Overall survival with [177Lu]Lu-PSMA-617 versus cabazitaxel in metastatic castration-resistant prostate cancer (TheraP): secondary outcomes of a randomised, open-label, phase 2 trial.

BACKGROUND: The TheraP study reported improved prostate-specific antigen responses with lutetium-177 [177Lu]Lu-PSMA-617 versus cabazitaxel in men with metastatic castration-resistant prostate cancer progressing after docetaxel. In this Article, we report the secondary outcome of overall survival with mature follow-up, and an updated imaging biomarker analysis. We also report the outcomes of participants excluded due to ineligibility on gallium-68 [68Ga]Ga-PSMA-11 and 2-[18F]fluoro-2-deoxy-D-glucose (2-[18F]FDG) PET-CT. METHODS: TheraP was an open-label, randomised phase 2 trial at 11 centres in Australia. Eligible participants had metastatic castration-resistant prostate cancer progressing after docetaxel, and PET imaging with [68Ga]Ga-PSMA-11 and 2-[18F]FDG that showed prostate-specific membrane antigen (PSMA)-positive disease and no sites of metastatic disease with discordant 2-[18F]FDG-positive and PSMA-negative findings. Participants were randomly assigned (1:1) to treatment with [177Lu]Lu-PSMA-617 (every 6 weeks for a maximum of six cycles; starting at 8·5 GBq, decreasing by 0.5 GBq to 6·0 GBq for the sixth cycle) versus cabazitaxel (20 mg/m2 every 3 weeks, maximum of ten cycles). Overall survival was analysed by intention-to-treat and summarised as restricted mean survival time (RMST) to account for non-proportional hazards, with a 36-month restriction time corresponding to median follow-up. This trial is registered with ClinicalTrials.gov, NCT03392428, and is complete. FINDINGS: 291 men were registered from Feb 6, 2018, to Sept 3, 2019; after study imaging, 200 were eligible and randomly assigned to treatment with [177Lu]Lu-PSMA-617 (n=99) or cabazitaxel (n=101). After completing study treatment, 20 (20%) participants assigned to cabazitaxel and 32 (32%) assigned to [177Lu]Lu-PSMA-617 were subsequently treated with the alternative regimen. After a median follow-up of 35·7 months (IQR 31·1 to 39·2), 77 (78%) participants had died in the [177Lu]Lu-PSMA-617 group and 70 (69%) participants had died in the cabazitaxel group. Overall survival was similar among those assigned to [177Lu]Lu-PSMA-617 versus those assigned to cabazitaxel (RMST 19·1 months [95% CI 16·9 to 21·4] vs 19·6 months [17·4 to 21·8]; difference -0·5 months [95% CI -3·7 to 2·7]; p=0·77). No additional safety signals were identified with the longer follow-up in this analysis. 80 (27%) of 291 men who were registered after initial eligibility screening were excluded after [68Ga]Ga-PSMA-11 and 2-[18F]FDG PET. In the 61 of these men with follow-up available, RMST was 11·0 months (95% CI 9·0 to 13·1). INTERPRETATION: These results support the use of [177Lu]Lu-PSMA-617 as an alternative to cabazitaxel for PSMA-positive metastatic castration-resistant prostate cancer progressing after docetaxel. We did not find evidence that overall survival differed between the randomised groups. Median overall survival was shorter for men who were excluded because of low PSMA expression or 2-[18F]FDG-discordant disease. FUNDING: Australian and New Zealand Urogenital and Prostate Cancer Trials Group, Prostate Cancer Foundation of Australia, Endocyte (a Novartis company), Australian Nuclear Science and Technology Organization, Movember, It's a Bloke Thing, CAN4CANCER, and The Distinguished Gentleman's Ride.

Talazoparib plus enzalutamide in men with first-line metastatic castration-resistant prostate cancer (TALAPRO-2): a randomised, placebo-controlled, phase 3 trial.

