise tolerate a PET scan and radiation treatment planning and delivery Patients undergoing a PET/MR must meet local institutional safety guidelines for MRI Patient must not have history of seizures or known condition that may cause predisposal to seizures (e.g., stroke or head trauma resulting in loss of consciousness) within 1 year prior to registration Patient must not have history of inflammatory bowel disease or any gastrointestinal disorder affecting absorption that is expected to increase risk of complication from radiotherapy Hemoglobin (Hgb) >= 9.0 g/dL (independent of transfusion and/or growth factors within 3 months prior to Step 0 registration) (obtained within 8 weeks prior to Step 0 registration) Leukocytes >= 3,000/mcL (obtained within 8 weeks prior to Step 0 registration) Absolute neutrophil count >= 1,500/mcL (obtained within 8 weeks prior to Step 0 registration) Platelets >= 100,000/mcL (obtained within 8 weeks prior to Step 0 registration) Total bilirubin < 1.5 x institutional upper limit of normal (ULN) (patients with Gilbert's syndrome, if total bilirubin is > 1.5 x ULN, must have a direct bilirubin of < 1.5 x ULN to be eligible) (obtained within 8 weeks prior to Step 0 registration) Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase [SGOT])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT]) =< 2.5 x institutional ULN (obtained within 8 weeks prior to Step 0 registration) Creatine < 1.5 x instituional ULN (or measured creatinine clearance > 30 mL/min) Human immunodeficiency virus (HIV)-infected patients on effective anti-retroviral therapy with undetectable viral load within 6 months are eligible for this trial Patients with known history or current symptoms of cardiac disease, or history of treatment with cardiotoxic agents, should have a clinical risk assessment of cardiac function using the New York Heart Association Functional Classification. To be eligible for this trial, patients should be class I or II (by patient symptoms) or A or B (by objective assessment) Patient must not have completed a course of prior pelvic radiation therapy for any reason Patient must agree not to father children while on study Patient must be English or Spanish speaking to be eligible for the QOL component of the study NOTE: Sites cannot translate the associated QOL forms STEP 1: RANDOMIZATION ELIGIBILITY CRITERIA Patient must have completed a baseline SOC PET/CT or PET/MR (PET1 scan) using FDA approved radiotracer with results of extra-pelvic metastases involvement known (positive or negative). The PET1 must have been completed after Step 0 registration and prior to Step 1 randomization OR up to 12 weeks prior to Step 0 registration For patients with negative extra-pelvic metastases, PET-imaging status of intra-pelvic nodes must be known (positive or negative) For patients with positive extra-pelvic metastases (defined as any PET positive lesions outside of standard salvage RT fields [prostate bed +/- typical whole pelvis]), the number of extra-pelvic lesions must be known (1 - 5 or > 5 extra-pelvic lesions)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Arm A (EBRT, short-term androgen deprivation therapy [STAD])<br>STEP 0: Patients undergo SOC PET/CT or PET/MR scan at baseline. Patients randomized to Arms C or D and receiving fluciclovine F18 IV undergo a repeat PET2 at time of PSA progression or clinical concerns for progression or 12 months after completion of enhanced systemic therapy, whichever occurs first. Patients in Arm C or D using another tracer for PET1 do not undergo PET2. STEP 1: Patients who are PET negative for extera pelvic metastases undergo SOC EBRT for 6 months. Patients also receive goserelin acetate SC, leuprolide acetate IM, triptorelin IM, relugolix PO, or degarelix SC for 6 months starting up to 3 months prior to EBRT but no later than 7 days after start of EBRT. All treatment continues for 6 months in the absence of disease progression or unacceptable toxicity. | Procedure: Computed Tomography<br>* Undergo PET/CT<br>* Other names: tomography;Drug: Degarelix<br>* Given SC<br>* Other names: Firmagon;Radiation: External Beam Radiation Therapy<br>* Undergo EBRT<br>* Other names: Teletherapy Radiation;Other: Fluciclovine F18<br>* Given IV<br>* Other names: GE-148 F-18;Drug: Goserelin Acetate<br>* Given SC<br>* Other names: Zoladex;Drug: Leuprolide Acetate<br>* Given IM<br>* Other names: Viadur;Procedure: Magnetic Resonance Imaging<br>* Undergo PET/MR<br>* Other names: Nuclear Magnetic Resonance Imaging;Procedure: Positron Emission Tomography<br>* Undergo PET/CT or PET/MR<br>* Other names: PT;Other: Quality-of-Life Assessment<br>* Ancillary studies<br>* Other names: Quality of Life Assessment;Other: Questionnaire Administration<br>* Ancillary studies<br>Drug: Relugolix<br>* Given PO<br>* Other names: TAK-385;Drug: Triptorelin<br>* Given IM<br>* Other names: Detryptoreline;|
