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Dueck, Amylou C.

https://orcid.org/0000-0002-9912-1085

Mayo Clinic

Mayo Clinic

Citations 357

PROSPECT: A randomized phase III trial of neoadjuvant chemoradiation versus neoadjuvant FOLFOX chemotherapy with selective use of chemoradiation, followed by total mesorectal excision (TME) for treatment of locally advanced rectal cancer (LARC) (Alliance N
Weiser, Martin R. , Gollub, Marc J. , Musher, Benjamin , Goldberg, Joel E. , Baghdadi, Tareq Al, Farma, Jeffrey M. , Kennecke, Hagen F. , Basch, Ethan , Chang, George J. , Mamon, Harvey J. , Gollub, Marc , Baghdadi, Tareq Al , Schrag, Deborah , Shi, Qian , Saltz, Leonard B. , Goodman, Karyn A. , McWilliams, Robert R. , George, Thomas J. , Venook, Alan P. , O’Reilly, Eileen M. , Meyerhardt, Jeffrey A. , Dueck, Amylou C. , Basch, Ethan

Journal of Clinical Oncology | June 7, 2023 | Volume: 41 | Issue: 17_suppl | Pages: LBA2-LBA2

10.1200/jco.2023.41.17_suppl.lba2 Get It

LBA2 Background: Radiation with sensitizing fluoropyrimidine (5FUCRT) is a standard curative intent treatment for LARC. It improves disease-free survival (DFS) by decreasing pelvic recurrence but has short- and long-term toxicity. The PROSPECT trial compares FOLFOX chemotherapy with selective use of 5FUCRT (intervention) to 5FUCRT (control) for neoadjuvant treatment prior to TME for LARC. Methods: Eligible patients (pts) had cT2N+, cT3N-, cT3N+ rectal cancers deemed appropriate for neoadjuvant therapy prior to low anterior resection with TME. Pts with distal, T4 tumors, threatened radial margins or > 4 enlarged lymph nodes were ineligible. Pts were randomized 1:1 without blinding. Pts in the control group received 5FUCRT with 5040 cGy over 5.5 weeks with either capecitabine or 5FU. Pts in the intervention group had 6 cycles of mFOLFOX6 followed by restaging. If tumor regression was > 20%, then TME was performed without radiation; if < 20%, 5FUCRT was given before TME. DFS was the 1°outcome, defined as time from randomization to any recurrence or death, analyzed in the per-protocol population. One interim analysis was conducted with α spending = 0.001. Noninferiority (NI) of the intervention could be claimed if the upper limit of the 2-sided 90.2% confidence interval (CI) of the DFS hazard ratio did not exceed 1.29 (NI margin). Secondary endpoints included overall survival (OS), local recurrence free survival, R0 resection, pathologic complete response (CR), and toxicity. Results: From June 2012 to December 2018, 1194, pts were randomized and 1128 initiated protocol-assigned treatment. Median age was 57, 34.5% were women and 61.9% had clinically positive nodes. 53 of 585 pts in the intervention group (9%) received preop 5FUCRT. DFS was analyzed after 227 events and median follow-up of 58 months. Conclusions: FOLFOX chemotherapy with selective use of 5FUCRT is non-inferior to 5FUCRT for neoadjuvant treatment of LARC prior to low anterior resection with TME. Patients and physicians have alternative strategies for management of LARC. Clinical trial information: NCT01515787 . [Table: see text]
Alliance A021804: A prospective, multi-institutional phase II trial evaluating temozolomide versus temozolomide and olaparib for advanced pheochromocytoma and paraganglioma.
Perez, Kimberly , Geyer, Susan M. , Khalil, Maged, Vijendran, Aishwarya, Kordaris-Corkill, Andrea, Shergill, Ardaman , Spencer, Kristen , Lopez, Charles D. , Rivero, Jaydira Del , Soares, Heloisa P. , Nixon, Andrew B. , Dueck, Amylou C. , Meyerhardt, Jeffrey A. , O’Reilly, Eileen M.

