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Contains fulltext : 220820.pdf (Publisher’s version ) (Open Access) BACKGROUND: Multiple loss-of-function alterations in genes that are involved in DNA repair, including homologous recombination repair, are associated with response to poly(adenosine diphosphate-ribose) polymerase (PARP) inhibition in patients with prostate and other cancers. METHODS: We conducted a randomized, open-label, phase 3 trial evaluating the PARP inhibitor olaparib in men with metastatic castration-resistant prostate cancer who had disease progression while receiving a new hormonal agent (e.g., enzalutamide or abiraterone). All the men had a qualifying alteration in prespecified genes with a direct or indirect role in homologous recombination repair. Cohort A (245 patients) had at least one alteration in BRCA1, BRCA2, or ATM; cohort B (142 patients) had alterations in any of 12 other prespecified genes, prospectively and centrally determined from tumor tissue. Patients were randomly assigned (in a 2:1 ratio) to receive olaparib or the physician's choice of enzalutamide or abiraterone (control). The primary end point was imaging-based progression-free survival in cohort A according to blinded independent central review. RESULTS: In cohort A, imaging-based progression-free survival was significantly longer in the olaparib group than in the control group (median, 7.4 months vs. 3.6 months; hazard ratio for progression or death, 0.34; 95% confidence interval, 0.25 to 0.47; P

Background We have shown previously in multivariable analysis that black men had 19% lower risk of death than white men with metastatic castration-resistant prostate cancer (mCRPC) treated with a docetaxel and prednisone (DP)-based regimen. The primary goal of this analysis was to compare progression-free survival (PFS), biochemical PFS, ≥50% decline in prostate-specific antigen (PSA) from baseline and objective response rate (ORR) in white, black and Asian men with mCRPC treated with a DP-based regimen. Patients and methods Individual patient data from 8820 mCRPC men randomized on nine phase III trials to a DP-containing regimen were combined. Race used in the analysis was based on self-report. End points were PFS, biochemical PSA, ≥50% decline in PSA from baseline and ORR. The proportional hazards and the logistic regression models were employed to assess the prognostic importance of race in predicting outcomes adjusting for established prognostic factors. Results Of 8820 patients, 7528 (85%) were white, 500 (6%) were black, 424 were Asian (5%) and 368 (4%) had race unspecified. Median PFS were 8.3 [95% confidence interval (CI) 8.2–8.5], 8.2 (95% CI 7.4–8.8) and 8.3 (95% CI 7.6–8.8) months in white, black and Asian men, respectively. Median PSA PFS were 9.9 (95% CI 9.7–10.4), 8.5 (95% CI 8.0–10.3) and 11.1 (95% CI 9.9–12.5) months in white, black and Asian men, respectively. Conclusions We observed no differences in clinical outcomes by race and ethnic groups in men with mCRPC enrolled on these phase III clinical trials with DP.

INTRODUCTION AND OBJECTIVE:TITAN showed that apalutamide (APA) + androgen deprivation therapy (ADT) improves overall survival (OS), radiographic progression-free survival (rPFS), and time to prosta...

Objective To evaluate the efficacy and safety of apalutamide + androgen deprivation therapy versus androgen deprivation therapy alone in Japanese patients with metastatic castration-sensitive prostate cancer from the phase 3, randomized, global TITAN study. Methods Men with metastatic castration-sensitive prostate cancer randomly (1:1) received 240 mg apalutamide + androgen deprivation therapy or matching placebo + androgen deprivation therapy. The primary efficacy endpoints were radiographic progression-free survival and overall survival. Secondary efficacy endpoints were time to cytotoxic chemotherapy, pain progression, chronic opioid use, and skeletal-related events. Safety was also assessed. Results Of the 1052 patients included in the TITAN study, 51 (4.85%) were Japanese (apalutamide group, n = 28; placebo group, n = 23). In all, 81.8% of patients in the apalutamide and 71.8% in the placebo group did not experience radiographic progression or death, and the hazard ratio for radiographic progression-free survival favored treatment with apalutamide (hazard ratio 0.712, 95% confidence interval 0.205-2.466; P = 0.59). At 24 months, 85.7% of patients in the apalutamide group and 81.5% in the placebo group were alive, and the hazard ratio for overall survival favored apalutamide (hazard ratio 0.840, 95% confidence interval 0.210-3.361; P = 0.805). In the interim analysis, the median radiographic progression-free survival and overall survival were not reached in the apalutamide group and time to cytotoxic chemotherapy was delayed following apalutamide treatment. The safety profile of apalutamide in the Japanese subpopulation was comparable with that of the global population, except for skin rash. Conclusions The results of the present analyses suggest that apalutamide + androgen deprivation therapy in Japanese patients had favorable efficacy compared with androgen deprivation therapy alone, and these findings are comparable to those in the overall population. Apalutamide + androgen deprivation therapy can be considered as one of the therapeutic options for a broad spectrum of metastatic castration-sensitive prostate cancer regardless of prior treatment and disease extent in Japanese patients.

Background Activating mutations in AKT1 and PIK3CA are undercharacterised in metastatic castration-resistant prostate cancer (mCRPC), but are linked to activation of phosphatidylinositol 3-kinase (PI3K) signalling and sensitivity to pathway inhibitors in other cancers. Objective To determine the prevalence, genomic context, and clinical associations of AKT1/PIK3CA activating mutations in mCRPC. Design, setting, and participants We analysed targeted cell-free DNA (cfDNA) sequencing data from 599 metastatic prostate cancer patients with circulating tumour DNA (ctDNA) content above 2%. Outcome measurements and statistical analysis In patients with AKT1/PIK3CA mutations, cfDNA was subjected to PTEN intron sequencing and matched diagnostic tumour tissue was analysed when possible. Results and limitations Of the patients, 6.0% (36/599) harboured somatic clonal activating mutation(s) in AKT1 or PIK3CA. Mutant allele-specific imbalance was common. Clonal mutations in mCRPC ctDNA were typically detected in pretreatment primary tissue and were consistent across serial ctDNA collections. AKT1/PIK3CA-mutant mCRPC had fewer androgen receptor (AR) gene copies than AKT1/PIK3CA wild-type mCRPC (median 4.7 vs 10.3, p = 0.003). AKT1 mutations were mutually exclusive with PTEN alterations. Patients with and without AKT1/PIK3CA mutations showed similar clinical outcomes with standard of care treatments. A heavily pretreated mCRPC patient with an AKT1 mutation experienced a 50% decline in prostate-specific antigen with Akt inhibitor (ipatasertib) monotherapy. Ipatasertib also had a marked antitumour effect in a patient-derived xenograft harbouring an AKT1 mutation. Limitations include the inability to assess AKT1/PIK3CA correlatives in ctDNA-negative patients. Conclusions AKT1/PIK3CA activating mutations are relatively common and delineate a distinct mCRPC molecular subtype with low-level AR copy gain. Clonal prevalence and evidence of mutant allele selection propose PI3K pathway dependency in selected patients. The use of cfDNA screening enables prospective clinical trials to test PI3K pathway inhibitors in this population. Patient summary Of advanced prostate cancer cases, 6% have activating mutations in the genes AKT1 or PIK3CA. These mutations can be identified using a blood test and may help select patients suitable for clinical trials of phosphatidylinositol 3-kinase inhibitors.

Although DNA methylation is a key regulator of gene expression, the comprehensive methylation landscape of metastatic cancer has never been defined. Through whole-genome bisulfite sequencing paired with deep whole-genome and transcriptome sequencing of 100 castration-resistant prostate metastases, we discovered alterations affecting driver genes that were detectable only with integrated whole-genome approaches. Notably, we observed that 22% of tumors exhibited a novel epigenomic subtype associated with hypermethylation and somatic mutations in TET2, DNMT3B, IDH1 and BRAF. We also identified intergenic regions where methylation is associated with RNA expression of the oncogenic driver genes AR, MYC and ERG. Finally, we showed that differential methylation during progression preferentially occurs at somatic mutational hotspots and putative regulatory regions. This study is a large integrated study of whole-genome, whole-methylome and whole-transcriptome sequencing in metastatic cancer that provides a comprehensive overview of the important regulatory role of methylation in metastatic castration-resistant prostate cancer.

There are few data regarding disparities in overall survival (OS) between Asian and white men with metastatic castration-resistant prostate cancer (mCRPC). We compared OS of Asian and white mCRPC men treated in phase III clinical trials with docetaxel and prednisone (DP) or a DP-containing regimen. Individual participant data from 8820 men with mCRPC randomly assigned on nine phase III trials to receive DP or a DP-containing regimen were combined. Men enrolled in these trials had a diagnosis of prostate adenocarcinoma. The median overall survival was 18.8 months (95% confidence interval [CI] = 17.4 to 22.1 months) and 21.2 months (95% CI = 20.8 to 21.7 months) for Asian and white men, respectively. The pooled hazard ratio for death for Asian men compared with white men, adjusted for baseline prognostic factors, was 0.95 (95% CI = 0.84 to 1.09), indicating that Asian men were not at increased risk of death. This large analysis showed that Asian men did not have shorter OS duration than white men treated with docetaxel.

Chemotherapy is a fundamental component in the treatment of urological cancers. It is utilised in localised disease to reduce the risk of relapse, disseminated disease to palliate symptoms and improve survival, and to cure patients with advanced disease, in particular germ cell cancers. This review will summarize chemotherapy regimens indicated for urologic cancers and their benefits.

