scholarly journals Titration of Androgen Signaling: How Basic Studies Have Informed Clinical Trials Using High-Dose Testosterone Therapy in Castrate-Resistant Prostate Cancer

Life ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 884
Author(s):  
Steven K. Nordeen ◽  
Lih-Jen Su ◽  
Gregory A. Osborne ◽  
Perry M. Hayman ◽  
David J. Orlicky ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
High Dose ◽  
Castration Resistant Prostate Cancer ◽  
Androgen Ablation ◽  
Clinical Observations ◽  
Clinical Benefits ◽  
Castrate Resistant Prostate Cancer ◽  
Prostate Cancers ◽  
Castrate Resistant ◽  
Basic Studies

Since the Nobel Prize-winning work of Huggins, androgen ablation has been a mainstay for treatment of recurrent prostate cancer. While initially effective for most patients, prostate cancers inevitably develop the ability to survive, grow, and metastasize further, despite ongoing androgen suppression. Here, we briefly review key preclinical studies over decades and include illustrative examples from our own laboratories that suggest prostate cancer cells titrate androgen signaling to optimize growth. Such laboratory-based studies argue that adaptations that allow growth in a low-androgen environment render prostate cancer sensitive to restoration of androgens, especially at supraphysiologic doses. Based on preclinical data as well as clinical observations, trials employing high-dose testosterone (HDT) therapy have now been conducted. These trials suggest a clinical benefit in cancer response and quality of life in a subset of castration-resistant prostate cancer patients. Laboratory studies also suggest that HDT may yet be optimized further to improve efficacy or durability of response. However, laboratory observations suggest that the cancer will inevitably adapt to HDT, and, as with prior androgen deprivation, disease progression follows. Nonetheless, the adaptations made to render tumors resistant to hormonal manipulations may reveal vulnerabilities that can be exploited to prolong survival and provide other clinical benefits.

Studies of a novel modified E2F-targeted peptide with activity against castration-resistant prostate cancer.

2017 ◽  
Vol 35 (6_suppl) ◽  
pp. 205-205
Author(s):  
Joseph R. Bertino ◽  
Zoltan Szekely ◽  
Kathleen W Scotto
Keyword(s):  
Prostate Cancer ◽  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Target Genes ◽  
Replication Proteins ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Castrate Resistant Prostate Cancer ◽  
Castrate Resistant ◽  
The Stability

205 Background: The E2F family of genes encodes transcription factors that are key to the regulation of a number of target genes, including those encoding cyclins , CDKs , checkpoints regulators, and DNA repair and replication proteins. One of the primary functions of the E2Fs is to control the cell cycle, playing a major role in regulating the G1/S transition. One of the primary regulators of E2F expression is the retinoblastoma gene, RB, a chromatin associated protein that, in its unphosphorylated state, binds to and negatively regulates E2F; hyperphosphorylation of RB releases E2F, allowing cell cycle progression. Many tumor cells have mutant or dysfunctional RB, allowing the aberrant overexpression of the E2Fs and tumor cell proliferation; this aberrant overexpression is better tolerated when p53 is mutated, suppressing subsequent apoptosis. Overexpression of E2F, particularly E2F1, has thus been an attractive target for therapeutic intervention. However, this approach has not yet been successful, most likely due to the redundancy of the E2Fs and the lack of biomarkers for sensitivity. Methods: Using phage display, we have previously identified a novel peptide that, when coupled with penetratin (PEP) to enhance uptake), targets the E2F consensus site in E2F1,2 and 3a, leading to the downregulation of the activating E2Fs and their downstream targets. We have recently enhanced the stability and potency of this peptide by substituting L-Arg within the peptide with D-Arg. Results: Castrate resistant prostate cancer (CRPC) cells, DU-145, lack functional RB, have mutant p53, and are more sensitive to the D-Arg PEP than LnCap or PC-3 cells, with functional RB. Xenograft studies in mice show that the PEP, when encapsulated in PEGylated liposomes (PL-D-Arg PEP) , regresses DU-145 tumors without toxicity. Current studies are examining the combination of the (PL-D-Arg PEP) with taxotere, cisplatin and irradiation in prostate cancer xenografts and organoids from patients. Conclusions: A peptide that inhibits transcription of the activating E2Fs has promise to treat CRPC.

