Subsequent Chemotherapy and Treatment Patterns After Abiraterone Acetate in Patients with Metastatic Castration-resistant Prostate Cancer: Post Hoc Analysis of COU-AA-302

EAU-EANM-ESTRO-ESUR-ISUP-SIOG Guidelines on Prostate Cancer. Part II-2024 Update: Treatment of Relapsing and Metastatic Prostate Cancer

BACKGROUND AND OBJECTIVE

The European Association of Urology (EAU)-European Association of Nuclear Medicine (EANM)-European Society for Radiotherapy and Oncology (ESTRO)-European Society of Urogenital Radiology (ESUR)-International Society of Urological Pathology (ISUP)-International Society of Geriatric Oncology (SIOG) guidelines on the treatment of relapsing, metastatic, and castration-resistant prostate cancer (PCa) have been updated. Here we provide a summary of the 2024 guidelines.

METHODS

The panel performed a literature review of new data, covering the time frame between 2020 and 2023. The guidelines were updated and a strength rating for each recommendation was added on the basis of a systematic review of the evidence.

KEY FINDINGS AND LIMITATIONS

Risk stratification for relapsing PCa after primary therapy may guide salvage therapy decisions. New treatment options, such as androgen receptor-targeted agents (ARTAs), ARTA + chemotherapy combinations, PARP inhibitors and their combinations, and prostate-specific membrane antigen-based therapy have become available for men with metastatic PCa.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Evidence for relapsing, metastatic, and castration-resistant PCa is evolving rapidly. These guidelines reflect the multidisciplinary nature of PCa management. The full version is available online (http://uroweb.org/guideline/ prostate-cancer/).

PATIENT SUMMARY

This article summarises the 2024 guidelines for the treatment of relapsing, metastatic, and castration-resistant prostate cancer. These guidelines are based on evidence and guide doctors in discussing treatment decisions with their patients. The guidelines are updated every year.

Second-line treatment options in metastatic castration-resistant prostate cancer after progression on first-line androgen-receptor targeting therapies: A systematic review and Bayesian network analysis

OBJECTIVE

To summarize and indirectly compare the efficacy and safety of different second-line systematic therapies after first-line androgen-receptor targeting therapies (ARTs) for biomarker-unselected metastatic castration-resistant prostate cancer (mCRPC) patients.

METHODS

Studies published in English up to May 2023 were identified in PubMed, Web of Science and ASCO-GU 2023. Studies accessing the efficacy and safety of second-line systematic therapies after first-line ARTs for biomarker-unselected mCRPC patients were eligible for current systematic review and network meta-analysis (NMA).

RESULTS

Thirty-two studies with 5388 patients and 10 unique treatment modalities met our inclusion criteria. Current evidence suggested that docetaxel (DOC) combined with the same ART as first-line (ART1) (ART1 + DOC) were associated with significantly improved PSA response, PSA progression-free survival (PFS) and clinical or radiographic PFS (rPFS) compared with other reported second-line systematic therapies, including DOC. An increase in toxicity was observed with ART1 + DOC. Our NMA indicated that DOC monotherapy was only inferior to ART1 + DOC in improvement disease outcomes. The incidence of toxicity between patients received second-line DOC and an alternative ART (ART2) was similar.

CONCLUSION

The available evidence reviewed in our work suggested a clinical benefit of DOC nomotherapy and DOC plus ART1 as the second-line systematic therapy for biomarker-unselected mCRPC patients progressed on a first-line ART. More studies and RCTs are needed to evaluate the optimal second-line treatments for mCRPC patients with one prior first-line ART.

The Prognostic Nutritional Index (PNI): A New Biomarker for Determining Prognosis in Metastatic Castration-Sensitive Prostate Carcinoma

Prognostic nutritional index (PNI), which is calculated using the albumin level reflecting nutritional status and lymphocyte count reflecting immune status, is useful in showing nutritional and immunological status related to survival and prognosis in many cancers. In this study, we aimed to evaluate the biomarker potential and effect of PNI in determining the prognosis of metastatic castration-sensitive prostate cancer (mCSPC). This retrospective observational study included the complete data of 108 patients with mCPSC who were treated for at least three months between 1 January 2010, and 1 June 2021. The relationships between cancer-specific survival (CSS), overall survival (OS), progression-free survival (PFS), and PNI were evaluated. The Kaplan-Meier method for OS, PFS, and CSS, as well as univariate and multivariate Cox regression models, were used for the statistical analyses. The median age of 108 patients included in the study was 68.54 (61.05-74.19) years. A value of 49.75 was determined to be the best cut-off point for the PNI. OS (months) was found to be significantly lower in patients with low PNI (median: 34.93, 95% CI: 21.52-48.34) than in patients with high PNI (median: 65.60, 95% CI: 39.36-91.83) (p = 0.016). Patients with high PNI (median: 48.20, 95% CI: 34.66-61.73) had significantly better CSS (months) than patients with low PNI (median: 27.86, 95% CI: 24.16-31.57) (p = 0.001). There was no statistically significant difference in PFS between patients with high PNI values (median: 24.60, 95% CI: 10.15-39.05) and patients with low PNI values (median: 20.03, 95% CI: 11.06-29.03) (p = 0.092). The PNI is a good predictor of OS and CSS in patients with mCSPC. The prediction of PFS, albeit showing a trend towards significance, was not statistically significant, probably due to the small number of cases.

Health-related quality of life in GALAHAD: A multicenter, open-label, phase 2 study of niraparib for patients with metastatic castration-resistant prostate cancer and DNA-repair gene defects

BACKGROUND: Niraparib is a highly selective poly (adenosine diphosphateribose) polymerase-1 and poly (adenosine diphosphate-ribose) polymerase-2 inhibitor indicated for select patients with ovarian, fallopian tube, and primary peritoneal cancer. The phase 2 GALAHAD trial (NCT02854436) demonstrated that niraparib monotherapy is tolerable and efficacious in patients with metastatic castration-resistant prostate cancer (mCRPC) and homologous recombination repair (HRR) gene alterations, particularly those with breast cancer gene (BRCA) alterations who had progressed on prior androgen signaling inhibitor therapy and taxane-based chemotherapy. OBJECTIVE: To report the prespecified patient-reported outcomes analysis from GALAHAD. METHODS: Eligible patients with alterations to BRCA1 and/or BRCA2 (BRCA cohort) and with pathogenic alterations in other HRR genes (other HRR cohort) were enrolled and received niraparib 300 mg once daily. Patient-reported outcome instruments included the Functional Assessment of Cancer Therapy-Prostate and the Brief Pain Inventory-Short Form. Changes from baseline were compared using a mixed-effect model for repeated measures. RESULTS: On average, health-related quality of life (HRQoL) improved in the BRCA cohort by cycle 3 (mean change = 6.03; 95% CI = 2.76-9.29) and was maintained above baseline until cycle 10 (mean change = 2.84; 95% CI = -1.95 to 7.63), whereas the other HRR cohort showed no early change in HRQoL from baseline (mean change = -0.07; 95% CI = -4.69 to 4.55) and declined by cycle 10 (mean change = -5.10; 95% CI = -15.3 to 5.06). Median time to deterioration in pain intensity and pain interference could not be estimated in either cohort. CONCLUSIONS: Patients with advanced mCRPC and BRCA alterations treated with niraparib experienced more meaningful improvement in overall HRQoL, pain intensity, and pain interference compared with those with other HRR alterations. In this population of castrate, heavily pretreated patients with mCRPC and HRR alterations, stabilization, and improvement in HRQoL may be relevant to consider when making treatment decisions. DISCLOSURES: This work was supported by Janssen Research & Development, LLC (no grant number). Dr Smith has received grants and personal fees from Bayer, Amgen, Janssen, and Lilly; and has received personal fees from Astellas Pharma, Novartis, and Pfizer. Dr Sandhu has received grants from Amgen, Endocyte, and Genentech; has received grants and personal fees from AstraZeneca and Merck; and has received personal fees from Bristol Myers Squibb and Merck Serono. Dr George has received personal fees from the American Association for Cancer Research, Axess Oncology, Capio Biosciences, Constellation Pharma, EMD Serono, Flatiron, Ipsen, Merck Sharp & Dohme, Michael J. Hennessey Association, Millennium Medical Publishing, Modra Pharma, Myovant Sciences, Inc., NCI Genitourinary, Nektar Therapeutics, Physician Education Resource, Propella TX, RevHealth, LLC, and UroGPO; has received grants and personal fees from Astellas Pharma, AstraZeneca, Bristol Myers Squibb, and Pfizer; has received personal fees and nonfinancial support from Bayer and UroToday; has received grants from Calithera and Novartis; and has received grants, personal fees, and nonfinancial support from Exelixis, Inc., Sanofi, and Janssen Pharma. Dr Chi has received grants from Janssen during the conduct of the study; has received grants and personal fees from AstraZeneca, Bayer, Astellas Pharma, Novartis, Pfizer, POINT Biopharma, Roche, and Sanofi; and has received personal fees from Daiichi Sankyo, Merck, and Bristol Myers Squibb. Dr Saad has received grants, personal fees, and nonfinancial support from Janssen during the conduct of the study; and has received grants, personal fees, and nonfinancial support from AstraZeneca, Astellas Pharma, Pfizer, Bayer, Myovant, Sanofi, and Novartis. Dr Thiery-Vuillemin has received grants, personal fees, and nonfinancial support from Pfizer; has received personal fees and nonfinancial support from AstraZeneca, Janssen, Ipsen, Roche/Genentech, Merck Sharp & Dohme, and Astellas Pharma; and has received personal fees from Sanofi, Novartis, and Bristol Myers Squibb. Dr Olmos has received grants, personal fees, and nonfinancial support from AstraZeneca, Bayer, Janssen, and Pfizer; has received personal fees from Clovis, Daiichi Sankyo, and Merck Sharp & Dohme; and has received nonfinancial support from Astellas Pharma, F. Hoffman-LaRoche, Genentech, and Ipsen. Dr Danila has received research support from the US Department of Defense, the American Society of Clinical Oncology, the Prostate Cancer Foundation, Stand Up to Cancer, Janssen Research & Development, Astellas Pharma, Medivation, Agensys, Genentech, and CreaTV. Dr Gafanov has received grants from Janssen during the conduct of the study. Dr Castro has received grants from Janssen during the conduct of the study; has received grants and personal fees from Janssen, Bayer, AstraZeneca, and Pfizer; and has received personal fees from Astellas Pharma, Merck Sharp & Dohme, Roche, and Clovis. Dr Moon has received research funding from SeaGen, HuyaBio, Janssen, BMS, Aveo, Xencor, and has received personal fees from Axess Oncology, MJH, EMD Serono, and Pfizer. Dr Joshua has received nonfinancial support from Janssen; consulted or served in an advisory role for Neoleukin, Janssen Oncology, Ipsen, AstraZeneca, Sanofi, Noxopharm, IQvia, Pfizer, Novartis, Bristol Myers Squibb, Merck Serono, and Eisai; and received research funding from Bristol Myers Squibb, Janssen Oncology, Merck Sharp & Dohme, Mayne Pharma, Roche/Genentech, Bayer, MacroGenics, Lilly, Pfizer, AstraZeneca, and Corvus Pharmaceuticals. Drs Mason, Liu, Bevans, Lopez-Gitlitz, and Francis and Mr Espina are employees of Janssen Research & Development. Dr Mason owns stocks with Janssen. Dr Fizazi has participated in advisory boards and talks for Amgen, Astellas, AstraZeneca, Bayer, Clovis, Daiichi Sankyo, Janssen, MSD, Novartis/AAA, Pfizer, and Sanofi, with honoraria to his institution (Institut Gustave Roussy); has participated in advisory boards for, with personal honoraria from, Arvinas, CureVac, MacroGenics, and Orion. Study registration number: NCT02854436.