279 Background: PSMA expression is increased in response to anti-androgen therapies and is a promising therapeutic target for the treatment of prostate cancer (PCa). JNJ-081 is a bispecific antibody with one arm binding PSMA on cancer cells and the other binding CD3 on T-cells to promote anti-tumor activity. Methods: This Phase 1 Dose Escalation Study evaluated JNJ-081 in mCRPC participants (pts) who progressed after novel androgen targeting therapy (eg, abiraterone, enzalutamide or apalutamide). Prior chemotherapy was permitted. JNJ-081 was administered initially by intravenous (IV) then by subcutaneous (SC) route. Dose escalation followed a continuous reassessment method based on a Bayesian regression model. The primary endpoint to determine the recommended phase 2 dose (RP2D) was based on safety. Pharmacokinetics (PK), pharmacodynamics (PD), immunogenicity, and preliminary anti-tumor activity were also evaluated. Cytokine release syndrome (CRS) was graded by CTCAE V5. Results: As of 10 May 2021, 39 pts were dosed in 10 cohorts ranging from 0.1 µg/kg to 3 µg/kg IV and from 3 µg/kg to 60 µg/kg SC. Premedications included high dose corticosteroids. Step-up priming was implemented at higher SC doses. Most common treatment-emergent AEs were CRS (65%), fatigue (49%) and nausea (43%). 2 pts developed DLTs of Grade (G) 3 or G4 transaminases increased, 1 each at 30 µg/kg SC and priming with 10 µg/kg SC then 55 µg/kg SC, respectively. Both DLTs were in conjunction with or followed an episode of G2 CRS. SC route as well as step-up priming helped mitigate CRS and infusion-related reaction (IRR) during escalation to higher doses: at 3 µg/kg IV, 4 of 5 pts had G2 CRS or IRR; at 30 µg/kg SC, 3 of 4 pts had G2 CRS; priming with 10 µg/kg then 55 µg/kg SC, 4 of 5 pts had G2 CRS. Injection site reactions (G1 or G2) occurred in 24 of 26 pts treated via SC JNJ-081. No treatment related death was reported. Transient PSA decreases were observed at treatment doses greater than 30 µg/kg SC. Two subjects treated with 55 µg/kg had PSA decreases > 50%. No radiographic responses were observed. PK of JNJ-081 was linear over the dose range of 3-60 µg/kg following SC administration. SC bioavailability was approximately 25%. Anti-drug antibodies (ADA) were detected in 2 of 12 subjects treated by IV administration and 14 of 23 pts treated by SC administration. ADA resulted in loss of exposure in some SC pts. Intrapatient dose escalation in 3 pts did not overcome the reduced exposure after ADA seropositivity. Conclusions: JNJ-081 demonstrated transient decreases in PSA in mCRPC patients. Grade 2 CRS was observed at higher doses and was partially mitigated by SC and step-up dosing. ADA resulting in decreased exposure occurred in the majority of pts treated SC. PSMA remains a potential therapeutic target for T-cell redirection for the treatment of PCa. Clinical trial information: NCT03926013.

12 Background: Approximately 20% of mCRPC has alterations in genes associated with HRR and is responsive to PARP inhibitors (PARPi) such as NIRA. Combined PARPi with androgen receptor pathway targeting may also benefit unselected mCRPC. MAGNITUDE assessed whether adding NIRA to AAP improves outcomes in pts with mCRPC with or without alterations in HRR associated genes. Methods: MAGNITUDE (NCT03748641) is a randomized, double-blind phase 3 study. In eligible mCRPC pts, ≤4 mos of prior AAP for mCRPC was allowed. Pts with (HRR biomarker [BM]+; ATM, BRCA1, BRCA2, BRIP1, CDK12, CHEK2, FANCA, HDAC2, PALB2) and without specified gene alterations (HRR BM-) were randomized 1:1 to receive NIRA 200 mg once daily + AAP or placebo (PBO) + AAP. Primary endpoint was radiographic progression-free survival (rPFS) assessed by blinded independent central review (BICR) in the BRCA1/2 group followed by all HRR BM+ pts. Secondary endpoints were time to initiation of cytotoxic chemotherapy (TTCC), time to symptomatic progression (TTSP) and overall survival (OS). Other endpoints included time to PSA progression (TTPP) and objective response rate (ORR). Results: 423 HRR BM+ pts were randomized to NIRA + AAP (n = 212) or PBO + AAP (n = 211). Median age was 69, 23% had prior AAP, 21% had visceral metastases, and 53% had BRCA1/2 mutations. Median follow-up was 18.6 mos. NIRA + AAP significantly improved rPFS by BICR in the BRCA1/2 subgroup and in all HRR BM+ pts, reducing the risk of progression or death by 47% (16.6 vs 10.9 mo) and 27% (16.5 vs 13.7 mo) respectively (Table), vs PBO + AAP. Investigator assessed rPFS was consistent with BICR. NIRA + AAP delayed TTCC, TTSP, and TTPP and improved ORR in HRR BM+ pts (Table). First interim analysis of OS is immature. The preplanned futility analysis in 233 HRR BM- pts showed no benefit of adding NIRA to AAP in the prespecified composite endpoint (first of PSA progression or rPFS; HR, 1.09; 95% CI, 0.75-1.57). No new safety signals were seen. In HRR BM+ pts, 67% and 46.4% had grade 3/4 AEs and 9% and 3.8% discontinued treatment in the NIRA + AAP and PBO + AAP arms, respectively. There were no clinically significant differences in overall quality of life (FACT-P). Conclusions: NIRA + AAP improves rPFS and other clinically relevant outcomes in pts with mCRPC and alterations in HRR associated genes. There was no evidence of benefit with the addition of NIRA to AAP in HRR BM- pts with mCRPC. Clinical trial information: NCT03748641. [Table: see text]

89 Background: Addition of androgen receptor signaling inhibitors to ADT + DOC has been shown to improve clinical outcomes in pts with mCSPC. TITAN, a placebo-controlled phase 3 study, showed that APA + ADT improved overall survival (OS) and other clinical outcomes in mCSPC (Chi, J Clin Oncol 2021). This post hoc analysis of TITAN evaluated outcomes in pts who had received DOC prior to treatment with APA + ADT versus those who did not. Methods: In TITAN, 1052 pts were randomized 1:1 to APA (240 mg QD) or placebo added to ongoing ADT. We assessed radiographic progression-free survival (rPFS), OS, and time to prostate-specific antigen (PSA) progression in pts receiving DOC and ADT prior to adding APA vs those receiving only ADT plus APA. Outcomes by prior DOC were also assessed in pts with high- or low-volume disease at randomization (baseline [BL]) per adapted CHAARTED criteria, or those with matched BL characteristics. A Cox proportional hazards model was used to derive hazard ratios (HRs) and p values. rPFS was assessed using the first interim analysis cutoff (23 mo median follow-up); OS and time to PSA progression were assessed using the final analysis cutoff (44 mo median follow-up). Results: A total of 58/525 (11%) pts from the APA + ADT group had received DOC prior to randomization: 76% (n = 44) had high-volume disease, 62% (n = 36) had bone-only metastases, 16% (n = 9) had visceral metastases, and 59% (n = 34) had > 10 bone lesions. In the overall APA-treated population and in the subset of pts with high-volume disease, OS, rPFS, and time to PSA progression were similar in those who received prior DOC and those who did not (Table). Pts with low-volume disease also had similar results, although the number of pts was small. Clinical outcomes in pts with matched BL characteristics (including PSA and time from initial diagnosis to randomization, among others) were similar regardless of prior use of DOC (Table). The safety profile of APA was not substantially different between pts with or without prior DOC. Limitations of this analysis include lack of data on tumor volume and other disease characteristics at the initiation of prior DOC treatment; interpretation was based on small number of pts with prior DOC (only 11% of TITAN pts), most notably in the rPFS analysis. Conclusions: Prior use of DOC in pts with mCSPC did not further improve clinical benefits of APA + ADT in TITAN. Clinical trial information: NCT02489318. [Table: see text]

86 Background: Treatment options for patients with mCSPC have rapidly evolved with the introduction of androgen receptor axis targeted therapies (ARATs) and chemotherapy. The GURC cohort study is a phase 4, multicentre, non-interventional, longitudinal cohort study of Canadian men with advanced prostate cancer. We prospectively examined the evolving real world management and treatment patterns of patients with mCSPC, with a focus on treatment intensification beyond ADT and germline DNA damage repair (DDR) testing. Methods: Clinical management patterns, baseline patient characteristics, germline DDR alteration status, treatment intensification with ARATs (abiraterone acetate [AA], apalutamide [Apa], enzalutamide [Enza]) and chemotherapy within the mCSPC cohort were analyzed. Results: 204 patients with mCSPC were enrolled from 2018 to 2021 across 25 Canadian sites. The median age was 71 (range 64 - 77), median PSA at study entry was 24, 88% (158/180) of patients had de novo mCSPC, 69% (110/204) of patients had a Gleason Score > 7, and 4% (2/49) of the patients who received a germline testing harbored a germline DDR alteration (BRCA2 = 1, MUTYH/MEN1 = 1). The distribution of high and low volume mCSPC at study entry was 62% (118/189) and 37% (71/189), respectively. Overall, patients received ADT alone 27% (51/189), AA 45% (86/189), apalutamide 17% (33/189), docetaxel 8% (15/189), and enzalutamide 3% (6/189). Treatment intensification with ARATs/docetaxel was administered to 69% [141/189]) of patients. Patients treated with ADT alone had a significantly lower volume of disease at treatment initiation (low volume rates of 49% [24/49] in ADT alone vs 33% [47/143] in treatment intensified patients, p = 0.044). Among those receiving treatment intensification with ARATs/docetaxel, time to intensification was ≤ 3 months in 78.5 % (113/144). Conclusions: This cohort study demonstrates that patients with mCSPC continue to receive ADT alone and docetaxel over time, despite an ever-increasing list of accessible ARATs. Patients receiving ADT alone appear to have lower volume of disease. Germline DDR testing is not yet comprehensively performed. This underlines the real world need to provide greater education and resources to encourage ARAT treatment and genetic testing in this setting.