Journal of Clinical Oncology | June 4, 2023 | Volume: 41 | Issue: 16_suppl | Pages: TPS4191-TPS4191

10.1200/jco.2023.41.16_suppl.tps4191 Get It

TPS4191 Background: Pheochromocytomas (PHEOs) and paragangliomas (PGLs) are rare neuroendocrine tumors (NETs) that arise from chromaffin cells. Few antitumor therapies have been developed for patients (pts) with advanced PHEO/PGLs (APP). Potent poly (ADP-ribose) polymerase (PARP) is activated after DNA damage and regulates base excision repair, homologous recombination and non-homologous end joining. Inhibition of PARP enzymatic activity blocks PARP-mediated DNA repair, therefore PARP inhibitors can be directly cytotoxic to tumor cells which then permits synergy with agents that increase prevalence of single-strand breaks in tumor models. Temozolomide (TMZ) is an alkylating agent that induces single-strand DNA breaks and therefore is an optimal therapeutic pair with a PARP inhibitor. We are conducting a phase II multi-institutional study to evaluate the antitumor activity of TMZ and olaparib [OLA (a PARP inhibitor)] in patients with APP. Methods: Patients with APP with radiographic evidence of disease progression by RECIST v1.1 in the 12 months prior to registration can be enrolled in this phase II randomized study. Patients will be randomized in a 2:1 allocation with more patients to Arm 1. Arm 1 will receive TMZ 75 mg/m2 daily and OLA 200 mg twice daily on days 1-7 of a 21-day cycle. Arm 2 will receive TMZ 200 mg/m2 daily on days 1-5 of a 28-day cycle. Treatment on Arm 1 will continue for 13 cycles, followed by OLA maintenance until disease progression. Treatment on Arm 2 will continue for 13 cycles or until disease progression. The primary objective is to compare the progression-free survival between the two arms with a planned interim analysis for futility. Secondary endpoints include safety, response rate, and overall survival. Correlative endpoints include biochemical response and biomolecular markers (germline succinyl dehydrogenase mutations and tumor status of the repair enzyme methylguanine-DNA methyltransferase). We anticipate a null PFS median of approximately 5.4 months. We plan to accrue a total of 76 patients (randomized at a rate of 2:1 with more patients enrolled to the TMZ+OLA arm) in 38 months with a minimum follow-up of 2.5 months to achieve 56 PFS events. This design includes one interim analysis for futility using Rho Family spending functions (Rho = 2.5) and will yield 89% power to detect a hazard ratio (HR) of 0.5 (median PFS of 5.4 vs. 10.8 months) assuming exponential survival and using a one-sided log-rank test with type I error rate of 0.11. Clinical trial information: NCT04394858 .
A randomized trial of consolidation-targeted adjuvant therapy with encorafenib and cetuximab versus usual care for patients with stage II/III BRAF V600E colon cancer: Alliance for Clinical Trials in Oncology A022004.
Yaeger, Rona , Dib, Elie G. , Krishnamurthi, Smitha , Shergill, Ardaman , Shi, Qian , Dueck, Amylou C. , Kazmi, Syed Mohammad Ali , Alese, Olatunji B. , Nixon, Andrew B. , O’Reilly, Eileen M. , Meyerhardt, Jeffrey A.

Journal of Clinical Oncology | June 4, 2023 | Volume: 41 | Issue: 16_suppl | Pages: TPS3641-TPS3641

