ImportanceEarly anhydramnios during pregnancy, resulting from fetal bilateral renal agenesis, causes lethal pulmonary hypoplasia in neonates. Restoring amniotic fluid via serial amnioinfusions may promote lung development, enabling survival.ObjectiveTo assess neonatal outcomes of serial amnioinfusions initiated before 26 weeks’ gestation to mitigate lethal pulmonary hypoplasia.Design, Setting, and ParticipantsProspective, nonrandomized clinical trial conducted at 9 US fetal therapy centers between December 2018 and July 2022. Outcomes are reported for 21 maternal-fetal pairs with confirmed anhydramnios due to isolated fetal bilateral renal agenesis without other identified congenital anomalies.ExposureEnrolled participants initiated ultrasound-guided percutaneous amnioinfusions of isotonic fluid before 26 weeks’ gestation, with frequency of infusions individualized to maintain normal amniotic fluid levels for gestational age.Main Outcomes and MeasuresThe primary end point was postnatal infant survival to 14 days of life or longer with dialysis access placement.ResultsThe trial was stopped early based on an interim analysis of 18 maternal-fetal pairs given concern about neonatal morbidity and mortality beyond the primary end point despite demonstration of the efficacy of the intervention. There were 17 live births (94%), with a median gestational age at delivery of 32 weeks, 4 days (IQR, 32-34 weeks). All participants delivered prior to 37 weeks’ gestation. The primary outcome was achieved in 14 (82%) of 17 live-born infants (95% CI, 44%-99%). Factors associated with survival to the primary outcome included a higher number of amnioinfusions (P = .01), gestational age greater than 32 weeks (P = .005), and higher birth weight (P = .03). Only 6 (35%) of the 17 neonates born alive survived to hospital discharge while receiving peritoneal dialysis at a median age of 24 weeks of life (range, 12-32 weeks).Conclusions and RelevanceSerial amnioinfusions mitigated lethal pulmonary hypoplasia but were associated with preterm delivery. The lower rate of survival to discharge highlights the additional mortality burden independent of lung function. Additional long-term data are needed to fully characterize the outcomes in surviving neonates and assess the morbidity and mortality burden.Trial RegistrationClinicalTrials.gov Identifier: NCT03101891
A Multicenter Real-World Analysis (RWA) of Primary Cutaneous Anaplastic Large Cell Lymphoma (PCALCL) Treated in the Modern Era
Introduction: The real-world outcomes in patients (pts) with PCALCL in the era of targeted therapies like Brentuximab Vedotin (BV) is not well defined due to lack of large multicenter studies. We conducted a multicenter retrospective RWA to assess patient and disease characteristics, treatment patterns, survival outcomes and impact of novel therapies in this rare type of cutaneous T cell lymphoma (CTCL). Methods: A total of 95 adult (≥18 years) pts from 8 academic institutions in the United States diagnosed from 2010-2022 were included in the analysis. The study was approved by the Institutional Review Boards at the respective sites. Demographic and disease factors were summarized by descriptive statistics. Overall survival (OS) was estimated by Kaplan-Meier method and compared using log rank method. Results: In our cohort, the median age at diagnosis was 63 (range 18-93) years. The majority of pts were male 60%, white 79%, and had good performance status (PS) ECOG 0-1 (93%). Median time from initial presentation to diagnosis was 1.8 (range 0-211) months. Most common initial skin presentation was tumor 46% (44/95), followed by plaques 27% (26/95) and patches 15% (14/95). No pt presented with erythroderma. Median size of the largest lesion was 2 (range 0.5-20) cm. 63% had early stage (IA-IIA) disease and 86% had <5 skin lesions at the time of initial diagnosis. Furthermore, palpable lymph node (LN) (10%) and elevated LDH (18%) were uncommon at diagnosis. Initial treatments include localized radiation 60%, surgical excision 21% and topical steroids 11%. A small subset of pts received systemic treatments like CHOP 13% (12/95), BV 8% (8/95) and oral methotrexate 7% (7/95) as frontline therapy. A proportion of pts received XRT with CHOP (6/12) and BV (2/8). The overall response rate (ORR) to initial therapy was 68% (65/95) with 61% achieving a CR and 17% had primary refractory disease (stable and progressive disease). Relapse rate after 1st line therapy was 52% (49/95). In our cohort a total of 22 pts received BV after frontline therapy, of which 19 were BV naïve and 3 were re-treated. At the time of last follow up, 27% of our cohort were still on treatment, 78% were alive and 21% were dead; only 3% of deaths were attributed to the lymphoma. The median OS was 128 months (95% CI: 78.4-NA) (Figure 1) with a median follow up of 42 (range 0.5-123.5) months. The 5-year OS was 77%. On univariate analysis, older age (≥65 vs <65 years) (median OS 78 vs 128 months; p=0.004) and higher number of lesions (5-10 vs <5) (mOS 34 vs 128 months; p=<0.0001) were significant associated with OS (Table 1). Type and size of the skin lesions, presence of palpable LN, elevated LDH, stage, and treatment modalities had no impact on OS. Results of multivariate analysis will be presented at the conference. Conclusion: In this large multicenter RWA of PCALCL, excellent long-term survival was observed following frontline therapies that were mostly skin directed. The use of systemic therapies including BV were infrequent even in relapsed disease. Older age and increased number of skin lesions were associated with poor OS.
