Targeted Treatment for Metastatic Prostate Cancer, The PREDICT Trial

The primary and secondary objectives of the study: PRIMARY OBJECTIVE: I. Evaluate objective response rate in patients with measurable disease by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 for measurable disease, in each treatment arm. SECONDARY OBJECITVES: I. To determine safety and tolerability as determined by Common Terminology Criteria in Adverse Events (CTCAE) version 5.0 in each treatment arm. II. To evaluate 9-month radiographic progression free survival in each arm as defined by Prostate Cancer Clinical Trials Working Group 3 (PCWG-3) for patients with bone metastases and RECIST version 1.1 for patients with measurable disease. III. To evaluate radiographic progression free survival in each arm as defined by PCWG-3 for patients with bone metastases and RECIST version 1.1 for patients with measurable disease. IV. To evaluate prostate-specific antigen (PSA) response defined as ≥ 50% decline in PSA from baseline using PCWG-3 criteria in patients in each treatment arm. V. To evaluate time to PSA progression as defined by PCWG-3 criteria in patients in each treatment arm. VI. To evaluate time to occurrence of first symptomatic skeletal event. VII. To evaluate time to first subsequent anti-cancer therapy (including androgen receptor signaling agents, cytotoxic chemotherapy, immunotherapy, or investigational agents) or death. VIII. To evaluate overall survival, defined as time from registration to death due to any cause censored at the date of last follow-up, in each treatment arm. IX. To evaluate patient-reported outcomes (PRO) via Patient-Reported Outcomes (PRO)-CTCAE in each treatment arm. X. To evaluate duration of response as defined by RECIST version 1.1 for patients with measurable disease. CORRELATIVE OBJECTIVES: I. Correlate presence of molecular abnormalities with baseline clinical characteristics. II. Evaluate co-occurring molecular alterations within each biomarker arm. III. Evaluate mechanisms of response and resistance using available tissue (archival or baseline) and circulating cell free tumor DNA (cfDNA) and circulating tumor cells (CTCs) at baseline, on treatment, and at progression. IV. Evaluate efficacy parameters (objective response rate \[ORR\], PSA response, 9-month radiographic progression-free survival \[rPFS\], rPFS) based on arm allocation by: IVa. DNA versus RNA qualifying molecular alterations; IVb. Blood versus tissue-based qualifying molecular alteration; IVc. Primary versus metastasis qualifying molecular alteration. V. Evaluate efficacy parameters (ORR, PSA response, 9-month rPFS, rPFS) based on the following clinical parameters: Va. Presence or absence of visceral metastases at baseline; Vb. Number of prior lines of therapy for metastatic castration resistant cancer (mCRPC) (one versus \> 1); Vc. In patients having had prior exposure to taxane chemotherapy; Vd. Presence or absence of neuroendocrine differentiation at baseline. VI. Evaluate exceptional responders (defined as those with rPFS ≥ 18 months) and exceptional non-responders. VII. To determine how circulating biomarker quantification correlates with clinical features and outcomes. VIII. To determine the clinical impact of lineage plasticity alterations in predicting outcomes and response to therapy. EXPLORATORY OBJECTIVE: I. To compare patient-assessed adverse events via PRO-CTCAE™ with clinician-assessed adverse events in each treatment arm. OUTLINE: Patients undergo genetic testing on previously-collected tissue samples. Patients are then assigned to 1 of 3 arms based on genetic testing results and Molecular Tumor Board (MTB) decision. ARM A: Patients receive valemetostat tosylate orally (PO) once daily (QD) on days 1-28 of each cycle. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. ARM B: Patients receive carboplatin intravenously (IV) over 30 minutes and cabazitaxel IV over 60 minutes on day 1 of each cycle. Cycles repeat every 21 days in the absence of disease progression or unacceptable toxicity. ARM C: Patients receive one of the following treatment regimens per treating physician: 1) Cabazitaxel IV over 60 minutes on day 1 of each cycle. Cycles repeat every 21 days in the absence of disease progression or unacceptable toxicity. 2) Abiraterone acetate PO QD on days 1-28 of each cycle and prednisone PO twice daily (BID) on days 1-28 of each cycle. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. 3) Enzalutamide PO QD on days 1-28 of each cycle. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. 4) Lutetium Lu 177 vipivotide tetraxetan IV on day 1 of each cycle. Treatment repeats every 42 days for up to 6 cycles in the absence of disease progression or unacceptable toxicity. All patients also undergo magnetic resonance imaging (MRI) or computed tomography (CT) and bone scan throughout the trial. Patients may also undergo optional fludeoxyglucose F-18 (FDG) or prostate-specific membrane antigen (PSMA) positron emission tomography (PET), as well as optional blood collection throughout the trial. After completion of study treatment, patients without disease progression are followed every 2 months for the first 6 months and then every 3 months after that for up to 5 years. Patients with disease progression are followed every 6 months for 5 years.