TPS211 Background: [177Lu]Lu-PSMA-617 (177Lu-PSMA-617) is a high-affinity prostate-specific membrane antigen (PSMA)-targeted radioligand therapy that delivers β-particle radiation to PSMA-expressing cells and their surrounding microenvironment. In the phase 3 VISION trial, 177Lu-PSMA-617 significantly prolonged radiographic progression-free survival (rPFS) and overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC) previously treated with ≥1 androgen receptor pathway inhibitor (ARPI) and 1–2 taxanes. PSMAfore is investigating the effect on rPFS in taxane-naïve patients with mCRPC treated with either 177Lu-PSMA-617 or a change in ARPI. Methods: PSMAfore (NCT04689828) is a multicenter, open-label, randomized phase 3 trial in adults with progressive mCRPC and confirmed PSMA expression by [68Ga]Ga-PSMA-11 PET/CT. Eligible patients are taxane-naïve in the metastatic setting and have: received one prior ARPI and are candidates for a change in ARPI; an Eastern Cooperative Oncology Group performance status of 0 or 1; a castrate level of serum/plasma testosterone ( < 50 ng/dL or < 1.7 nmol/L); and recovered to grade ≤2 from toxicities related to prior therapies. Approximately 450 patients will be randomized 1:1 to receive 177Lu-PSMA-617 (7.4 GBq i.v. every 6 weeks for 6 cycles) or a change in ARPI to either abiraterone or enzalutamide. Best supportive care is allowed in both arms. Stratification factors are prior ARPI use in castration-resistant vs hormone-sensitive prostate cancer settings and pain symptomatology (score 0–3 vs 4–10 on the worst pain intensity item of the Brief Pain Inventory–Short Form). The primary endpoint is rPFS according to PCWG3-modified RECIST v1.1 criteria. Participants with blinded independent centrally confirmed radiographic progression in the ARPI arm can crossover to the 177Lu-PSMA-617 arm. The planned sample size provides 95% power to detect a hazard ratio of 0.56 for rPFS after 156 events with an overall one-sided significance level of 0.025. The key secondary endpoint is OS; other secondary endpoints include safety and tolerability of 177Lu-PSMA-617 and health-related quality of life. Previously presented at the 2021 European Society for Medical Oncology Congress, FPN 942, Morris M et al. Reused with permission. Clinical trial information: NCT04689828.

252 Background: The management of patients with mCRPC has evolved since the introduction of androgen-receptor axis targeted agents (ARATs). The Genitourinary Research Consortium (GURC) initiated a prospective, phase 4, multicentre, non-interventional, longitudinal cohort study of Canadian men with advanced prostate cancer to determine real-world treatment patterns and outcomes. Methods: 25 sites across Canada participated in this study including patients managed by urologists, medical- and radiation-oncologists between 2018 to 2021. Baseline patient characteristics and mCRPC treatment patterns are reported here. Treatment patterns reviewed included time to second-line treatment use and time to progression or death. Results: 136 mCRPC patients were enrolled. Median age was 73 years (range 66 to 80) with 54 (40%) having a Gleason score of >8 at diagnosis. Median PSA at enrollment was 8.9 (2.4 to 25.1) ng/ml. At study entry, 90/132 (66%) patients with mCSPC and 42/132 (31%) patients nmCRPC had progressed to develop mCRPC. One hundred and twenty-one (89%) of patients in this cohort received first-line treatment for mCRPC, the most common was abiraterone acetate + prednisone in 67 (49%) and enzalutamide in 41 (30%), followed by docetaxel in 6 (4.4%), and Radium-223 in 5 (3.7%) patients. During the 25-month median follow-up period (range 6-28), 59 (49%) of the patients receiving first line mCRPC therapy had documented disease progression or death. At the time of last recorded follow-up, 37 (28%) patients who progressed received a second-line therapy for mCRPC. Median time to progression in this cohort was 21 months (95% CI: 15.2 - NE), with ARAT-to-ARAT being the most common sequencing pattern observed in 15 (39%) patients, followed by ARAT to chemotherapy in 14 (37%). Conclusions: In this real-world analysis of mCRPC patients, ARAT therapy was the preferred approach for first-line treatment intensification in over 108 (80%) patients. Despite evidence of poor response rates, ARAT-to-ARAT was the most common sequencing for second line therapy, followed by ARAT-to-chemotherapy treatment. Further analysis and follow-up will help define optimal mCRPC management, in real world setting.

60 Background: Combined ADT and ARPI is associated with improved overall survival (OS) compared with ADT alone in patients with mCSPC. The activity of subsequent therapies for mCRPC is not well characterized. Methods: We conducted a retrospective analysis of patients enrolled on a biobank at 6 cancer centres in British Columbia, Canada. Patients who received abiraterone or apalutamide for mCSPC were included. Data including baseline clinical prognostic factors and clinical outcomes (per Prostate Cancer Working Group III) were collected from patient records. Survival was analyzed by Kaplan-Meier method and Log Rank test and prognostic variables were determined using Cox regression. Results: 168 patients were identified of which 126 (75%) received abiraterone, 38 (23%) received apalutamide, and 4 (2%) received one ARPI and switched to the other for toxicity. Median age was 69 years and Gleason score ≥ 8 in 61%. Site of metastasis (mets) at mCSPC was lymph node (n=91), bone (n=141), and liver (n=6). As of August 28 2021, a total of 46 patients progressed to mCRPC, of which 38 received subsequent systemic therapy. First-line mCRPC treatments were docetaxel (n=12), Radium-223 (10), enzalutamide (6), platinum chemotherapy (3), and others (7) including immune checkpoint inhibitors (1) and Lutetium177-PSMA-617 (1) and other investigational agents (5). Outcomes are shown in the table. On univariate Cox analysis, clinical factors at time of mCRPC associated with worse OS were: LDH above upper limit of normal (HR 5.0, 95% CI 1.7-14.5), hemoglobin below lower limit of normal (5.2, 1.1-23.8), presence of ≥ 20 bone mets (3.7, 1.4-9.8), and increasing PSA (1.002, 1.001-1.003). Conclusions: PSA decline rates and survival are modest for patients who have progressed following upfront abiraterone or apalutamide plus ADT for mCSPC. Further follow-up is required to accurately determine outcomes with current mCRPC standard therapies following up-front ADT+ ARPI. Recently approved treatment options such as Lutetium177-PSMA-617 and PARP inhibitors for DNA damage repair deficient tumors may help to improve outcomes for these patients.[Table: see text]

Background Adding docetaxel to androgen deprivation therapy (ADT) for the treatment of metastatic castration-sensitive prostate cancer (mCSPC) has known efficacy, with an overall survival benefit in Phase III clinical trials. The effectiveness of docetaxel with ADT in the general patient population remains undefined. Patients and methods We conducted a population-based retrospective review using the British Columbia Provincial Pharmacy Database. To be included, patients had to have castration-sensitive prostate cancer not previously treated (except in the adjuvant setting) and have received at least one cycle of docetaxel, with complete records available for review. Safety and clinical effectiveness were evaluated. Results From April 2015 to February 2017, we identified 183 cases; 156 met inclusion criteria. Most patients had high-volume disease (80%). All 6 planned docetaxel cycles were delivered in 126 cases (81%). Dose reductions and delays were required in 39% and 16% of cases. Grade 3-4 adverse events were noted in 40%, with no treatment-related deaths. The rate of febrile neutropenia was 18% and was significantly associated with the presence of high-volume disease (P = 0.038). PSA ≤ 0.2 ng/L was achieved in 27% of patients after 6 months of ADT and maintained in 16% after 12 months. Patients with over 20 bone metastases had worse time to castration resistant prostate cancer (CRPC) and time to treatment for CRPC, and a trend toward worse overall survival. CRPC developed in 41% within 1 year, with a median time to CRPC of 14.4 months. Treatment for CRPC was given in 84 cases, with 90% receiving either abiraterone or enzalutamide in the first-line, with a PSA decline ≥50% occurring in 47%. Conclusions The effectiveness of docetaxel with ADT in a general population of patients with mCSPC was associated with poorer outcomes and high rates of toxicity compared to the published studies. Response rates to first-line treatment for mCRPC with abiraterone or enzalutamide appear similar to reported outcomes.

