Inclusion Criteria:

1. Subjects will be between the ages of 15 and 75, inclusive. 2. Subjects must have a histologically confirmed diagnosis of a solid tumor metastatic to bone, or a histologically confirmed diagnosis of a solid tumor to the bone or metastatic to the bone. 3. Subjects must have measurable disease on anatomic imaging that is also avid for phosphonate compounds as demonstrated by a positive 99mTc diphosphonate bone scan. Not all lesions must be positive on bone scan. 4. Adequate organ function, including: i. Adequate renal function, defined as a measured creatinine clearance >70 mL/min/1.73 m2 or normal radioisotope glomerular filtration rate (GFR). ii. Adequate hematologic function, defined as a platelet count >100,000 cells/mm3 and an absolute neutrophil count (ANC) >1,000 cells/mm3. 5. Life expectancy of at least eight weeks. 6. Karnofsky performance status >50%. 7. Subjects must have adequately recovered from the effects of any prior chemotherapy, as determined by the treating physician and study team, based in part on organ function defined above. Toxicities from previous therapies must have recovered to CTCAE v5.0 grade ≤1. Subjects with Grade 2 anemia per CTCAE v5.0 will be permitted as long as the subject has normal cardiac function. 8. Adequate cardiac function. Subjects with previously identified cardiac disease will be eligible, as 153Sm-DOTMP is not expected to cause cardiac dysfunction and is only expected to result in very transient hypocalcemia. 9. A stem cell product collected either by peripheral stem cell mobilization or bone marrow harvest prior to the infusion of CycloSam® must be available, prior to trial entry. A minimum of 2 x 106 CD34+ cells/kg ideal body weight are required. 10. Female subjects of child-bearing potential (defined as premenopausal and capable of becoming pregnant) must have a negative serum pregnancy test at the Screening visit. Females must be surgically sterile, postmenopausal for at least one year prior to Screening (no other medical cause involved) with a Follicle Stimulating Hormone (FSH) level of greater than 40 mIU/mL or must be using a highly effective method of birth control and agree to its use for at least 30 days following the last dose of 153Sm-DOTMP. Highly effective methods of contraceptive are defined as tubal ligation or an approved hormonal contraceptive such as oral contraceptives, patches, implants, injections, rings, or hormonally-impregnated intrauterine device. 11. Male subjects with partners of child-bearing potential must agree to use highly effective methods of contraception for at least 90 days after the last dose of 153Sm-DOTMP. 12. The subject and/or the subject's legally authorized guardian, if the subject is a minor, must acknowledge in writing that informed consent to become a study subject has been obtained, in accordance with institutional policies approved by the U.S. Department of Health and Human Services. 13. Subjects must have previously received effective treatment for their underlying disease and have no potentially curative options available. 14. The concurrent use of hormonal therapies or bisphosphonates is acceptable, provided the latter do not render target lesions invisible on 99mTc bone scan. Subjects will have the option to re-screen up to once more after seven days if they do not initially meet all of the inclusion criteria

Exclusion Criteria:

1. Subject is pregnant or breastfeeding. 2. Subject is sexually active and does not agree to use accepted, effective forms of contraceptive. 3. Subject has received prior radiotherapy to all known areas of current active disease. 4. Subject has a body mass index (BMI) > 50 kg/m2.

Inclusion Criteria:

• There is no age limit for the low risk stratum (stage I ovarian immature teratoma and stage I non-seminoma or seminoma malignant GCT [all sites])
• Standard risk 1: Patient must be < 11 years of age at enrollment
• Standard risk 2: Patients must be >= 11 and < 25 years of age at enrollment
• Patients enrolling on one of the low risk arms must be newly diagnosed with a stage I germ cell tumor; for the standard risk arms, patients must be newly diagnosed with metastatic germ cell tumor (stage II or higher); histologic confirmation of a primary extracranial germ cell tumor in any of the categories outlined below is required of all patients at enrollment except for those who were initially diagnosed with stage I non-seminoma malignant GCT and later recur during observation post surgery off study; for these patients, if elevated tumor markers rise to > 5 x upper limit of normal (ULN) on at least 2 measurements taken at least 1 week apart, a diagnostic biopsy is not required for enrollment
• Low risk stage I immature teratoma (IT); site: ovarian; stage: Children's Oncology Group (COG) stage I, Federation of Gynecology and Obstetrics (FIGO) stage IA and IB; grade: 2 or 3; histology: pure immature teratoma (may contain microscopic foci of yolk sac tumor), mixed immature and mature teratoma, (no pathological evidence of MGCT); tumor markers: alpha-FP =< 1,000 ng/mL, beta-HCG institutional normal; all ages
• Low risk stage I non-seminoma MGCT; site: ovarian, testicular, or extragonadal; stage: COG stage I, FIGO stage IA and IB, American Joint Committee on Cancer (AJCC) testicular stage IA, IB and IS; histology: must contain at least one of the following: yolk sac tumor, embryonal carcinoma, or choriocarcinoma (pure or mixed); all ages
• Low risk stage I seminoma-MGCT; site: testicular; stage: COG stage I; AJCC testicular stage IA IB, and IS; histology: must contain at least one of the following: may contain immature/mature teratoma; may NOT contain yolk sac tumor, embryonal carcinoma, or choriocarcinoma; all ages
• Standard risk 1 (SR1); site: ovarian, testicular, or extragonadal; stage: COG stage II-IV, FIGO stage IC, FIGO stage II-IV (International Germ Cell Consensus Classification [IGCCC] criteria DO NOT apply); histology: must contain at least one of the following: yolk sac tumor, embryonal carcinoma, or choriocarcinoma; age (years) < 11
• Standard risk 2 (SR2)
• Site: ovarian; stage: COG stage II and III, FIGO stage IC, II and III; histology: must contain at least one of the following: yolk sac tumor, embryonal carcinoma, or choriocarcinoma; age (years) >= 11 and < 25
• Site: testicular; stage: COG stage II-IV, AJCC stage II, III, IGCCC good risk; histology: must contain at least one of the following: yolk sac tumor, embryonal carcinoma, or choriocarcinoma; tumor markers: must be IGCCC good risk; post op: alpha-FP < 1,000 ng/mL, beta-HCG < 5,000 IU/mL and lactate dehydrogenase (LDH) < 3.0 x normal; age (years) >= 11 and < 25
• Site: extragonadal; stage: COG stage II; histology: must contain at least one of the following: yolk sac tumor, embryonal carcinoma, or choriocarcinoma; age (years) >= 11 and < 25
• Notes:
• IGCCC criteria only apply to SR2 patients with a testicular primary tumor
• Use post-op tumor marker levels to determine IGCCC risk group
• Stage 1 seminoma patients are not eligible for the standard risk arms of the study
• For the low risk stage I non-seminoma MGCT and the standard risk arms, components of yolk sac tumor, embryonal carcinoma, or choriocarcinoma can be mixed with other forms of GCT, such as seminoma or mature or immature teratoma; if yolk sac tumor is the only malignant component present, then it must be deemed by the pathologist to be greater than a "microscopic component" of yolk sac tumor
• Patients must have a performance status corresponding to Eastern Cooperative Oncology Group (ECOG) scores of 0, 1, 2 or 3; use Karnofsky for patients > 16 years of age and Lansky for patients =< 16 years of age
• Organ function requirements apply ONLY to patients who will receive chemotherapy (SR1 and SR2 patients)
• Adequate renal function defined as:
• Creatinine clearance or radioisotope glomerular filtration rate (GFR) >= 70 mL/min/1.73 m^2 (within 7 days prior to enrollment) OR
• A serum creatinine based on age/gender as follows (within 7 days prior to enrollment): (mg/dL)
• 1 month to < 6 months male: 0.4 female: 0.4
• 6 months to < 1 year male: 0.5 female: 0.5
• 1 to < 2 years male: 0.6 female: 0.6
• 2 to < 6 years male: 0.8 female: 0.8
• 6 to < 10 years male: 1 female: 1
• 10 to < 13 years male: 1.2 female: 1.2
• 13 to < 16 years: male: 1.5 female: 1.4
• >= 16 years male: 1.7 female: 1.4
• Total bilirubin =< 1.5 x upper limit of normal (ULN) for age (within 7 days prior to enrollment)
• Serum glutamic-oxaloacetic transaminase (SGOT) (aspartate aminotransferase [AST]) or serum glutamate pyruvate transaminase (SGPT) (alanine aminotransferase [ALT]) < 2.5 x upper limit of normal (ULN) for age (for the purpose of this study, the ULN for SGPT is 45 U/L) (within 7 days prior to enrollment)
• Peripheral absolute neutrophil count (ANC) >= 1,000/mm^3 (within 7 days prior to enrollment) AND
• Platelet count >= 100,000/mm^3 (within 7 days prior to enrollment)
• Patients enrolling on the standard risk arms must be medically fit to receive protocol treatment and with no contraindications to protocol treatment
• Eligibility criteria to participate in the pilot study of the AYA-Hears instrument (patient reported outcomes [PROs] of ototoxicity) Note: participants in group 1 will not receive AGCT1531 protocol-directed therapy; all other AYA-HEARS patients must be enrolled on the AGCT1531 SR2 arm in order to participate
• >= 11 and < 25 years old at enrollment
• Able to fluently speak and read English
• Has received prior cisplatin- or carboplatin-based chemotherapy regimen for malignancy including diagnoses other than germ cell tumor
• Followed for cancer or survivorship care at one of the following institutions:
• Baylor College of Medicine/Dan L Duncan Comprehensive Cancer Center
• Dana Farber/Harvard Cancer Center
• Hospital for Sick Children
• Children's Hospital of Eastern Ontario
• Oregon Health and Science University
• Seattle Children's Hospital
• Yale University

Exclusion Criteria:

• Patients with any diagnoses not listed including:
• Stage I testicular cancer patients who have undergone primary RPLND (retroperitoneal lymph node dissection)
• Pure dysgerminoma
• Pure mature teratoma
• Pure immature teratoma COG stage I, grade I
• Pure immature teratoma COG stage I, grade 2,3 with alpha-fetoprotein (AFP) >= 1000 ng/mL
• Pure immature teratoma COG stage II - IV or FIGO stage IC to IV
• "Poor risk" GCT (age >= 11 years old and COG stage IV ovarian, COG stage III or IV EG, or IGCCC intermediate or poor risk testicular), or
• Primary central nervous system (CNS) germ cell tumor
• Germ cell tumor with somatic malignant transformation
• Spermatocytic seminoma
• Patients must have had no prior systemic therapy for the current cancer diagnosis
• Patients must have had no prior radiation therapy with the exception of CNS irradiation of brain metastases; (this exception only applies to SR1 patients; any patients over age 11 with distant metastases to brain [stage IV disease] would be considered poor risk and therefore not eligible for this trial)
• Patients with significant, pre-existing co-morbid respiratory disease that contraindicate the use of bleomycin are ineligible for the standard risk arms of the trial
• Female patients who are pregnant since fetal toxicities and teratogenic effects have been noted for several of the study drugs; a pregnancy test is required for female patients of childbearing potential; (this criteria applies ONLY to patients who will receive chemotherapy [SR1 and SR2 patients])
• Lactating females who plan to breastfeed their infants; (this criteria applies ONLY to patients who will receive chemotherapy [SR1 and SR2 patients])
• Sexually active patients of reproductive potential who have not agreed to use an effective contraceptive method for the duration of their study participation; (this criteria applies ONLY to patients who will receive chemotherapy [SR1 and SR2 patients])

Inclusion Criteria:

• Patients must have metastatic, histologically confirmed well-differentiated neuroendocrine tumor with positive gallium 68 DOTATATE or copper 64 DOTATATE scan. Lesions on dotatate scan will be considered positive if the standardized uptake volume maximum (SUVmax) of target lesion is > 2 times standardized uptake value (SUV) mean of normal liver parenchyma. Patients with lung neuroendocrine tumors (NETs) are excluded from the trial
• Patients must have progressive disease based on RECIST criteria, version 1.1 evidenced with CT scans/MRI obtained within 24 months from enrollment
• Patients must have measurable disease per RECIST 1.1
• Failure of at least one prior systemic cancer treatment with somatostatin analogs
• No prior exposure to peptide receptor radionuclide therapy
• Recovered from adverse events of previously administered therapeutic agents (i.e., to grade 2 or less toxicity) according to Common Terminology Criteria for Adverse Events (CTCAE) 5.0
• Age >= 18 years
• Because no dosing or adverse event data are currently available on the use of triapine in combination with lutetium Lu 177 dotatate in patients < 18 years of age, children are excluded from this study
• Eastern Cooperative Oncology Group (ECOG) performance status =< 2 (Karnofsky >= 60%)
• Absolute neutrophil count >= 1,500/mcL
• Platelets >= 100,000/mcL
• Total bilirubin =< 1.5 x institutional upper limit of normal (ULN)
• Aspartate aminotransferase (AST) (serum glutamic-oxaloacetic transaminase [SGOT])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT]) =< 3 x institutional ULN
• Serum creatinine =< 1.5 x institutional ULN. Creatinine > 1.5 ULN will require a measured creatinine clearance (CrCl) > 50 ml/min to qualify
• Hemoglobin > 5.0 mmol/L (> 8.0 g/dL)
• Human immunodeficiency virus (HIV)-infected patients on effective anti-retroviral therapy with undetectable viral load within 6 months are eligible for this trial
• For patients with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral load must be undetectable on suppressive therapy, if indicated
• Patients with a history of hepatitis C virus (HCV) infection must have been treated and cured. For patients with HCV infection who are currently on treatment, they are eligible if they have an undetectable HCV viral load
• Patients with treated brain metastases and off steroids are eligible if follow-up brain imaging after central nervous system (CNS)-directed therapy shows no evidence of progression for at least 4 weeks prior to enrollment in the study. Patients with a history of brain metastases must have a head CT with contrast to document stable disease prior to enrollment in the study
• Patients with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen 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 2B or better
• Pregnancy precaution: Men and women should avoid pregnancy for seven months after the date of their last treatment with lutetium Lu 177 dotatate. It is noteworthy that beta-human chorionic gonadotropin (beta-HCG) may be secreted by a small percentage of NETs, such that, in addition to being a pregnancy marker, it also is a tumor marker. Consequently, NET female patients with positive beta-HCG (> 5 mIU/mL) at baseline can be eligible to enter the study and receive treatment if pregnancy can be excluded by lack of expected doubling of beta-HCG and negative pelvic ultrasound. Normally, in pregnant subjects beta-HCG doubles every 2 days during the first 4 weeks of pregnancy and every 3.5 days by weeks 6 to 7. Women of childbearing potential include any female who has experienced menarche and who has not undergone successful surgical sterilization (hysterectomy, bilateral tubal ligation, or bilateral ovariectomy) or is not postmenopausal (defined as amenorrhea > 12 consecutive months, and for women on hormone replacement therapy, only with a documented plasma follicle-stimulating hormone [FSH] level > 35 mIU/mL). Even women who are using oral, implanted, or injected contraceptive hormones, an intrauterine device (IUD), or barrier methods (diaphragm, condoms, spermicidal) to prevent pregnancy, are practicing abstinence or where the partner is sterile (e.g., vasectomy) should be considered to be of childbearing potential. Postmenopausal women who have fertilized eggs implanted are also considered to be of childbearing potential. Acceptable methods of contraception may include total abstinence at the discretion of the Investigator in cases where the age, career, lifestyle, or sexual orientation of the patient ensures compliance. Periodic abstinence (e.g., calendar, ovulation, symptothermal, post-ovulation methods) and withdrawal are not acceptable methods of contraception. Reliable contraception (hormonal or barrier method of birth control; abstinence) should be maintained throughout the study and for 7 months after study treatment discontinuation. All men and women of childbearing potential and male partners must use a double-barrier method of birth control or practice continuous abstinence from heterosexual contact throughout the study and for seven months after the end of the last treatment
• Ability to understand and the willingness to sign a written informed consent document

Exclusion Criteria:

• Patients who have not recovered from adverse events of previously administered therapeutic agents (i.e., have residual toxicities > grade 2) according to CTCAE 5.0, with the exception of alopecia
• Patients who are receiving any other investigational agents
• History of allergic reactions attributed to compounds of similar chemical or biologic composition to triapine or lutetium Lu 177 dotatate
• Patients with uncontrolled intercurrent illness
• Uncontrolled congestive heart failure (New York Heart Association [NYHA] III, IV)
• Pregnant women are excluded from this study because triapine is a ribonucleotide reductase (RNR) inhibitor and lutetium Lu 177 dotatate is a peptide receptor radionuclide therapy with the potential for teratogenic or abortifacient effects. Because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with triapine and lutetium Lu 177 dotatate, breastfeeding should be discontinued if the mother is treated with triapine and lutetium Lu 177 dotatate and for 2.5 months following the last treatment
• Inability to swallow oral medications or gastrointestinal disease limiting absorption of oral agents
• Patients with any other significant condition, currently uncontrolled by treatment, which may interfere with completion of the study

Inclusion Criteria:

• Histologically confirmed adenocarcinoma of the prostate diagnosed within the last 9 months. Patients on active surveillance with evidence of disease progression are eligible to the protocol as long as they meet the eligibility criteria and have a recent prostate biopsy (within 9 months)
• Low-risk and intermediate-risk patients are eligible according to the following guidelines:
• Low and intermediate-risk disease defined as:
• Clinical stage T1-T2 and Gleason =< 7 and prostate specific antigen (PSA) < 15 ng/ml
• Lymph node evaluation by either computed tomography (CT) or magnetic resonance imaging (MRI) and bone scan are optional and are left at the discretion of the treating physician
• Prostate MRI is recommended by not mandatory
• No alpha reductase inhibitors use within 2 weeks of randomization. A washout period of 2 weeks is required prior to randomization
• Eastern Cooperative Oncology Group status 0-1
• Judged to be medically fit for brachytherapy by a radiation oncologist
• Concurrent, neoadjuvant and/or adjuvant androgen deprivation therapy (ADT) is not permitted
• Prostate volume by trans-rectal ultrasound (TRUS) =< 60 cc
• International Prognostic Scoring System (IPSS) =< 20 (alpha blockers allowed)
• Patients must sign a study specific informed consent form prior to study entry
• Patients must by accessible for treatment and follow-up. Patients registered on this trial must be treated and followed at the participating center. Investigators must assure themselves that patients enrolled in this trial will be available for complete documentation of the treatment, adverse events, and follow up
• Protocol treatment is to begin within 4 weeks of patient randomization

Exclusion Criteria:

• Patients with a history of other malignancies, except: adequately treated non-melanoma skin cancer, or other solid tumors curatively treated with no evidence of disease for >= 5 years
• Prior or current bleeding diathesis
• Radical surgery for carcinoma of the prostate, prior pelvic radiation, prior chemotherapy for prostate cancer, prior transurethral resection of the prostate (TURP), prior cryosurgery of the prostate
• Stage T3b and evidence of nodal or distant metastatic disease on diagnostic CT, MRI or bone scan
• Subjects who have plans to receive other concomitant or post treatment adjuvant antineoplastic therapy while on this protocol including surgery, cryotherapy, conventionally fractionated radiotherapy, hormonal therapy, or chemotherapy given as part of the treatment of prostate cancer
• Severe, active co-morbidity, defined as follows:
• Unstable angina and/or congestive heart failure requiring hospitalization within the last 6 months
• Transmural myocardial infarction within the last 6 months
• Acute bacterial for fungal infection requiring intravenous antibiotics at the time of registration
• Chronic obstructive pulmonary disease exacerbation or other respiratory illness requiring hospitalization or precluding study therapy within 30 days before registration
• Hepatic insufficiency resulting in clinical jaundice and/or coagulations defects; note, however, that laboratory tests for liver function and coagulation parameters are not required for entry into this protocol
• Acquired immune deficiency syndrome (AIDS) based upon current Centers for Disease Control and Prevention (CDC) definition; note, however, that human immunodeficiency virus (HIV) testing is not required for entry into this protocol. The need to exclude patients with AIDS from this protocol is necessary because the treatments involved in this protocol may be significantly immunosuppressive. Protocol-specific requirements may also exclude immumo-compromised patients
• Patients with history of inflammatory colitis (including Crohn's disease and ulcerative colitis) or collagen vascular diseases including rheumatoid arthritis and lupus are not eligible
• Subjects who have a history of significant psychiatric illness
• Men of reproductive potential who do not agree that they or their partner will use an effective contraceptive method such as condom/diaphragm and spermicidal foam, intrauterine device (IUD), or prescription birth control pills

Inclusion Criteria:

• PRIOR TO STEP 1 REGISTRATION
• Pathologically proven diagnosis of adenocarcinoma of prostate cancer within 180 days prior to registration
• High-risk disease defined as having at least one or more of the following:
• PSA > 20 ng/mL prior to starting ADT Note: Patients receiving a 5-alpha reductase inhibitor (ex. finasteride) at the time of enrollment are eligible. The baseline PSA value should be doubled for PSAs taken while on 5-alpha reductase inhibitors and the medication should be discontinued prior to randomization but a washout period is not required.
• cT3a-T4 by digital exam or imaging (American Joint Committee on Cancer [AJCC] 8th edition [Ed.])
• Gleason score of 8-10
• Node positive by conventional imaging with a short axis of at least 1.0 cm
• Appropriate stage for study entry based on the following diagnostic workup:
• History/physical examination within 120 days prior to registration;
• Bone imaging within 120 days prior to registration;
• Note: To be eligible, patient must have no definitive evidence of bone metastases (M0) on bone scan or sodium fluoride (NaF) PET within 120 days prior to registration (negative NaF PET/CT or negative Axumin or choline PET or negative fluciclovine, choline or prostate-specific membrane antigen (PSMA) PET within 120 days prior to registration is an acceptable substitute if they have been performed). Patients who have bone metastases established only fluciclovine, choline, or PSMA PET but not definitive on bone scan or NaF PET will still be eligible
• CT or MRI of the pelvis within 120 days prior to registration (negative fluciclovine, choline, or PSMA PET within 120 days prior to registration is an acceptable substitute). As with bone staging, nodal staging for trial purposes will be based off of conventional imaging findings only
• Patients with confirmed N1 metastases on conventional imaging (CT/MRI) as defined by ≥10 mm on short axis are eligible but will be automatically assigned to the intensification study. Patients who are positive by fluciclovine, choline, or PSMA PET (i.e. N1), but whose nodes do not meet traditional size criteria for positivity (i.e. they measure ≥ 10 mm on either the CT or MRI portion of the PET or on a dedicated CT or MRI) will not be considered N1 for the trial and will not automatically be assigned to the intensification study
• Age ≥ 18
• Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 within 120 days prior to registration
• Hemoglobin ≥ 9.0 g/dL, independent of transfusion and/or growth factors (within 120 days prior to registration)
• Platelet count ≥ -100 x 10^3/uL independent of transfusion and/or growth factors (within 120 days prior to registration)
• Creatinine clearance (CrCl) ≥ 30 mL/min estimated by Cockcroft-Gault equation (within 120 days prior to registration)
• For Black patients whose renal function is not considered adequate by Cockcroft-Gault formula, an alternative formula that takes race into account (Chronic Kidney Disease Epidemiology Collaboration CKD-EPI formula) may be used for calculating creatinine clearance for trial eligibility
• Either a CrCl ≥ 30 ml/min or calculated glomerular filtration rate (GFR) ≥ 30 will make a patient eligible
• Total bilirubin =< 1.5 x institutional upper limit of normal (ULN) (within 120 days prior to registration)
• Note: In subjects with Gilbert's syndrome, if total bilirubin is > 1.5 x ULN, measure direct and indirect bilirubin and if direct bilirubin is ≤ 1.5 x ULN, subject is eligible
• Aspartate aminotransferase (AST) (serum glutamic-oxaloacetic transaminase [SGOT]) or alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT]) ≤ 2.5 x institutional ULN (within 120 days prior to registration)
• Serum albumin ≥ 3.0 g/dL (within 120 days prior to registration)
• The patient must agree to use a condom (even men with vasectomies) and another effective method of birth control if he is having sex with a woman of childbearing potential or agree to use a condom if he is having sex with a woman who is pregnant while on study drug and for 3 months following the last dose of study drug
• Human immunodeficiency virus (HIV)-infected patients on effective anti-retroviral therapy with undetectable viral load within 6 months are eligible for this trial and have a CD4 count ≥ 200 cells/microliter within 60 days prior to registration. Note: HIV testing is not required for eligibility for this protocol. Of note, for patients with HIV in the intensification trial randomized to apalutamide, highly active antiretroviral therapy (HAART) may need to be adjusted to medications that do not interact with apalutamide
• For patients with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral load must be undetectable after or on suppressive therapy within 60 days prior to registration, if indicated. Note: HBV viral testing is not required for eligibility for this protocol
• Patients with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial. Note: Any patient with a cancer (other than keratinocyte carcinoma or carcinoma in situ or low-grade non-muscle invasive bladder cancer) who has been disease-free for less than 3 years must contact the principal investigator
• The patient or a legally authorized representative must provide study-specific informed consent prior to study entry
• PRIOR TO STEP 2 RANDOMIZATION
• Confirmation of Decipher score
• Patients with a history of hepatitis C virus (HCV) infection must have been treated and cured. For patients with HCV infection who are currently on treatment, they are eligible if they have an undetectable HCV viral load within 60 days prior. Note: Apalutamide may interfere with HCV drugs. Patients on HCV medications should alert their infectious diseases physician if they get randomized to apalutamide due to the possibility that apalutamide can affect the bioavailability of some HCV medications. HCV viral testing is not required for eligibility for this protocol
• For patients entering the Intensification Cohort ONLY: Patients must discontinue or substitute concomitant medications known to lower the seizure threshold at least 30 days prior to Step 2 randomization

Exclusion Criteria:

• PRIOR TO STEP 1 REGISTRATION:
• Definitive radiologic evidence of metastatic disease outside of the pelvic nodes (M1a, M1b or M1c) on conventional imaging (i.e. bone scan, CT scan, MRI)
• Prior systemic chemotherapy within ≤ 3 years prior to registration; note that prior chemotherapy for a different cancer is allowed (completed > 3 years prior to registration
• Prior radical prostatectomy
• Prior radiotherapy to the region of the study cancer that would result in overlap of radiation therapy fields
• Current use of 5-alpha reductase inhibitor. NOTE: If the alpha reductase inhibitor is stopped prior to randomization the patient is eligible
• History of any of the following:
• Seizure disorder
• Current severe or unstable angina
• New York Heart Association Functional Classification III/IV (Note: 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.)
• History of any condition that in the opinion of the investigator, would preclude participation in this study
• Evidence of any of the following at registration:
• Active uncontrolled infection requiring IV antibiotics
• Baseline severe hepatic impairment (Child Pugh Class C)
• Inability to swallow oral pills
• Any current condition that in the opinion of the investigator, would preclude participation in this study
• Prior pharmacologic androgen ablation for prostate cancer is allowed only if the onset of androgen ablation (both luteinizing hormone-releasing hormone [LHRH] agonist and oral anti-androgen) is ≤ 60 days prior to registration; Please note: baseline PSA must be obtained prior to the start of any ADT
• PRIOR TO STEP 2 RANDOMIZATION:
• Evidence of known gastrointestinal disorder affecting absorption of oral medications at registration
• For patients entering the Intensification Cohort ONLY: Presence of uncontrolled hypertension (persistent systolic blood pressure [BP] ≥ 160 mmHg or diastolic BP ≥ 100 mmHg). Subjects with a history of hypertension are allowed, provided that BP is controlled to within these limits by anti-hypertensive treatment

Inclusion Criteria:

• Pathologically (histologically or cytologically) proven diagnosis of adenocarcinoma of the prostate within 270 days prior to registration
• Unfavorable intermediate risk prostate cancer, defined as having ALL the following bulleted criteria:
• Has at least one intermediate risk factor (IRF):
• PSA 10-20 ng/mL
• Clinical stage T2b-c (digital rectal examination [DRE] and/or imaging) by American Joint Committee on Cancer (AJCC) 8th edition
• Gleason score 7 (Gleason 3+4 or 4+3 [ International Society of Urological Pathology (ISUP) Grade Group 2-3])
• Has ONE or more of the following 'unfavorable' intermediate-risk designators:
• > 1 immature reticulocyte fraction (IRF)
• Gleason 4+3=7 (ISUP Grade Group 3)
• >= 50% of biopsy cores positive
• Biopsies may include 'sextant' sampling of right/left regions of the prostate, often labeled base, mid-gland and apex. All such 'sextant' biopsy cores should be counted. Men may also undergo 'targeted' sampling of prostate lesions (guided by MRI, ultrasound or other approaches). A targeted lesion that is biopsied more than once and demonstrates cancer (regardless of number of targeted cores involved) should count as a single additional positive core sampled and positive. In cases of uncertainty, count the biopsy sampling as sextant core(s)
• Absence of high-risk features
• Appropriate stage for study entry based on the following diagnostic workup:
• History/physical examination within 120 days prior to registration;
• Negative bone imaging (M0) within 120 days prior to registration; Note: Tc-99m bone scan or sodium fluoride (NaF) positron emission tomography (PET) are allowed. Equivocal bone scan findings are allowed if plain films X-ray, computed tomography (CT) or magnetic resonance imaging (MRI) are negative for metastasis at the concerned site(s). While a negative fluciclovine, choline, or prostate specific membrane antigen (PSMA) PET may be counted as acceptable substitute for bone imaging, any suspicious findings must be confirmed and correlated with conventional imaging (Tc-99m bone scan, NaF PET, CT, X-ray, or MRI) to determine eligibility based on the latter modalities (e.g. M0 based on conventional imaging modalities)
• Clinically negative lymph nodes (N0) as established by conventional imaging (pelvic +/- abdominal CT or MR), within 120 days prior to registration. Patients with lymph nodes equivocal or questionable by imaging are eligible if the nodes are =< 1.0 cm in short axis and/or if biopsy is negative. Note: While a negative fluciclovine, choline, or prostate specific membrane antigen (PSMA) PET may be counted as acceptable substitute for pelvic imaging, any suspicious findings must be confirmed by conventional imaging (CT, MRI or biopsy). If the findings do not meet pathological criteria based on the latter modalities (e.g. node =< 10 mm in short axis, negative biopsy), the patient will still be eligible
• Age >= 18
• Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 within 120 days prior to registration
• Non-castrate testosterone level (> 50 ng/dL) within 120 days prior to registration
• Absolute neutrophil >= 1,000 cells/mm^3 (within 120 days prior to registration)
• Hemoglobin >= 8.0 g/dL, independent of transfusion and/or growth factors (within 120 days prior to registration)
• Platelet count >= 100,000 cells/mm^3 independent of transfusion and/or growth factors (within 120 days prior to registration)
• Creatinine clearance (CrCl) >= 30 mL/min estimated by Cockcroft-Gault equation (within 120 days prior to registration)
• For African American patients specifically whose renal function is not considered adequate by the formula above, an alternative formula that takes race into account (Chronic Kidney Disease Epidemiology Collaboration CKD-EPI formula) should be used for calculating the related estimated glomerular filtration rate (GFR) with a correction factor for African American race creatinine clearance for trial eligibility, where GFR >= 30 mL/min/1.73m^2 will be considered adequate
• Total bilirubin: 1.5 =< institutional upper limit of normal (ULN) (within 120 days prior to registration) (Note: In subjects with Gilbert's syndrome, if total bilirubin is > 1.5 x ULN, measure direct and indirect bilirubin. If direct bilirubin is less than or equal to 1.5 x ULN, subject is eligible)
• Aspartate aminotransferase (AST)(serum glutamic-oxaloacetic transaminase [SGOT]) and alanine aminotransferase (ALT)(serum glutamate pyruvate transaminase [SGPT]): =< 2.5 x institutional ULN (within 120 days prior to registration)
• Human immunodeficiency virus (HIV)-infected patients on effective anti-retroviral therapy with undetectable viral load within 6 months are eligible for this trial; Note: HIV testing is not required for eligibility for this protocol
• For patients with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral load must be undetectable on suppressive therapy, if indicated.
• Note: Known positive test for hepatitis B virus surface antigen (HBV sAg) indicating acute or chronic infection would make the patient ineligible unless the viral load becomes undetectable on suppressive therapy. Patients who are immune to hepatitis B (anti-Hepatitis B surface antibody positive) are eligible (e.g. patients immunized against hepatitis B)
• For patients with a history of hepatitis C virus (HCV) infection must have been treated and cured. For patients with HCV infection who are currently on treatment, they are eligible if they have an undetectable HCV viral load
• Note: Known positive test for hepatitis C virus ribonucleic acid (HCV RNA) indicating acute or chronic infection would make the patient ineligible unless the viral load becomes undetectable on suppressive therapy
• The patient or a legally authorized representative must provide study-specific informed consent prior to study entry and, for patients treated in the United States (U.S.), authorization permitting release of personal health information

Exclusion Criteria:

• Previous radical surgery (prostatectomy) or any form of curative-intent ablation whether focal or whole-gland (e.g., cryosurgery, high intensity focused ultrasound [HIFU], laser thermal ablation, etc.) for prostate cancer
• Definitive clinical or radiologic evidence of metastatic disease (M1)
• Prior invasive malignancy (except non-melanomatous skin cancer) unless disease free for a minimum of 3 years. History of or current diagnosis of hematologic malignancy is not allowed
• Prior radiotherapy to the prostate/pelvis region that would result in overlap of radiation therapy fields
• Previous bilateral orchiectomy
• Previous hormonal therapy, such as luteinizing hormone-releasing hormone (LHRH) agonists (e.g., leuprolide, goserelin, buserelin, triptorelin) or LHRH antagonist (e.g. degarelix), anti-androgens (e.g., flutamide, bicalutamide, cyproterone acetate). ADT started prior to study registration is not allowed
• Prior use of 5-alpha-reductase inhibitors is allowed, however, it must be stopped prior to enrollment on the study with at least a 30 day washout period before baseline study PSA measure and registration
• Active testosterone replacement therapy; any replacement therapy must be stopped at least 30 days prior to registration
• Severe, active co-morbidity defined as follows:
• Current severe or unstable angina;
• New York Heart Association Functional Classification III/IV (Note: 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)
• History of any condition that in the opinion of the investigator, would preclude participation in this study
• Inability to swallow oral pills
• High risk features, which includes any of the following:
• Gleason 8-10 [ISUP Grade Group 4-5]
• PSA > 20
• cT3-4 by digital exam OR gross extra-prostatic extension on imaging [indeterminate MRI evidence will not count and the patient will be eligible]