Improved Survival of R/R Double Hit/Triple Hit Lymphoma in the Era of CD19 Chimeric Antigen T Cell (CART) Therapy
Introduction: DH/THL also classified as high-grade B cell lymphomas (HGBCL) with MYC and BCL2 and/or BCL6 rearrangements have higher risk of progression after initial treatment and poor response to salvage therapies compared to diffuse large B cell lymphoma (DLBCL), NOS. Recently, CART cell therapy has shown encouraging responses in treatment of relapsed refractory (R/R) DLBCL. In this retrospective study, we evaluated whether survival of (R/R) DH/THL is improved in the CART era. Methods: In this multicenter retrospective study, adult pts (pts) with R/R DH/THL after anthracycline-based therapy were included. Demographic and clinical variables were obtained from electronic health records. Study objectives was overall survival (OS) at 2 year landmark. We utilized full propensity score matching to compare progression free survival (PFS) and OS of CART with 2 nd line chemoimmunotherapy. Results: 278 DH/THL pts treated between 2010-2020 were included. Median age was 63 years (range 52-74), 163 (58%) were male, 119 (43%) were classified as DLBCL and 116 (42%) as HGBCL; 40 (14%) were transformed from follicular lymphoma. 225 (82%) had advanced stage, 161 (67%) had elevated LDH, 85 (33%) had bulky disease, 74 (59%) had B symptoms. 105 (38%) pts treated for relapsed disease before 2018 were included in the pre-CART era cohort. 168 (60%) pts treated from 2018 onwards were included in the CART era cohort. 102 (60%) pts in CART cell era received CART cells, 40 (14%) received polatuzumab vedotin (pola), 10 (3.5%) received loncastuximab tesirine, tafasitamab and bispecific antibody each. Characteristics at relapse were similar in both groups. Median follow up was 8.9 (0.2-146) months. 2-year OS estimate was 36% (CI 95: 30-42%) in entire population. Patients treated in CART cell era had significantly higher OS (2 yr OS: 43% [CI 95: 35-53]) compared to pts treated in pre-CART cells era (2-year OS: 24% [CI 95: 16-34], p=0.0006) (Figure 1). In multivariable analyses, increasing age (HR = 1.02 (CI 95: 1.01, 1.04), p=0.003), extranodal disease (HR = 1.41 (CI 95: 1.00, 1.99), p<0.001), elevated LDH (HR = 1.57 (CI 95: 1.11, 2.24), p=0.01) were associated with inferior OS. Increasing time to relapse (HR = 0.98 (CI 95: 0.97, 0.99), p<0.001) was associated with superior OS. BCL6 rearrangement did not affect OS. When adjusted for these factors, treatment with CART cells was associated with higher 2 yr OS (HR = 0.33 (CI 95: 0.22, 0.49), p<0.001). Treatment with polatuzumab (HR = 1.07 (CI 95: 0.71, 1.6), p=0.07) was not significantly associated with OS in univariable analysis. 102 pts underwent CART cell therapy at any point for relapse; 94 (93%) were refractory to prior chemotherapy. 62 (60%) responded and 52 (50%) had CR after CART cells. 2-year PFS and OS after CART cell therapy were 28% (CI 95: 19-40) and 40% (CI 95: 30-53), respectively. Increasing time to CART was associated with inferior OS (HR: 1.02 (CI 95: 1.0-1.03, p=0.03) but not PFS (HR: 1.02 (CI 95: 0.99-1.04), p=0.2). 219 (79%) pts received curative intent salvage chemotherapy for 2 nd line. 2-year PFS and OS were 15% (CI 95: 11-20) and 38% (CI 95: 31-45), respectively. 