Background There is a lack of molecularly-informed biomarkers for patients with metastatic renal cell carcinoma (RCC). Plasma cell-free DNA (cfDNA) sequencing is a minimally-invasive alternative to tissue for profiling the genome in other cancers but relevance in metastatic RCC remains unclear. Materials and Methods Whole blood was collected from 55 patients with metastatic RCC. Plasma cfDNA and leukocyte DNA were subjected to targeted sequencing across 981 cancer genes. Matched tumor tissue from 14 patients was analyzed. Results Thirty-three percent of patients had evidence for RCC-derived circulating tumor DNA (ctDNA), significantly lower than patients with metastatic prostate or bladder cancer analyzed using the same approach. Among ctDNA-positive patients, ctDNA fraction averaged only 3.9% and showed no strong association with clinical variables. In these patients, the most commonly mutated genes were VHL, BAP1, and PBRM1, and matched tissue concordance was 77%. Evidence of somatic expansions unrelated to RCC, such as clonal hematopoiesis of indeterminate potential, were detected in 43% of patients. Pathogenic germline mutations in DNA repair genes were detected in 11% of patients. CtDNA-positive patients had shorter overall survival and progression-free survival on first-line therapy. Patients with evidence of clonal hematopoiesis of indeterminate potential had an intermediate prognosis compared with ctDNA-positive and -negative patients. Conclusions CfDNA sequencing enables straightforward characterization of the somatic RCC genome in a minority of patients with metastatic RCC. Owing to low ctDNA abundance, and the presence of non-RCC derived somatic clones in circulation, cfDNA sequencing may not be a simple pan-patient alternative to tissue biopsy in metastatic RCC.

BACKGROUND:Metastatic castration resistant prostate cancer (mCRPC) is incurable and progression after drugs that target the androgen receptor-signaling axis is inevitable. Thus, there is an urgent need to develop more effective treatments beyond hormonal manipulation. We sought to identify activated kinases in mCRPC as therapeutic targets for existing, approved agents, with the goal of identifying candidate drugs for rapid translation into proof of concept Phase II trials in mCRPC. METHODS:To identify evidence of activation of druggable kinases in these patients, we compared mRNA expression from metastatic biopsies of patients with mCRPC (n = 101) to mRNA expression in localized prostate from TCGA and used this analysis to infer differential kinase activity. In addition, we assessed the differential phosphorylation levels for key MAPK pathway kinases between mCRPC and localized prostate cancers. RESULTS:Transcriptomic profiling of 101 patients with mCRPC as compared to patients with localized prostate cancer identified evidence of hyperactive ERK1, and whole genome sequencing revealed frequent amplifications of members of the MAPK pathway in 32% of this cohort. Next, we confirmed elevated levels of phosphorylated ERK1/2 in castration resistant prostate cancer as compared to untreated primary prostate cancer. We observed that the presence of detectable phosphorylated ERK1/2 in the primary tumor is associated with biochemical failure after radical prostatectomy independent of clinicopathologic features. ERK1 is the immediate downstream target of MEK1/2, which is druggable with trametinib, an approved therapeutic for melanoma. Trametinib elicited a profound biochemical and clinical response in a patient who had failed multiple prior treatments for mCRPC. CONCLUSIONS:We conclude that pharmacologic targeting of the MEK/ERK pathway may be a viable treatment strategy for patients with refractory metastatic prostate cancer. An ongoing Phase II trial tests this hypothesis.

Small-cell prostate carcinoma (SCPC) is an aggressive malignancy that is managed similarly to small-cell lung cancer. SCPC can evolve from prostate adenocarcinoma in response to androgen deprivation therapy, but, in rare cases, is present at initial cancer diagnosis. The molecular aetiology of de novo SCPC is incompletely understood, owing to the scarcity of tumour tissue and the short life-expectancy of patients. Through a retrospective search of our regional oncology pharmacy database, we identified 18 patients diagnosed with de novo SCPC between 2004 and 2017. Ten patients had pure SCPC pathology, and the remainder had some admixed adenocarcinoma foci, but all were treated with first-line platinum-based chemotherapy. The median overall survival was 28 months. We performed targeted DNA sequencing, whole exome sequencing and mRNA profiling on formalin-fixed paraffin-embedded archival tumour tissue. We observed frequent biallelic deletion and/or mutation of the tumour suppressor genes TP53, RB1, and PTEN, similarly to what was found in treatment-related SCPC. Indeed, at the RNA level, pure de novo SCPC closely resembled treatment-related SCPC. However, five patients had biallelic loss of DNA repair genes, including BRCA1, BRCA2, ATM, and MSH2/6, potentially underlying the high genomic instability of this rare disease variant. Two patients with pure de novo SCPC harboured ETS gene rearrangements involving androgen-driven promoters, consistent with the evolution of de novo SCPC from an androgen-driven ancestor. Overall, our results reveal a highly aggressive molecular landscape that underlies this unusual pathological variant, and suggest opportunities for targeted therapy strategies in a disease with few treatment options. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Purpose: Primary resistance to abiraterone acetate (AA), a key medication for the treatment of metastatic castration-resistant prostate cancer, occurs in 20% to 40% of patients. We aim to identify predictive biomarkers for AA-treatment response and understand the mechanisms related to treatment resistance. Experimental Design: We used the Infinium Human Methylation 450K BeadChip to monitor modification profiles of cell-free circulating DNA (cfDNA) in 108 plasma samples collected from 33 AA-treated patients. Results: Thirty cytosines showed significant modification differences (FDR Q < 0.05) between AA-sensitive and AA-resistant patients during the treatment, of which 21 cytosines were differentially modified prior to treatment. In addition, AA-sensitive patients, but not AA-resistant patients, lost interindividual variation of cfDNA modification shortly after starting AA treatment, but such variation returned to initial levels in the later phases of treatment. Conclusions: Our findings provide a list of potential biomarkers for predicting AA-treatment response, highlight the prognostic value of using cytosine modification variance as biomarkers, and shed new insights into the mechanisms of prostate cancer relapse in AA-sensitive patients. Clin Cancer Res; 24(14); 3317–24. ©2018 AACR.

// Bernhard Josef Eigl 1 , Kim Chi 1 , Dongsheng Tu 2 , Sebastien J. Hotte 3 , Eric Winquist 4 , Christopher M. Booth 5 , Christina Canil 6 , Kylea Potvin 4 , Richard Gregg 2 , Scott North 7 , Muhammad Zulfiqar 1 , Susan Ellard 8 , Joseph Dean Ruether 9 , Lyly Le 10 , A. Saranya Kakumanu 11 , Mohammad Salim 12 , Alison L. Allan 4 , Harriet Feilotter 2 , Ashley Theis 2 and Lesley Seymour 2 1 BC Cancer Agency, Vancouver, BC, Canada 2 Canadian Cancer Trials Group, Kingston, ON, Canada 3 Juravinski Cancer Centre, Hamilton, ON, Canada 4 London Health Sciences Centre, London, ON, Canada 5 Cancer Centre of Southeastern Ontario, Kingston, ON, Canada 6 Ottawa Regional Cancer Center, Ottawa, ON, Canada 7 Cross Cancer Centre, Edmonton, AB, Canada 8 BC Cancer Agency, Kelowna, BC, Canada 9 Tom Baker Cancer Centre, Calgary, AB, Canada 10 BC Cancer Agency, Surrey, BC, Canada 11 Cancer Care Manitoba, Winnipeg, MB, Canada 12 Regina Cancer Centre, Regina, SK, Canada Correspondence to: Bernhard Josef Eigl, email: Bernie.eigl@bccancer.bc.ca Keywords: prostate cancer; oncolytic viruses; chemotherapy; clinical trial Received: October 12, 2017 Accepted: January 02, 2018 Published: January 17, 2018 ABSTRACT Background: Pelareorep is an oncolytic virus with activity in many cancers including prostate. It has in vitro synergism with microtubule-targeted agents. We undertook a clinical trial evaluating pelareorep in mCRPC patients receiving docetaxel. Patients and Methods: In this randomized, open-label phase II study, patients received docetaxel 75mg/m 2 on day 1 of a 21-day cycle and prednisone 5mg twice daily, in combination with pelareorep (arm A) or alone (arm B). The primary endpoint was 12 weeks lack of disease progression rate (LPD). Results: Eighty-five pts were randomized. Median age was 69, ECOG performance status was 0/1/2 in 31%/66%/3% of patients. Bone/regional lymph node/liver metastases were present in 98%/24%/6%. The median prognostic score was slightly higher in Arm A (144 vs. 129 p= 0.005). Adverse events were as expected but more prevalent in arm A. The 12-week LPD rate was 61% and 52.4% in arms A/B (p=0.51). Median survival was 19.1 on Arm A and 21.1 months on Arm B (HR 1.83; 95% CI 0.96 to 3.52; p=0.06). No survival benefit of pelareorep was found. Conclusion: Pelareorep with docetaxel was tolerable with comparable LPD in both arms but response and survival were inferior and so this combination does not merit further study.

Purpose Heat shock protein 27 (Hsp27) is implicated in prostate cancer progression. Apatorsen is a second generation phosphorothioate antisense inhibitor of Hsp27 expression. We evaluated apatorsen in patients with metastatic castration resistant prostate cancer (mCRPC). Experimental design Eligible patients were randomized 1:1 to receive intravenous apatorsen (3 loading doses of 600 mg within 5-9 days followed by weekly doses of 1000 mg) with oral prednisone 5 mg twice daily or prednisone alone. The primary endpoint was disease progression at 12 weeks. Crossover from prednisone alone was allowed after radiographic progression. Results 74 patients received apatorsen + prednisone (n = 36) or prednisone alone (n = 38). Twenty-five patients crossed-over to receive apatorsen + prednisone. Apatorsen treated patients received a median of 19 infusions. 50% of apatorsen + prednisone patients (95% CI: 32.9%, 67.1%) compared with 42% of prednisone patients (95% CI: 26.3%, 59.2%) did not have disease progression at week 12 (P = 0.33). A PSA decline of ≥50% was observed in 47% of apatorsen + prednisone and 24% of prednisone patients (P = 0.04), with a median duration of response of 24.1 weeks (95% CI: 12.0, 52) and 14.0 weeks (95% CI: 4.0, 44.4), respectively. A PSA decline of ≥50% was observed in 5 patients (20%) that received cross-over apatorsen. Infusion reactions were the most commonly reported adverse event occurring in 77% of apatorsen-treated patients. Conclusions Apatorsen + prednisone did not change the proportion of CRPC patients without disease progression at 12 weeks compared to prednisone but was associated with significant PSA declines. Further evaluation of Hsp27 targeting in prostate cancer is warranted.