BACKGROUND: Co-inhibition of poly(ADP-ribose) polymerase (PARP) and androgen receptor activity might result in antitumour efficacy irrespective of alterations in DNA damage repair genes involved in homologous recombination repair (HRR). We aimed to compare the efficacy and safety of talazoparib (a PARP inhibitor) plus enzalutamide (an androgen receptor blocker) versus enzalutamide alone in patients with metastatic castration-resistant prostate cancer (mCRPC). METHODS: TALAPRO-2 is a randomised, double-blind, phase 3 trial of talazoparib plus enzalutamide versus placebo plus enzalutamide as first-line therapy in men (age ≥18 years [≥20 years in Japan]) with asymptomatic or mildly symptomatic mCRPC receiving ongoing androgen deprivation therapy. Patients were enrolled from 223 hospitals, cancer centres, and medical centres in 26 countries in North America, Europe, Israel, South America, South Africa, and the Asia-Pacific region. Patients were prospectively assessed for HRR gene alterations in tumour tissue and randomly assigned (1:1) to talazoparib 0·5 mg or placebo, plus enzalutamide 160 mg, administered orally once daily. Randomisation was stratified by HRR gene alteration status (deficient vs non-deficient or unknown) and previous treatment with life-prolonging therapy (docetaxel or abiraterone, or both: yes vs no) in the castration-sensitive setting. The sponsor, patients, and investigators were masked to talazoparib or placebo, while enzalutamide was open-label. The primary endpoint was radiographic progression-free survival (rPFS) by blinded independent central review, evaluated in the intention-to-treat population. Safety was evaluated in all patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov (NCT03395197) and is ongoing. FINDINGS: Between Jan 7, 2019, and Sept 17, 2020, 805 patients were enrolled and randomly assigned (402 to the talazoparib group and 403 to the placebo group). Median follow-up for rPFS was 24·9 months (IQR 21·9-30·2) for the talazoparib group and 24·6 months (14·4-30·2) for the placebo group. At the planned primary analysis, median rPFS was not reached (95% CI 27·5 months-not reached) for talazoparib plus enzalutamide and 21·9 months (16·6-25·1) for placebo plus enzalutamide (hazard ratio 0·63; 95% CI 0·51-0·78; p<0·0001). In the talazoparib group, the most common treatment-emergent adverse events were anaemia, neutropenia, and fatigue; the most common grade 3-4 event was anaemia (185 [46%] of 398 patients), which improved after dose reduction, and only 33 (8%) of 398 patients discontinued talazoparib due to anaemia. Treatment-related deaths occurred in no patients in the talazoparib group and two patients (<1%) in the placebo group. INTERPRETATION: Talazoparib plus enzalutamide resulted in clinically meaningful and statistically significant improvement in rPFS versus standard of care enzalutamide as first-line treatment for patients with mCRPC. Final overall survival data and additional long-term safety follow-up will further clarify the clinical benefit of the treatment combination in patients with and without tumour HRR gene alterations. FUNDING: Pfizer.

TALAPRO-3 clinical trial protocol: phase III study of talazoparib plus enzalutamide in metastatic castration-sensitive prostate cancer.

Poly(ADP-ribose) polymerase inhibitors in combination with androgen-receptor signaling inhibitors are a promising therapeutic option for patients with metastatic castration-sensitive prostate cancer (mCSPC) and homologous recombination repair (HRR) gene alterations. Here, we describe the design and rationale of the multinational, phase III, TALAPRO-3 study comparing talazoparib plus enzalutamide versus placebo plus enzalutamide in patients with mCSPC and HRR gene alterations. The primary end point is investigator-assessed radiographic progression-free survival (rPFS) per RECIST 1.1 in soft tissue, or per PCWG3 criteria in bone. The TALAPRO-3 study will demonstrate whether the addition of talazoparib can improve the efficacy of enzalutamide as assessed by rPFS in patients with mCSPC and HRR gene alterations undergoing androgen deprivation therapy. Clinical Trial Registration:NCT04821622 (ClinicalTrials.gov) Registry Name: Study of Talazoparib With Enzalutamide in Men With DDR Gene Mutated mCSPC. Date of Registration: 29 March 2021.

Plain language summary of the results from the TALAPRO-2 study: Talazoparib plus enzalutamide versus placebo plus enzalutamide for patients with advanced prostate cancer.

WHAT IS THIS SUMMARY ABOUT?: This summary describes the results from the TALAPRO-2 research study (also known as a clinical trial). The TALAPRO-2 study tested the combination of two medicines called talazoparib plus enzalutamide. This combination of medicines was used as the first treatment for adult patients with metastatic castration-resistant prostate cancer. The combination of talazoparib plus enzalutamide was compared with a placebo plus enzalutamide. WHAT IS METASTATIC CASTRATION-RESISTANT PROSTATE CANCER?: Metastatic castration-resistant prostate cancer is a type of cancer that starts in the prostate and has spread to other parts of the body. Castration-resistant means that the cancer continues to grow even when testosterone levels in the blood are reduced to very low levels. Taking medicines to lower testosterone levels in the blood is a standard treatment for men with advanced prostate cancer. WHAT ARE THE AIMS OF THE TALAPRO-2 TRIAL?: TALAPRO-2 looked at if combining talazoparib plus enzalutamide would increase the length of time patients lived before their cancer got worse or they died compared with a placebo plus enzalutamide. Researchers looked at how treatment affected the size and number of tumors and the length of time before patients needed to change to a new cancer medicine. Researchers also looked at any side effects patients had during the study. WHAT ARE THE KEY TAKEAWAYS?: A total of 805 patients with metastatic castration-resistant prostate cancer took part in the study. Compared with patients who took a placebo plus enzalutamide, the group of patients who took talazoparib plus enzalutamide had a 37% reduced risk of their cancer getting worse or dying. Some patients had tumors that at the start of the study could be measured with scans. Sixty-two percent of patients who took talazoparib plus enzalutamide had their tumors decrease or shrink to the point that they could no longer be seen on scans versus 44% of patients who took a placebo plus enzalutamide. Patients who took talazoparib plus enzalutamide were more likely to have a longer time before they needed to change to a new cancer medicine. The most common side effects of talazoparib plus enzalutamide were low levels of red blood cells (66% of patients) and neutrophils (36% of patients), and excessive tiredness or exhaustion (34% of patients).Clinical Trial Registration: NCT03395197 (TALAPRO-2) (ClinicalTrials.gov).

Future directions in systemic treatment of metastatic hormone-sensitive prostate cancer.