10.1200/jco.2023.41.16_suppl.tps3641 Get It

TPS3641 Background: Patients with mismatch repair proficient (pMMR) BRAF V600E mutant high-risk stage II (T4) or stage III colon cancer have a substantial risk of recurrence despite standard adjuvant therapy. In patients with metastatic BRAF V600E mutant colorectal cancer, the combination of the RAF inhibitor encorafenib and the EGFR inhibitor cetuximab has been shown to improve overall and progression-free survival compared to standard therapy after at least one prior line of therapy. This study will evaluate if this combination improves disease-free survival (DFS) in patients with resected BRAF V600E mutant pMMR/microsatellite stable (MSS) high-risk stage II (T4) or stage III colon cancer after standard adjuvant therapy. Methods: The study has a seamless phase II/III design, enrolling a maximum of 394 patients. BRAF mutation status can be determined locally or submitted for central testing in trial pre-screening. Eligible patients will be randomized 1:1 to usual surveillance versus 6 months of treatment with encorafenib (300mg oral daily) plus cetuximab (500mg/m2 intravenous every 14 days). Stratification factors are adjuvant chemotherapy regimen (FOLFOX versus CAPOX), duration of adjuvant therapy (3 months versus > 3 months), tumor stage (T4N0 versus T1-3N1 versus T4N1/TanyN2), and ctDNA marker status (detectable versus undetectable) at randomization. Adjuvant therapy must be completed at most 8 weeks prior to registration. For the phase II component, in the ctDNA detectable cohort, the primary endpoint will be ctDNA clearance rate at 6 months, and, in the ctDNA undetectable cohort, the primary endpoint will be 6-month ctDNA recurrence-free survival, where events consist of death, recurrence, or ctDNA positivity. The primary endpoint of the phase III component is DFS, and secondary endpoints are overall survival, adverse events, and alternative DFS calculated from the date of primary resection, rather than date of study randomization. Patient reported symptoms (PRO-CTCAE) will be collected and analyzed as an exploratory endpoint, and serial blood banking will support future correlative studies. The trial will proceed to the phase III portion if either of the two endpoints in the phase II cohorts is statistically superior in patients receiving encorafenib plus cetuximab. The phase III study sample size will provide 80% power at a one-sided α of 0.05 to detect an approximately 10% improvement in the three-year DFS rate, assuming 68% in the control arm. Two interim analyses will be performed for DFS endpoint. Support: U10CA180821, U10CA180882; https://acknowledgments.alliancefound.org . U10CA180820 (ECOG-ACRIN); U10CA180868 (NRG); U10CA180888 (SWOG); Pfizer, Eli Lilly; Clinicaltrials.gov ID: NCT05710406. Clinical trial information: NCT05710406 .
Surgical care and outcomes in older patients with cancer through implementation of a pre-surgical toolkit (OPTI-Surg): Interim results of a phase III cluster randomized trial (Alliance A231601CD).
Chang, George J. , Gunn, Heather, Barber, Anne, Lowenstein, Lisa M. , Dohan, Daniel , Broering, Jenny, Dockter, Travis , Tan, Angelina D., Bailey, Lisa, Chow, Selina , Mesleh, Marc G., Woodall, Charles E., Solfelt, Marc L, Finlayson, Emily , Dueck, Amylou C. , Cleary, Robert K.

Journal of Clinical Oncology | June 4, 2023 | Volume: 41 | Issue: 16_suppl | Pages: 1541-1541

