Testing the Addition of the Drug Relugolix to the Usual Radiation Therapy for Advanced-Stage Prostate Cancer, The NRG Promethean Study

PRIMARY OBJECTIVE:

I. Compare conventional radiological progression-free survival (rPFS) for positron emission tomography (PET)-detected, biochemically recurrent, oligometastatic, castration-sensitive prostate cancer patients treated with stereotactic ablative body radiation therapy (SABR) plus placebo versus (vs.) SABR plus relugolix.

SECONDARY OBJECTIVES:

I. Compare conventional or PET-based radiological progression-free survival (prPFS) between treatment arms.

II. Compare patient-reported sexual and hormonal quality of life as assessed by corresponding Expanded Prostate Cancer Index Composite Short Form (EPIC-26) domains between treatment arms.

III. Compare other measures of quality of life obtained from the European Quality of Life Five Dimension Five Level Scale Questionnaire (EQ5D-5L), European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 (QLQ-30), Patient Reported Outcomes Measurement Information System (PROMIS) Fatigue instruments between the two treatment arms.

IV. Compare time to salvage therapy and time to castration-resistance between treatment arms.

V. Compare local progression (SABR-targeted lesion), biochemical progression, distant metastases, prostate cancer-specific mortality, metastasis-free survival, and overall survival between treatment arms.

VI. Determine adverse events rates and compare rates between the two treatment arms.

EXPLORATORY OBJECTIVE:

I. Evaluate genomic and peripheral tissue and blood markers of treatment response.

OUTLINE: Patients are randomized to 1 of 2 arms.

ARM I: Patients receive placebo orally (PO) once daily (QD) on days 1-180 and undergo SABR for 1-3 weeks in the absence of disease progression or unacceptable toxicity.

ARM II: Patients receive relugolix PO QD on days 1-180 and undergo SABR for 1-3 weeks in the absence of disease progression or unacceptable toxicity.

Patients may also undergo bone scan, computed tomography (CT), magnetic resonance imaging (MRI), prostate-specific membrane antigen (PSMA) positron emission tomography (PET)/CT or PET/MRI, and/or fluciclovine F18 PET/CT or PET/MRI at time of disease progression. Patients may optionally undergo urine and blood sample collection throughout the trial.

After completion of study treatment, patients are followed up at 9 and 12 months, subsequently every 6 months to month 60, and then annually thereafter or at the time of progression.

Inclusion criteria

• Pathologically (histologically or cytologically) proven diagnosis of prostate adenocarcinoma at any anatomical location (for example, prostate, metastatic site), including intraductal or ductal carcinoma, at any time before registration
• Age >= 18 years
• Eastern Cooperative Oncology Group (ECOG) performance status 0-2 within 180 days prior to registration
• Prior curative-intent treatment to the prostate, by either:

• External beam and/or brachytherapy to: Prostate alone, prostate and seminal vesicles, prostate and pelvic nodes, or radiation to all three sites
• Radical prostatectomy alone, radical prostatectomy plus postoperative radiotherapy to the prostate bed, or radical prostatectomy plus postoperative radiotherapy to the pelvic nodes.

• Note: Patients who have received curative intent with radiation prior to prostatectomy are eligible and should be categorized as RT to Intact Prostate since that was the first curative intent
• Must meet study entry criteria based on the following diagnostic workup within 120 days prior to registration:

• History and physical examination;
• Fluciclovine or PSMA PET scan;
• PET must be combined with either CT or MRI, but a diagnostic CT or MRI reading/interpretation is not required
• 1 - 5 oligometastatic lesions in bone and/or nodal/soft tissue (non-abutting nodes are counted separately) sites on fluciclovine or PSMA PET within 180 days prior to registration and includes at least ONE of the following:

• Bone - each metastasis is counted (for example, 2 distinct lesions in the right ilium count as 2 oligometastatic lesions)
• Extrapelvic Nodal/ soft tissue - requires at least one extrapelvic inguinal or a nodal/soft tissue lesion superior to the iliac bifurcation (that is, American Joint Committee on Cancer [AJCC] M1a version 8)
• Note: Although a patient must have bone and/or extrapelvic disease to be eligible, when counting the number of oligometastatic lesions, each lymph node lesion, whether pelvic or extrapelvic, is counted (for example, 2 distinct lymph nodes in the right external iliac basin count as 2 oligometastatic lesions; one extrapelvic and one pelvic node count as 2 oligometastic lesions, etc)
• Serum total prostate-specific antigen (PSA) =< 10.0 ng/mL that also meets ONE of the following PSA recurrence definitions:

• If patient has received-radiation therapy to intact prostate, either

• PSA > post-RT nadir PSA + 2 ng/mL obtained within 180 days prior to registration, or
• PSA > 0.2 ng/mL with at least two rises from post-treatment nadir with the most recent PSA within 180 days prior to registration
• If patient has received a radical prostatectomy with or without post-op RT, either

• Current PSA > 0.2 ng/mL, with a second confirmatory PSA > 0.2 ng/mL, with most recent PSA obtained within 180 days prior to registration, or
• Two consecutive PSA rises from post-operative nadir, with most recent PSA obtained within 180 days prior to registration
• Must have >= 3 PSA values within the last two years since end of primary treatment or within the last 2 years prior to registration, whichever is less

• Note: PSA doubling time must be calculated by entering all PSA values since end of primary treatment or within the last 2 years prior to registration (whichever is less) into the PSA Doubling Time Calculator found at MDCalc.com
• Serum total testosterone >= 100 ng/dL within 180 days prior to registration

• Note: Prior androgen deprivation therapy (other than bilateral orchiectomy) is allowed if discontinued prior to registration and serum total testosterone is >= 100 ng/dL
• 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, subject is eligible if direct bilirubin is =< 1.5 x ULN) (within 180 days prior to registration)
• Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase [SGOT]) and alanine aminotransferase (ALT) (serum glutamic pyruvic transaminase [SGPT]): =< 2.5 x institutional ULN (within 180 days prior to registration)
• 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)
• 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
• Human immunodeficiency virus (HIV)-infected patients on effective anti-retroviral therapy with undetectable viral load within 6 months are eligible for this trial
• The patient must agree to use a highly effective contraception (even men with vasectomies) if he is having sex with a woman of childbearing potential or with a woman who is pregnant while on study drug and for 2 weeks following the last dose of study drug
• 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

• Currently on androgen deprivation or anti-androgen therapy
• Spinal cord compression, or spinal intramedullary, brain, and/or visceral (for example liver, etc.) metastasis

• Note: Spinal metastases (PET-detected) with epidural extension are eligible if there is > 0.3 cm spatial separation between the gross tumor volume and spinal cord. Lung metastases are eligible
• Biopsy-proven prostatic carcinoma with signet-ring, sarcomatoid, or neuroendocrine features (for example, small cell)
• Prior metastatic or non-metastatic, invasive malignancy (except non metastatic, non-melanomatous skin cancer) unless continuously disease free for >= 3 years
• Prior chemotherapy for prostate cancer or bilateral orchiectomy

• Note: Prior chemotherapy for a different cancer is allowed if continuously disease-free for >= 3 years
• Prior high dose radiotherapy to a lesion (i.e. oligometastatic recurrence by PET)

• Note: Lesions included in or near a previously irradiated planning target volume (PTV) are eligible as long as previous delivered dose is estimated to be less than an EQD2 of 50 Gy
• Inability to treat all oligometastatic sites with radiotherapy in the judgement of the investigator
• Intrapelvic lymph nodes as only site of prostate cancer recurrence
• Inability to swallow whole, undivided, unchewed, and uncrushed pills
• Known gastrointestinal disorder affecting oral medication absorption
• Co-morbidity defined as follows:

• Patients with any comorbidities that would prohibit completion of protocol specified therapy
• Inflammatory bowel disease in patients in whom abdominopelvic radiotherapy is planned
• History of congenital long QT syndrome
• Current severe or unstable angina
• New York Heart Association functional classification III/IV heart failure (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)