Introduction: Recently, a prognostic index including six risk factors (RFs) (unfavourable Eastern Cooperative Oncology Group performance status [ECOG PS], presence of liver metastases, short response to luteinizing hormone-releasing hormone [LHRH] agonists/ antagonists, low albumin, increased alkaline phosphatase [ALP] and lactate dehydrogenase [LDH]) was developed from the COUAA- 301 trial in post-chemotherapy metastatic castration-resistant prostate cancer (mCRPC) patients treated with abiraterone acetate. Our primary objective was to evaluate this model in a cohort of chemotherapy-naive mCRPC patients receiving abiraterone.Methods: We identified 197 chemotherapy-naive patients who received abiraterone at six BC Cancer Agency centres and who had complete information on all six RFs. Study endpoints were prostate-specific antigen (PSA) response rate (RR), time to PSA progression, time on treatment, and overall survival (OS). PSA RR and survival outcomes were compared using Χ2 test and log-rank test. Multivariable Cox proportional hazard analysis was performed to identify RFs independently associated with OS.Results: Patients were classified into good (0‒1 RFs), intermediate (2‒3 RFs), and poor (4‒6 RFs) prognostic groups (33%, 52%, and 15%, respectively). For good-, intermediate-, and poor-risk patients, PSA RR (≥50% decline) was 60% vs. 42% vs. 40% (p=0.05); median time to PSA progression was 7.3 vs. 5.3 vs. 5.0 months (p=0.02); and median OS was 29.4 vs. 13.8 vs. 8.7 months (p

Improved imaging has consistently led to refinements in clinical care and outcomes. Prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography is no exception and has emerged as a critical tool for more accurate staging of prostate cancer. PSMA radioligand therapy has demonstrated promising efficacy in heavily pretreated men with metastatic castration-resistant prostate cancer.

Background: Apalutamide (APA) is an approved treatment in various countries of Latin America to treat patients with metastatic hormone-sensitive prostate cancer (mCSPC) patients based on the TITAN study interim analysis, which demonstrated an improved overall survival (HR 0.48; 95% CI 0.39-0.60) and radiographic progression-free survival (HR 0.67; 95% CI 0.51-0.89) for patients receiving APA + androgen deprivation therapy (ADT) compared to placebo (PBO) + ADT (KN Chi, et al. N Engl J Med 2019; 381:13-24). As there can be geographical differences in disease presentation and management, we undertook a post-hoc analysis of the Latin American (LATAM) patients enrolled to TITAN. Methods: mCSPC patients were randomly assigned 1:1 to receive APA (240 mg per day) plus ADT or PBO plus ADT. Patients previously treated for localized disease were eligible and treatment with prior docetaxel was permitted. Radiographic progression-free survival (rPFS) and overall survival (OS) were TITAN's dual primary endpoints. Results: In total, 177 LATAM patients from Argentina, Brazil and Mexico were recruited (16.8% of the study population). Of the 177 patients, 94 were assigned to the APA-ADT arm and 83 randomized to PBO-ADT arm. The LATAM APA and PBO patients were similar with a median age of 69, 64% of the patients had an ECOG Performance Status of 0, and the majority of patients had a high-volume disease, 57% , which was comparable to the TITAN intention to treat (ITT) population. Prior docetaxel was used in 4% of the LATAM population versus 10.7% in the TITAN ITT population. At the first interim analysis of OS with a median follow-up of 22.7 months, the 2 year OS rate was 84% in the APA group versus 79% in the PBO group (HR for death 0.77; 95% CI of 0.38-1.55; p=0.4567). Median rPFS was not reached in the APA group versus 22.0 months for PBO (HR for radiographic progression or death 0.44; 95% CI of 0.26-0.75; p=0.0019). The benefit of APA-ADT for the LATAM patients appeared consistent to the overall ITT population for the primary, secondary and exploratory efficacy endpoints. The frequency of grade 3 or 4 adverse events was 48.9% in the APA group and 42.2% in the placebo group; discontinuation due to adverse events were more frequent in the APA arm than in the placebo group (11.7% vs. 2.4%). Conclusion: This analysis of the LATAM patients with mCSPC enrolled in the TITAN study confirms the benefit of the addition of APA to ADT with a safety profile that was consistent with the results shown in the ITT population. Citation Format: Alvaro Juarez, Kim N. Chi, Andrea J. Pereira, Simon Chowdhury, Spyros Triantos, Sharon McCarthy, Amitabha Bhaumik, Suneel Mundle, Esteban Velasquez, Sara Rosas, Vanessa Fabricio, Neeraj Agarwal. Latin American patient subgroup analysis of the phase 3 TITAN study: Apalutamide plus ADT in metastatic Hormone-Sensitive Prostate Cancer (mHSPC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT190.

Background: TITAN, a phase 3 placebo (PBO)-controlled study in a broad population of pts with mCSPC (NCT02489318), demonstrated that the addition of APA to androgen deprivation therapy (ADT) significantly improved radiographic progression-free survival (rPFS) (median rPFS in the APA and PBO groups was not reached and was 22.1 months, respectively) and overall survival (OS) compared with PBO + ADT (Chi N Engl J Med 2019). This exploratory analysis investigated molecular signatures of pts with mCSPC who had long-term responses to APA. Methods: Pts (n = 222) in the biomarker cohort of TITAN were characterized as long-term responders (LTR) or early progressors (EP) by separating rPFS into quartiles. The last quartile with longest rPFS (APA, n = 28; PBO, n = 28) represented LTR. The first quartile, with shortest rPFS (APA, n = 17; PBO, n = 21) represented EP. Gene expression profiles of TITAN pts were generated from archival primary prostate tumors; data were summarized based on 110 predefined gene signatures. Mean signature scores between LTR and EP groups were compared within treatment groups using 2 sample t tests to evaluate whether effects were prognostic or specific to APA treatment. Signatures were also evaluated for association with outcome using Cox proportional hazard models in each treatment group. Results: At primary analysis, with median 22.7 months follow-up, median rPFS was, respectively, not reached and 32.9 months in APA and PBO pts in the LTR group, and 10.9 and 3.7 months in APA and PBO pts in the EP group. A higher level of expression (above median) of either polycomb repressor complex 2 activation or the Decipher signature was more frequently associated with EP in both groups. LTR in the APA treatment group, but not those in the PBO group, had lower expression of transcriptional signatures describing myeloid-derived suppressor cells (MDSCs) and cell cycle progression. These results suggest that pts with mCSPC who have relatively lower levels of MDSCs in the tumor, indicative of a less immune-suppressed tumor microenvironment, may have long-term benefit from treatment with APA. Conclusions: Consistent clinical benefit was observed with the addition of APA to ADT in both EP and LTR. Although the data require confirmation in larger studies, these molecular signatures may have utility in selecting pts with mCSPC who may derive the most benefit from APA and other androgen signaling inhibitors. Citation Format: Justin Lucas, Neeraj Agarwal, Felix Feng, Clemente Aguilar-Bonavides, Shibu Thomas, Michael Gormley, Suneel Mundle, Sabine Brookman-May, Sharon A. McCarthy, Anders Bjartell, Hirotsugu Uemura, Simon Chowdhury, Kim N. Chi. Molecular signatures associated with long-term response to apalutamide (APA) in patients (pts) with metastatic castration-sensitive prostate cancer (mCSPC) in TITAN [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 359.

Pelareorep, a serotype 3 reovirus, has demonstrated preclinical and early clinical activity in breast cancer and synergistic cytotoxic activity with microtubule targeting agents. This multicentre, randomized, phase II trial was undertaken to evaluate the efficacy and safety of adding pelareorep to paclitaxel for patients with metastatic breast cancer (mBC). Following a safety run-in of 7 patients, 74 women with previously treated mBC were randomized either to paclitaxel 80 mg/m2 intravenously on days 1, 8, and 15 every 4 weeks plus pelareorep 3 × 1010 TCID50 intravenously on days 1, 2, 8, 9, 15, and 16 every 4 weeks (Arm A) or to paclitaxel alone (Arm B). Primary endpoint was progression-free survival (PFS). Secondary endpoints were objective response rate, overall survival (OS), circulating tumour cell counts, safety, and exploratory correlative analyses. All comparisons used a two-sided test at an alpha level of 20%. Survival analyses were adjusted for prior paclitaxel. Final analysis was performed after a median follow-up of 29.5 months. Pelareorep was well tolerated. Patients in Arm A had more favourable baseline prognostic variables. Median adjusted PFS (Arm A vs B) was 3.78 mo vs 3.38 mo (HR 1.04, 80% CI 0.76–1.43, P = 0.87). There was no difference in response rate between arms (P = 0.87). Median OS (Arm A vs B) was 17.4 mo vs 10.4 mo (HR 0.65, 80% CI 0.46–0.91, P = 0.1). This first, phase II, randomized study of pelareorep and paclitaxel in previously treated mBC did not show a difference in PFS (the primary endpoint) or RR. However, there was a significantly longer OS for the combination. Further exploration of this regimen in mBC may be of interest.

