Androgen Receptor Rediscovered: The New Biology and Targeting the Androgen Receptor Therapeutically

2011 ◽  
Vol 29 (27) ◽  
pp. 3651-3658 ◽  
Author(s):  
Charles J. Ryan ◽  
Donald J. Tindall
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Clinical Success ◽  
Abiraterone Acetate ◽  
Clinical Findings ◽  
Phase Iii ◽  
Clinical Activity ◽  
Castration Resistant Prostate Cancer ◽  
Androgen Synthesis ◽  
Castration Resistant

Discoveries over the past decade suggest that castration-resistant prostate cancer (CRPC) is sensitive, but not resistant to, further manipulation of the androgen–androgen receptor (AR) axis. Several new therapies that target this axis have demonstrated clinical activity. In this article, preclinical and clinical findings occurring in the field of AR-targeted therapies are reviewed. Reviews of scientific and clinical development are divided into those occurring prereceptor (androgen production and conversion) and at the level of the receptor (AR aberrations and therapies targeting AR directly). Intracrine androgen production and AR amplification, among others, are among the principal aberrancies driving CRPC growth. Phase III data with abiraterone acetate and phase II data with MDV-3100, along with other similar therapies, confirm for the clinician that the scientific findings related to persistent AR signaling in a castrate milieu can be harnessed to produce significant clinical benefit for patients with the disease. Studies aimed at optimizing the timing of their use and exploring the mechanisms of resistance to these therapies are under way. The clinical success of therapies that directly target androgen synthesis as well as the most common aberrancies of the AR confirm that prostate cancer retains dependence on AR signaling, even in the castrate state.

scholarly journals Minireview: Androgen Metabolism in Castration-Resistant Prostate Cancer

2013 ◽  
Vol 27 (5) ◽  
pp. 708-714 ◽  
Author(s):  
Nima Sharifi
Keyword(s):  
Prostate Cancer ◽  
Abiraterone Acetate ◽  
Castration Resistant Prostate Cancer ◽  
Synthesis Inhibitor ◽  
Androgen Independence ◽  
Androgen Synthesis ◽  
Androgen Receptor Antagonist ◽  
Castration Resistant ◽  
Hormonal Therapies ◽  
Additional Clinical Benefit

Abstract The decades-old terminology of androgen independence has been replaced in recent years with castration-resistant prostate cancer. Biological and clinical evidence have together conspired to support the use of this revised terminology by demonstrating that in the vast majority of cases tumors are neither truly depleted of androgens, nor are they free of the requirement for androgens to sustain growth and progression. Abiraterone acetate, an androgen synthesis inhibitor, and enzalutamide, a potent androgen receptor antagonist, both exploit the continued requirement for androgens. A central question, given the therapeutic gains enabled by further suppression of the androgen axis with these newer agents, is whether there may be additional clinical benefit gained by moving the goal posts of androgen suppression even further. The answer lies in part with the mechanisms utilized by tumors that enable resistance to these therapies. The aims of this review were to give a broad outline of steroidogenesis in prostate cancer and to highlight recent developments in understanding resistance to hormonal therapies.

Novel therapies and emerging strategies for the treatment of patients with castration-resistant prostate cancer

2017 ◽  
Author(s):  
Deborah Mukherji ◽  
Aurelius Omlin ◽  
Carmel Pezaro ◽  
Johann De Bono
Keyword(s):  
Prostate Cancer ◽  
Abiraterone Acetate ◽  
Phase Iii ◽  
Trial Participation ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Radium 223 ◽  
New Treatments ◽  
Phase Iii Studies ◽  
Clinical And Translational Research

Castration-resistant prostate cancer (CRPC) represents a final stage of this malignancy for many men and is defined as the progression of prostate cancer despite castrate levels of testosterone. CRPC may present as a rising PSA, the development of new metastases, or worsening of known metastases. Recent advances have resulted in five new treatments for CRPC: the immunotherapy sipuleucel-T; the cytotoxic cabazitaxel; the androgen biosynthesis inhibitor abiraterone acetate; the radioisotope radium-223; and the antiandrogen enzalutamide. These have all improved overall survival in randomized phase III studies for patients with metastatic CRPC. Furthermore, multiple agents and combinations are currently in late-stage clinical testing. Men with advanced prostate cancer represent an important population for clinical and translational research and clinical trial participation should be considered as part of standard care.

scholarly journals Clinical Development of PARP Inhibitors in Treating Metastatic Castration-Resistant Prostate Cancer

Cells ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 860 ◽  
Author(s):  
Jacob J. Adashek ◽  
Rohit K. Jain ◽  
Jingsong Zhang
Keyword(s):  
Prostate Cancer ◽  
Unmet Need ◽  
Parp Inhibitors ◽  
Phase Iii ◽  
Clinical Activity ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Phase Ii Studies ◽  
Phase Iii Trials ◽  
Signaling Inhibitors