10.1200/jco.2023.41.16_suppl.1541 Get It

1541 Background: Frailty is common in older adults undergoing major cancer surgery. Mounting evidence indicates multimodal interventions to optimize patient functional status by addressing vulnerabilities associated with frailty before surgery result in decreased complications and enhanced functional recovery. This study tested the effectiveness of OPTI-Surg, a surgical prehabilitation toolkit for improving surgical care and outcomes in older patients undergoing major cancer surgery. Here, we report results from the planned futility interim analysis (IA). Methods: Thoracic (T), gastrointestinal (GI), and urologic (GU) oncological surgery practices affiliated with NCI’s Community Oncology Research Program were randomized 1:1:1, stratified by practice type, to usual care (control), OPTI-Surg toolkit, or OPTI-Surg with an implementation coach. The toolkit was implemented at the practice level. It consisted of the 12-item Edmonton Frail Scale and guided recommendations for interventions directed at identified vulnerabilities. Eligible patients were adults ≥70 years old undergoing curative intent surgery for lung, gastrointestinal, or urologic cancers. Primary outcome was 8-week post-operative function (weekly caloric expenditure) derived from the validated Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire. A linear mixed model was used to compare usual care to the 2 OPTI-Surg arms combined, controlling for baseline function. Results: From July 2019 to October 2021, 225 patients, 50% of the total accrual goal, were enrolled from 29 practices, triggering the IA. Study was suspended to new patient accrual March to June 2020 due to the COVID-19 pandemic. There were no differences in demographics by arm (mean age 76.2 years; 46.4% women; 79.6% white; 20.4% lung resection, 69.8% major GI surgery, 9.8% total cystectomy). Of the 225 patients, 140 (47 Usual Care, 93 OPTI-Surg) were evaluable for the IA. There was no significant difference in post-operative function between OPTI-Surg and usual care (mean decrease of 0.59 kCal/week for OPTI-Surg patients and 0.19 kCal/week for usual care patients, p = 0.762, intraclass correlation = 0.033). Based on the futility analysis, the DSMB recommended closure of recruitment on September 16, 2022. Conclusions: Implementation of the OPTI-Surg toolkit did not significantly improve functional outcomes 8 weeks after surgery for patients aged 70 and older undergoing major cancer surgery compared to usual care. Future analysis of implementation and ethnographic data may identify reasons why significant differences between the intervention and usual care arms were not observed, potentially including disruptions due to the COVID-19 pandemic. Clinical trial information: NCT03857620 .
Patient-Reported Outcomes During and After Treatment for Locally Advanced Rectal Cancer in the PROSPECT Trial (Alliance N1048)
Basch, Ethan , Dueck, Amylou C. , Mitchell, Sandra A. , Mamon, Harvey J. , Weiser, Martin R. , Gollub, Marc J. , Rogak, Lauren J. , Ginos, Brenda, Mazza, Gina L. , Colgrove, B., Chang, George J. , Minasian, Lori M. , Denicoff, Andrea , Thanarajasingam, Gita , Musher, Benjamin , Farma, Jeffrey M. , Meyerhardt, Jeffrey A. , Shi, Qian , Dueck, A. C. , Mamon, Harvey , Weiser, Martin , Gollub, Marc , Mazza, Gina L , Colgrove, Brian, Chang, George , Thanarajasingam, Gita , Musher, Benjamin , George, Thomas J , Venook, Alan P , Farma, Jeffrey , O'Reilly, Eileen M , Meyerhardt, Jeffrey A , Shi, Qian , Mitchell, Sandra A , Basch, Ethan , Saltz, Leonard B. , George, Thomas J. , Venook, Alan P. , O’Reilly, Eileen M. , Schrag, Deborah

Journal of Clinical Oncology | June 4, 2023 | Volume: 41 | Issue: 21 | Pages: 3724-3734