Impact of DNA damage repair alterations on prostate cancer progression and metastasis

Prostate cancer is among the most common diseases worldwide. Despite recent progress with treatments, patients with advanced prostate cancer have poor outcomes and there is a high unmet need in this population. Understanding molecular determinants underlying prostate cancer and the aggressive phenotype of disease can help with design of better clinical trials and improve treatments for these patients. One of the pathways often altered in advanced prostate cancer is DNA damage response (DDR), including alterations in BRCA1/2 and other homologous recombination repair (HRR) genes. Alterations in the DDR pathway are particularly prevalent in metastatic prostate cancer. In this review, we summarise the prevalence of DDR alterations in primary and advanced prostate cancer and discuss the impact of alterations in the DDR pathway on aggressive disease phenotype, prognosis and the association of germline pathogenic alterations in DDR genes with risk of developing prostate cancer.

Survival of Patients with Metastatic Prostate Cancer After Disease Progression on an Androgen Receptor Axis-Targeted Therapy Given in the Metastatic Castration-Sensitive Versus Metastatic Castration-Resistant Prostate Cancer Setting

Androgen receptor axis-targeted therapies (ARATs; androgen receptor or androgen synthesis inhibitors) have been approved for the treatment of patients with metastatic castration-sensitive and castration-resistant prostate cancer (mCSPC and mCRPC) on the basis of improved overall survival (OS) in randomized clinical trials. However, it is not clear whether the OS for patients after progression on first-line ARAT differs if the first ARAT was administered in the mCSPC versus mCRPC setting and what its estimates are. We assessed the OS after disease progression on ARAT given as first-line therapy in mCSPC versus mCRPC. Patient-level data were collected retrospectively, and only those treated with first-line ARAT for mCSPC or mCRPC were included. For patients receiving ARAT in the mCRPC setting, no prior ARAT was allowed in the mCSPC setting. The median OS and hazard ratio (HR) were determined via Kaplan-Meier analysis from the time of progression on ARAT. Of 382 patients treated with first-line ARAT, 172 (44 mCSPC and 128 mCRPC) had experienced disease progression and were included in the analysis. Median OS was similar in the mCSPC (23 mo) and mCRPC (17 mo) settings (HR 0.99, 95% confidence interval 0.62-1.56; p = 0.95). A total of 138 patients received subsequent systemic therapy after progression. Our results suggest that median OS is similar after progression on one ARAT, whether given in the first-line mCSPC or first-line mCRPC setting, and is estimated to be <2 yr. These data have implications for patient prognostication and the design of clinical trials in the post-ARAT setting for further drug development. PATIENT SUMMARY: We investigated whether the survival benefit differs between metastatic castration-sensitive and castration-resistant prostate cancer for patients who have already experienced cancer progression after first-line treatment with one drug targeting the androgen receptor pathway  (called ARAT). We found that the median survival benefit was less than 2 years and was similar for the two groups.

Clinical Outcomes of First Subsequent Therapies After Abiraterone Acetate Plus Prednisone for High-Risk Metastatic Castration-Sensitive Prostate Cancer in the LATITUDE Study

BACKGROUND

Abiraterone acetate plus prednisone with androgen deprivation therapy is a standard treatment option for patients with high-risk metastatic castration-sensitive prostate cancer (mCSPC). However, no data are available on the optimal subsequent treatment option in patients treated with abiraterone acetate plus prednisone for high-risk mCSPC.

OBJECTIVE

We aimed to compare the clinical outcomes of subsequent therapy after discontinuation of abiraterone acetate plus prednisone in patients with high-risk mCSPC.

METHODS

Overall survival and time to treatment failure from initiation of subsequent therapies were estimated by applying a marginal structural Cox proportional hazards model using inverse probability of treatment weighting with a change of time scale to time on treatment.

RESULTS

A total of 217 patients received subsequent therapies: 127 received chemotherapy, 49 received non-chemotherapy, and 41 received other treatments. For overall survival, when adjusted with the marginal structural Cox proportional hazards model using inverse probability of treatment weighting, the hazard ratio was 1.212 (95% confidence interval [CI] 0.742-1.979) for chemotherapy versus non-chemotherapy, 0.534 (95% CI 0.267-1.066) for non-chemotherapy versus other treatments, and 0.635 (95% CI 0.317-1.271) for chemotherapy versus other treatments. For time to treatment failure, the hazard ratio was 1.287 (95% CI 0.832-1.989) for chemotherapy versus non-chemotherapy, 0.785 (95% CI 0.486-1.269) for non-chemotherapy versus other treatments, and 0.898 (95% CI 0.612-1.318) for chemotherapy versus other treatments.

CONCLUSIONS

No differences were observed between the treatment effects of chemotherapy and non-chemotherapy in patients with high-risk mCSPC after abiraterone acetate plus prednisone. These findings suggest that life-extending subsequent therapy after abiraterone acetate plus prednisone for mCSPC should be chosen at the physician's discretion and patient's preference.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT01715285, registered 26 October, 2012.

A phase II randomised trial of abiraterone acetate plus prednisone in combination with docetaxel or docetaxel plus prednisone after disease progression to abiraterone acetate plus prednisone in patients with metastatic castration-resistant prostate cancer: The ABIDO-SOGUG trial

BACKGROUND

We aimed to compare the efficacy and safety of maintaining or withdrawing abiraterone acetate plus prednisone (AAP) in patients with metastatic castration-resistant prostate cancer who had experienced cancer progression to this treatment and were beginning a docetaxel-based therapy.

PATIENTS AND METHODS

Phase II, randomised, open-label study conducted in patients with metastatic castration-resistant prostate cancer who were asymptomatic or mildly symptomatic. After open-label treatment with AAP, patients who had experienced cancer progression to AAP were randomised to 75 mg/m² of docetaxel plus AAP or to receive 75 mg/m² of docetaxel plus 10 mg of prednisone orally daily. The primary outcome was the radiographic progression-free survival rate at 12 months as evaluated by the investigators in all randomised patients.

RESULTS

A total of 148 patients were included in open-label treatment with AAP, and of them, 94 patients were randomised to receive either docetaxel plus AAP (intervention group; n = 47) or docetaxel plus prednisone (control group; n = 47). The 12-month radiographic progression-free survival rates did not differ between the intervention group (34.9%; 95% CI 20.7-49.2) and the control group (33.9%; 95% CI 19.5-48.3). There were no significant differences in the time to radiographic progression and the overall survival between the intervention and control groups. Grade 3-5 neutropenia with the combination of docetaxel plus prednisone and AA was more frequent than with docetaxel plus prednisone (59.6% versus 27.7%).

CONCLUSION

Our results indicate that the therapeutic strategy of maintaining AAP added to docetaxel in chemotherapy-naïve patients who have experienced cancer progression to AAP treatment should not be further evaluated and should be avoided in clinical practice.

CLINICAL TRIALS

NCT02036060 https://clinicaltrials.gov/ct2/show/NCT02036060.

Androgen Annihilation Versus Advanced Androgen Blockage as First Line Treatment for Metastatic Castration Resistant Prostate Cancer: a systematic review and meta-analysis

BACKGROUND

Despite recent advances in the treatments of metastatic castration resistant prostate cancer (mCRPC), patients' prognosis remains suboptimal and novel treatment combinations are under scrutiny. On this matter, the recent ACIS trial tested the role of abiraterone plus apalutamide (androgen annihilation) in addition to androgen deprivation therapy, versus abiraterone plus androgen deprivation therapy. Herein, we performed a meta-analysis to compare overall survival (OS) and progression free survival (PFS) among patients who received androgen annihilation versus advanced androgen blockage (abiraterone or enzalutamide), in addition to conventional androgen deprivation therapy.

METHODS

A comprehensive search for all published phase III randomized control trials on first line mCRPC that evaluated advanced androgen blockage (COU-AA-302, PREVAIL) or androgen annihilation (ACIS) was conducted PubMed, EMBASE, Web of Science, and Scopus databases up to 31/12/2021. We reconstructed survival data from published Kaplan-Meier curves on overall survival (OS) and progression free survival (PFS) and meta-analyzed androgen annihilation versus advanced androgen blockage (grouping together abiraterone and enzalutamide) versus androgen deprivation therapy. The outcomes of interest were assessed using difference in restricted mean survival time (ΔRMST) at different time points.