The landscape of advanced prostate cancer treatment has evolved tremendously in past decades. The treatment paradigm has shifted from androgen deprivation therapy (ADT) alone to doublet combinations comprising ADT with docetaxel or an androgen receptor inhibitor, and now triplet therapy involving all 3 classes of agents. Robust clinical data has demonstrated survival benefits with this strategy of upfront treatment intensification. Subgroup analysis has alluded to the importance of tailoring treatment according to metastatic disease burden. However, defining the volume of disease is becoming increasingly controversial due to the advent of next generation molecular imaging. Several trials testing established agents in the castrate-resistant setting are now underway in metastatic hormone sensitive prostate cancer patients. As the treatment milieu is enriched earlier in the disease trajectory, future studies should elucidate biomarkers to further define specific patient populations who will benefit most from treatment intensification and/or de-escalation, with what agents and for what duration.

PSMA and FDG-PET as predictive and prognostic biomarkers in patients given [177Lu]Lu-PSMA-617 versus cabazitaxel for metastatic castration-resistant prostate cancer (TheraP): a biomarker analysis from a randomised, open-label, phase 2 trial.

BACKGROUND: Previously, results from the TheraP trial showed that treatment with lutetium-177 [177Lu]Lu-PSMA-617 improved frequency of prostate-specific antigen (PSA) response rate and progression-free survival compared with cabazitaxel in men with metastatic castration-resistant prostate cancer. In this study, we aimed to analyse gallium-68 [68Ga]Ga-PSMA-11 PET (PSMA-PET) and 2-[18F]fluoro-2-deoxy-D-glucose PET (FDG-PET) imaging parameters as predictive and prognostic biomarkers in this patient population. METHODS: TheraP was a multicentre, open-label, randomised phase 2 trial that recruited men with metastatic castration-resistant prostate cancer after treatment with docetaxel who were suitable for cabazitaxel from 11 hospitals in Australia. Participants were required to be 18 years old or older; have adequate haematological, renal, and liver function; and an Eastern Cooperative Oncology Group performance status of 0-2. Participants were randomly assigned (1:1) using a centralised system using minimisation with a random component and that stratified patients by disease burden, previous treatment with enzalutamide or abiraterone, and study site. Patients were either given cabazitaxel (20 mg/m2 intravenously every 3 weeks for up to ten cycles) or [177Lu]Lu-PSMA-617 (6·0-8·5 GBq intravenously every 6 weeks for up to six cycles). The primary study endpoint, analysed previously, was PSA response rate. The prespecified tertiary study endpoint was association between total tumour quantitative parameters on PSMA-PET, FDG-PET, and baseline characteristics with clinical outcomes. A SUVmean of 10 or higher on PSMA-PET was evaluated as a predictive biomarker for response to [177Lu]Lu-PSMA-617 versus cabazitaxel. A metabolic tumour volume (MTV) of 200 mL or higher on FDG-PET was tested as a prognostic biomarker. Both cutoff points were prespecified. The analysis was intention-to-treat, using logistic regression. This trial is registered with ClinicalTrials.gov, NCT03392428. FINDINGS: 200 patients were randomly assigned between Feb 6, 2018, and Sept 3, 2019. 101 men were assigned to the cabazitaxel group and 99 were assigned to the [177Lu]Lu-PSMA-617 group. The median follow-up at data cutoff of July 20, 2020, was 18·4 months (IQR 12·8-21·8). 35 (35%) of 99 men who were assigned [177Lu]Lu-PSMA-617 and 30 (30%) of 101 men who were assigned cabazitaxel had high PSMA uptake (SUVmean of ≥10). Odds of PSA response to [177Lu]Lu-PSMA-617 versus cabazitaxel were significantly higher for men with SUVmean of 10 or higher compared with those with SUVmean of less than 10 (odds ratio [OR] 12·19 [95% CI 3·42-58·76] vs 2·22 [1·11-4·51]; padj=0·039 for treatment-by-SUVmean interaction). PSA response rate for [177Lu]Lu-PSMA-617 compared with cabazitaxel was 32 (91% [95% CI 76-98]) of 35 men versus 14 (47% [29-65]) of 30 men in patients with SUVmean of 10 or higher, and 33 (52% [39-64]) of 64 men versus 23 (32% [22-45]) of 71 men in those with SUVmean of less than 10. High-volume disease on FDG-PET (MTV ≥200 mL) was seen in 30 (30%) of 99 men who were assigned [177Lu]Lu-PSMA-617 and 30 (30%) of 101 men who were assigned cabazitaxel. PSA response rate for both treatment groups combined for FDG-PET MTV of 200 mL or higher versus FDG-PET MTV of less than 200 mL was 23 (38% [95% CI 26-52]) of 60 men versus 79 (56% [48-65]) of 140 men (OR 0·44, 95% CI 0·23-0·84; padj=0·035). INTERPRETATION: In men with metastatic castration-resistant prostate cancer, PSMA-PET SUVmean was predictive of higher likelihood of favourable response to [177Lu]Lu-PSMA-617 than cabazitaxel, which provides guidance for optimal [177Lu]Lu-PSMA-617 use. High FDG-PET MTV was associated with lower responses regardless of randomly assigned treatment, warranting further research for treatment intensification. A strength of this analysis is the validation of pre-specified cutpoints within a multicentre, randomised, controlled trial. Quantitative PET parameters used, however, require specialised software and are not yet routinely available in most clinics. FUNDING: Prostate Cancer Foundation of Australia, Endocyte (a Novartis Company), Australian Nuclear Science and Technology Organisation, Movember Foundation, It's a Bloke Thing, CAN4CANCER, The Distinguished Gentleman's Ride.