10.1200/jco.23.00903 Get It

PURPOSE The standard of care for locally advanced rectal cancer in North America is neoadjuvant pelvic chemoradiation with fluorouracil (5FUCRT). Neoadjuvant chemotherapy with fluorouracil and oxaliplatin (FOLFOX) is an alternative that may spare patients the morbidity of radiation. Understanding the relative patient experiences with these options is necessary to inform treatment decisions. METHODS PROSPECT was a multicenter, unblinded, noninferiority, randomized trial of neoadjuvant FOLFOX versus 5FUCRT, which enrolled adults with rectal cancer clinically staged as T2N+, cT3N–, or cT3N+ who were candidates for sphincter-sparing surgery. Neoadjuvant FOLFOX was given in six cycles over 12 weeks, followed by surgery. Neoadjuvant 5FUCRT was delivered in 28 fractions over 5.5 weeks, followed by surgery. Adjuvant chemotherapy was suggested but not mandated in both groups. Enrolled patients were asked to provide patient-reported outcomes (PROs) at baseline, during neoadjuvant treatment, and at 12 months after surgery. PROs included 14 symptoms from the National Cancer Institute's Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE). Additional PRO instruments measured bowel, bladder, sexual function, and health-related quality of life (HRQL). RESULTS From June 2012 to December 2018, 1,194 patients were randomly assigned, 1,128 initiated treatment, and 940 contributed PRO-CTCAE data (493 FOLFOX; 447 5FUCRT). During neoadjuvant treatment, patients reported significantly lower rates of diarrhea and better overall bowel function with FOLFOX while anxiety, appetite loss, constipation, depression, dysphagia, dyspnea, edema, fatigue, mucositis, nausea, neuropathy, and vomiting were lower with 5FUCRT (all multiplicity adjusted P < .05). At 12 months after surgery, patients randomly assigned to FOLFOX reported significantly lower rates of fatigue and neuropathy and better sexual function versus 5FUCRT (all multiplicity adjusted P < .05). Neither bladder function nor HRQL differed between groups at any time point. CONCLUSION For patients with locally advanced rectal cancer choosing between neoadjuvant FOLFOX and 5FUCRT, the distinctive PRO profiles inform treatment selection and shared decision making.
Ruxolitinib Versus Best Available Therapy for Polycythemia Vera Intolerant or Resistant to Hydroxycarbamide in a Randomized Trial
Harrison, Claire , Nangalia, Jyoti , Boucher, Rebecca H. , Jackson, Aimee , Yap, Christina , O’Sullivan, Jennifer , Fox, Sonia, Ailts, Isaak , Dueck, Amylou C. , Geyer, Holly L. , Nadezhdin, Eugene, Curto‐García, Natalia , Green, Anna , Wilkins, Bridget S., Coppell, Jason, Laurie, John , Garg, Mamta , Ewing, Joanne, Knapper, Steven , Crowe, Josephine , Koutsavlis, Ioannis , Godfrey, Anna L. , Arami, Siamak , Drummond, Mark W., Clark, Fiona , Mead‐Harvey, Carolyn , Baxter, E. Joanna , Mead, Adam J. , Dueck, A. C. , Harrison, Claire N , Boucher, Rebecca , Mesa, Ruben , Dunn, William G , Garg, Mamta , Knapper, Steven , Crowe, Josephine , Koutsavlis, Ioannis , Arami, Siamak , Byrne, Jennifer , Baxter, Elizabeth Joanna , McMullin, Mary Frances , Mead, Adam J , Yap, Christina , Mesa, Ruben A. , Dunn, William G. , Chen, Frederick , Byrne, Jenny , McMullin, Mary Frances

Journal of Clinical Oncology | May 1, 2023 | Volume: 41 | Issue: 19 | Pages: 3534-3544

10.1200/jco.22.01935 Get It

PURPOSE Polycythemia vera (PV) is characterized by JAK/STAT activation, thrombotic/hemorrhagic events, systemic symptoms, and disease transformation. In high-risk PV, ruxolitinib controls blood counts and improves symptoms. PATIENTS AND METHODS MAJIC-PV is a randomized phase II trial of ruxolitinib versus best available therapy (BAT) in patients resistant/intolerant to hydroxycarbamide (HC-INT/RES). Primary outcome was complete response (CR) within 1 year. Secondary outcomes included duration of response, event-free survival (EFS), symptom, and molecular response. RESULTS One hundred eighty patients were randomly assigned. CR was achieved in 40 (43%) patients on ruxolitinib versus 23 (26%) on BAT (odds ratio, 2.12; 90% CI, 1.25 to 3.60; P = .02). Duration of CR was superior for ruxolitinib (hazard ratio [HR], 0.38; 95% CI, 0.24 to 0.61; P < .001). Symptom responses were better with ruxolitinib and durable. EFS (major thrombosis, hemorrhage, transformation, and death) was superior for patients attaining CR within 1 year (HR, 0.41; 95% CI, 0.21 to 0.78; P = .01); and those on ruxolitinib (HR, 0.58; 95% CI, 0.35 to 0.94; P = .03). Serial analysis of JAK2V617F variant allele fraction revealed molecular response was more frequent with ruxolitinib and was associated with improved outcomes (progression-free survival [PFS] P = .001, EFS P = .001, overall survival P = .01) and clearance of JAK2V617F stem/progenitor cells. ASXL1 mutations predicted for adverse EFS (HR, 3.02; 95% CI, 1.47 to 6.17; P = .003). The safety profile of ruxolitinib was as previously reported. CONCLUSION The MAJIC-PV study demonstrates ruxolitinib treatment benefits HC-INT/RES PV patients with superior CR, and EFS as well as molecular response; importantly also demonstrating for the first time, to our knowledge, that molecular response is linked to EFS, PFS, and OS.
Lessons learned from conducting the first cancer care delivery trial in the Alliance for Clinical Trials in Oncology (Alliance A191402CD)
Pacyna, Joel E. , Dueck, Amylou C. , Chang, George J. , Chow, Selina , Tilburt, Jon C. , Dueck, A. C. , Paskett, Electra D. , Kim, Simon