21 pts received CART cell therapy for 2 nd line. 2 year PFS and OS in this small number of pts were 52% (CI 95: 35-79) and 70% (CI 95: 52-94), respectively. Due in part to the small number of pts who received CART cells in 2 nd line, we utilized full propensity score matched analysis to compare each patient in CART cell group to all possible matched controls in salvage chemotherapy group. Variables matched were age, LDH, extra nodal disease and time to relapse. In propensity score matched analysis, pts who received CART cells had significantly higher 2 year PFS (HR: 10.5 (CI 95: 3.4-17.5), p=002) and 2 year OS (HR: 7.5 (CI 95: 1.4-13), p=0.01). Conclusions: Survival of r/r DH/THL appears to have improved in the era of CART cell therapy. About 2/3 of pts refractory to chemotherapy respond to CART cells, and in multivariable analysis, receipt of CART cells was associated with improved OS. Increasing time to CART cells was associated with inferior survival. In a propensity score matched analysis utilizing full matching, CART cell therapy in 2 nd line was associated with significantly higher 2 year PFS and OS compared to curative intent salvage therapy. Other CD 19 and CD 20 targeting agents approved after CART cell therapy might contribute to favorable survival, effect of these agents could not be assessed because of small numbers.
Abstract A048: Novel murine models of ARID1A and PBRM1-deficient cholangiocarcinoma for preclinical discovery and development
Abstract Genes encoding SWI/SNF chromatin remodeling complex subunits are recurrently mutated across human cancers. In cholangiocarcinoma (CCA), AT-rich interaction domain-1A (ARID1A) and polybromo-1 (PBRM1) loss of function mutations occur in approximately 18 and 10% of cases respectively. Yet our mechanistic understanding and ability to therapeutically exploit ARID1A and PBRM1 deficiency are immature. Genetically accurate preclinical models are needed to define the role of ARID1A and PBRM1 and test therapeutic approaches in CCA. Analysis of human CCA tumors showed that loss of function mutations in ARID1A and PBRM1 frequently co-occur with each other and with PI3K/AKT pathway activation. Therefore, we developed novel murine models of cholangiocarcinoma initiated by Arid1a knockout or dual Arid1a/Pbrm1 knockout in the context of AKT activation, employing a surgical biliary transfection method for somatic gene editing with CRISPR/Cas9. Mice with cholangiocyte Arid1a knockout and AKT activation (AAC) or dual Arid1a/Pbrm1 knockout and AKT activation (APAC) formed numerous liver tumors within 8 months. Histologically, tumors were predominantly CCA and mixed HCC/CCA, with a similar spectrum of tumors across AAC and APAC mice. Gene editing with CRISPR/Cas9 was confirmed at the DNA level, and loss of protein expression was confirmed in tumor cells by immunohistochemistry. Similar to human CCA, many tumors were densely infiltrated with cancer-associated fibroblasts and a variable degree of CD45+ immune cells. To generate scalable models for preclinical testing, tumors from AAC and APAC mice were dissociated to create cell lines for in vitro studies and propagated by orthotopic transplantation for in vivo studies. Cell lines and orthotopic tumors were validated and retained the genetic features and histologic characteristics of the parental tumors. Collectively these studies have produced a suite of novel, well-characterized, genetically relevant mouse models of epigenetic dysregulation in CCA due to ARID1A and PBRM1 deficiency, which can be used broadly for discovery research and preclinical testing of novel treatment approaches. Citation Format: Caitlin B. Conboy, Jennifer L. Tomlinson, Ryan D. Watkins, Jayla T. Millender, Danielle M. Carlson, Rory L. Smoot, Keith D. Robertson, Greg J. Gores. Novel murine models of ARID1A and PBRM1-deficient cholangiocarcinoma for preclinical discovery and development [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A048.