RESULTS

Three trials were included involving 3787 patients. Overall, patients receiving androgen annihilation exhibited similar OS compared to advanced androgen blockage: ΔRMST at 36 months of -0.2 (95%CI: -1.1, 0.8, p=0.8). At 36 months, relatively to ADT alone, patients receiving androgen annihilation or advanced androgen blockage exhibited longer OS: ΔRMST of 1.6 (95%CI: 0.6, 2.7, p=0.002) and 1.8 months (95%CI: 1.1, 2.5, p<0.001), respectively. Patients receiving androgen annihilation exhibited better PFS compared to advanced androgen blockage: ΔRMST at 36 months of 2.4 months (95%CI: 1.0, 3.8, p=0.001).

CONCLUSION

We found no OS benefit for patients with mCRPC treated with androgen annihilation compared to advanced androgen blockage. This might be ascribed to an increased rate of other cause mortality that might determine the absence of an OS benefit or to the efficacy of second line therapies. Optimal treatment sequence and patient selection for androgen annihilation remain open points. However, a PFS benefit was found in case of combination therapy, whose clinical meaning is not yet clear.

Abiraterone plus prednisone added to androgen deprivation therapy and docetaxel in de novo metastatic castration-sensitive prostate cancer (PEACE-1): a multicentre, open-label, randomised, phase 3 study with a 2 × 2 factorial design

BACKGROUND

Current standard of care for metastatic castration-sensitive prostate cancer supplements androgen deprivation therapy with either docetaxel, second-generation hormonal therapy, or radiotherapy. We aimed to evaluate the efficacy and safety of abiraterone plus prednisone, with or without radiotherapy, in addition to standard of care.

METHODS

We conducted an open-label, randomised, phase 3 study with a 2 × 2 factorial design (PEACE-1) at 77 hospitals across Belgium, France, Ireland, Italy, Romania, Spain, and Switzerland. Eligible patients were male, aged 18 years or older, with histologically confirmed or cytologically confirmed de novo metastatic prostate adenocarcinoma, and an Eastern Cooperative Oncology Group performance status of 0-1 (or 2 due to bone pain). Participants were randomly assigned (1:1:1:1) to standard of care (androgen deprivation therapy alone or with intravenous docetaxel 75 mg/m² once every 3 weeks), standard of care plus radiotherapy, standard of care plus abiraterone (oral 1000 mg abiraterone once daily plus oral 5 mg prednisone twice daily), or standard of care plus radiotherapy plus abiraterone. Neither the investigators nor the patients were masked to treatment allocation. The coprimary endpoints were radiographic progression-free survival and overall survival. Abiraterone efficacy was first assessed in the overall population and then in the population who received androgen deprivation therapy with docetaxel as standard of care (population of interest). This study is ongoing and is registered with ClinicalTrials.gov, NCT01957436.

FINDINGS

Between Nov 27, 2013, and Dec 20, 2018, 1173 patients were enrolled (one patient subsequently withdrew consent for analysis of his data) and assigned to receive standard of care (n=296), standard of care plus radiotherapy (n=293), standard of care plus abiraterone (n=292), or standard of care plus radiotherapy plus abiraterone (n=291). Median follow-up was 3·5 years (IQR 2·8-4·6) for radiographic progression-free survival and 4·4 years (3·5-5·4) for overall survival. Adjusted Cox regression modelling revealed no interaction between abiraterone and radiotherapy, enabling the pooled analysis of abiraterone efficacy. In the overall population, patients assigned to receive abiraterone (n=583) had longer radiographic progression-free survival (hazard ratio [HR] 0·54, 99·9% CI 0·41-0·71; p<0·0001) and overall survival (0·82, 95·1% CI 0·69-0·98; p=0·030) than patients who did not receive abiraterone (n=589). In the androgen deprivation therapy with docetaxel population (n=355 in both with abiraterone and without abiraterone groups), the HRs were consistent (radiographic progression-free survival 0·50, 99·9% CI 0·34-0·71; p<0·0001; overall survival 0·75, 95·1% CI 0·59-0·95; p=0·017). In the androgen deprivation therapy with docetaxel population, grade 3 or worse adverse events occurred in 217 (63%) of 347 patients who received abiraterone and 181 (52%) of 350 who did not; hypertension had the largest difference in occurrence (76 [22%] patients and 45 [13%], respectively). Addition of abiraterone to androgen deprivation therapy plus docetaxel did not increase the rates of neutropenia, febrile neutropenia, fatigue, or neuropathy compared with androgen deprivation therapy plus docetaxel alone.

INTERPRETATION

Combining androgen deprivation therapy, docetaxel, and abiraterone in de novo metastatic castration-sensitive prostate cancer improved overall survival and radiographic progression-free survival with a modest increase in toxicity, mostly hypertension. This triplet therapy could become a standard of care for these patients.

FUNDING

Janssen-Cilag, Ipsen, Sanofi, and the French Government.

A Phase Ib/II Study of the CDK4/6 Inhibitor Ribociclib in Combination with Docetaxel plus Prednisone in Metastatic Castration-Resistant Prostate Cancer

PURPOSE

Ribociclib, a CDK4/6 inhibitor, demonstrates preclinical antitumor activity in combination with taxanes. We evaluated the safety and efficacy of ribociclib plus docetaxel in a phase Ib/II study in metastatic castration-resistant prostate cancer (mCRPC).

PATIENTS AND METHODS

Patients had chemotherapy-naïve mCRPC with progression on ≥ 1 androgen receptor signaling inhibitor (ARSI). The phase II primary endpoint was 6-month radiographic progression-free survival (rPFS) rate, with an alternative hypothesis of 55% versus 35% historical control. Circulating tumor cells (CTC) were collected at baseline and genomically profiled.

RESULT

Forty-three patients were enrolled (N = 30 in phase II). Two dose-limiting toxicities were observed (grade 4 neutropenia and febrile neutropenia). The recommended phase II dose (RP2D) and schedule was docetaxel 60 mg/m2 every 21 days plus ribociclib 400 mg/day on days 1-4 and 8-15 with filgrastim on days 5-7. At the RP2D, neutropenia was the most common grade ≥ 3 adverse event (37%); however, no cases of febrile neutropenia were observed. The primary endpoint was met; the 6-month rPFS rate was 65.8% [95% confidence interval (CI): 50.6%-85.5%; P = 0.005] and median rPFS was 8.1 months (95% CI, 6.0-10.0 months). Thirty-two percent of evaluable patients achieved a PSA50 response. Nonamplified MYC in baseline CTCs was associated with longer rPFS (P = 0.052).

CONCLUSIONS

The combination of intermittent ribociclib plus every-3-weeks docetaxel demonstrated acceptable toxicity and encouraging efficacy in ARSI-pretreated mCRPC. Genomic profiling of CTCs may enrich for those most likely to derive benefit. Further evaluation in a randomized clinical trial is warranted.

Considerations on the identification and management of metastatic prostate cancer patients with DNA repair gene alterations in the Canadian context

Olaparib is the first Health Canada-approved agent in metastatic prostate cancer to use a companion diagnostic to identify alterations in BRCA1, BRCA2, or ATM. As olaparib is introduced, clinicians must learn to access and interpret germline and somatic next-generation sequencing (NGS) results, and how to manage affected patients who appear to have distinct clinical features. The traditional model of referring patients to a hereditary cancer clinic (HCC) for germline testing is likely impractical in this disease, as the metastatic prostate cancer patient population would be overwhelming. Alternate approaches to this are clinician-ordered genetic testing (so-called “mainstreaming”), out-of-pocket payment for third-party private company genetic testing, or germline testing done in conjunction with somatic testing, particularly cell free circulating tumor DNA (ctDNA). Germline testing alone is not sufficient for identifying Olaparib-eligible patients, as less than half of BRCA1, BRCA2, or ATM alterations are germline in origin, but it is critically important to identify family members who are carriers so that risk-reduction measures can be undertaken. Somatic testing is not widely available in Canada, but some patients can access it through research protocols or by paying out-of-pocket. Somatic testing can be performed on archival or fresh solid tissue biopsy samples, or through whole blood samples to access plasma-derived circulating tumor DNA (ctDNA). Both testing approaches have relative advantages and disadvantages, but neither may be informative in all patients and, therefore, ideal somatic NGS pathways should provide options for both tissue and ctDNA testing. We advocate that clinicians begin discussions with their provincial lab formularies, HCC, and molecular pathology labs to highlight the importance of germline and somatic testing in this population and identify pathways for patient access. While olaparib has approval for use in BRCA1, BRCA2, and ATM-altered mCRPC, emerging evidence suggests that PARP inhibitors have variable activity in these three genes, with BRCA2 alterations appearing to be the most responsive. Retrospective and prospective series have reported varying outcomes to standard of care therapies, such as ARATs and taxane-based chemotherapy, in metastatic castration-resistant prostate cancer (mCRPC) patients with DNA damage repair (DDR) gene alterations, such as BRCA2. In the absence of high-level evidence showing a lack of benefit, we believe this patient population should still be considered for these treatments. In addition, platinum-based chemotherapy appears to have activity in DDR gene-altered mCRPC and should be considered another option when access to olaparib is not possible. At present, there is no evidence to support an optimal treatment sequence in this patient population, therefore, physician and patient preferences will need to be taken into consideration when selecting therapies. As olaparib and other PARP inhibitors are tested in different disease states and in combination with other therapies, we will likely see a more refined approach to use of these agents and management of this new biomarker-defined patient population.

Correlation Between Imaging-Based Intermediate Endpoints and Overall Survival in Men With Metastatic Castration-Resistant Prostate Cancer: Analysis of 28 Randomized Trials Using the Prostate Cancer Clinical Trials Working Group (PCWG2) Criteria in 16,511 Patients

INTRODUCTION/BACKGROUND

Radiographic progression-free survival (rPFS) based on Prostate Cancer Working Group 2 (PCWG2) has been increasingly used as a meaningful imaging-based intermediate endpoint (IBIE) for overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC). In randomized phase III trials, rPFS showed good correlation with OS at the individual trial level. We aimed to assess the correlation between the hazard ratios (HR) of IBIE and OS among PCWG2-based randomized trials.