| Experimental: Arm B (EBRT, STAD, apalutamide)<br>STEP 0: Patients undergo SOC PET/CT or PET/MR scan at baseline. Patients randomized to Arms C or D and receiving fluciclovine F18 IV undergo a repeat PET2 at time of PSA progression or clinical concerns for progression or 12 months after completion of enhanced systemic therapy, whichever occurs first. Patients in Arm C or D using another tracer for PET1 do not undergo PET2. STEP 1: Patients who are PET negative for extra pelvic metastases undergo SOC EBRT and receive goserelin acetate SC, leuprolide acetate IM, triptorelin IM, relugolix PO, or degarelix SC as in Arm A. Patients also receive apalutamide PO QD for 6 months in the absence of disease progression or unacceptable toxicity. | Drug: Apalutamide<br>* Given PO<br>* Other names: JNJ-56021927;Procedure: Computed Tomography<br>* Undergo PET/CT<br>* Other names: tomography;Drug: Degarelix<br>* Given SC<br>* Other names: Firmagon;Radiation: External Beam Radiation Therapy<br>* Undergo EBRT<br>* Other names: Teletherapy Radiation;Other: Fluciclovine F18<br>* Given IV<br>* Other names: GE-148 F-18;Drug: Goserelin Acetate<br>* Given SC<br>* Other names: Zoladex;Drug: Leuprolide Acetate<br>* Given IM<br>* Other names: Viadur;Procedure: Magnetic Resonance Imaging<br>* Undergo PET/MR<br>* Other names: Nuclear Magnetic Resonance Imaging;Procedure: Positron Emission Tomography<br>* Undergo PET/CT or PET/MR<br>* Other names: PT;Other: Quality-of-Life Assessment<br>* Ancillary studies<br>* Other names: Quality of Life Assessment;Other: Questionnaire Administration<br>* Ancillary studies<br>Drug: Relugolix<br>* Given PO<br>* Other names: TAK-385;Drug: Triptorelin<br>* Given IM<br>* Other names: Detryptoreline;|
| Experimental: Arm C (EBRT, STAD, apalutamide)<br>STEP 0: Patients undergo SOC PET/CT or PET/MR scan at baseline. Patients randomized to Arms C or D and receiving fluciclovine F18 IV undergo a repeat PET2 at time of PSA progression or clinical concerns for progression or 12 months after completion of enhanced systemic therapy, whichever occurs first. Patients in Arm C or D using another tracer for PET1 do not undergo PET2. STEP 1: Patients who are PET positive for extra pelvic metastases undergo SOC EBRT and receive goserelin acetate SC, leuprolide acetate IM, triptorelin IM, relugolix PO, or degarelix SC as in Arm A. Patients also receive apalutamide PO QD as in Arm B. | Drug: Apalutamide<br>* Given PO<br>* Other names: JNJ-56021927;Procedure: Computed Tomography<br>* Undergo PET/CT<br>* Other names: tomography;Drug: Degarelix<br>* Given SC<br>* Other names: Firmagon;Radiation: External Beam Radiation Therapy<br>* Undergo EBRT<br>* Other names: Teletherapy Radiation;Other: Fluciclovine F18<br>* Given IV<br>* Other names: GE-148 F-18;Drug: Goserelin Acetate<br>* Given SC<br>* Other names: Zoladex;Drug: Leuprolide Acetate<br>* Given IM<br>* Other names: Viadur;Procedure: Magnetic Resonance Imaging<br>* Undergo PET/MR<br>* Other names: Nuclear Magnetic Resonance Imaging;Procedure: Positron Emission Tomography<br>* Undergo PET/CT or PET/MR<br>* Other names: PT;Other: Quality-of-Life Assessment<br>* Ancillary studies<br>* Other names: Quality of Life Assessment;Other: Questionnaire Administration<br>* Ancillary studies<br>Drug: Relugolix<br>* Given PO<br>* Other names: TAK-385;Drug: Triptorelin<br>* Given IM<br>* Other names: Detryptoreline;|
| Experimental: Arm D (EBRT, STAD, apalutamide, RT)<br>STEP 0: Patients undergo SOC PET/CT or PET/MR scan at baseline. Patients randomized to Arms C or D and receiving fluciclovine F18 IV undergo a repeat PET2 at time of PSA progression or clinical concerns for progression or 12 months after completion of enhanced systemic therapy, whichever occurs first. Patients in Arm C or D using another tracer for PET1 do not undergo PET2. STEP 1: Patients who are PET positive for extra pelvic metastases undergo SOC EBRT and receive goserelin acetate SC, leuprolide acetate IM, triptorelin IM, relugolix PO, or degarelix SC as in Arm A and apalutamide PO QD as in Arm B. Patients also undergo SBRT or 3D CRT, IMRT (including VMAT), and IMPT over 3-10 fractions in the absence of disease progression or unacceptable toxicity. | Radiation: 3-Dimensional Conformal Radiation Therapy<br>* Undergo 3D CRT<br>* Other names: Three dimensional external beam radiation therapy (procedure);Drug: Apalutamide<br>* Given PO<br>* Other names: JNJ-56021927;Procedure: Computed Tomography<br>* Undergo PET/CT<br>* Other