Clinical Trials | April 13, 2023 | Volume: 20 | Issue: 5 | Pages: 559-563

10.1177/17407745231167123 Get It

Introduction: Testing healthcare delivery interventions in rigorous clinical trials is a critical step in improving patient care, but conducting multisite randomized clinical trials to test the effect of care delivery interventions has unique challenges and requires foresight and planning. Methods: We conducted the first care delivery trial (A191402CD) in the Alliance for Clinical Trials in Oncology, a National Cancer Institute Community Oncology Research Program research base, which tested the effectiveness of two different decision aids for supporting shared decision-making about prostate cancer treatment. Our experience illustrates the kind of challenges that confront care delivery researchers as they seek to test interventions to improve the experiences of patients. Results: Lessons learned include the following: cluster-randomized designs introduce complexity; workflow disruption can discourage site participation; evidence-based methods may not always be sufficient. Conclusion: We conclude with the following recommendations: assessing feasibility requires special rigor; relationships and interpersonal dynamics must be leveraged. Our experiences may inform future care delivery research.
Phase 1/1b study of azacitidine and hedgehog pathway inhibitor sonidegib in patients with myeloid neoplasms
Dueck, Amylou C. , Palmer, Jeanne , Sproat, Lisa, Hashmi, Shahrukh K. , Mesa, Ruben A. , Litzow, Mark R. , Al‐Kali, Aref , Dueck, A. C. , Palmer, Jeanne M , Hashmi, Shahrukh K , Mesa, Ruben , Al-Kali, Aref , Tibes, Raoul , Kosiorek, Heidi , Bogenberger, James M. , Hogan, William J.

Cancer | April 12, 2023 | Volume: 129 | Issue: 15 | Pages: 2321-2330

10.1002/cncr.34800 Get It

AbstractBackgroundMyeloid neoplasms (myelodysplastic syndrome [MDS], myelofibrosis, and chronic myelomonocytic [CMML]) are aggressive hematological malignancies for which, despite recent approvals, novel therapies are needed to improve clinical outcomes. The hedgehog (HH) pathway is one of the main pathways for cancer stem cells survival and several HH inhibitors (HHi) are approved in clinical practice.MethodsSonidegib (SON), an oral HHi, was tested in this phase 1/1b trial in combination with azacitidine (AZA, 75 mg/m2 days ×7) in patients with newly diagnosed and relapsed/refractory (r/r) chronic MN or acute myeloid leukemia (AML).ResultsSixty‐two patients (28 [45%] newly diagnosed) were treated in this study, including 10 patients in the dose‐finding component and 52 patients in phase 1b. SON 200 mg oral daily on days 1–28 each cycle was deemed the recommended dose for phase 1b. Out of 21 rrAML patients, two achieved response (one complete response/one morphologic leukemia‐free state) with no responses seen in seven r/r MDS/CMML patients. In newly diagnosed AML/MDS, response was seen in six (three had complete remission, two had morphological leukemia‐free status) of 27 patients. Median overall survival was 26.4 and 4.7 months for newly diagnosed MDS and AML, respectively. Safety was satisfactory with common (>20%) side effects including fatigue, constipation, nausea, cough, insomnia, and diarrhea. Only 7% of patients died in the study, and none of the deaths were deemed related to treatment.ConclusionsOur study shows that AZA + SON are a safe combination in a patient with MN. Similar to other hedgehog inhibitors, this combination yielded limited response rate in patients with myeloid neoplasms.
Alliance A031902 (CASPAR): A randomized phase (ph) 3 trial of enzalutamide with rucaparib/placebo in first-line metastatic castration-resistant prostate cancer (mCRPC).
Ryan, Charles J. , Tan, Alan , Watt, Colleen, Gartrell, Benjamin A. , Grubb, Robert L., Wen, Yujia , Rao, Arpit , Heller, Glenn , VanderWeele, David James , Lewis, Lionel D. , Chen, Ronald C. , Kohli, Manish , Barata, Pedro C. , Dueck, Amylou C. , Morris, Michael J.