Safety, pharmacokinetic, pharmacodynamic and clinical activity of molibresib for the treatment of nuclear protein in testis carcinoma and other cancers: Results of a Phase I/II open-label, dose escalation study.

Molibresib is an orally bioavailable, selective, small molecule BET protein inhibitor. Results from a first time in human study in solid tumors resulted in the selection of a 75 mg once daily dose of the besylate formulation of molibresib as the recommended Phase 2 dose (RP2D). Here we present the results of Part 2 of our study, investigating safety, pharmacokinetics, pharmacodynamics and clinical activity of molibresib at the RP2D for nuclear protein in testis carcinoma (NC), small cell lung cancer, castration-resistant prostate cancer (CRPC), triple-negative breast cancer, estrogen receptor-positive breast cancer and gastrointestinal stromal tumor. The primary safety endpoints were incidence of adverse events (AEs) and serious AEs; the primary efficacy endpoint was overall response rate. Secondary endpoints included plasma concentrations and gene set enrichment analysis (GSEA). Molibresib 75 mg once daily demonstrated no unexpected toxicities. The most common treatment-related AEs (any grade) were thrombocytopenia (64%), nausea (43%) and decreased appetite (37%); 83% of patients required dose interruptions and 29% required dose reductions due to AEs. Antitumor activity was observed in NC and CRPC (one confirmed partial response each, with observed reductions in tumor size), although predefined clinically meaningful response rates were not met for any tumor type. Total active moiety median plasma concentrations after single and repeated administration were similar across tumor cohorts. GSEA revealed that gene expression changes with molibresib varied by patient, response status and tumor type. Investigations into combinatorial approaches that use BET inhibition to eliminate resistance to other targeted therapies are warranted.

The impact of enzalutamide on quality of life in men with metastatic hormone-sensitive prostate cancer based on prior therapy, risk, and symptom subgroups.

BACKGROUND: Enzalutamide plus androgen deprivation therapy (ADT) improved radiographic progression-free survival versus ADT alone in patients with metastatic hormone-sensitive prostate cancer (mHSPC) in ARCHES (NCT02677896). While health-related quality of life (HRQoL) was generally maintained in the intent-to-treat population, we further analyzed patient-reported outcomes (PROs) in defined subgroups. METHODS: ARCHES was a randomized, double-blind, placebo-controlled, phase 3 study. Patients with mHSPC received enzalutamide (160 mg/day) plus ADT (n = 574) or placebo plus ADT (n = 576). Questionnaires, including the Functional Assessment of Cancer Therapy-Prostate, Brief Pain Inventory-Short Form, and EuroQol 5-Dimension, 5-Level (EQ-5D-5L), were completed at baseline, Week 13, and every 12 weeks until disease progression. PRO endpoints were time to first confirmed clinically meaningful deterioration (TTFCD) in HRQoL or pain. Subgroups included prognostic risk, pain/HRQoL, prior docetaxel, and local therapy (radical prostatectomy [RP] and/or radiotherapy [RT]). RESULTS: There were several between-treatment differences in TTFCD for pain and functioning/HRQoL PROs. Enzalutamide plus ADT delayed TTFCD for worst pain in the prior RT group (not reached vs. 14.06 months; hazard ratio [HR]: 0.56 [95% confidence interval: 0.34-0.94]) and pain interference in low-baseline-HRQoL group (19.32 vs. 11.20 months; HR: 0.64 [0.44-0.94]) versus placebo plus ADT. In prior/no prior RP, prior RT, prior local therapy, no prior docetaxel, mild baseline pain, and low-risk subgroups, TTFCD was delayed for the EQ-5D-5L visual analog scale. CONCLUSION: Enzalutamide plus ADT provides clinical benefits in defined patient subgroups versus ADT alone, while maintaining lack of pain and high HRQoL, with delayed deterioration in several HRQoL measures.

[177Lu]Lu-PSMA-617 versus cabazitaxel in patients with metastatic castration-resistant prostate cancer (TheraP): a randomised, open-label, phase 2 trial.