Background The phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) signalling axis and androgen receptor (AR) pathways exhibit reciprocal feedback regulation in phosphatase and tensin homologue (PTEN)-deficient metastatic castration-resistant prostate cancer (CRPC) in preclinical models. This phase Ib study evaluated the pan-PI3K inhibitor buparlisib (BKM120) and the dual pan-PI3K/ mammalian target of rapamycin (mTOR) inhibitor dactolisib (BEZ235) in combination with abiraterone acetate (AA) in patients with CRPC. Materials and methods Patients with CRPC who had progressed on AA therapy received escalating doses of either buparlisib or dactolisib, along with fixed doses of AA (1000 mg once daily (qd)) and prednisone (5 mg twice daily (bid)). The primary objective was to define the maximum tolerated dose (MTD) and/or the recommended dose for expansion (RDE) of either buparlisib or dactolisib in combination with AA. Secondary objectives included safety, antitumour activity (Prostate Cancer Working Group 2 (PCWG2) criteria; 30% of prostate-specific antigen (PSA) decline at ≥week 12) and pharmacokinetic (PK) profile. Results In buparlisib + AA arm, 25 patients received buparlisib + AA (median age, 67 years; Eastern Cooperative Oncology Group performance status (ECOG PS) of 0/1/2 for 7/17/1 patients, respectively). At 100 mg qd; two patients experienced dose-limiting toxicities (DLTs) (grade 3 hyperglycaemia; grade 2 asthenia), and this was the maximum buparlisib dose explored. Buparlisib + AA showed a 26% lower median area under the curve from time zero to 24°h (AUC0–24) and 48% lower median maximum serum concentration (Cmax) versus the single-agent buparlisib assessed in first-in-human study. No objective response and few PSA decreases were reported. In dactolisib + AA arm, 18 patients (median age, 71 years; ECOG PS of 0/1 for 6/12 patients, respectively) received dactolisib + AA at the first dose level (200 mg bid). Five patients had 9 DLTs (grades 2&3 stomatitis; grade 3 hyperglycaemia; grades 2& 3 diarrhoea; grades 1& 2 pyrexia, grade 2 vomiting, and grade 2 chills). Conclusions Based on the assessment of available pharmacokinetics, safety, and efficacy data, no further study is planned for either buparlisib or dactolisib in combination with AA in CRPC.

Summary Background Clusterin is a chaperone protein associated with treatment resistance and upregulated by apoptotic stressors such as chemotherapy. Custirsen is a second-generation antisense oligonucleotide that inhibits clusterin production. The aim of the SYNERGY trial was to investigate the effect of custirsen in combination with docetaxel and prednisone on overall survival in patients with metastatic castration-resistant prostate cancer. Methods SYNERGY was a phase 3, multicentre, open-label, randomised trial set at 134 study centres in 12 countries. Patients were eligible for participation if they had: metastatic castration-resistant prostate cancer and had received no previous chemotherapy; prostate-specific antigen greater than 5 ng/mL; and a Karnofsky performance score of 70% or higher. Patients were randomly assigned 1:1 centrally to either the docetaxel, prednisone, and custirsen combination or docetaxel and prednisone alone. Patients were not masked to treatment allocation. Randomisation was stratified by opioid use for cancer-related pain and radiographic evidence of progression. All patients received docetaxel 75 mg/m 2 intravenously with 5 mg of prednisone orally twice daily. Patients assigned docetaxel, prednisone, and custirsen received weekly doses of custirsen 640 mg intravenously after three loading doses of 640 mg. The primary endpoint was overall survival analysed in the intention-to-treat population. Patients who received at least one study dose were included in the safety analysis set. This trial is registered with ClinicalTrials.gov, number NCT01188187. The trial is completed and final analyses are reported here. Findings Between Dec 10, 2010, and Nov 7, 2012, 1022 patients were enrolled to the trial, of whom 510 were assigned docetaxel, prednisone, and custirsen and 512 were allocated docetaxel and prednisone. No difference in overall survival was recorded between the two groups (median survival 23·4 months [95% CI 20·9–24·8] with docetaxel, prednisone, and custirsen vs 22·0 months [19·5–24·0] with docetaxel and prednisone; hazard ratio [HR] 0·93, 95% CI 0·79–1·10; p=0·415). The most common adverse events of grade 3 or worse in the docetaxel, prednisone and custirsen group (n=501) compared with the docetaxel and prednisone alone group (n=499) were neutropenia (grade 3, 63 [13%] vs 28 [6%]; grade 4, 98 [20%] vs 77 [15%]), febrile neutropenia (grade 3, 52 [10%] vs 31 [6%]; grade 4, four [1%] vs two [ vs 41 [8%]; grade 4, three [1%] vs one [ Interpretation Addition of custirsen to first-line docetaxel and prednisone was reasonably well tolerated, but overall survival was not significantly longer for patients with metastatic castration-resistant prostate cancer treated with this combination, compared with patients treated with docetaxel and prednisone alone. Funding OncoGenex Technologies.

Castration-resistant prostate cancer (CRPC) is defined by disease progression despite castrate levels of testosterone and may present as either a continuous rise in serum prostate-specific antigen (PSA) levels, the progression of pre-existing disease, and/or the appearance of new metastases. Advanced prostate cancer has been known under a few names over the years, including hormone-resistant prostate cancer (HRPC) and androgen-insensitive prostate cancer (AIPC). Most recently, the terms castration-resistant prostate cancer or castration-recurrent prostate cancer were introduced with the realization that extra-testicular androgen production plays a significant role in the resistance of prostate cancer cells to medical or surgical castration therapy.1 In their second publication, the Prostate Cancer Working Group defined CRPC as a continuum on the basis of whether metastases are detectable (clinically or by imaging) and whether the serum testosterone is in the castrate range by surgical orchidectomy or medical therapy.2 This definition creates a clinical-states model, where patients can be classified. The rising PSA states (castrate and non-castrate) signify that no detectable (measurable or non-measurable) disease has ever been found. The clinical metastases states (castrate and non-castrate) signify that disease was detectable at some point in the past, regardless of whether it is detectable now.3 Prognosis is associated with several factors that go beyond PSA levels. These include performance status, presence of visceral metastases, presence of bone pain, extent of disease on bone scan, and serum lactate dehydrogenase and alkaline phosphatase levels. Bone metastases will occur in 90% of men with CRPC and can produce significant morbidity, including pain, pathological fractures, spinal cord compression, and bone marrow failure. Paraneoplastic effects, including anemia, weight loss, fatigue, hypercoagulability, and increased susceptibility to infection, are also common. CRPC includes patients without metastases or symptoms with rising PSA levels despite androgen-deprivation therapy (ADT) to patients with metastases and significant debilitation due to cancer symptoms.

[Image: see text] Inhibition of the androgen receptor (AR) is the mainstay treatment for advanced prostate cancer. Ralaniten (formally EPI-002) prevents AR transcriptional activity by binding to its N-terminal domain (NTD) which is essential for transcriptional activity. Ralaniten acetate (EPI-506) the triacetate pro-drug of ralaniten, remains the only AR-NTD inhibitor to have entered clinical trials (NCT02606123). While well tolerated, the trial was ultimately terminated due to poor pharmacokinetic properties and resulting pill burden. Here we discovered that ralaniten was glucuronidated which resulted in decreased potency. Long-term treatment of prostate cancer cells with ralaniten results in upregulation of UGT2B enzymes with concomitant loss of potency. This has proven to be a useful model with which to facilitate the development of more potent second-generation AR-NTD inhibitors. Glucuronidated metabolites of ralaniten were also detected in the serum of patients in Phase 1 clinical trials. Therefore, we tested an analogue of ralaniten (EPI-045) which was resistant to glucuronidation and demonstrated superiority to ralaniten in our resistant model. These data support that analogues of ralaniten designed to mitigate glucuronidation may optimize clinical responses to AR-NTD inhibitors.

PURPOSE Increases in androgen receptor ( AR) copy number (CN) can be detected in plasma DNA when patients develop metastatic castration-resistant prostate cancer. We aim to evaluate the association between AR CN as a continuous variable and clinical outcome. PATIENTS AND METHODS PCR2023 was an international, multi-institution, open-label, phase II study of abiraterone acetate plus prednisolone (AAP) or abiraterone acetate plus dexamethasone that included plasma AR assessment as a predefined exploratory secondary end point. Plasma AR CN data (ClinicalTrials.gov identifier: NCT01867710 ) from this study (n = 133) were pooled with data from the following three other cohorts: cohort A, which was treated with either AAP or enzalutamide (n = 73); the PREMIERE trial (ClinicalTrials.gov identifier: NCT02288936 ) of biomarkers for enzalutamide (n = 94); and a phase II trial from British Columbia (ClinicalTrials.gov identifier: NCT02125357 ) that randomly assigned men to either AAP or enzalutamide (n = 201). The primary outcome measures for the biomarker analysis were overall survival and progression-free survival. RESULTS Using multivariable fractional polynomials analysis using Cox regression models, a nonlinear relationship between plasma AR CN and outcome was identified for overall survival, where initially for small incremental gains in CN there was a large added hazard ratio that plateaued at higher CN. The CN cut point associated with the highest local hazard ratio was 1.92. A similar nonlinear association was observed with progression-free survival. In an exploratory analysis of PCR2023, the time from start of long-term androgen-deprivation therapy to start of AAP or abiraterone acetate plus dexamethasone was significantly shorter in patients with plasma AR CN of 1.92 or greater than patients with plasma AR CN of less than 1.92 (43 v 130 weeks, respectively; P = .005). This was confirmed in cohort A ( P = .003), the PREMIERE cohort ( P = .03), and the British Colombia cohort ( P = .003). CONCLUSION Patients with metastatic castration-resistant prostate cancer can be dichotomized by a plasma AR CN cut point of 1.92. Plasma AR CN value of 1.92 or greater identifies aggressive disease that is poorly responsive to AR targeting and is associated with a prior short response to primary androgen-deprivation therapy.