names: tomography;Drug: Degarelix<br>* Given SC<br>* Other names: Firmagon;Radiation: External Beam Radiation Therapy<br>* Undergo EBRT<br>* Other names: Teletherapy Radiation;Other: Fluciclovine F18<br>* Given IV<br>* Other names: GE-148 F-18;Drug: Goserelin Acetate<br>* Given SC<br>* Other names: Zoladex;Procedure: Intensity-Modulated Proton Therapy<br>* Undergo IMPT<br>* Other names: IMPT;Radiation: Intensity-Modulated Radiation Therapy<br>* Undergo IMRT<br>* Other names: Radiation, Intensity-Modulated Radiotherapy;Drug: Leuprolide Acetate<br>* Given IM<br>* Other names: Viadur;Procedure: Magnetic Resonance Imaging<br>* Undergo PET/MR<br>* Other names: Nuclear Magnetic Resonance Imaging;Procedure: Positron Emission Tomography<br>* Undergo PET/CT or PET/MR<br>* Other names: PT;Other: Quality-of-Life Assessment<br>* Ancillary studies<br>* Other names: Quality of Life Assessment;Other: Questionnaire Administration<br>* Ancillary studies<br>Drug: Relugolix<br>* Given PO<br>* Other names: TAK-385;Radiation: Stereotactic Body Radiation Therapy<br>* Undergo SBRT<br>* Other names: Stereotactic Ablative Body Radiation Therapy;Drug: Triptorelin<br>* Given IM<br>* Other names: Detryptoreline;Radiation: Volume Modulated Arc Therapy<br>* Undergo VMAT<br>* Other names: Volumetric Modulated Arc Therapy (procedure);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Progression-free survival (PFS) | The power of the PFS analysis is 85% using one-sided 0.025 level stratified logrank test. The overall type I error will be controlled using an O'Brien-Fleming boundary function | From randomization to radiographic progression by conventional imaging or positron emission tomography (PET), symptomatic disease or death, whichever occurs first, assessed up to 10 years | 
| PFS prolongation in patients without PET-evidence of extrapelvic metastases | Will evaluate whether the addition of enhanced systemic therapy to standard of care salvage therapy could prolong PFS in this patient population. Will be an intention-to-treat analysis of all randomized patients and performed in parallel with patients with PET-evidence of extrapelvic metastases. | Up to 10 years | 
| PFS prolongation in patients with PET-evidence of extrapelvic metastases | Will evaluate whether the addition of metastasis-directed radiation therapy to standard of care salvage therapy and enhanced systemic therapy could prolong PFS in this patient population. Will be an intention-to-treat analysis of all randomized patients and performed in parallel without patients with PET-evidence of extrapelvic metastases. | Up to 10 years | 
| Quality of life (QOL) | Descriptive statistics will be used to characterize QOL over time in each arm. | Up to 24 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Overall survival (OS) | Will be characterized by the method of Kaplan and Meier and a logrank test will be used to compare OS between the two arms in each cohort. | From randomization to death or date last known alive, assessed up to 10 years | 
| Event-free survival | Will be characterized by the method of Kaplan and Meier and a logrank test will be used to compare EFS between the two arms in each cohort. | From randomization to radiographic progression by conventional imaging or PET, symptomatic disease, or initiation of new treatment for the disease or death, whichever occurs first, assessed up to 10 years | 
| Time to prostate-specific antigen (PSA) progression | Patients without any progression will be censored at the date of last disease assessment that shows free of PSA progression. Will be characterized by the method of Kaplan and Meier and a logrank test will be used to compare time to PSA progression between the two arms in each cohort. | From randomization to documented PSA progression or radiographic progression, whichever occurs first, assessed up to 10 years | 
| Incidence of adverse events | Toxicity will be defined using the Common Terminology Criteria for Adverse Events. | Up to 10 years | 
| Detection rate of fluciclovine F18 (18F-fluciclovine) PET | For the detection rate, the proportion of baseline standard of care 18F-fluciclovine PET (PET1) positive results at the patient and regional (prostate fossa, intrapelvic soft tissue/lymph node, extrapelvic soft tissue/lymph node, and bone metastases) level will be calculated and its 95% confidence interval will be estimated using the Exact method based on the binomial distribution. | At time of PSA recurrence, as clinically indicated or 12 months after completion of enhanced systemic therapy (whichever occurs first), assessed up to 10 years | 