scholarly journals Bone-Targeted Therapies in Metastatic Castration-Resistant Prostate Cancer: Evolving Paradigms

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Joelle El-Amm ◽  
Ashley Freeman ◽  
Nihar Patel ◽  
Jeanny B. Aragon-Ching
Keyword(s):  
Prostate Cancer ◽  
Bone Metastases ◽  
Kinase Inhibitors ◽  
Targeted Agents ◽  
Pain Palliation ◽  
Castration Resistant Prostate Cancer ◽  
Humanized Monoclonal Antibody ◽  
Castrate Resistant Prostate Cancer ◽  
Castrate Resistant ◽  
Overall Survival Benefit

Majority of patients with metastatic castrate resistant prostate cancer (mCRPC) develop bone metastases which results in significant morbidity and mortality as a result of skeletal-related events (SREs). Several bone-targeted agents are either in clinical use or in development for prevention of SREs. Bisphosphonates were the first class of drugs investigated for prevention of SREs and zoledronic acid is the only bisphosphonate that is FDA-approved for this indication. Another bone-targeted agent is denosumab which is a fully humanized monoclonal antibody that binds to the RANK-L thereby inhibiting RANK-L mediated bone resorption. While several radiopharmaceuticals were approved for pain palliation in mCRPC including strontium and samarium, alpharadin is the first radiopharmaceutical to show significant overall survival benefit. Contemporary therapeutic options including enzalutamide and abiraterone have effects on pain palliation and SREs as well. Other novel bone-targeted agents are currently in development, including the receptor tyrosine kinase inhibitors cabozantinib and dasatinib. Emerging therapeutics in mCRPC has resulted in great strides in preventing one of the most significant sources of complications of bone metastases.

Docetaxel and imatinib every 21 days for castration resistant prostate cancer: A phase II trial

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. e16086-e16086
Author(s):  
T. L. Gillison ◽  
L. J. Appleman ◽  
D. M. Friedland ◽  
T. L. Evans ◽  
P. N. Lara ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Kinase Inhibitor ◽  
Performance Status ◽  
Castration Resistant Prostate Cancer ◽  
Meaningful Improvement ◽  
Neutropenic Sepsis ◽  
Significant Toxicity ◽  
Psa Response ◽  
Castrate Resistant Prostate Cancer ◽  
Castrate Resistant

e16086 Background: Docetaxel (D) IV every 21 days, is the only cytotoxic agent that prolongs survival in men with castrate resistant prostate cancer (CRPC). Imatinib (I), a tyrosine kinase inhibitor, modulates PDGFR-ß in tumor vasculature. Based on phase I data from our institution, we hypothesized that D plus I would prolong time to progression (TTP) in patients (pts) with CRPC. Methods: Subjects with CRPC received D 60 mg/m2 IV every 21 days plus I 400 mg PO daily. After 10 pts, the study treatment was modified due to toxicity so that pts received I 400 mg on 10 of 21 days/cycle. The primary endpoint was TTP. Secondary endpoints were rate of PSA response and overall survival (OS). The sample size of 43 pts was designed to provide 90% power to detect an increase in TTP from 5 to 8 months. Results: 43 pts enrolled from 8/05 to 9/08. Age at enrollment ranged from 54–86 years (median 69 years). 14 pts received <1 cycle of D plus I and were unevaluable: 10 had significant toxicity, 4 due to non-treatment related reasons. Primary toxicities were hematologic: 21% G4 neutropenia, 5% G4 anemia, and no G4 thrombocytopenia. Fatigue, nausea, diarrhea, and electrolyte abnormalities were common, but <2 cases each of G3-G4 toxicity occurred. 1 case of G5 non-neutropenic sepsis occurred. 29 pts received >2 cycles of chemotherapy (mean 4.6). 12 pts had PR (41.4%), 9 had SD (31.0%), and 8 had no response (27.6%) by PSA. No objective responses were seen by CT imaging among 10 pts with measurable disease. 3 pts remain on trial. For evaluable pts, overall median TTP was 6.4 months (95% CL: 4.8, 8.4 months) compared with TTP of 5 months seen in previous trials. 23 (79%) pts had PSA progression, 3 pts died before progression, and 3 pts remain on trial. For all evaluable pts who had PR or SD by PSA (N = 21), median TTP was 7.1 months (95% CL: 5.5, 9.1 months). Median OS was 23.1 months (95% CL: 11.61 months, NR), compared with 18.9 months for GC Conclusions: Docetaxel on day 1 plus imatinib 10 days of each 21-day cycle resulted in meaningful improvement in TTP in the subset of pts who showed a response. Toxicity precludes its use in the general population, although its role in select pts with good performance status needs to be explored. [Table: see text]