Introduction: The management of advanced prostate cancer (PCa) continues to evolve with the emergence of new diagnostic and therapeutic strategies. As a result, there are multiple areas in this landscape with a lack of high-level evidence to guide practice. Consensus initiatives are an approach to establishing practice guidance in areas where evidence is unclear. We conducted a Canadian-based consensus forum to address key controversial areas in the management of advanced PCa. Methods: As part of a modified Delphi process, a core scientific group of PCa physicians (n=8) identified controversial areas for discussion and developed an initial set of questions, which were then reviewed and finalized with a larger group of 29 multidisciplinary PCa specialists. The main areas of focus were non-metastatic castration-resistant prostate cancer (nmCRPC), metastatic castration-sensitive prostate cancer (mCSPC), metastatic castration-resistant prostate cancer (mCRPC), oligometastatic prostate cancer, genetic testing in prostate cancer, and imaging in advanced prostate cancer. The predetermined threshold for consensus was set at 74% (agreement from 20 of 27 participating physicians). Results: Consensus participants included uro-oncologists (n=13), medical oncologists (n=10), and radiation oncologists (n=4). Of the 64 questions, consensus was reached in 30 questions (n=5 unanimously). Consensus was more common for questions related to biochemical recurrence, sequencing of therapies, and mCRPC. Conclusions: A Canadian consensus forum in PCa identified areas of agreement in nearly 50% of questions discussed. Areas of variability may represent opportunities for further research, education, and sharing of best practices. These findings reinforce the value of multidisciplinary consensus initiatives to optimize patient care.

Summary Background In the phase 3 TITAN study, the addition of apalutamide to androgen deprivation therapy (ADT) significantly improved the primary endpoints of overall survival and radiographic progression-free survival in patients with metastatic castration-sensitive prostate cancer. We aimed to assess health-related quality of life (HRQOL) in TITAN, including pain and fatigue. Methods In this randomised, placebo-controlled, double-blind, phase 3 study, patients with metastatic castration-sensitive prostate cancer (defined as not receiving ADT at the time of metastatic disease progression) aged 18 years and older, receiving continuous ADT (selected at the investigator's discretion), and with an Eastern Cooperative Oncology Group performance status score of 0 or 1 were randomly assigned (1:1), using an interactive web response system, to receive oral apalutamide (four 60 mg tablets, once daily) or matching placebo. Previous localised disease treatment or previous docetaxel for metastatic castration-sensitive prostate cancer were allowed. Randomisation was stratified by Gleason score at diagnosis, region, and previous docetaxel treatment. Randomisation was done using randomly permuted blocks (block size of four). Investigators, research staff, sponsor study team, and patients were masked to the identities of test and control treatments. Patient-reported outcomes were prespecified exploratory endpoints and were the Brief Pain Inventory-Short Form (BPI-SF), Brief Fatigue Inventory (BFI), Functional Assessment of Cancer Therapy-Prostate (FACT-P), and EuroQoL 5D questionnaire 5 level (EQ-5D-5L). BPI and BFI were completed for 7 consecutive days (days −6 to 1 inclusive of each cycle visit), then at months 4, 8, and 12 in follow-up. FACT-P and EQ-5D-5L were completed during cycles 1–7, then every other cycle until the end of treatment, and at months 4, 8, and 12 in follow-up. Analyses were based on the intention-to-treat population. Missing patient-reported outcome assessments were calculated as the expected number of assessments for a visit minus the actual number of assessments received for that visit. For time-to-event endpoints, when median values could not be calculated because less than 50% of patients had degradation, 25th percentiles were compared. This study is registered with ClinicalTrials.gov, number NCT02489318, and is ongoing. Findings Between Dec 9, 2015, and July 25, 2017, 1052 eligible patients were enrolled randomly assigned to apalutamide (n=525) or placebo (n=527). Data cutoff for this analysis of patient-reported outcomes was Nov 23, 2018. Median follow-up for time to pain-related endpoints ranged from 19·4 to 22·1 months. Patients were mostly asymptomatic at baseline: on the BPI-SF pain severity scale of 0–10, median pain scores (indicating worst pain in the past 24 h) were 1·14 (IQR 0–3·17) in the apalutamide group and 1·00 (0–2·86) in the placebo group, and median worst fatigue scores on the BFI were 1·29 (IQR 0–3·29) in the apalutamide group and 1·43 (0·14–3·14) in the placebo group. Patient experience of pain and fatigue (intensity and interference) did not differ between the groups for the duration of treatment. Median time to worst pain intensity progression was 19·09 months (95% CI 11·04–not reached) in the apalutamide group versus 11·99 months (8·28–18·46) in the placebo group (HR 0·89 [95% CI 0·75–1·06]; p=0·20). Median time to pain interference progression was not reached in either group (95% CI 28·58–not reached in the apalutamide group; not reached–not reached in the placebo group). 25th percentiles for time to pain interference progression were 9·17 months (5·55–11·96) in the apalutamide group and 6·24 months (4·63–7·43) in the placebo group (HR 0·90 [95% CI 0·73–1·10]; p=0·29). FACT-P total scores and EQ-5D-5L data showed preservation of HRQOL in both groups. The median time to deterioration as determined by FACT-P total score was 8·87 months (95% CI 4·70–11·10) in the apalutamide group and 9·23 months (7·39–12·91) in the placebo group (HR 1·02 [95% CI 0·85–1·22]; p=0·85). Interpretation Apalutamide with ADT is a well-tolerated and effective option for men with metastatic castration-sensitive prostate cancer. The combination significantly improves survival outcomes compared with ADT alone while maintaining HRQOL despite additive androgen blockade. Funding Janssen Research & Development.

Enzalutamide, an androgen-receptor inhibitor, has been associated with improved overall survival in men with castration-resistant prostate cancer. It is not known whether adding enzalutamide to testosterone suppression, with or without early docetaxel, will improve survival in men with metastatic, hormone-sensitive prostate cancer.In this open-label, randomized, phase 3 trial, we assigned patients to receive testosterone suppression plus either open-label enzalutamide or a standard nonsteroidal antiandrogen therapy (standard-care group). The primary end point was overall survival. Secondary end points included progression-free survival as determined by the prostate-specific antigen (PSA) level, clinical progression-free survival, and adverse events.A total of 1125 men underwent randomization; the median follow-up was 34 months. There were 102 deaths in the enzalutamide group and 143 deaths in the standard-care group (hazard ratio, 0.67; 95% confidence interval [CI], 0.52 to 0.86; P = 0.002). Kaplan-Meier estimates of overall survival at 3 years were 80% (based on 94 events) in the enzalutamide group and 72% (based on 130 events) in the standard-care group. Better results with enzalutamide were also seen in PSA progression-free survival (174 and 333 events, respectively; hazard ratio, 0.39; P0.001) and in clinical progression-free survival (167 and 320 events, respectively; hazard ratio, 0.40; P0.001). Treatment discontinuation due to adverse events was more frequent in the enzalutamide group than in the standard-care group (33 events and 14 events, respectively). Fatigue was more common in the enzalutamide group; seizures occurred in 7 patients in the enzalutamide group (1%) and in no patients in the standard-care group.Enzalutamide was associated with significantly longer progression-free and overall survival than standard care in men with metastatic, hormone-sensitive prostate cancer receiving testosterone suppression. The enzalutamide group had a higher incidence of seizures and other toxic effects, especially among those treated with early docetaxel. (Funded by Astellas Scientific and Medical Affairs and others; ENZAMET (ANZUP 1304) ANZCTR number, ACTRN12614000110684; ClinicalTrials.gov number, NCT02446405; and EU Clinical Trials Register number, 2014-003190-42.).