BACKGROUND: Lutetium-177 [177Lu]Lu-PSMA-617 is a radiolabelled small molecule that delivers ß radiation to cells expressing prostate-specific membrane antigen (PSMA), with activity and safety in patients with metastatic castration-resistant prostate cancer. We aimed to compare [177Lu]Lu-PSMA-617 with cabazitaxel in patients with metastatic castration-resistant prostate cancer. METHODS: We did this multicentre, unblinded, randomised phase 2 trial at 11 centres in Australia. We recruited men with metastatic castration-resistant prostate cancer for whom cabazitaxel was considered the next appropriate standard treatment. Participants were required to have adequate renal, haematological, and liver function, and an Eastern Cooperative Oncology Group performance status of 0-2. Previous treatment with androgen receptor-directed therapy was allowed. Men underwent gallium-68 [68Ga]Ga-PSMA-11 and 2-flourine-18[18F]fluoro-2-deoxy-D-glucose (FDG) PET-CT scans. PET eligibility criteria for the trial were PSMA-positive disease, and no sites of metastatic disease with discordant FDG-positive and PSMA-negative findings. Men were randomly assigned (1:1) to [177Lu]Lu-PSMA-617 (6·0-8·5 GBq intravenously every 6 weeks for up to six cycles) or cabazitaxel (20 mg/m2 intravenously every 3 weeks for up to ten cycles). The primary endpoint was prostate-specific antigen (PSA) response defined by a reduction of at least 50% from baseline. This trial is registered with ClinicalTrials.gov, NCT03392428. FINDINGS: Between Feb 6, 2018, and Sept 3, 2019, we screened 291 men, of whom 200 were eligible on PET imaging. Study treatment was received by 98 (99%) of 99 men randomly assigned to [177Lu]Lu-PSMA-617 versus 85 (84%) of 101 randomly assigned to cabazitaxel. PSA responses were more frequent among men in the [177Lu]Lu-PSMA-617 group than in the cabazitaxel group (65 vs 37 PSA responses; 66% vs 37% by intention to treat; difference 29% (95% CI 16-42; p<0·0001; and 66% vs 44% by treatment received; difference 23% [9-37]; p=0·0016). Grade 3-4 adverse events occurred in 32 (33%) of 98 men in the [177Lu]Lu-PSMA-617 group versus 45 (53%) of 85 men in the cabazitaxel group. No deaths were attributed to [177Lu]Lu-PSMA-617. INTERPRETATION: [177Lu]Lu-PSMA-617 compared with cabazitaxel in men with metastatic castration-resistant prostate cancer led to a higher PSA response and fewer grade 3 or 4 adverse events. [177Lu]Lu-PSMA-617 is a new effective class of therapy and a potential alternative to cabazitaxel. FUNDING: Prostate Cancer Foundation of Australia, Endocyte (a Novartis company), Australian Nuclear Science and Technology Organization, Movember, The Distinguished Gentleman's Ride, It's a Bloke Thing, and CAN4CANCER.

Combined impact of lipidomic and genetic aberrations on clinical outcomes in metastatic castration-resistant prostate cancer.

BACKGROUND: Both changes in circulating lipids represented by a validated poor prognostic 3-lipid signature (3LS) and somatic tumour genetic aberrations are individually associated with worse clinical outcomes in men with metastatic castration-resistant prostate cancer (mCRPC). A key question is how the lipid environment and the cancer genome are interrelated in order to exploit this therapeutically. We assessed the association between the poor prognostic 3-lipid signature (3LS), somatic genetic aberrations and clinical outcomes in mCRPC. METHODS: We performed plasma lipidomic analysis and cell-free DNA (cfDNA) sequencing on 106 men with mCRPC commencing docetaxel, cabazitaxel, abiraterone or enzalutamide (discovery cohort) and 94 men with mCRPC commencing docetaxel (validation cohort). Differences in lipid levels between men ± somatic genetic aberrations were assessed with t-tests. Associations between the 3LS and genetic aberrations with overall survival (OS) were examined using Kaplan-Meier methods and Cox proportional hazard models. RESULTS: The 3LS was associated with shorter OS in the discovery (hazard ratio [HR] 2.15, 95% confidence interval [CI] 1.4-3.3, p < 0.001) and validation cohorts (HR 2.32, 95% CI 1.59-3.38, p < 0.001). Elevated plasma sphingolipids were associated with AR, TP53, RB1 and PI3K aberrations (p < 0.05). Men with both the 3LS and aberrations in AR, TP53, RB1 or PI3K had shorter OS than men with neither in both cohorts (p ≤ 0.001). The presence of 3LS and/or genetic aberration was independently associated with shorter OS for men with AR, TP53, RB1 and PI3K aberrations (p < 0.02). Furthermore, aggressive-variant prostate cancer (AVPC), defined as 2 or more aberrations in TP53, RB1 and/or PTEN, was associated with elevated sphingolipids. The combination of AVPC and 3LS predicted for a median survival of ~12 months. The relatively small sample size of the cohorts limits clinical applicability and warrants future studies. CONCLUSIONS: Elevated circulating sphingolipids were associated with AR, TP53, RB1, PI3K and AVPC aberrations in mCRPC, and the combination of lipid and genetic abnormalities conferred a worse prognosis. These findings suggest that certain genotypes in mCRPC may benefit from metabolic therapies.

Genetics of neuroendocrine prostate cancer: recent progress in genetic understanding is translating into therapeutic opportunities.

PURPOSE OF REVIEW: Neuroendocrine prostate cancer (NEPC) is a rare histologic subtype of prostate cancer with extremely aggressive clinical behaviour and very limited data regarding treatment options. This review is intended to relay new research advances in the understanding of the genetic and epigenetic aberrations underlying NEPC development and to review new targeted therapeutic options developed based on NEPC genetics. RECENT FINDINGS: Multiple genomic alterations and epigenetic regulators have been identified in NEPC development. Among these are amplifications of oncogenic transcriptional factors, changes in expression of cell surface markers and epigenetic alterations. This in turn has facilitated a number of new targeted therapies for NEPC that act via different mechanisms including catalytic inhibitors, immune-modulators and epigenetic modifiers. These targeted therapies are now being studied in different phases of clinical trials with some preliminary results showing efficacy. SUMMARY: NEPC is a highly aggressive malignancy with currently lack of effective treatments. Considerable challenges still remains to improve clinical outcomes in NEPC; however, ongoing trials exploiting novel genetic and epigenetic alterations hold promise for patients suffering from this aggressive disease.