MATERIALS AND METHODS

PubMed and EMBASE databases were systematically searched for randomized trials evaluating systemic treatments on mCRPC using PCWG2 up to April 15, 2020. Hazard ratios for OS and IBIEs were extracted and their correlation was assessed using weighted linear regression. Subgroup analyses were performed according to various clinical settings: prior chemotherapy, drug category, type of IBIE (rPFS vs. composite IBIE, latter defined as progression by imaging and one or a combination of PSA, pain, skeletal-related events, and performance status), and publication year.

RESULTS

Twenty-eight phase II-III randomized trials (16,511 patients) were included. Correlation between OS and IBIE was good (R² = 0.57, 95% confidence interval [CI], 0.35-0.78). Trials using rPFS showed substantially higher correlation than those using a composite IBIE (R² = 0.58, 95% CI, 0.32-0.82 vs. 0.00, 95% CI, -0.01 to 0.01). Correlations between OS and IBIE in other subgroups were at least moderate in nearly all subgroups (R² = 0.32-0.91).

CONCLUSION

IBIEs in the era of PCWG2 correlate well with OS in randomized trials for systemic drugs in patients with mCRPC. PCWG2-based rPFS should be used instead of a composite IBIE that includes PSA and other clinical variables.

Nivolumab plus docetaxel in patients with chemotherapy-naïve metastatic castration-resistant prostate cancer: results from the phase II CheckMate 9KD trial

BACKGROUND

Docetaxel has immunostimulatory effects that may promote an immunoresponsive prostate tumour microenvironment, providing a rationale for combination with nivolumab (programmed death-1 inhibitor) for metastatic castration-resistant prostate cancer (mCRPC).

METHODS

In the non-randomised, multicohort, global phase II CheckMate 9KD trial, 84 patients with chemotherapy-naive mCRPC, ongoing androgen deprivation therapy and ≤2 prior novel hormonal therapies (NHTs) received nivolumab 360 mg and docetaxel 75 mg/m² every 3 weeks with prednisone 5 mg twice daily (≤10 cycles) and then nivolumab 480 mg every 4 weeks (≤2 years). The co-primary end-points were objective response rate (ORR) and prostate-specific antigen response rate (PSA₅₀-RR; ≥50% decrease from baseline).

RESULTS

The confirmed ORR (95% confidence interval [CI]) was 40.0% (25.7-55.7), and the confirmed PSA₅₀-RR (95% CI) was 46.9% (35.7-58.3). The median (95% CI) radiographic progression-free survival (rPFS) and overall survival (OS) were 9.0 (8.0-11.6) and 18.2 (14.6-20.7) months, respectively. In subpopulations with versus without prior NHT, the ORR was 38.7% versus 42.9%, the PSA₅₀-RR was 39.6% versus 60.7%, the median rPFS was 8.5 versus 12.0 months and the median OS was 16.2 months versus not reached. Homologous recombination deficiency status or tumour mutational burden did not appear to impact efficacy. The most common any-grade and grade 3-4 treatment-related adverse events were fatigue (39.3%) and neutropenia (16.7%), respectively. Three treatment-related deaths occurred (1 pneumonitis related to nivolumab; 2 pneumonias related to docetaxel).

CONCLUSIONS

Nivolumab plus docetaxel has clinical activity in patients with chemotherapy-naïve mCRPC. Safety was consistent with the individual components. These results support further investigation in the ongoing phase III CheckMate 7DX trial. CLINICALTRIALS.

GOV REGISTRATION

NCT03338790.

Evaluating the Role of Stereotactic Body Radiation Therapy With Respect to Androgen Receptor Signaling Inhibitors for Oligometastatic Prostate Cancer

Purpose

Outcomes of stereotactic body radiation therapy (SBRT) with respect to androgen receptor signaling inhibitors (ARSI) have not been characterized for oligometastatic prostate cancer. We sought to characterize prostate specific antigen (PSA) response and progression-free survival (PFS) after SBRT among men who have progressed on ARSI therapy in the oligometastatic castration-resistant setting.

Methods and Materials

A single-institution retrospective analysis was performed for men with ARSI-resistant, oligometastatic, castrate-resistant prostate cancer (omCRPC). Intervention consisted of SBRT. PSA reduction greater than 50% and median PFS (PSA or radiographic progression) as determined by routine care comprised outcome measurements. Cox regression analysis was used to determine factors influencing PFS.

Results

Thirty-five men with ARSI-resistant omCRPC and 65 lesions treated with SBRT were followed for a median of 17.2 months. In 63% of men PSA reduction greater than 50% was achieved. Median PFS was 9.0 months. Incomplete ablation (defined as the presence of untreated lesions after SBRT or receipt of prior palliative radiation therapy doses) was associated with worse PFS (hazard ratio 4.21 [1.74-10.19]; P < .01). For a subgroup of 22 men with complete ablation of metastatic sites with SBRT, the median PFS was 13.1 months. One-year overall survival was 93.1% (95% confidence interval, 84.4-100).

Conclusions

SBRT may augment the efficacy of ARSI in omCRPC, provided that all lesions receive ablative radiation doses. Future prospective study of SBRT for men receiving ARSI is warranted.

Impact of abiraterone acetate plus prednisone in patients with castration-sensitive prostate cancer and visceral metastases over four years of follow-up: A post-hoc exploratory analysis of the LATITUDE study

BACKGROUND

A post-hoc analysis of the phase-3 LATITUDE study assessed the impact of abiraterone acetate plus prednisone (AA+P) on overall survival (OS) and radiographic progression-free survival (rPFS) in men with metastatic castration-sensitive prostate cancer (mCSPC) and visceral metastases (VM).

METHODS

Newly diagnosed mCSPC patients were randomized (1:1) to AA+P and androgen deprivation therapy (ADT) or placebo+ADT. Patients with VM in liver or lungs with or without other soft tissue and bone metastases (based on CT/MRI) at baseline were analyzed, after 51.8 months' median follow-up. Co-primary endpoints, OS and rPFS, were analyzed.

RESULTS

Among 1199 patients enrolled, 228 (19%) had VM at baseline (114 each in AA+P and placebo groups), of which 53 (23.2%; AA+P = 29, Placebo = 24) had liver metastases and 117 (51.3%; AA+P = 60, Placebo = 57) had lung metastases. In patients with VM, treatment with AA+P versus placebo showed an improvement in OS (median 55.4 vs 33.0 months; HR = 0.582; 95%CI = 0.406-0.835;P = 0.0029) and rPFS (median 30.7 vs 18.3 months; HR = 0.527; 95%CI = 0.366-0.759;P = 0.0005), comparable to that of patients without VM. AA+P versus placebo in lung metastases patients was associated with greater improvement in OS (HR = 0.60; 95%CI = 0.35-1.04;P = 0.0678) than in liver metastases patients (HR = 0.82; 95%CI = 0.41-1.66;P = 0.5814). AA+P versus placebo showed improvement in rPFS in lung metastases patients (HR = 0.50; 95%CI = 0.29-0.89;P = 0.0157), but not in liver metastases patients (HR = 1.05; 95%CI = 0.53-2.09; P = 0.8970).

CONCLUSION

AA+P treatment improved both rPFS and OS in men with mCSPC and visceral disease, especially those with lung metastases. Men with liver metastases had a poorer prognosis and their optimal treatment remains to be defined.

REGISTRATION

ClinicalTrials.gov, number NCT01715285.

Mipsagargin: The Beginning-Not the End-of Thapsigargin Prodrug-Based Cancer Therapeutics

Søren Brøgger Christensen isolated and characterized the cell-penetrant sesquiterpene lactone Thapsigargin (TG) from the fruit Thapsia garganica. In the late 1980s/early 1990s, TG was supplied to multiple independent and collaborative groups. Using this TG, studies documented with a large variety of mammalian cell types that TG rapidly (i.e., within seconds to a minute) penetrates cells, resulting in an essentially irreversible binding and inhibiting (IC₅₀~10 nM) of SERCA 2b calcium uptake pumps. If exposure to 50–100 nM TG is sustained for >24–48 h, prostate cancer cells undergo apoptotic death. TG-induced death requires changes in the cytoplasmic Ca²⁺, initiating a calmodulin/calcineurin/calpain-dependent signaling cascade that involves BAD-dependent opening of the mitochondrial permeability transition pore (MPTP); this releases cytochrome C into the cytoplasm, activating caspases and nucleases. Chemically unmodified TG has no therapeutic index and is poorly water soluble. A TG analog, in which the 8-acyl groups is replaced with the 12-aminododecanoyl group, afforded 12-ADT, retaining an EC₅₀ for killing of <100 nM. Conjugation of 12-ADT to a series of 5–8 amino acid peptides was engineered so that they are efficiently hydrolyzed by only one of a series of proteases [e.g., KLK3 (also known as Prostate Specific Antigen); KLK2 (also known as hK2); Fibroblast Activation Protein Protease (FAP); or Folh1 (also known as Prostate Specific Membrane Antigen)]. The obtained conjugates have increased water solubility for systemic delivery in the blood and prevent cell penetrance and, thus, killing until the TG-prodrug is hydrolyzed by the targeting protease in the vicinity of the cancer cells. We summarize the preclinical validation of each of these TG-prodrugs with special attention to the PSMA TG-prodrug, Mipsagargin, which is in phase II clinical testing.

Treatment Pattern and Outcomes with Systemic Therapy in Men with Metastatic Prostate Cancer in the Real-World Patients in the United States

Simple Summary

Novel hormonal therapies (such as abiraterone and enzalutamide) and docetaxel are approved treatments for metastatic prostate cancer. Upfront use of these agents has been shown to improve overall survival. However, we do not know the real-world treatment patterns of these agents or the comparative effectiveness of these agents after treatment with a prior novel hormonal therapy in patients with metastatic prostate cancer. In this large study, we found that most patients with metastatic prostate cancer received only androgen deprivation therapy as upfront therapy without novel hormonal therapies or docetaxel. In patients treated with one novel hormonal therapy, alternate novel hormonal therapy was the most common next therapy and was associated with improved overall survival over docetaxel with the caveat of this being a non-randomized comparison. The study’s limitations also include its retrospective design.