In the interim analyses of the LATITUDE study, the addition of abiraterone acetate plus prednisone to androgen deprivation therapy (ADT) led to a significant improvement in overall survival and radiographic progression-free survival compared with placebos plus ADT in men with newly diagnosed high-risk metastatic castration-sensitive prostate cancer (mCSPC). Here, we present long-term survival outcomes and safety of abiraterone acetate plus prednisone and ADT from the final analysis of the LATITUDE study.This is a multicentre, randomised, double-blind, phase 3 trial done at 235 sites in 34 countries. Eligible patients (men aged ≥18 years) had newly diagnosed, histologically or cytologically confirmed prostate cancer with metastases, Eastern Cooperative Oncology Group (ECOG) performance status of 0-2, and at least two of the three high-risk prognostic factors (Gleason score of ≥8, presence of three or more lesions on bone scan, or presence of measurable visceral metastasis except lymph node metastasis). Patients were randomly assigned (1:1) to receive abiraterone acetate (1000 mg) once daily orally plus prednisone (5 mg) once daily orally and ADT (abiraterone acetate plus prednisone group) or matching placebos plus ADT (placebo group); each treatment cycle was 28 days. Randomisation was done by a centralised interactive web response system in a country-by-country scheme using permuted block randomisation, stratified by presence of visceral disease and ECOG performance status. The coprimary endpoint of overall survival was assessed in the intention-to-treat population. This study is registered at ClinicalTrials.gov, number NCT01715285 and is complete.Between Feb 12, 2013, and Dec 11, 2014, 1209 patients were screened, of whom ten were ineligible because of study site violations. 1199 patients were randomly assigned to either the abiraterone acetate plus prednisone group (n=597) or placebo group (n=602). After the results of the first interim analysis (cutoff date Oct 31, 2016), the study was unmasked to patients and investigators, and patients in the placebo group were allowed to cross over to receive abiraterone acetate and prednisone plus ADT treatment as per a protocol amendment (Feb 15, 2017) in an open-label extension phase of the study (up to 18 months from the protocol amendment). This final analysis (data cutoff Aug 15, 2018) was done after a median follow-up of 51·8 months (IQR 47·2-57·0) and 618 deaths (275 [46%] of 597 in the abiraterone acetate plus prednisone group and 343 [57%] of 602 in the placebo group). Overall survival was significantly longer in the abiraterone acetate plus prednisone group (median 53·3 months [95% CI 48·2-not reached]) than in the placebo group (36·5 months [33·5-40·0]), with a hazard ratio of 0·66 (95% CI 0·56-0·78; p0·0001). The most common grade 3-4 adverse events were hypertension (125 [21%] in the abiraterone acetate plus prednisone group vs 60 [10%] in the placebo group vs three [4%] in the 72 patients who crossed over from placebo to abiraterone acetate plus prednisone) and hypokalaemia (70 [12%] vs ten [2%] vs two [3%]). Serious adverse events of any grade occurred in 192 (32%) of 597 patients in the abiraterone acetate plus prednisone group, 151 (25%) of 602 in the placebo group, and four (6%) of 72 in the crossover group. The most common treatment-related serious adverse event was hypokalaemia (four [1%] patients in the abiraterone acetate plus prednisone group and none in the other groups). Treatment-related deaths occurred in three (1%) patients each in the abiraterone acetate plus prednisone group (gastric ulcer perforation, sudden death, and cerebrovascular accident) and the placebo group (sudden death, cerebrovascular accident, and pneumonia), with none in the crossover group.The combination of abiraterone acetate plus prednisone with ADT was associated with significantly longer overall survival than placebos plus ADT in men with newly diagnosed high-risk mCSPC and had a manageable safety profile. These findings support the use of abiraterone acetate plus prednisone as a standard of care in patients with high-risk mCSPC.Janssen ResearchDevelopment.

Purpose: DNA mismatch repair defects (MMRd) and tumor hypermutation are rare and under-characterized in metastatic prostate cancer (mPC). Furthermore, because hypermutated MMRd prostate cancers can respond to immune checkpoint inhibitors, there is an urgent need for practical detection tools. Experimental Design: We analyzed plasma cell-free DNA-targeted sequencing data from 433 patients with mPC with circulating tumor DNA (ctDNA) purity ≥2%. Samples with somatic hypermutation were subjected to 185 × whole-exome sequencing and capture of mismatch repair gene introns. Archival tissue was analyzed with targeted sequencing and IHC. Results: Sixteen patients (3.7%) had somatic hypermutation with MMRd etiology, evidenced by deleterious alterations in MSH2, MSH6, or MLH1, microsatellite instability, and characteristic trinucleotide signatures. ctDNA was concordant with mismatch repair protein IHC and DNA sequencing of tumor tissue. Tumor suppressors such as PTEN, RB1, and TP53 were inactivated by mutation rather than copy-number loss. Hotspot mutations in oncogenes such as AKT1, PIK3CA, and CTNNB1 were common, and the androgen receptor (AR)-ligand binding domain was mutated in 9 of 16 patients. We observed high intrapatient clonal diversity, evidenced by subclonal driver mutations and shifts in mutation allele frequency over time. Patients with hypermutation and MMRd etiology in ctDNA had a poor response to AR inhibition and inferior survival compared with a control cohort. Conclusions: Hypermutated MMRd mPC is associated with oncogene activation and subclonal diversity, which may contribute to a clinically aggressive disposition in selected patients. In patients with detectable ctDNA, cell-free DNA sequencing is a practical tool to prioritize this subtype for immunotherapy. See related commentary by Schweizer and Yu, p. 981

BackgroundCyclin-dependent kinase 12 (CDK12) loss occurs in 3-7% of metastatic prostate cancer patients and is characterized by a genomic instability signature, but the clinical implications of CDK12 loss are not well established.ObjectiveTo determine the clinical course of patients with CDK12 mutant advanced prostate cancer compared with other genomic subtypes.Design, setting, and participantsA retrospective analysis of data from three academic medical centers, including 317 patients with advanced prostate cancer and prior next-generation sequencing from tumor tissue (n = 172) or circulating tumor DNA (n = 145), was performed. Forty-six patients had CDK12 mutations; 34 had biallelic CDK12 loss (79%).Outcome measurements and statistical analysisPatients were stratified by mutation status (CDK12, homologous recombination deficiency [HRD; BRCA1/2 and ATM], TP53, and other cohort). The Kaplan-Meier method was used to evaluate time to event outcomes: time to development of metastatic disease, time to development of castration resistance, and time to prostate-specific antigen (PSA) progression after first-line androgen receptor pathway inhibitor (ARPI) therapy in a patient subset.Results and limitationsThe median follow-up was 66.6 mo. Patients with CDK12 mutant prostate cancer exhibited shorter time to metastasis (median = 34.9 mo, p = 0.004) and development of castration-resistant disease (median = 32.7 mo, p

Patients with urothelial carcinoma (uc) have a poor prognosis after progression on first-line cisplatin-based chemotherapy. Real-world data about second-line cytotoxic therapies are limited. We sought to characterize patients with metastatic uc who receive more than 1 line of systemic therapy and to describe their treatments and outcomes. Using BC Cancer&rsquo, s pharmacy database, we identified patients with documented metastatic uc who had received more than 1 line of systemic therapy. A retrospective chart review was then performed to collect clinicopathologic, treatment, and outcomes data. The 51 included patients, of whom 42 were men (82%), had a median age of 65 years (range: 38&ndash, 81 years). Sites of metastasis included lymph nodes (n = 30), bone (n = 7), lung (n = 9), and peritoneum (n = 2). Second-line chemotherapy regimens included gemcitabine&ndash, cisplatin [gc (n = 14)], paclitaxel (n = 24), docetaxel (n = 12), and an oral topoisomerase i inhibitor (n = 1). Median time to progression (ttp) and overall survival (os) were 2.0 and 6.83 months respectively. Compared with patients who received a different agent, patients who had experienced a prior response to first-line gc and who were re-challenged with second-line gc had a better median ttp (11.0 months vs. 6.0 months, p = 0.02) and survived longer (4.0 months vs. 1.0 months, p = 0.02). No differences in os between non-gc regimens were evident. In patients with metastatic uc, overall outcomes remain poor, but compared with patients receiving other agents, the subgroup of patients re-challenged with second-line gc demonstrated improved ttp. Conventional chemotherapy regimens provide only modest benefits in the second-line setting and have largely been replaced with immunotherapy.

The development of castration-resistant prostate cancer (CRPC) heralds significant morbidity and an incurable condition. Since 2004, there are now six proven life-prolonging therapies available, including androgen receptor pathway inhibitor (ARPI) , chemotherapeutic agents, radiopharmaceutical, and immunotherapy for the first-line management of metastatic CRPC. Recent advances have seen enzalutamide and apalutamide approved by US FDA for the treatment of nonmetastatic CRPC, with darolutamide the latest ARPI demonstrating efficacy in nonmetastatic CRPC. ARPI is the treatment of choice in the first-line setting for most CRPC patients, and this approach has been endorsed by clinical guidelines and expert consensus, although treatment must be individualized. Advances in the molecular profiling of CRPC promise to select suitable patients for trials involving targeted therapy and identify biomarkers to guide treatment selection. This review contains 2 figures, 1 table, and 54 references. Keywords: abiraterone acetate, apalutamide, cabazitaxel, castration-resistant prostate cancer, docetaxel, enzalutamide, first-line treatment, radium-223, sipuleucel-T

Introduction: Clinical trials have shown that radium-223 (Ra223) can prolong survival and improve quality of life in patients with metastatic castration-resistant prostate cancer (mCRPC). The objectives of this study were to evaluate pain responses with Ra223 at a population-based level and to determine if there is an association between pain response and alkaline phosphatase (ALP) response. Methods: All patients from the Vancouver and Kelowna Cancer Centers (CC) in British Columbia who were treated with Ra223 between June 2015 and December 2016 were identified. Patients completed the Brief Pain Inventory (BPI) just prior to each Ra223 injection. Pain response was defined as a two or more point improvement in worst pain relative to baseline, without an increase in pain medication level. ALP was determined at each visit, with a response threshold defined as a 30% decrease from baseline, consistent with the definition of response used in the ALSYMPCA trial. Results: A total of 65 patients in Vancouver and Kelowna CC received Ra223 during the study period and 56 patients had at least one BPI record, of which 44 (79%) patients were assessable for change in worst pain. Of the assessable patients, 23 (52%, 95% confidence interval [CI] 38–67) had a pain response, although the use of concurrent external beam radiotherapy was a confounder in four cases. Of the 44 patients assessable for change in worst pain, 59% had ALP responses greater than 30%. An ALP response was seen in 56% of pain-responders vs. 43% of non-pain-responders. There was no association between pain response and ALP response (Phi =-0.05; p=0.77). Conclusions: Ra223 administration was associated with a meaningful pain response rate in this cohort. There was no correlation between pain response and ALP response.