Modern paradigms for prostate cancer detection and management.

Early detection and management of prostate cancer has evolved over the past decade, with a focus now on harm minimisation and reducing overdiagnosis and overtreatment, given the proven improvements in survival from randomised controlled trials. Multiparametric magnetic resonance imaging (mpMRI) is now an important aspect of the diagnostic pathway in prostate cancer, improving the detection of clinically significant prostate cancer, enabling accurate localisation of appropriate sites to biopsy, and reducing unnecessary biopsies in most patients with normal magnetic resonance imaging scans. Biopsies are now performed transperineally, substantially reducing the risk of post-procedure sepsis. Australian-led research has shown that prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) has superior accuracy in the staging of prostate cancer than conventional imaging (CT and whole-body bone scan). Localised prostate cancer that is low risk (International Society for Urological Pathology [ISUP] grade 1, Gleason score 3 + 3 = 6; and ISUP grade group 2, Gleason score 3 + 4 = 7 with less than 10% pattern 4) can be offered active surveillance, reducing harms from overtreatment. Prostatectomy and definitive radiation remain the gold standard for localised intermediate and high risk disease. However, focal therapy is an emerging experimental treatment modality in Australia in carefully selected patients. The management of advanced prostate cancer treatment has evolved to now include several novel agents both in the metastatic hormone-sensitive and castration-resistant disease settings. Multimodal therapy with androgen deprivation therapy, additional systemic therapy and radiotherapy are often recommended. PSMA-based radioligand therapy has emerged as a treatment option for metastatic castration-resistant prostate cancer and is currently being evaluated in earlier disease states.

A phase III, randomized, open-label study (CONTACT-02) of cabozantinib plus atezolizumab versus second novel hormone therapy in patients with metastatic castration-resistant prostate cancer.

Cabozantinib inhibits multiple receptor tyrosine kinases, including the TAM kinase family, and may enhance response to immune checkpoint inhibitors. One cohort of the ongoing phase Ib COSMIC-021 study (NCT03170960) evaluating cabozantinib plus the PD-L1 inhibitor atezolizumab in men with metastatic castration-resistant prostate cancer (mCRPC) that has progressed in soft tissue on/after enzalutamide and/or abiraterone treatment for metastatic disease has shown promising efficacy. Here, we describe the rationale and design of a phase III trial of cabozantinib plus atezolizumab versus a second novel hormone therapy (NHT) in patients who have previously received an NHT for mCRPC, metastatic castration-sensitive PC or nonmetastatic CRPC and have measurable visceral disease and/or extrapelvic adenopathy - a population with a significant unmet need for treatment options. Trial Registration Clinical Trial Registration: NCT04446117 (ClinicalTrials.gov) Registered on 24 June 2020.

Plain language summary of the design of the TALAPRO-2 study comparing talazoparib and enzalutamide versus enzalutamide and placebo in men with metastatic castration-resistant prostate cancer.

WHAT IS THIS SUMMARY ABOUT?: This summary describes the design of an ongoing research study (also known as a clinical trial) called TALAPRO-2. The TALAPRO-2 trial is testing the combination of two medicines called talazoparib and enzalutamide as a first treatment in adult men with metastatic castration-resistant prostate cancer. The study began in December 2017 and has enrolled 1037 adult men with metastatic castration-resistant prostate cancer from 26 countries. WHAT IS METASTATIC CASTRATION-RESISTANT PROSTATE CANCER?: Metastatic castration-resistant prostate cancer is a type of cancer that has advanced beyond the prostate and continues to grow even when testosterone levels in the blood are suppressed. WHICH MEDICINES ARE BEING TESTED?: The combination of talazoparib plus enzalutamide will be compared with enzalutamide plus placebo. Enzalutamide is approved to treat men with prostate cancer. Talazoparib is not approved to treat men with prostate cancer. A placebo does not contain any active ingredients and is also known as a sugar pill. WHAT ARE THE AIMS OF THE TALAPRO-2 TRIAL?: The TALAPRO-2 trial will find out if combining talazoparib with enzalutamide increases the length of time the men in the study live without their cancer getting worse compared with enzalutamide plus placebo. The study will also measure how long men in the study live and any side effects the men have while they are taking the study medicines. Researchers are also testing the DNA from the tumor cells of all men in the study to find out if they have faulty DNA repair genes. Clinical Trial Registration: NCT0339519 (ClinicalTrials.gov).

Talazoparib plus enzalutamide in metastatic castration-resistant prostate cancer: TALAPRO-2 phase III study design.