Key Inclusion Criteria:

1. Histologically or cytologically confirmed adenocarcinoma of the prostate without pure small cell carcinoma 2. Metastatic, castration-resistant prostate cancer (mCRPC) with PSA value at screening ≥4 ng/mL that has progressed within 6 months prior to screening, according to 1 of the following: 1. PSA progression as defined by a rising PSA level confirmed with an interval of ≥1 week between each assessment 2. Radiographic disease progression in soft tissue based on Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 criteria with or without PSA progression 3. Radiographic disease progression in bone defined as the appearance of 2 or more new bone lesions on bone scan with or without PSA progression NOTE: Measurable disease per RECIST version 1.1 per local reading at screening is not an eligibility criterion for enrollment 3. Has progressed upon or intolerant to ≥2 lines prior systemic therapy approved in the metastatic and/or castration-resistant setting (in addition to androgen deprivation therapy [ADT]) including at least one second-generation anti-androgen therapy (e.g. abiraterone, enzalutamide, apalutamide, or darolutamide)

Key Exclusion Criteria:

1. Has received treatment with an approved systemic therapy within 3 weeks of dosing or has not yet recovered (ie, grade ≤1 or baseline) from any acute toxicities 2. Has received any previous systemic biologic or immune-modulating therapy (except for Sipuleucel-T) within 5 half-lives of first dose of study therapy, as described in the protocol 3. Has received prior PSMA-targeting therapy. Exception: Prior therapy with approved PSMA-targeted radioligand(s) is permitted 4. Any condition that requires ongoing/continuous corticosteroid therapy (>10 mg prednisone/day or anti-inflammatory equivalent) within 1 week prior to the first dose of study therapy 5. Ongoing or recent (within 5 years) evidence of significant autoimmune disease that required treatment with systemic immunosuppressive treatments 6. Encephalitis, meningitis, neurodegenerative disease (with the exception of mild dementia that does not interfere with activities of daily living [ADLs]) or uncontrolled seizures in the year prior to first dose of study therapy 7. Uncontrolled infection with human immunodeficiency virus (HIV), hepatitis B or hepatitis C infection; or diagnosis of immunodeficiency, as described in the protocol.

NOTE: Other protocol defined Inclusion/Exclusion Criteria apply

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)

Inclusion Criteria:

• Pathologically (histologically) proven diagnosis of prostate adenocarcinoma. Any type of radical prostatectomy is permitted, including retropubic, perineal, laparoscopic or robotically assisted
• Any T-stage is eligible (American Joint Committee on Cancer [AJCC] 8th edition [ed])
• Appropriate stage for study entry based on fluciclovine F-18 positron emission tomography (PET) scan (FACBC, Axumin) within 90 days prior to registration that is negative for distant metastatic (M1a, M1b, M1c) disease; Note that though every effort should be made to obtain a fluciclovine F-18 PET (FACBC, Axumin) scan; however, if the patient has already had a recent F-18 PSMA PET (PyLarify) scan or gallium Ga 68-labeled PSMA-11 (Ga-68 PSMA) PET scan or C-11 or F-18 choline PET scan within 90 days prior to registration (to include scan report) then repeat molecular imaging with a fluciclovine F-18 PET (FACBC, Axumin) scan will not be required.
• Pathologically node positive disease with nodal involvement only in the pelvis in the prostatectomy specimen (including external iliacs, internal iliacs, and/or obturator nodes); peri-prostatic and peri-rectal nodes can also be considered regional lymphadenopathy and are allowed
• History/physical examination within 90 days prior to registration
• Eastern Cooperative Oncology Group (ECOG) performance status of 0-1 within 90 days prior to registration
• Detectable PSA after radical prostatectomy. Detectable PSA is defined as serum PSA > 0 ng/mL at least 30 days after prostatectomy and within 180 days of registration and before start of GnRH agonist/antagonist
• Patients who have already started on post-prostatectomy GnRH agonist/antagonist for =< 180 days prior to registration are eligible (Note: patients who started on an oral antiandrogen are eligible if started =< 180 days and stopped prior to registration)
• Hemoglobin >= 9.0 g/dL, independent of transfusion and/or growth factors (within 90 days prior to registration)
• Platelet count >= 100,000 x 10^9/uL independent of transfusion and/or growth factors (within 90 days prior to registration)
• Serum potassium >= 3.5 mmol/L within 90 days prior to registration
• Creatinine clearance (CrCl) >= 30 mL/min estimated by Cockcroft-Gault (please use actual weight for calculation unless greater than 30% above ideal body weight then use the adjusted body weight) (within 90 days prior to registration)
• Total bilirubin =< 1.5 x institutional upper limit of normal (ULN) (Note: In subjects with Gilbert's syndrome, if total bilirubin is > 1.5 x ULN, measure direct and indirect bilirubin and if direct bilirubin is =< 1.5 x ULN, subject is eligible) (within 90 days prior to registration)
• Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase [SGOT]) or alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT]) =< 2.5 x institutional ULN (within 90 days prior to registration)
• Serum albumin >= 3.0 g/dL (within 90 days prior to registration)
• Discontinue or substitute concomitant medications known to lower the seizure threshold at least 30 days prior to registration
• The patient must agree to use a condom (even men with vasectomies) and another effective method of birth control if he is having sex with a woman of childbearing potential or agree to use a condom if he is having sex with a woman who is pregnant while on study drug and for 3 months following the last dose of study drug
• Human immunodeficiency virus (HIV)-infected patients on effective anti-retroviral therapy with undetectable viral load within 6 months are eligible for this trial and have a CD4 count >= 200 cells/microliter within 30 days prior to registration. Note: HIV testing is not required for eligibility for this protocol
• For patients with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral load must be undetectable on suppressive therapy within 30 days prior to registration, if indicated. Note: HBV viral testing is not required for eligibility for this protocol
• Patients with a history of hepatitis C virus (HCV) infection must have been treated and cured. For patients with HCV infection who are currently on treatment, they are eligible if they have an undetectable HCV viral load within 30 days prior to registration
• Patients with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial. Note: Any patient with a cancer (other than keratinocyte carcinoma or carcinoma in situ) who has no evidence of disease for < 3 years must contact the principal investigator, Ronald Chen, Doctor of Medicine (MD)
• The patient or a legally authorized representative must provide study-specific informed consent prior to study entry