The approval of upfront abiraterone for castration-sensitive prostate cancer and the approval of enzalutamide and apalutamide for non-metastatic castration-resistant prostate cancer have led to early utilization of potent androgen receptor (AR) signaling inhibitors in treating advanced prostate cancer. There is an unmet need to develop novel therapies beyond targeting AR signaling for metastatic castration-resistant prostate cancer (mCRPC). Poly (ADP-ribose) polymerase inhibitors (PARPi) belong to a class of targeted agents being developed for the treatment of homologous recombination repair (HRR) deficient tumors. Olaparib, rucaparib, niraparib, veliparib, and talazoparib were evaluated in early phase trials as a monotherapy for HRR-deficient mCRPC. Among them, olaparib and rucaparib have breakthrough designations for BRCA1/2-mutated mCRPC. Phase II studies also reported clinical activity of the PARPi and abiraterone combination and the PARPi checkpoint inhibitor combination in HRR-intact mCRPC. Ongoing phase III trials are testing these combinations as frontline or later line treatments for mCRPC. This review summarizes the critical clinical data as well as ongoing clinical trials for developing PARPi in treating mCRPC.

scholarly journals Consequences of Different Corticosteroids on Serum Potassium and Prostate-Specific Antigen in Patients Receiving Abiraterone for Castration-Resistant Prostate Cancer: A Retrospective Observational Study

2017 ◽  
Vol 11 ◽  
pp. 117955491773773 ◽  
Author(s):  
Masaomi Tatsuzawa ◽  
Ryuichi Ogawa ◽  
Naoki Kinjo ◽  
Soan Kim ◽  
Fumitaka Shimizu ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Prostate Specific Antigen ◽  
Serum Potassium ◽  
Medical Records ◽  
Specific Antigen ◽  
Abiraterone Acetate ◽  
Castration Resistant Prostate Cancer ◽  
Synthesis Inhibitor ◽  
Androgen Synthesis ◽  
Castration Resistant

Background: Abiraterone acetate is an androgen synthesis inhibitor approved for the treatment of castration-resistant prostate cancer (CRPC). Although co-administration of either prednisone or prednisolone at 10 mg/d has been recommended to reduce the risk of abiraterone-induced hyperaldosteronism (notably hypokalemia) and to give adjunctive pain relief effects, whether these glucocorticoids can be substituted by dexamethasone remains unknown. Methods: We performed a retrospective review of medical records of patients who were given abiraterone for the treatment of CRPC with either prednisolone (ABI/PSL) 10 mg/d or dexamethasone (ABI/DEX) 0.5 or 1 mg/d between 2014 and 2017 in Juntendo University Nerima Hospital. Demographic and biochemical data including prostate-specific antigen (PSA) level were retrieved from the electronic medical records. Results: Fifty-three eligible patients (27 in ABI/PSL group and 26 in ABI/DEX group) were extracted from the records. Both groups showed no significant changes in serum potassium level before and after starting treatment. In the ABI/PSL group, 12 patients (46%) showed elevations of PSA and 7 patients (27%) discontinued treatment within 3 months. In contrast, in the ABI/DEX group, only 6 patients (25%) showed elevations of PSA and 3 patients (13%, all were given dexamethasone 1 mg/d) discontinued treatment. Conclusions: Dexamethasone and prednisolone may be equally effective in preventing abiraterone-induced hypokalemia.

Recent Developments in Treatments for Metastatic Castration-resistant Prostate Cancer—A Mechanistic Perspective

2012 ◽  
Vol 08 (02) ◽  
pp. 89
Author(s):  
Guru Sonpavde ◽  
E David Crawford ◽  
◽  
Keyword(s):  
Prostate Cancer ◽  
Abiraterone Acetate ◽  
Chemotherapeutic Agents ◽  
New Drugs ◽  
Phase Iii ◽  
Castration Resistant Prostate Cancer ◽  
Microtubule Inhibitor ◽  
Phase Iii Clinical Trials ◽  
Castration Resistant ◽  
Radium 223

Over the past decade, the treatment landscape in metastatic castration-resistant prostate cancer (CRPC) has markedly changed, with the introduction of three new chemotherapeutic agents. The mechanism of CRPC is not fully understood, but it may result from multiple pathways, including a loss or androgen receptor (AR) specificity and increased downstream signalling activity that provide multiple targets for therapeutic agents. For some years, docetaxel was the mainstay of treatment in CRPC, but recently, cabazitaxel (a microtubule inhibitor), sipuleucel-T (a cancer vaccine), and abiraterone acetate (a CYP17 inhibitor) were approved for CRPC treatment. In Phase III clinical trials, these agents have shown significant improvements in survival—over mitoxantrone (for cabazitaxel) and over placebo (for sipuleucel-T and abiraterone acetate)—and were well tolerated. There are also two treatments in late-stage development, MDV3100 (an oral AR antagonist) and radium-223 (an isotope that creates breaks in double-stranded DNA). These have also shown improvements in survival in Phase III trials; their regulatory approval is expected soon. The modes of actions of the existing and new drugs in CRPC are varied, but some are complementary and investigations of different combinations of these medications are much needed; they may enhance efficacy, further extend survival, and improve outcomes in this formerly untreatable disease.