PARP inhibitors in combination with androgen receptor-targeted therapy have demonstrated potential in the treatment of metastatic castration-resistant prostate cancer (mCRPC). Here, we describe the design and rationale of the multinational, phase III, two-part TALAPRO-2 study comparing talazoparib plus enzalutamide versus placebo plus enzalutamide as a first-line treatment for patients with mCRPC with or without DNA damage response (DDR) alterations. This study has two co-primary end points: radiographic progression-free survival (rPFS) by blinded independent clinical review in all-comers (cohort 1) and in patients with DDR alterations (cohort 2). TALAPRO-2 will demonstrate whether talazoparib plus enzalutamide can significantly improve the efficacy of enzalutamide in terms of rPFS in both molecularly unselected and DDR-deficient patients with mCRPC (NCT03395197). Clinical Trial Registration: NCT03395197 (ClinicalTrials.gov).

Predictors of real-world utilisation of docetaxel combined with androgen deprivation therapy in metastatic hormone-sensitive prostate cancer.

BACKGROUND: Docetaxel has emerged as a standard-of-care for metastatic hormone-sensitive prostate cancer (mHSPC). Uptake of docetaxel for mHSPC in Australia has not previously been reported. AIMS: To investigate the real-world uptake of docetaxel in mHSPC and to identify predictors of utilisation of docetaxel in mHSPC. METHODS: Men diagnosed from June 2014 to December 2018 and enrolled in the Prostate Cancer Outcomes Registry-Victoria (PCOR-Vic) were included. Data collected include demographics, diagnosis method and institution, staging investigations and treatments within 12 months of diagnosis. Wilcoxon rank-sum, Chi-squared and trend tests were used to identify predictors of docetaxel utilisation. All predictors were entered as covariates simultaneously into a multivariable logistic regression model. Statistical significance was set at 0.05 (two sided). RESULTS: In all, 1014 men with mHSPC were analysed, 25% of whom received docetaxel with androgen deprivation therapy. Uptake of docetaxel increased from 20% in 2014 to 33% in 2018. Predictors of higher usage of docetaxel were younger age and treatment in a private hospital, with both remaining significant on multivariable analysis. Notably, the proportion of men aged <70 years receiving docetaxel increased from 54% in 2014-2015 to 64% in 2016-2018, while in men aged ≥70 years the comparative figures were 15% and 22% respectively. CONCLUSIONS: Although docetaxel was not used in the majority of cases, there was a clear increase in docetaxel uptake, especially in younger men following publication of the CHAARTED and STAMPEDE trials. Identifying barriers to real-world implementation of pivotal clinical trial data is critical to improving outcomes in mHSPC.

Independent prognostic impact of plasma NCOA2 alterations in metastatic castration-resistant prostate cancer.

BACKGROUND: The androgen receptor (AR) pathway-associated gene nuclear receptor coactivator 2 (NCOA2) has an established oncogenic role in early prostate cancer and likewise is a driver of metastatic disease and castration-resistant prostate cancer. However, its significance as a biomarker in metastatic castration-resistant prostate cancer (mCRPC), both alone and in conjunction with co-occurring AR alterations using a liquid biopsy approach has not been investigated. METHODS: Ninety-one patients were included in this study, (n = 68 receiving an androgen receptor pathway inhibitor and n = 23 receiving taxane chemotherapy). Up to 30 ml of peripheral blood was collected before commencing treatment from each patient. Plasma cell-free DNA, along with a matched germline sample, underwent targeted next-generation sequencing using a validated, highly sensitive in-house prostate cancer panel. Variants in AR and NCOA2 were identified and correlated with clinical outcomes. RESULTS: Plasma AR and NCOA2 aberrations were identified in 35% and 13% of the cohort, respectively, whilst 8% had concurrent AR and NCOA2 alterations. NCOA2 copy number gain and any NCOA2 aberration predicted for lower prostate-specific antigen (PSA) response rates. Likewise, median overall survival was shorter for NCOA2 gain (10.1 vs. 18.3 months; p = .004), remaining significant after adjusting for covariates including circulating tumor DNA fraction and tumor suppressor gene alterations. Importantly, dual AR and NCOA2 aberrations were also associated with inferior outcomes, including no PSA responses in patients treated with AR pathway inhibitors (0% vs. 64%; p = .02). CONCLUSIONS: These data highlight the importance of identifying multiple markers of AR pathway modulation in mCRPC and represent the first instance of the assessment of plasma NCOA2 status as a prognostic biomarker for standard-of-care therapies. Further assessment is warranted to determine if NCOA2 aberrations are a marker of primary resistance to AR pathway inhibitors.

Efficacy of Enzalutamide plus Androgen Deprivation Therapy in Metastatic Hormone-Sensitive Prostate Cancer by Pattern of Metastatic Spread: ARCHES Post Hoc Analyses.