Abstract

Background: Both novel hormonal therapies and docetaxel are approved for treatment of metastatic prostate cancer (mPC; in castration sensitive or refractory settings). Present knowledge gaps include lack of real-world data on treatment patterns in patients with newly diagnosed mPC, and comparative effectiveness of novel hormonal therapies (NHT) versus docetaxel after treatment with a prior NHT. Methods: Herein we extracted patient-level data from a large real-world database of patients with mPC in United States. Utilization of NHT or docetaxel for mPC and comparative effectiveness of an alternate NHT versus docetaxel after one prior NHT was evaluated. Comparative effectiveness was examined via Cox proportional hazards model with propensity score matching weights. Each patient’s propensity for treatment was modeled via random forest based on 22 factors potentially driving treatment selection. Results: The majority of patients (54%) received only androgen deprivation therapy for mPC. In patients treated with an NHT, alternate NHT was the most common next therapy and was associated with improved median overall survival over docetaxel (abiraterone followed by docetaxel vs. enzalutamide (8.7 vs. 15.6 months; adjusted hazards ratio; aHR 1.32; p = 0.009; and enzalutamide followed by docetaxel vs. abiraterone (9.7 vs. 13.2 months aHR 1.40; p = 0.009). Limitations of the study include retrospective design.

Optimal Sequencing and Predictive Biomarkers in Patients with Advanced Prostate Cancer

The treatment landscape of advanced prostate cancer has completely changed during the last decades. Chemotherapy (docetaxel, cabazitaxel), androgen-receptor signaling inhibitors (ARSi) (abiraterone acetate, enzalutamide), and radium-223 have revolutionized the management of metastatic castration-resistant prostate cancer (mCRPC). Lutetium-177-PSMA-617 is also going to become another treatment option for these patients. In addition, docetaxel, abiraterone acetate, apalutamide, enzalutamide, and radiotherapy to primary tumor have demonstrated the ability to significantly prolong the survival of patients with metastatic hormone-sensitive prostate cancer (mHSPC). Finally, apalutamide, enzalutamide, and darolutamide have recently provided impactful data in patients with nonmetastatic castration-resistant disease (nmCRPC). However, which is the best treatment sequence for patients with advanced prostate cancer? This comprehensive review aims at discussing the available literature data to identify the optimal sequencing approaches in patients with prostate cancer at different disease stages. Our work also highlights the potential impact of predictive biomarkers in treatment sequencing and exploring the role of specific agents (i.e., olaparib, rucaparib, talazoparib, niraparib, and ipatasertib) in biomarker-selected populations of patients with prostate cancer (i.e., those harboring alterations in DNA damage and response genes or PTEN).

Prognostic role of docetaxel-induced suppression of free testosterone serum levels in metastatic prostate cancer patients

To date, only few data concerning the biologically active, free form of testosterone (FT) are available in metastatic prostate cancer (mPC) and the impact of FT on disease, therapy and outcome is largely unknown. We retrospectively studied the effect of docetaxel on FT and total testosterone (TT) serum levels in 67 mPC patients monitored between April 2008 and November 2020. FT and TT levels were measured before and weekly during therapy. The primary endpoint was overall survival (OS). Secondary endpoints were prostate-specific antigen response and radiographic response (PSAR, RR), progression-free survival (PFS), FT/TT levels and safety. Median FT and TT serum levels were completely suppressed to below the detection limit during docetaxel treatment (FT: from 0.32 to < 0.18 pg/mL and TT: from 0.12 to < 0.05 ng/mL, respectively). Multivariate Cox regression analyses identified requirement of non-narcotics, PSAR, complete FT suppression and FT nadir values < 0.18 pg/mL as independent parameters for PFS. Prior androgen-receptor targeted therapy (ART), soft tissue metastasis and complete FT suppression were independent prognostic factors for OS. FT was not predictive for treatment outcome in mPC patients with a history of ART.

KEYNOTE-921: Phase III study of pembrolizumab plus docetaxel for metastatic castration-resistant prostate cancer

Despite recent advances, treatment options for men with metastatic castration-resistant prostate cancer (mCRPC) progressing after next-generation hormonal agents (NHAs) are limited and provide only modest survival benefit. Thus, an unmet need remains for mCRPC patients after treatment with targeted endocrine therapy or NHA therapy. Pembrolizumab, a humanized monoclonal antibody for PD-1, has been found to have activity as monotherapy in patients with mCRPC and as combination therapy in a Phase Ib/II study with docetaxel and prednisone/prednisolone for patients previously treated with enzalutamide or abiraterone acetate. The aim of the randomized, double-blind, Phase III KEYNOTE-921 study is to evaluate the efficacy and safety of pembrolizumab plus docetaxel in patients with mCRPC who were previously treated with an NHA. Clinical trial registration: NCT03834506 (ClinicalTrials.gov).

2020 Korean guidelines for the management of metastatic prostate cancer

In 2017, Korean Society of Medical Oncology (KSMO) published the Korean management guideline of metastatic prostate cancer. This paper is the 2nd edition of the Korean management guideline of metastatic prostate cancer. We updated recent many changes of management in metastatic prostate cancer in this 2nd edition guideline. The present guideline consists of the three categories: management of metastatic hormone sensitive prostate cancer; management of metastatic castration resistant prostate cancer; and clinical consideration for treating patients with metastatic prostate cancer. In category 1 and 2, levels of evidence (LEs) have been mentioned according to the general principles of evidence-based medicine. And grades of recommendation (GR) was taken into account the quality of evidence, the balance between desirable and undesirable effects, the values and preferences, and the use of resources and GR were divided into strong recommendations (SR) and weak recommendations (WR). A total of 16 key questions are selected. And we proposed recommendations and described key evidence for each recommendation. The treatment landscape of metastatic prostate cancer is changing very rapid and many trials are ongoing. To verify the results of the future trials is necessary and should be applied to the treatment for metastatic prostate cancer patients in the clinical practice. Especially, many prostate cancer patients are old age, have multiple underlying medical comorbidities, clinicians should be aware of the significance of medical management as well as clinical efficacy of systemic treatment.

Hong Kong Urological Association-Hong Kong Society of Uro-Oncology consensus statements on the management of advanced prostate cancer-2019 Updates

BACKGROUND

To update the Hong Kong Urological Association-Hong Kong Society of Uro-Oncology consensus statements on the management of advanced prostate cancer, the same panelists as in the previous consensus panel held a series of meetings to discuss updated clinical evidence and experiences.

METHODS

The previous consensus statements were retained, deleted, or revised, and new statements were added. At the final meeting, all statements were reviewed and amended as appropriate, followed by panel voting.

RESULTS

There were significant changes and additions to the previous consensus statements, primarily driven by the advances in androgen receptor signaling inhibitors, treatment sequencing in metastatic castration-resistant prostate cancer, and increasing recognition of oligometastatic prostate cancer since the introduction of prostate-specific membrane antigen positron emission tomography. In this update, a total of 59 consensus statements were accepted and established.

CONCLUSIONS

The consensus panel updated consensus statements on the management of advanced prostate cancer, aiming to allow physicians in the region to keep abreast of the recent evidence on optimal clinical practices.

Cross-resistance and drug sequence in prostate cancer

The treatment landscape of advanced prostate cancer has widely expanded over the past years with androgen receptor signaling inhibitors (ARSIs) and taxane chemotherapy moving to earlier disease stages in the treatment of prostate cancer. With the increasing use of ARSIs in earlier disease stages, cross-resistance between treatments has emerged, which is a dominant impediment in current clinical practice. To overcome cross-resistance in the treatment of prostate cancer, it is of paramount importance to decipher the mechanisms of cross-resistance between ARSIs and between ARSIs and chemotherapy. Here, molecular mechanisms of resistance to the available therapies including androgen receptor (AR) splice variants, AR overexpression, AR mutations and glucocorticoid receptor upregulation are described. Based on these underlying mechanisms, clinical data of cross-resistance between ARSIs and chemotherapy have been reported. Only recently these data have been confirmed in prospective randomized trials. From these studies, it has become clear that sequential ARSI treatment has no place in the treatment of advanced prostate cancer due to emerging drug resistance. In addition, based on prospective evidence, we argue that it is worth considering an early switch to cabazitaxel treatment in case of lack of benefit on docetaxel regimen after an ARSI treatment. Based on these new insights from randomized trials, several recommendations for treatment sequence are proposed.

Treatment of metastatic castration resistant prostate cancer with radium-223: a retrospective study at a US tertiary oncology center

BACKGROUND

Guidelines for optimal sequencing of radium-223 and chemotherapy for metastatic castration resistant prostate cancer (mCRPC) do not exist. This study evaluated treatment patterns and overall survival (OS) among patients with mCRPC treated with radium-223 in an academic clinical setting.

METHODS

A retrospective study was conducted of bone metastases-predominant mCRPC patients treated with radium-223. Treatment patterns from 2013 to 2018 were evaluated in patients treated with radium-223 pre- vs. post-chemotherapy. OS was examined using Kaplan-Meier medians and 95% confidence intervals.

RESULTS

In total, 220 patients were treated with radium-223 (64 pre-chemotherapy, 83 post-chemotherapy, 73 no chemotherapy). Mean radium-223 injections per patient was 5.3 and 4.3 in the pre- vs. post-chemotherapy cohorts, respectively (p < 0.001). The number of chemotherapy cycles was similar for chemotherapy given pre- or post-radium-223. Mean line of mCRPC therapy of radium-223 was 3rd and 5th when given pre- and post-chemotherapy, respectively (p < 0.001). 41.8% patients were treated with radium-223 in combination with another mCRPC therapy, commonly abiraterone acetate (43.5%) or enzalutamide (52.2%). The majority received combination therapy for the duration of radium-223 treatment; 20.7% started another agent after radium-223 initiation; 20.7% initiated radium-223 while on established therapy. Median OS from first mCRPC treatment was 39.4 months (95% CI 33.0, 48.8) for patients with radium-223 pre-chemotherapy vs. 37.4 months (95% CI 32.0, 43.5) post-chemotherapy (and 35.2 months [95% CI 27.9, 43.3] vs. 32.0 months [95% CI 26.9, 36.0] for patients with radium-223 combination vs. monotherapy).