Genotype-Phenotype Taxonomy of Hypertrophic Cardiomyopathy
BACKGROUND: Hypertrophic cardiomyopathy (HCM) is an important cause of sudden cardiac death associated with heterogeneous phenotypes, but there is no systematic framework for classifying morphology or assessing associated risks. Here, we quantitatively survey genotype-phenotype associations in HCM to derive a data-driven taxonomy of disease expression. METHODS: We enrolled 436 patients with HCM (median age, 60 years; 28.8% women) with clinical, genetic, and imaging data. An independent cohort of 60 patients with HCM from Singapore (median age, 59 years; 11% women) and a reference population from the UK Biobank (n=16 691; mean age, 55 years; 52.5% women) were also recruited. We used machine learning to analyze the 3-dimensional structure of the left ventricle from cardiac magnetic resonance imaging and build a tree-based classification of HCM phenotypes. Genotype and mortality risk distributions were projected on the tree. RESULTS: Carriers of pathogenic or likely pathogenic variants for HCM had lower left ventricular mass, but greater basal septal hypertrophy, with reduced life span (mean follow-up, 9.9 years) compared with genotype negative individuals (hazard ratio, 2.66 [95% CI, 1.42–4.96]; P <0.002). Four main phenotypic branches were identified using unsupervised learning of 3-dimensional shape: (1) nonsarcomeric hypertrophy with coexisting hypertension; (2) diffuse and basal asymmetrical hypertrophy associated with outflow tract obstruction; (3) isolated basal hypertrophy; and (4) milder nonobstructive hypertrophy enriched for familial sarcomeric HCM (odds ratio for pathogenic or likely pathogenic variants, 2.18 [95% CI, 1.93–2.28]; P =0.0001). Polygenic risk for HCM was also associated with different patterns and degrees of disease expression. The model was generalizable to an independent cohort (trustworthiness, M 1 : 0.86–0.88). CONCLUSIONS: We report a data-driven taxonomy of HCM for identifying groups of patients with similar morphology while preserving a continuum of disease severity, genetic risk, and outcomes. This approach will be of value in understanding the causes and consequences of disease diversity.
Reconstituted Extracellular Vesicles from Human Platelets Decrease Viral Myocarditis in Mice
AbstractPatients with viral myocarditis are at risk of sudden death and may progress to dilated cardiomyopathy (DCM). Currently, no disease‐specific therapies exist to treat viral myocarditis. Here it is examined whether reconstituted, lyophilized extracellular vesicles (EVs) from platelets from healthy men and women reduce acute or chronic myocarditis in male mice. Human‐platelet‐derived EVs (PEV) do not cause toxicity, damage, or inflammation in naïve mice. PEV administered during the innate immune response significantly reduces myocarditis with fewer epidermal growth factor (EGF)‐like module‐containing mucin‐like hormone receptor‐like 1 (F4/80) macrophages, T cells (cluster of differentiation molecules 4 and 8, CD4 and CD8), and mast cells, and improved cardiac function. Innate immune mediators known to increase myocarditis are decreased by innate PEV treatment including Toll‐like receptor (TLR)4 and complement. PEV also significantly reduces perivascular fibrosis and remodeling including interleukin 1 beta (IL‐1β), transforming growth factor‐beta 1, matrix metalloproteinase, collagen genes, and mast cell degranulation. PEV given at days 7–9 after infection reduces myocarditis and improves cardiac function. MicroRNA (miR) sequencing reveals that PEV contains miRs that decrease viral replication, TLR4 signaling, and T‐cell activation. These data show that EVs from the platelets of healthy individuals can significantly reduce myocarditis and improve cardiac function.