PURPOSE: Enzalutamide plus androgen deprivation therapy has previously been shown to improve clinical outcomes in men with metastatic hormone-sensitive prostate cancer (ARCHES; NCT02677896). Here, we assessed if and how the pattern of metastatic spread impacts efficacy of enzalutamide plus androgen deprivation therapy in men enrolled in ARCHES. MATERIALS AND METHODS: Men with metastatic hormone-sensitive prostate cancer were randomized 1:1 to enzalutamide (160 mg/day) plus androgen deprivation therapy or placebo plus androgen deprivation therapy, stratified by disease volume and prior docetaxel treatment. The primary end point was radiographic progression-free survival. Secondary end points included time to prostate specific antigen progression, initiation of new antineoplastic therapy, first symptomatic skeletal event and castration resistance. Post hoc analyses were performed by pattern of metastatic spread based on study entry imaging. RESULTS: Of the overall population with metastases identified at enrollment (1,146), the largest patient subgroups were those with bone metastases only (513) and those with bone plus lymph node metastases (351); there were fewer men with lymph node metastases only (154) and men with visceral±bone or lymph node metastases (128). Enzalutamide plus androgen deprivation therapy reduced the risk of radiographic progression vs placebo plus androgen deprivation therapy in men with bone metastases only (HR 0.33) and bone plus lymph node metastases (HR 0.31). Similar improvements in secondary end points were also observed in these subgroups. CONCLUSIONS: These findings indicate that treatment with enzalutamide plus androgen deprivation therapy provides improvements in men with bone and/or lymph node metastases but may be less effective in men with visceral patterns of spread.

Real-world use of first-generation antiandrogens: impact on patient outcomes and subsequent therapies in metastatic castration-resistant prostate cancer.

OBJECTIVES: To investigate the recent real-world use of first-generation antiandrogens (FGAs) in metastatic castration-resistant prostate cancer (mCRPC) using a retrospective multicentre cohort study. PATIENTS AND METHODS: The electronic CRPC Australian Database (ePAD) was interrogated to identify patients with mCRPC. Clinicopathological features, treatment and outcome data, stratified by FGA use, were retrieved and reported through descriptive statistics. Survival analyses were calculated using the Kaplan-Meier method and groups compared using log-rank tests. Factors influencing overall survival (OS) were analysed using Cox proportional hazards regression model. RESULTS: We identified 634 patients with mCRPC, enrolled in ePAD between January 2016 and March 2019, including 322 (51%) who received FGAs. The median follow-up was 21.9 months. Patients treated with FGAs were more likely to have lower International Society of Urological Pathologists (ISUP) grade group (P = 0.04), longer median time to CRPC (25.6 vs 16.0 months, P < 0.001), and were less likely to have visceral metastases (5.0% vs 11.2%, P = 0.005) or to have received upfront docetaxel (P < 0.001). A ≥50% reduction from pre-treatment prostate-specific antigen (PSA) level (PSA50 response) during FGA treatment occurred in 119 (37%) patients and was independently associated with improved OS (hazard ratio 0.233, P < 0.001). Prior FGA treatment did not significantly influence the selection of subsequent life-prolonging treatments for mCRPC or their PSA50 response rates. CONCLUSION: In our present cohort, FGAs were commonly used in lower-risk mCRPC and their use did not significantly influence the choice or duration of subsequent systemic therapy. A PSA50 response to FGA therapy was an independent favourable prognostic marker associated with improved OS.

ENZA-p trial protocol: a randomized phase II trial using prostate-specific membrane antigen as a therapeutic target and prognostic indicator in men with metastatic castration-resistant prostate cancer treated with enzalutamide (ANZUP 1901).

OBJECTIVES: To determine the activity and safety of lutetium-177 (177 Lu)-prostate-specific membrane antigen (PSMA)-617 in men with metastatic castration-resistant prostate cancer (mCRPC) commencing enzalutamide, who are at high risk of early progression, and to identify potential prognostic and predictive biomarkers from imaging, blood and tissue. PARTICIPANTS AND METHODS: ENZA-p (ANZUP 1901) is an open-label, randomized, two-arm, multicentre, phase 2 trial. Participants are randomly assigned (1:1) to treatment with enzalutamide 160 mg daily alone or enzalutamide plus 177 Lu-PSMA-617 7.5 GBq on Days 15 and 57. Two additional 177 Lu-PSMA-617 doses are allowed, informed by Day-92 Gallium-68 (68 Ga)-PSMA positron emission tomography (PET; up to four doses in total). The primary endpoint is prostate-specific antigen (PSA) progression-free survival (PFS). Other major endpoints include radiological PFS, PSA response rate, overall survival, health-related quality of life, adverse events and cost-effectiveness. Key eligibility criteria include: biochemical and/or clinical progression; 68 Ga-PSMA PET-avid disease; no prior androgen signalling inhibitor, excepting abiraterone; no prior chemotherapy for mCRPC; and ≥2 high-risk features for early enzalutamide failure. Assessments are 4 weekly during study treatment, then 6 weekly until radiographic progression. Response Evaluation Criteria in Solid Tumours (RECIST) are used to assess imaging conducted every 12 weeks, 68 Ga-PSMA PET at baseline, Days 15 and 92, and at progression, and 18 F-fluorine deoxyglucose (18 F-FDG) PET at baseline and progression. Translational samples include blood (and optional biopsies) at baseline, Day 92, and first progression. Correlative studies include identification of prognostic and predictive biomarkers from 68 Ga-PSMA and 18 F-FDG PET/CT, circulating tumour cells and circulating tumour DNA. The trial will enrol 160 participants, providing 80% power with a two-sided type-1 error rate of 5% to detect a hazard ratio of 0.625 assuming a median PSA-PFS of 5 months with enzalutamide alone. RESULTS AND CONCLUSION: The combination of 177 Lu-PSMA-617 and enzalutamide may be synergistic. ENZA-p will determine the safety and efficacy of the combination in addition to developing predictive and prognostic biomarkers to better guide treatment decisions.