CONCLUSIONS

This retrospective analysis of patients treated with radium-223 demonstrates that administration of radium-223 pre-chemotherapy increased likelihood of completion of radium-223 treatment. Radium-223 given pre- or post-chemotherapy and with or without combination therapy did not result in significant differences in OS. Additional studies are needed to determine the optimal sequencing strategy of mCRPC in the modern era.

[Systemic treatment of advanced prostate cancer]

In recent years there have been substantial changes in the therapeutic landscape for systemic treatment of advanced prostate cancer (PCa), which resulted in a multitude of novel treatment options for different stages of the disease. In the current narrative review currently available treatment options for metastatic hormone-sensitive PCa as well as nonmetastatic castration-resistant PCa are presented. In addition, current treatment sequence options and targeted treatment in the stage of metastatic castration-resistant PCa are highlighted.

EAU-EANM-ESTRO-ESUR-SIOG Guidelines on Prostate Cancer. Part II-2020 Update: Treatment of Relapsing and Metastatic Prostate Cancer

OBJECTIVE

To present a summary of the 2020 version of the European Association of Urology (EAU)-European Association of Nuclear Medicine (EANM)-European Society for Radiotherapy & Oncology (ESTRO)-European Society of Urogenital Radiology (ESUR)-International Society of Geriatric Oncology (SIOG) guidelines on the treatment of relapsing, metastatic, and castration-resistant prostate cancer (CRPC).

EVIDENCE ACQUISITION

The working panel performed a literature review of the new data (2016-2019). The guidelines were updated, and the levels of evidence and/or grades of recommendation were added based on a systematic review of the literature.

EVIDENCE SYNTHESIS

Prostate-specific membrane antigen positron emission tomography computed tomography scanning has developed an increasingly important role in men with biochemical recurrence after local therapy. Early salvage radiotherapy after radical prostatectomy appears as effective as adjuvant radiotherapy and, in a subset of patients, should be combined with androgen deprivation. New treatments have become available for men with metastatic hormone-sensitive prostate cancer (PCa), nonmetastatic CRPC, and metastatic CRPC, along with a role for local radiotherapy in men with low-volume metastatic hormone-sensitive PCa. Also included is information on quality of life outcomes in men with PCa.

CONCLUSIONS

The knowledge in the field of advanced and metastatic PCa and CRPC is changing rapidly. The 2020 EAU-EANM-ESTRO-ESUR-SIOG guidelines on PCa summarise the most recent findings and advice for use in clinical practice. These PCa guidelines are first endorsed by the EANM and reflect the multidisciplinary nature of PCa management. A full version is available from the EAU office or online (http://uroweb.org/guideline/prostate-cancer/).

PATIENT SUMMARY

This article summarises the guidelines for the treatment of relapsing, metastatic, and castration-resistant prostate cancer. These guidelines are evidence based and guide the clinician in the discussion with the patient on the treatment decisions to be taken. These guidelines are updated every year; this summary spans the 2017-2020 period of new evidence.

Adding carboplatin to chemotherapy regimens for metastatic castrate-resistant prostate cancer in postsecond generation hormone therapy setting: Impact on treatment response and survival outcomes

BACKGROUND

The clinical course in metastatic castrate-resistant prostate cancer (mCRPC) can be complicated when patients have disease progression after prior treatment with second generation hormone therapy (second HT), such as enzalutamide or abiraterone. Currently, limited data exist regarding the optimal choice of chemotherapy for mCRPC after failing second generation hormone therapy. We sought to evaluate three common chemotherapy regimens in this setting.

METHODS

We retrospectively identified 150 mCRPC patients with disease progression on enzalutamide or abiraterone. Of these 150 patients, 92 patients were chemo-naïve while 58 patients had previously received docetaxel chemotherapy before being started on second HT. After failing second HT, 90 patients were assigned for docetaxel-alone (group A), 33 patients received carboplatin plus docetaxel (group B), while 27 patients received cabazitaxel-alone (Group C). A favorable response was defined by more than or equal to 50% reduction in prostate-specific antigen from the baseline level after a complete course of chemotherapy. Survival outcomes were assessed for 30-month overall survival.

RESULTS

Patients in group (B) were 2.6 times as likely to have a favorable response compared to patients in group (A) (OR = 2.625, 95%CI: 1.15-5.99) and almost three times compared to patients in group (C) (OR = 2.975, 95%CI: 1.04-8.54) (P = .0442). 30-month overall survival was 70.7%, 38.9% and 30.3% for group (B), (A), and (C), respectively (P = .008). We report a Hazard Ratio of 3.1 (95% CI, 1.31-7.35; P = .0037) between patients in group (A) versus those in group (B) and a Hazard Ratio of 4.18 (95% CI, 1.58-11.06; P = .0037) between patients in group (C) compared to those in group (B) CONCLUSION: This data demonstrates improved response and overall survival in treatment-refractory mCRPC with a chemotherapy regimen of docetaxel plus carboplatin when compared to docetaxel alone or cabazitaxel alone. Further investigations are required.

Abiraterone vs. docetaxel for metastatic hormone-sensitive prostate cancer: A microsimulation model

INTRODUCTION

Our aim was to determine whether androgen deprivation therapy (ADT) with abiraterone acetate (AA) or ADT with docetaxel chemotherapy (DC) resulted in improved quality-adjusted life years (QALYs) among men with de novo metastatic castration-sensitive prostate cancer (mCSPC) and the cost effectiveness of the preferred strategy using decision analytic techniques.

METHODS

A microsimulation model with a lifetime time horizon was constructed. Our primary outcome was QALYs. Secondary outcomes included cost, incremental cost effectiveness ratio (ICER), unadjusted overall survival (OS), rates of second- and third-line therapy, and adverse events. A systematic literature review was used to generate probabilities and utilities to populate the model. The base case was a 65-year-old patient with de novo mCSPC.

RESULTS

A total of 100 000 microsimulations were generated. Initial AA resulted in a gain of 0.45 QALYs compared to DC (3.36 vs. 2.91 QALYs) with an ICER of $276 251.82 per QALY gained with initial AA therapy. Median crude OS was 51 months with AA and 48 months with DC. Overall, 46.6% and 42.6% of patients received second-line therapy and 8.7% and 7.9% patients received third-line therapy in the AA and DC groups, respectively. Grade 3/4 adverse events were experienced in 17.6% of patients receiving initial AA and 22.3% of patients receiving initial DC.

CONCLUSIONS

Although ADT with AA results in a gain in QALYs and crude OS compared to DC, AA therapy is not a cost-effective treatment strategy to apply uniformly to all patients. The availability of AA as a generic medication may help to close this gap. The ultimate choice should be based on patient and tumor factors.

Age, Gleason Score, and PSA are important prognostic factors for survival in metastatic castration-resistant prostate cancer. Results of The Uroncor Group (Uro-Oncological Tumors) of the Spanish Society of Radiation Oncology (SEOR)

INTRODUCTION

The treatment of metastatic castration-resistant prostate cancer (mCRPC) has changed significantly in recent years. Inhibitors of androgen receptors have shown especially significant benefits in overall (OS) and progression-free survival (PFS), with a good toxicity profile. Treatment selection depends on the patient's individual clinical, radiological, and biological characteristics.

OBJECTIVE

To describe treatment outcomes (efficacy, toxicity) in a cohort of patients with mCRPC in Spain.

MATERIALS AND METHODS

Multicenter, retrospective study of patients with mCRPC included in a database of the Urological Tumour Working Group (URONCOR) of the Spanish Society of Radiation Oncology (SEOR). Metastatic CRPC was defined according to the prostate cancer working group 3 (PCWG3) criteria. The Kaplan-Meier technique was used to evaluate OS and the Common Terminology Criteria for Adverse Events (CTCAE, v.4.0) were used to assess toxicity. Univariate and multivariate Cox regression analyses were performed to identify the factors significantly associated with OS.

RESULTS

A total of 314 patients from 17 hospitals in Spain diagnosed with mCRPC between June 2010 and September 2017 were included in this study. Mean age at diagnosis was 68 years (range 45-89). At a median follow-up of 35 months, OS at 1, 3, and 5 years were 92%, 38%, and 28%, respectively. Grades 1-2 and grade 3 toxicity rates were, respectively, 68% and 19%. No grade 4 toxicities were observed. On the multivariate analysis, the following factors were significantly associated with OS: age (hazard ratio [HR] 0.42, p = 0.010), PSA value at diagnosis of mCRPC (HR 0.55, p = 0.008), and Gleason score (HR 0.61, p = 0.009).

CONCLUSIONS

Age, Gleason score, and PSA at diagnosis of mCRPC are independently associated with overall survival in patients with mCRPC. The efficacy and toxicity outcomes in this patient cohort treated in radiation oncology departments in Spain are consistent with previous reports.

Cabazitaxel versus Abiraterone or Enzalutamide in Metastatic Prostate Cancer

BACKGROUND

The efficacy and safety of cabazitaxel, as compared with an androgen-signaling-targeted inhibitor (abiraterone or enzalutamide), in patients with metastatic castration-resistant prostate cancer who were previously treated with docetaxel and had progression within 12 months while receiving the alternative inhibitor (abiraterone or enzalutamide) are unclear.

METHODS

We randomly assigned, in a 1:1 ratio, patients who had previously received docetaxel and an androgen-signaling-targeted inhibitor (abiraterone or enzalutamide) to receive cabazitaxel (at a dose of 25 mg per square meter of body-surface area intravenously every 3 weeks, plus prednisone daily and granulocyte colony-stimulating factor) or the other androgen-signaling-targeted inhibitor (either 1000 mg of abiraterone plus prednisone daily or 160 mg of enzalutamide daily). The primary end point was imaging-based progression-free survival. Secondary end points of survival, response, and safety were assessed.