Spironolactone: A selective androgen receptor modulator in castration-resistant prostate cancer.

2014 ◽  
Vol 32 (4_suppl) ◽  
pp. 212-212 ◽  
Author(s):  
Philippe Barthelemy ◽  
Eva Erdmann ◽  
Brigitte Duclos ◽  
Jean Pierre Bergerat ◽  
Jean-Emmanuel Kurtz ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Abiraterone Acetate ◽  
Functional Assay ◽  
Castration Resistant Prostate Cancer ◽  
Lncap Cells ◽  
Selective Androgen Receptor Modulator ◽  
Receptor Modulator ◽  
Castration Resistant ◽  
High Concentrations

212 Background: Spironolactone is an effective drug to treat arterial hypertension as well as fluid retention and hypokalemia. Recently, some data suggested that spironolactone might induce progression in castration-resistant prostate cancer (CRPC) patients treated by abiraterone acetate, a recently approved selective CYP17 inhibitor. Nevertheless, no biological data are available to explain these clinical observations. The purpose of this study was to identify the potential underlying molecular mechanism. Methods: Effect of spironolactone with or without Abiraterone acetate (AA) on androgen receptor (AR) was assessed on LNCaP cells in this study. We performed a yeast-based functional assay with different levels of spironolactone with and without AA. The nuclear localization and activation of androgen receptor (AR) were detected by immunofluorescence and luciferase assays. Results: Results from the yeast-based functional assay show that the wild type androgen receptor is activated by high concentrations of spironolactone in an androgen-depleted environment. Moreover, spironolactone-induced AR transcriptional activity is downregulated by different AR antagonists as well as high concentrations of AA. These results suggest that spironolactone is possibly a potential AR modulator. Luciferase reporter assays showed that AR transcriptional activity in LNCaP cells was upregulated by spironolactone as well. Finally, AR immunoreactivity was almost nuclear in spironolactone-exposed cells. Taken together, these results suggest that spironolactone is a selective androgen receptor modulator. Conclusions: Spironolactone is a selective androgen receptor modulator and should be used with caution in routine practice in patient with metastatic prostate cancer treated by hormonotherapy especially AA.

Clinical activity of abiraterone acetate in patients with castration-resistant prostate cancer who received prior ketoconazole therapy.

2014 ◽  
Vol 32 (4_suppl) ◽  
pp. 99-99 ◽  
Author(s):  
Bo Zhao ◽  
Jorge A. Garcia ◽  
Timothy D. Gilligan ◽  
Brian I. Rini ◽  
Robert Dreicer
Keyword(s):  
Prostate Cancer ◽  
Specific Antigen ◽  
Underlying Mechanism ◽  
Abiraterone Acetate ◽  
Clinical Activity ◽  
Drug Discontinuation ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Psa Response ◽  
Psa Progression

99 Background: Studies have shown activity of Abiraterone acetate (AA) in patients (pts) with castration-resistant prostate cancer (CRPC) who have received prior ketoconazole. Prostate-specific antigen (PSA) response to AA in relation to previous PSA response to ketoconazole was investigated. Methods: A retrospective analysis was conducted to determine the clinical activity of AA in men with CRPC who have received prior ketoconazole therapy at our institution. Time to PSA progression (PSA TTP) was defined by PCWG2 criteria, a PSA reduction of 50% or more was considered as PSA response. Results: Thirty four pts were identified. Nineteen pts (56%) had previous PSA responses on ketoconazole, with a median PSA TTP of 11 months (95% confidence interval [CI] 6.8-19.9). Subsequently, 11 of 34 (33%) of pts achieved a PSA response on AA, with a median PSA TTP of 6 months (95% CI 4.9-9.5). Among the 19 pts having a PSA response on ketoconazole, only four (21%) pts subsequently had PSA response to AA. Two of these pts had transient PSA response with PSA TTP less than 3 months on kKetoconazole, one patient discontinued Ketoconazole due to side effects, one patient had intermittent non-castrate testosterone levels. In contrast, 7 of 15 (46.7%) pts without prior PSA response to ketoconazole subsequently achieved PSA response on AA (p=0.11). Of note, PSA reduction of less than 50% on AA was observed in 9 of 34 pts (26%), which was associated with a longer median PSA TTP compared to pts who had PSA-progressive disease (5.9 months [95% CI 3.5-7.3] vs.1.5 months [95% CI 1.0-3.5], p=0.028). Five of these nine patients had a prior PSA response to ketoconazole but required drug discontinuation for reasons other than disease progression. Conclusions: PSA response to prior ketoconazole therapy is associated with lower PSA response rate to subsequent AA. The observation suggests that there is a biologically distinct subset of patients who are ketoconazole-resistant but abiraterone-sensitive, the underlying mechanism needs to be further investigated.

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