Journal of Clinical Oncology | March 14, 2023 | Volume: 41 | Issue: 6_suppl | Pages: TPS277-TPS277

10.1200/jco.2023.41.6_suppl.tps277 Get It

TPS277 Background: Despite a growing number of treatment options for first-line mCRPC, approximately 40% of patients (pts) have radiographic progression within the first year. Co-inhibition of androgen receptor (AR) and PARP is a promising therapeutic strategy that leverages synthetic lethality induced by impaired double-strand DNA repair. Two phase III studies have shown improvement in radiographic progression-free survival (rPFS) in HRR-mutant pts with abiraterone + PARPi combinations vs abiraterone alone. However, the results in HRR-wild type pts are conflicting, with only one of the studies demonstrating a benefit with the abiraterone + PARPi combination. ENZ + RUCA has shown an acceptable safety profile & no significant drug-drug interactions (S-DDI) in a phase 1b trial. This allows its evaluation in mCRPC. Methods: CASPAR (A031902) is a phase 3 study in which 984 pts will be randomized on a 1:1 basis to ENZ plus RUCA/PBO. HRR gene aberration is not required for enrollment. All pts will undergo next-generation targeted exome sequencing from archival tumor tissue (new biopsy only required if no archival tissue is available). Treatment will be continued until disease progression and crossover is not allowed. Key eligibility criteria are age ≥ 18 years, ECOG PS 0-2, biopsy-proven prostate adenocarcinoma, progressive (PSA or radiographic) disease per Prostate Cancer Working Group 3 guidelines, measurable or non-measurable disease per RECIST 1.1, no prior treatment for mCRPC (prior docetaxel, abiraterone, darolutamide, or apalutamide in non-mCRPC setting is allowed), no significant uncontrolled comorbidity, and no medications with S-DDI with ENZ/RUCA. Hierarchical co-primary endpoints are overall survival (OS) and rPFS. The OS analysis will be undertaken as a primary endpoint if the rPFS endpoint is met. For a one-sided logrank test with a type 1 error rate equal to 0.025, the study has 90% power to detect a hazard ratio (HR) of 0.71 in rPFS (median rPFS of 15 and 21 months in control and combination arms, respectively), and 80% power to detect an HR of 0.80 in OS (median OS of 32 and 40 months, respectively). Key secondary endpoints are rPFS and OS in pts with vs without pathogenic BRCA1, BRCA2, or PALB2 alterations; and differences in adverse events and quality of life (QOL) outcomes between the treatment arms. QOL assessments include Functional Assessment of Cancer Therapy–Prostate (FACT-P), Brief Pain Inventory Short Form (BPI-SF), and EQ-5D-5L. A key correlative endpoint is the sensitivity of ctDNA testing for HRR gene alterations. Enrollment began in July 2021 & the study is available for participation to all US-NCTN sites. Clinical trial information: NCT04455750 .