Mutations associated with progression in follicular lymphoma predict inferior outcomes at diagnosis: Alliance A151303
Abstract Follicular lymphoma (FL) is clinically heterogeneous, with select patients tolerating extended watch-and-wait, whereas others require prompt treatment, suffer progression of disease within 24 months of treatment (POD24), and/or experience aggressive histologic transformation (t-FL). Because our understanding of the relationship between genetic alterations in FL and patient outcomes remains limited, we conducted a clinicogenomic analysis of 370 patients with FL or t-FL (from Cancer and Leukemia Group B/Alliance trials 50402/50701/50803, or real-world cohorts from Washington University School of Medicine, Cleveland Clinic, or University of Miami). FL subsets by grade, stage, watch-and-wait, or POD24 status did not differ by mutation burden, whereas mutation burden was significantly higher in relapsed/refractory (rel/ref) FL and t-FL than in newly diagnosed (dx) FL. Nonetheless, mutation burden in dx FL was not associated with frontline progression-free survival (PFS). CREBBP was the only gene more commonly mutated in FL than in t-FL yet mutated CREBBP was associated with shorter frontline PFS in FL. Mutations in 20 genes were more common in rel/ref FL or t-FL than in dx FL, including 6 significantly mutated genes (SMGs): STAT6, TP53, IGLL5, B2M, SOCS1, and MYD88. We defined a mutations associated with progression (MAP) signature as ≥2 mutations in these 7 genes (6 rel/ref FL or t-FL SMGs plus CREBBP). Patients with dx FL possessing a MAP signature had shorter frontline PFS, revealing a 7-gene set offering insight into FL progression risk potentially more generalizable than the m7–Follicular Lymphoma International Prognostic Index (m7-FLIPI), which had modest prognostic value in our cohort. Future studies are warranted to validate the poor prognosis associated with a MAP signature in dx FL, potentially facilitating novel trials specifically in this high-risk subset of patients.
Abstract 814: Novel strategy for aptamer-directed nanovesicle targeting in cholangiocarcinoma
Abstract Background: Cholangiocarcinoma (CCA) is a heterogeneous malignancy arising from the biliary epithelium. Its diverse molecular landscape and aggressive biology render many anti-cancer therapies ineffective. Nanovesicle technology provides an opportunity for therapeutic inhibition of oncogenic targets that have been previously classified as undruggable. EpCAM is an epithelial-specific, transmembrane glycoprotein with increased expression in human and murine CCA which can be used for nanovesicle targeting. As a proof of concept study, we designed and validated a novel strategy to direct therapeutic milk-derived nanovesicles (tMNVs) to CCA tumors. Methods: tMNVs were decorated with RNA nanoparticles containing a validated aptamer (EpDT3) against EpCAM conjugated to a cholesterol-triethylene-glycol (TEG) scaffold containing an Alexa647 fluorophore. Human and murine CCA cell lines were treated with aptamer directed tMNVs and assessed for nanovesicle uptake by fluorescent microscopy. CCA tumor tissue, derived from orthotopic implantation of a syngeneic CCA cell line, SB1, into a C57BL/6 mouse, was collected and treated with either aptamer-directed or bare tMNVs ex vivo, and compared with adjacent normal liver tissue. Flow cytometry was utilized to characterize tMNVs absorption profile. C57BL/6 mice who had previously undergone SB1 orthotopic and flank implantation were treated with aptamer-directed tMNVs by tail-vein injection and subsequently euthanized. Tissue was collected for biodistribution analyses by fluorescent microscopy. The experiment was repeated in NOD-scid mice following orthotopic implantation of patient derived xenograft (PDX) CCA tumor. Results: Both human and murine CCA cells treated with aptamer-directed tMNVs demonstrated high fluorescent signal consistent with tMNV absorption within 12 hours of application. Flow cytometry analysis showed aptamer-directed tMNVs were absorbed at a higher proportion by CCA tumors than bare tMNVs ex vivo. Aptamer-directed tMNVs also had better absorption by CCA tumors compared to adjacent normal liver tissue. Following treatment with aptamer-directed or bare tMNVs in vivo, fluorescent microscopy demonstrated that aptamer-directed tMNVs were significantly better absorbed in the orthotopic SB1 tumors, followed by the subcutaneous tumors. Minimal fluorescent signal was noted in the normal adjacent liver. Orthotopically implanted PDX tumors also demonstrated high fluorescent signals following intravenous treatment with aptamer-directed tMNVs. Conclusions: Utilizing a novel targeting strategy, we were able to design tMNVs capable of reliably and specifically targeting CCA in preclinical models. This work is foundational to the future application of nanovesicle technology in the CCA treatment paradigm. Citation Format: Mincheng Yu, Jennifer L. Tomlinson, Emilien J. Loeuillard, Ryan D. Watkins, Caitlin B. Conboy, Shohei Takaichi, Nathan W. Werneburg, Roberto Alva-Ruiz, Amro Abdelrahman, Danielle M. Carlson, Jingchun Yang, Sumera I. Ilyas, Gregory J. Gores, Tushar Patel, Rory L. Smoot. Novel strategy for aptamer-directed nanovesicle targeting in cholangiocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 814.