Exclusion Criteria:

• Definitive radiologic evidence of metastatic disease (M1a, M1b or M1c) on molecular imaging (e.g. fluciclovine F-18 PET, F-18 PSMA, PSMA, F-18 choline 11)
• Prior systemic chemotherapy for the study cancer; note that prior chemotherapy for a different cancer is allowed (completed > 3 years prior to registration)
• Prior radiotherapy to the region of the study cancer that would result in overlap of radiation therapy fields
• Androgen deprivation therapy (ADT) prior to radical prostatectomy
• Prior treatment with androgen receptor signaling inhibitor (including but not exclusive to a growing list of: abiraterone acetate, enzalutamide, apalutamide, darolutamide), unless started =< 180 days and stopped prior to registration, which is allowed
• Current use of 5-alpha reductase inhibitor. NOTE: if the alpha reductase inhibitor is stopped prior to randomization the patient is eligible
• History of any of the following:
• Seizure or known condition that may pre-dispose to seizure (e.g. prior stroke within 1 year prior to registration, brain arteriovenous malformation, Schwannoma, meningioma, or other benign central nervous system [CNS] or meningeal disease which may require treatment with surgery or radiation therapy)
• Severe or unstable angina, myocardial infarction, arterial or venous thromboembolic events (e.g., pulmonary embolism, cerebrovascular accident including transient ischemic attacks), or clinically significant ventricular arrhythmias within 12 months prior to registration
• New York Heart Association functional classification III/IV (Note: 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.)
• History of any condition that in the opinion of the investigator, would preclude participation in this study
• Current evidence of any of the following:
• Known gastrointestinal disorder affecting absorption of oral medications
• Active uncontrolled infection
• Presence of uncontrolled hypertension (persistent systolic blood pressure [BP] >= 160 mmHg or diastolic BP >= 100 mmHg). Subjects with a history of hypertension are allowed, provided that BP is controlled to within these limits by anti-hypertensive treatment
• Any chronic medical condition requiring a higher dose of corticosteroid than 10 mg prednisone/prednisolone once daily
• Baseline moderate and severe hepatic impairment (Child-Pugh Class B & C)
• Inability to swallow oral pills
• Any current condition that in the opinion of the investigator, would preclude participation in this study
• Patients must not plan to participate in any other therapeutic clinical trials while receiving treatment on this study
• Patients with inflammatory bowel disease

Inclusion Criteria:

1. Adult (≥ 18 years), capable of signing informed consent. 2. ECOG score 0 or 1. Life expectancy > 6 months. Adequate organ functions. 3. Histologically- or cytologically- confirmed diagnosis of metastatic prostate adenocarcinoma. 4. Patients must have a positive PSMA PET/CT scan. 5. Patients must have prior orchiectomy and/or ongoing androgen-deprivation therapy and a castrate level of serum testosterone (<50 ng/dL or <1.7 nmol/L). 6. Patients must have received at least one second generation AR-targeting agents (such as enzalutamide and/or abiraterone). 7. Patients must have been previously treated with at least 1, but no more than 2 previous taxane regimens. A taxane regimen is defined as a minimum exposure of 2 cycles of a taxane. If a patient has received only 1 taxane regimen, the patient is eligible if: 1. The patient is not willing to receive a second taxane regimen, or 2. The patient's physician deems him unsuitable to receive a second taxane regimen (e.g. frailty assessed by geriatric or health status evaluation or intolerance). 8. Patients must have progressive mCRPC. Documented progressive mCRPC will be based on at least 1 of the following criteria: 1. Serum PSA progression defined as 2 consecutive increases in PSA over a previous reference value measured at least 1 week prior. The minimal start value is 1.0 ng/mL. 2. Soft-tissue progression defined as an increase ≥20% in the sum of the diameter (SOD) (short axis for nodal lesions and long axis for non-nodal lesions) of all target lesions based on the smallest SOD since treatment started or the appearance of one or more new lesions. 3. Progression of bone disease: evaluable disease or new bone lesions(s) by bone scan (PCWG3 criteria). Patients must have ≥1 metastatic lesion that is present on baseline CT, MRI, or bone scan imaging obtained ≤28 days prior to beginning study therapy.

Exclusion Criteria:

1. Patients who have not recovered to NCI CTCAE grade≤ 1 from an adverse event (AE) due to prior cancer therapeutics. 2. Receiving other anti-cancer agent or device, or participating in other clinical trial, within 28 days of first dose of study treatment. 3. Receiving systemic steroid therapy with >10 mg/day prednisone or equivalent within 7 days prior to the first dose of study treatment or receiving any other form of immunosuppressive medication. 4. Previous treatment with Strontium-89, Samarium-153, Rhenium-186, Rhenium-188, Radium-223 or hemi-body irradiation within 6 months prior to randomization. Previous PSMA-targeted radioligand therapy is not allowed. 5. Symptomatic brain metastasis, symptomatic cord compression, or clinical or radiological findings indicative of impending cord compression. 6. Active GI disease, including peptic ulcer disease, pancreatitis, diverticulitis, or inflammatory bowel disease. 7. Active infections. 8. Impaired heart function. 9. Active or previously documented autoimmune disease and/or current use of immunosuppressive agents. Use of endocrine replacement therapy (e.g., thyroxine, insulin, low dose of steroid, etc.) is allowed. 10. Diagnosed with other malignancies that having ant-cancer treatment within 2 years.