RESULTS

A total of 255 patients underwent randomization. After a median follow-up of 9.2 months, imaging-based progression or death was reported in 95 of 129 patients (73.6%) in the cabazitaxel group, as compared with 101 of 126 patients (80.2%) in the group that received an androgen-signaling-targeted inhibitor (hazard ratio, 0.54; 95% confidence interval [CI], 0.40 to 0.73; P<0.001). The median imaging-based progression-free survival was 8.0 months with cabazitaxel and 3.7 months with the androgen-signaling-targeted inhibitor. The median overall survival was 13.6 months with cabazitaxel and 11.0 months with the androgen-signaling-targeted inhibitor (hazard ratio for death, 0.64; 95% CI, 0.46 to 0.89; P = 0.008). The median progression-free survival was 4.4 months with cabazitaxel and 2.7 months with an androgen-signaling-targeted inhibitor (hazard ratio for progression or death, 0.52; 95% CI, 0.40 to 0.68; P<0.001), a prostate-specific antigen response occurred in 35.7% and 13.5% of the patients, respectively (P<0.001), and tumor response was noted in 36.5% and 11.5% (P = 0.004). Adverse events of grade 3 or higher occurred in 56.3% of patients receiving cabazitaxel and in 52.4% of those receiving an androgen-signaling-targeted inhibitor. No new safety signals were observed.

CONCLUSIONS

Cabazitaxel significantly improved a number of clinical outcomes, as compared with the androgen-signaling-targeted inhibitor (abiraterone or enzalutamide), in patients with metastatic castration-resistant prostate cancer who had been previously treated with docetaxel and the alternative androgen-signaling-targeted agent (abiraterone or enzalutamide). (Funded by Sanofi; CARD ClinicalTrials.gov number, NCT02485691.).

[Treatment situation in metastastic Castration Naive Prostate Cancer (mCRPC) and the implications on clinical routine]

There is an ongoing change of paradigm in the treatment of metastatic prostate cancer (mPC). Taxan-based chemotherapy demonstrated a prolonged survival of patients in several randomized phase III trials. This is true in the situation of metastatic castration-resistent prostate cancer (mCRPC) as well as in the hormone-naïve stage (metastatic castration-naive PC [mCNPC]). In patients with mCNPC, treatment with docetaxel in combination with androgen deprivation therapy (ADT) prolonged the median total survival time by 15 months in comparison to ADT alone. Comparable results were obtained by the endocrine combination treatment with ADT/abiraterone. With the current data in mind it seems to be useful to discuss the value of early combination therapy with ADT/docetaxel or ADT/abiraterone as well as the impact on further treatment options in the mCRPC setting and to define criteria for treatment decisions in clinical practice.

Sequencing strategies in the new treatment landscape of prostate cancer

Over the last 10 years, a number of new agents approved for the treatment of metastatic castration-resistant prostate cancer have led to a significant improvement in overall survival. The addition of new agents to androgen deprivation therapy has also allowed a paradigmatic change in the treatment of metastatic hormone-sensitive prostate cancer by improving overall survival in comparison with androgen deprivation therapy alone. Furthermore, recent data concerning the efficacy of three different androgen receptor-targeting agents in patients with nonmetastatic castration-resistant prostate cancer have opened up new scenarios for future patients' management. Defining the best sequencing strategies for men with prostate cancer is a currently unmet medical need, and choosing treatment is often challenging for clinicians because of the lack of direct comparisons of the available agents. The aim of this paper is to provide a comprehensive review of the literature concerning current sequencing strategies for prostate cancer patients.

Efficacy and safety of abiraterone acetate plus prednisone vs. cabazitaxel as a subsequent treatment after first-line docetaxel in metastatic castration-resistant prostate cancer: results from a prospective observational study (CAPRO)

BACKGROUND

To describe the patterns of second-line treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) after docetaxel treatment in a Spanish population, to identify the factors associated with those patterns, and to compare the efficacy and safety of the treatments most frequently administered.

METHODS

Observational, prospective study conducted in patients with histologically or cytologically confirmed prostate adenocarcinoma; documented metastatic castration-resistant disease; progression after first-line, docetaxel-based chemotherapy with or without other agents.

RESULTS

Of the 150 patients recruited into the study, 100 patients were prescribed abiraterone acetate plus prednisone (AAP), 44 patients received cabazitaxel plus prednisone (CP), and 6 patients received other treatments. Age (odds ratio [OR] 1.06, 95% [confidence interval] CI 1.01 to 1.11) and not elevated lactate dehydrogenase (LDH) levels (OR 0.33, 95% CI 0.14 to 0.76) were independently associated with the administration of AAP. Treatment with AAP was associated with significantly longer clinical/radiographic progression-free survival (hazard ratio [HR] 0.57, 95% CI 0.38 to 0.85) and overall survival (OS; HR 0.40, 95% CI 0.21 to 0.76) compared to CP, while no significant differences between the treatments were found regarding biochemical progression-free survival (PFS; HR 0.78 [95% CI 0.49 to 1.24]). However, in a post-hoc Cox regression analysis adjusted for potential confounders there were not differences between AAP and CP in any of the time-to-event outcomes, including overall survival. We observed no new safety signals related to either regimen.

CONCLUSION

Second-line AAP for patients with mCRPC is the most common treatment strategy after progression with a docetaxel-based regimen. When controlling for potential confounders, patients receiving this treatment showed no differences in PFS and OS in comparison to those receiving CP, although these latter results should be confirmed in randomized controlled trials.

Cellular and Molecular Mechanisms Underlying Prostate Cancer Development: Therapeutic Implications

Prostate cancer is the most frequent nonskin cancer and second most common cause of cancer-related deaths in man. Prostate cancer is a clinically heterogeneous disease with many patients exhibiting an aggressive disease with progression, metastasis, and other patients showing an indolent disease with low tendency to progression. Three stages of development of human prostate tumors have been identified: intraepithelial neoplasia, adenocarcinoma androgen-dependent, and adenocarcinoma androgen-independent or castration-resistant. Advances in molecular technologies have provided a very rapid progress in our understanding of the genomic events responsible for the initial development and progression of prostate cancer. These studies have shown that prostate cancer genome displays a relatively low mutation rate compared with other cancers and few chromosomal loss or gains. The ensemble of these molecular studies has led to suggest the existence of two main molecular groups of prostate cancers: one characterized by the presence of ERG rearrangements (~50% of prostate cancers harbor recurrent gene fusions involving ETS transcription factors, fusing the 5' untranslated region of the androgen-regulated gene TMPRSS2 to nearly the coding sequence of the ETS family transcription factor ERG) and features of chemoplexy (complex gene rearrangements developing from a coordinated and simultaneous molecular event), and a second one characterized by the absence of ERG rearrangements and by the frequent mutations in the E3 ubiquitin ligase adapter SPOP and/or deletion of CDH1, a chromatin remodeling factor, and interchromosomal rearrangements and SPOP mutations are early events during prostate cancer development. During disease progression, genomic and epigenomic abnormalities accrued and converged on prostate cancer pathways, leading to a highly heterogeneous transcriptomic landscape, characterized by a hyperactive androgen receptor signaling axis.

Abiraterone acetate plus prednisone in patients with newly diagnosed high-risk metastatic castration-sensitive prostate cancer (LATITUDE): final overall survival analysis of a randomised, double-blind, phase 3 trial

BACKGROUND

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.

METHODS

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.

FINDINGS

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; p<0·0001). 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.

INTERPRETATION

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.

FUNDING

Janssen Research & Development.

Pantoprazole Affecting Docetaxel Resistance Pathways via Autophagy (PANDORA): Phase II Trial of High Dose Pantoprazole (Autophagy Inhibitor) with Docetaxel in Metastatic Castration-Resistant Prostate Cancer (mCRPC)

BACKGROUND

Enhancing the effectiveness of docetaxel for men with metastatic castration-resistant prostate cancer (mCRPC) is an unmet clinical need. Preclinical studies demonstrated that high-dose pantoprazole can prevent or delay resistance to docetaxel via the inhibition of autophagy in several solid tumor xenografts.

MATERIALS AND METHODS

Men with chemotherapy-naive mCRPC with a prostate-specific antigen (PSA) >10 ng/mL were eligible for enrolment. Men received intravenous pantoprazole (240 mg) prior to docetaxel (75 mg/m²) every 21 days, with continuous prednisone 5 mg twice daily. Primary endpoint was a confirmed ≥50% decline of PSA. The trial used a Simon's two-stage design.

RESULTS

Between November 2012 and March 2015, 21 men with a median age of 70 years (range, 58-81) were treated (median, 6 cycles; range, 2-11). Men had received prior systemic therapies (median, 1; range, 0-3), and 14 had received abiraterone and/or enzalutamide. PSA response rate was 52% (11/21), which did not meet the prespecified criterion (≥13/21 responders) to proceed to stage 2 of the study. At interim analysis with a median follow-up of 17 months, 18 (86%) men were deceased (15 castration-resistant prostate cancer, 2 unknown, 1 radiation complication). Of the men with RECIST measurable disease, the radiographic partial response rate was 31% (4/13). The estimated median overall survival was 15.7 months (95% confidence interval [CI], 9.3-19.6) and median PFS was 5.3 months (95% CI, 2.6-12.9). There were no toxic deaths, and all adverse events were attributed to docetaxel.

CONCLUSION

The combination of docetaxel and pantoprazole was tolerable, but the resultant clinical activity was not sufficient to meet the ambitious predefined target to warrant further testing.

IMPLICATIONS FOR PRACTICE

To date, no docetaxel combination regimen has reported superior efficacy over docetaxel alone in men with metastatic castration-resistant prostate cancer (mCRPC). The PANDORA trial has demonstrated that the combination of high dose pantoprazole with docetaxel is tolerable, but the clinical activity was not sufficient to warrant further testing. The chemotherapy standard of care for men with mCRPC remains docetaxel with prednisone. Future studies of autophagy inhibitors will need to measure autophagy inhibition accurately and determine the degree of autophagy inhibition required to produce a meaningful clinical response.