Tyrosine phosphorylation of YAP‐1 in biliary epithelial cells mediates posthepatectomy liver regeneration and is affected by serotonin
AbstractExperimental data suggested activation of yes‐associated protein (YAP‐1) as a critical regulator of liver regeneration (LR). Serotonin (5‐HT) promotes LR in rodent models and has been proposed to act via YAP‐1. How 5‐HT affects LR is incompletely understood. A possible mechanism how 5‐HT affects human LR was explored. Sixty‐one patients were included. Tissue samples prior and 2 h after induction of LR were collected. Circulating levels of 5‐HT and osteopontin (OPN) were assessed. YAP‐1, its phosphorylation states, cytokeratin 19 (CK‐19) and OPN were assessed using immunofluorescence. A mouse model of biliary epithelial cells (BECs) specific deletion of YAP/TAZ was developed. YAP‐1 increased as early as 2 h after induction of LR (p = 0.025) predominantly in BECs. BEC specific deletion of YAP/TAZ reduced LR after 70% partial hepatectomy in mice (Ki67%, p < 0.001). SSRI treatment, depleting intra‐platelet 5‐HT, abolished YAP‐1 and OPN induction upon LR. Portal vein 5‐HT levels correlated with intrahepatic YAP‐1 expression upon LR (R = 0.703, p = 0.035). OPN colocalized with YAP‐1 in BECs and its circulating levels increased in the liver vein 2 h after induction of LR (p = 0.017). In the context of LR tyrosine‐phosphorylated YAP‐1 significantly increased (p = 0.042). Stimulating BECs with 5‐HT resulted in increased YAP‐1 activation via tyrosine‐phosphorylation and subsequently increased OPN expression. BECs YAP‐1 appears to be critical for LR in mice and humans. Our evidence suggests that 5‐HT, at least in part, exerts its pro‐regenerative effects via YAP‐1 tyrosine‐phosphorylation in BECs and subsequent OPN‐dependent paracrine immunomodulation.
Rucaparib for metastatic castration-resistant prostate cancer (mCRPC): TRITON3 interim overall survival and efficacy of rucaparib vs docetaxel or second-generation androgen pathway inhibitor therapy.
18 Background: TRITON3 (NCT02975934) is a randomized, multicenter, open-label, phase 3 study of rucaparib vs physician’s choice (docetaxel [DTX], abiraterone [ABI] or enzalutamide [ENZ]) in patients (pts) with chemotherapy-naïve mCRPC with BRCA1/2 (BRCA) or ATM alterations. It was previously reported that rucaparib significantly improved the primary endpoint of radiographic progression-free survival (rPFS) vs physician’s choice in pts with BRCA or ATM alterations. We report here the interim overall survival (OS) and also report on efficacy of rucaparib compared individually with either DTX or ABI/ENZ. Methods: Pts had disease progression after 1 prior second-generation androgen pathway inhibitor therapy in any setting and were randomized 2:1 to rucaparib 600 mg BID or physician’s choice of DTX, ABI or ENZ. An ordered step-down multiple comparisons procedure was used to control the overall error rate. OS was a key secondary endpoint with rPFS as the primary endpoint tested first in the BRCA subgroup, then the intent-to-treat (ITT) population. Subgroup analyses based on physician’s choice were exploratory. Results: As of August 25, 2022, 302 pts with BRCA and 103 pts with ATM alterations were randomized. OS maturity was 54% in the BRCA subgroup and 59% in the ITT population. rPFS and OS are shown. The most frequent treatment-emergent adverse event (TEAE) in the rucaparib, DTX and ABI/ENZ groups was asthenia/fatigue (61.1%, 67.6% and 57.6%, respectively). The most frequent grade ≥3 TEAE in the rucaparib, DTX and ABI/ENZ groups was anemia (23.7%), neutropenia (14.1%), and hypertension (10.2%), respectively. Conclusions: Rucaparib significantly improved rPFS vs either DTX or ABI/ENZ; safety was consistent with prior reports. Interim OS results suggest a trend towards improvement for rucaparib vs DTX or ABI/ENZ in pts with mCRPC and BRCA alterations. Clinical trial information: NCT02975934 . [Table: see text]