| Concordance of detection rate with the follow-up conventional imaging modalities (CIM) | Will use Cohen's Kappa coefficient to measure the agreement between dichotomized PET results and the dichotomized CIM results. Baseline CIM comparison will not be performed because as per our study eligibility criteria, baseline CIM will be negative for metastases. | At time of PSA recurrence, as clinically indicated or 12 months after completion of enhanced systemic therapy (whichever occurs first), assessed up to 10 years | 
| Distribution of 18F-fluciclovine PET-positive lesions among anatomic sites | The rate of 18F-fluciclovine PET-positive lesions will be reported for each anatomic site, including prostate fossa, intrapelvic soft tissue/lymph node, extrapelvic soft tissue/lymph node, and bone metastases. Their confidence intervals will be estimated using the Exact method for the binomial distribution. To evaluate if PSA (level, doubling time, velocity) and other relevant clinical parameters affects the positivity distribution, will use the logistic regression to model with the binary outcome (positive vs. negative from PET) and covariates will include anatomic site, PSA, and other clinical parameters. Will test the interactions between anatomic site and PSA (plus other clinical parameters) to see if the positivity distribution across anatomic site may change according to the levels of the interacted terms. Will use the technique of generalized estimating equation to account for the outcome correlations within subjects. | Baseline | 
| Value of repeat PET to assess response to therapy compared to standard response assessments | Analyses will be conducted to evaluate qualitative visual evidence of 18F-fluciclovine PET positive metastatic lesions and quantitative PET standardized-uptake value (SUV) changes on a lesion-to-lesion basis from 18F-fluciclovine PET1 (baseline) to PET2 on visually determined sites of recurrence and metastatic disease. This will be compared to reference standard-of-care conventional imaging (Prostate Cancer Working Group 2 criteria) and PSA response at PET2 time point to determine PET2 response to therapy. PET2 visual and quantitative assessment will also be compared to PFS in the time-to-event analysis using a log-rank test (PET2 visual assessment) and a Cox proportional hazards regression (PET2 quantitative assessment). PET SUV parameters to be obtained at PET1 and PET2 will include SUVmax, SUVpeak. PET SUV change from PET1 to PET2 will include absolute SUVmax and SUVpeak change (PET2-PET1) and percent change of SUVmax and SUVpeak (% change = 100*[(PET2-PET1)/PET1]).) | At time of second PSA recurrence or 12 months after completion of enhanced systemic therapy (whichever occurs first), assessed up to 10 years | 
| Comparison - Functional Assessment of Cancer Therapy (FACT)- prostate (P) | For the PET-negative cohort, with 216 analyzable patients in each arm, the study will have about 84% power to detect a 6-point (0.29 standard deviation) difference between the two arms using a two-sample t test with two-sided type I error of 0.05. The power will be greater than 99% if the difference between the two arms is 10 points (0.48 standard deviation). For the PET-positive cohort, with 146 analyzable patients in each arm, the study will have 68% and 98% power to detect a 6-point (0.29 standard deviation) and a 10-point (0.48 standard deviation) differences between the two arms, respectively, using the same test. | At baseline and 3, 6, 9, 12 months | 
| Change in FACT-P and Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue | A paired t test will be used to compare FACT-P scores at these two time points in each arm. A two-sample t test will be performed to compare the changes in FACT-P scores from baseline to 6 months between the two arms of each cohort. The FACIT-Fatigue scores at 6 months will be compared between the two arms of each cohort using a two-sample t test. | Baseline up to 6 months | 
| QOL Assessments at Progression | A paired t test will be used to compare FACT-P total scores, FACIT-Fatigue scores and pain scores at these two time points in each arm. The changes in these scores from baseline to progression will be evaluated in each arm. | Up to 10 years | 
| FACT- cognitive functioning (Cog) | Will be compared between two groups of patients on this study, patients receiving antiandrogen therapy (ADT) + apalutamide (Arms B, C and D) and patients receiving ADT alone (Arm A), at different time points. To ensure similarity of the three arms with systemic treatments (Arms B, C and D), a comparison in FACT-Cog total scores among these three arms will be performed using the Kruskal-Wallis test before combining them together to be compared with Arm A. | Up to 12 months |