Abiraterone Acetate: A Review in Metastatic Castration-Resistant Prostrate Cancer

Oral abiraterone acetate (Zytiga^®) is a selective inhibitor of CYP17 and thereby inhibits androgen biosynthesis, with androgen signalling crucial in the progression from primary to metastatic prostate cancer (PC) and subsequently, in the development of metastatic castration-resistant PC (mCRPC). In large phase 3 trials and in the clinical practice setting, oral abiraterone acetate in combination with prednisone was an effective treatment and had an acceptable, manageable tolerability and safety profile in chemotherapy-naive and docetaxel-experienced men with mCRPC. In the pivotal global phase 3 trials, relative to placebo (+prednisone), abiraterone acetate (+prednisone) prolonged overall survival (OS) at data maturity (final analysis) and radiographic progression-free survival (rPFS) at all assessed timepoints. Given its efficacy in prolonging OS and its convenient once-daily oral regimen, in combination with prednisone, abiraterone acetate is an important first-line option for the treatment of mCRPC.

Radium-223 Within the Evolving Treatment Options for Metastatic Castration-resistant Prostate Cancer: Recommendations from a European Expert Working Group

Several ongoing clinical trials are investigating novel therapies and combinations of existing therapies for the treatment of patients with metastatic castration-resistant prostate cancer. One such trial, ERA 223, has shown that the combination of abiraterone plus radium-223 did not improve symptomatic skeletal event-free survival compared with abiraterone plus placebo. Furthermore, an increase in bone fractures was observed with the combination of abiraterone and radium-223 in the study, particularly in patients not receiving bone health agents (denosumab or zoledronic acid). The results led to a change in the indication of radium-223 in Europe and also highlighted a need for greater awareness of bone health in patients with prostate cancer. Following a meeting to discuss these issues, we report in this article our views on the role of radium-223 within the emerging treatment options for patients with metastatic castration-resistant prostate cancer. We discuss best practices, and provide expert recommendations for preserving bone health and sequencing of life-prolonging therapies in patients with prostate cancer in order to achieve optimal outcomes. PATIENT SUMMARY: We provide recommendations on maintaining bone health, sequencing of treatments, and the role of radium-223 therapy in prostate cancer. Radium-223 is a valuable treatment option for patients with castration-resistant prostate cancer and bone metastases. Monitoring and maintaining bone health are essential for patients with prostate cancer, and should be considered at the initiation of androgen deprivation therapy.

A multicenter observational study of the real-world use of docetaxel for metastatic castration-resistant prostate cancer in China

Aim

To investigate the use of docetaxel for the treatment of metastatic castration‐resistant prostate cancer (mCRPC) in real‐world clinical practice in China.

Methods

This single‐arm, prospective, observational study was conducted at 32 study centers in China and included male patients aged ≥18 years with histologically confirmed prostate cancer who received ≥1 dose of docetaxel following failure of hormonal therapy (disease progression with serum testosterone <50 ng/dL). The primary aim was to investigate patterns of docetaxel treatment.

Results

Overall 403 patients were included between August 2011 and June 2016; patients initiated docetaxel after failure of first‐ (42.2% [170]), second‐ (31.0% [125]) and ≥third‐line (12.7% [51]) hormonal therapy, estramustine (11.4% [46]) or other (2.7% [11]). The planned cycles of docetaxel therapy were completed by 30.8% of patients, and the mean (SD) number of cycles received was 4.4 (2.86). Median overall survival (mOS) was 22.4 (95% CI, 20.4–25.8) months and the prostate‐specific antigen (PSA) response rate in patients with available data was 70.9% (168/237), with no differences in mOS and PSA response rates between treatment settings. Subgroup analysis revealed higher mOS in patients without visceral metastasis versus those with such metastases (22.9 vs. 17.4 months; P = 0.022). No new safety signals were observed and the most common adverse events associated with docetaxel were granulocytopenia (5%) and leukopenia (4.5%).

Conclusion

Data from this study showed that around three‐quarters of Chinese patients with mCRPC treated with docetaxel initiated treatment following first‐ or second‐line hormonal therapy and no new safety signals were observed.

Metastatic prostate cancer remains incurable, why?

Metastatic prostate cancer patients present in two ways-with already disseminated disease at the time of presentation or with disease recurrence after definitive local therapy. Androgen deprivation therapy is given as the most effective initial treatment to patients. However, after the initial response, almost all patients will eventually progress despite the low levels of testosterone. Disease at this stage is termed castration resistant prostate cancer (CRPC). Before 2010, the taxane docetaxel was the first and only life prolonging agent for metastatic CRPC (mCRPC). The last decade has witnessed robust progress in CRPC therapeutics development. Abiraterone, enzalutamide, apalutamide and sipuleucel-T have been evaluated as first- and second-line agents in mCRPC patients, while cabazitaxel was approved as a second-line treatment. Radium-223 dichloride was approved in symptomatic patients with bone metastases and no known visceral metastases pre- and post-docetaxel. However, despite significant advances, mCRPC remains a lethal disease. Both primary and acquired resistance have been observed in CRPC patients treated by these new agents. It could be solely cell intrinsic or it is possible that the clonal heterogeneity in treated tumors may result from the adaptive responses to the selective pressures within the tumor microenvironment. The aim of this review is to list current treatment agents of CRPC and summarize recent findings in therapeutic resistance mechanisms.

Abiraterone in metastatic castration-resistant prostate cancer: Efficacy and safety in unselected patients

BACKGROUND

Abiraterone acetate (AA), an androgen biosynthesis inhibitor, is now a standard of care for men with metastatic, castration-sensitive and castration-resistant prostate cancer (mCRPC). Data exploring real-world toxicity and outcomes are scarce.

METHODS

Retrospective study on unselected patients with mCRPC on AA plus steroids.

RESULTS

93 patients were included in the study. Median duration of treatment by AA was 7.5 months (95% CI 5.7-12) among the 58 patients pretreated with chemotherapy, versus 12.7 months ( 95% CI 8.2-35.9) among the 33 chemo-naive patients. Median survivals would reach 13.4 months (95% CI 10.2-19.1) and 36.4 months (95% CI 24.7-41.5) respectively. Rates of hypokalemia, peripheral edema, hypertension, cardiac failure, and overall survival assessments in patients with and without prior chemotherapy were similar to that previously reported in phase 3 randomized trials. The median survival time without adverse event of special interest was 7.5 months for hypokalemia and hypertension, and 5.3 months for liver-function test abnormalities (it was not reached for cardiac disorders).

CONCLUSION

Our findings provide further evidence for the survival benefits of AA with a low frequency of additional adverse events among unselected patients. In patients who have not developed hypokalemia or a transaminase increase within 7.5 and 5.3 months respectively, a lighter systematic monitoring may be considered.

Sequencing of Taxanes and New Androgen-targeted Therapies in Metastatic Castration-resistant Prostate Cancer: Results of the International Multicentre Retrospective CATS Database

BACKGROUND

The optimal sequence of life-extending therapies in metastatic castration-resistant prostate cancer (mCRPC) is unknown.

OBJECTIVE

To evaluate outcomes among mCRPC patients treated with docetaxel (DOC), cabazitaxel (CABA), and a novel androgen receptor-targeted agent (ART; abiraterone acetate or enzalutamide) according to three different sequences.

DESIGN, SETTING, AND PARTICIPANTS

Data from 669 consecutive mCRPC patients were retrospectively collected between November 2012 and October 2016.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was the prostate-specific antigen (PSA) response (decrease ≥50% from baseline) to each therapy. Secondary endpoints included best clinical benefit, time to PSA progression, radiological progression-free survival (rPFS), overall survival (OS), and toxicity.

RESULTS AND LIMITATIONS

A total of 158 patients received DOC→CABA→ART (group 1), 456 received DOC→ART→CABA (group 2), and 55 received ART→DOC→CABA (group 3). At baseline, PSA progression only and Gleason <8 were more common in group 3. PSA response on DOC was lower in group 3 than in other groups (p=0.02) and PSA response on CABA was higher in the second than in the third line (p=0.001). In Group 3, rPFS on ART (6.6 mo) and DOC (9.2 mo) was also shorter than in the other groups. OS calculated from the first life-extending therapy reached 34.8, 35.8, and 28.9 mo in groups 1, 2 and 3, respectively (p=0.007). Toxicity was comparable between the arms. The main limitations of the trial are its retrospective design and the low number of patients in group 3.

CONCLUSIONS

In this retrospective trial, sequencing of DOC, CABA, and one ART, was associated with median OS of up to 35.8 mo. CABA seemed to retain its activity regardless of treatment sequence. DOC activity after ART appeared to be reduced, but the data are insufficient to conclude that cross-resistance occurs.

PATIENT SUMMARY

The order of drugs administered to patients with metastatic castration-resistant prostate cancer could impact their efficacy, with cabazitaxel appearing to retain its activity whatever the therapeutic sequence.

Current treatment strategies for advanced prostate cancer

During the past decade, treatment strategies for patients with advanced prostate cancer involving stage IV (T4N0M0, N1M0 or M1) hormone-sensitive prostate cancer and recurrent prostate cancer after treatment with curative intent, as well as castration-resistant prostate cancer, have extensively evolved with the introduction and approval of several new agents including sipuleucel-T, radium-223, abiraterone, enzalutamide and cabazitaxel, all of which have shown significant improvement on overall survival. The appropriate use of these agents and the proper sequencing of these agents are still not optimized. The results of several recently reported randomized controlled trials and retrospective studies could assist in developing a treatment strategy for advanced prostate cancer. In addition, prospective studies and molecular characterization of tumors to address these issues are ongoing.

Abiraterone acetate and its use in the treatment of metastatic prostate cancer: a review

Abiraterone acetate, which targets enzymatic complexes playing a central role in steroidogenesis, demonstrated to increase survival significantly in both chemo-naive and docetaxel pretreated, becoming one of the drugs of choice for metastatic castration-resistant prostate cancer. More recently, this agent in combination to androgen deprivation therapy demonstrated to be efficacious also in metastatic castration-sensitive prostate cancer. The present review is aimed to outline the clinical development of abiraterone acetate, the pivotal trials which led to its approval for the clinical practice, new evidence about its efficacy in metastatic castration-sensitive prostate cancer, its place in the therapeutic landscape of prostate cancer and future directions of development.