scholarly journals Effects of Abiraterone Acetate on Androgen Signaling in Castrate-Resistant Prostate Cancer in Bone

2012 ◽  
Vol 30 (6) ◽  
pp. 637-643 ◽  
Author(s):  
Eleni Efstathiou ◽  
Mark Titus ◽  
Dimitra Tsavachidou ◽  
Vassiliki Tzelepi ◽  
Sijin Wen ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Bone Marrow ◽  
Bone Marrow Aspirate ◽  
Specific Antigen ◽  
Abiraterone Acetate ◽  
Open Label ◽  
Clinical Observations ◽  
Castrate Resistant Prostate Cancer ◽  
Castrate Resistant ◽  
Tumor Expression

Purpose Persistent androgen signaling is implicated in castrate-resistant prostate cancer (CRPC) progression. This study aimed to evaluate androgen signaling in bone marrow–infiltrating cancer and testosterone in blood and bone marrow and to correlate with clinical observations. Patients and Methods This was an open-label, observational study of 57 patients with bone-metastatic CRPC who underwent transiliac bone marrow biopsy between October 2007 and March 2010. Patients received oral abiraterone acetate (1 g) once daily and prednisone (5 mg) twice daily. Androgen receptor (AR) and CYP17 expression were assessed by immunohistochemistry, testosterone concentration by mass spectrometry, AR copy number by polymerase chain reaction, and TMPRSS2-ERG status by fluorescent in situ hybridization in available tissues. Results Median overall survival was 555 days (95% CI, 440 to 965+ days). Maximal prostate-specific antigen decline ≥ 50% occurred in 28 (50%) of 56 patients. Homogeneous, intense nuclear expression of AR, combined with ≥ 10% CYP17 tumor expression, was correlated with longer time to treatment discontinuation (> 4 months) in 25 patients with tumor-infiltrated bone marrow samples. Pretreatment CYP17 tumor expression ≥ 10% was correlated with increased bone marrow aspirate testosterone. Blood and bone marrow aspirate testosterone concentrations declined to less than picograms-per-milliliter levels and remained suppressed at progression. Conclusion The observed pretreatment androgen-signaling signature is consistent with persistent androgen signaling in CRPC bone metastases. This is the first evidence that abiraterone acetate achieves sustained suppression of testosterone in both blood and bone marrow aspirate to less than picograms-per-milliliter levels. Potential admixture of blood with bone marrow aspirate limits our ability to determine the origin of measured testosterone.

scholarly journals From Bench to Bedside: Immunotherapy for Prostate Cancer

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Brian Wan-Chi Tse ◽  
Lidija Jovanovic ◽  
Colleen Coyne Nelson ◽  
Paul de Souza ◽  
Carl Andrew Power ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Current Treatment ◽  
Phase Iii ◽  
Rational Approach ◽  
Targeting Therapy ◽  
Treatment Regimes ◽  
Radium 223 ◽  
Clinical Benefits ◽  
Castrate Resistant Prostate Cancer ◽  
Castrate Resistant

The mainstay therapeutic strategy for metastatic castrate-resistant prostate cancer (CRPC) continues to be androgen deprivation therapy usually in combination with chemotherapy or androgen receptor targeting therapy in either sequence, or recently approved novel agents such as Radium 223. However, immunotherapy has also emerged as an option for the treatment of this disease following the approval of sipuleucel-T by the FDA in 2010. Immunotherapy is a rational approach for prostate cancer based on a body of evidence suggesting these cancers are inherently immunogenic and, most importantly, that immunological interventions can induce protective antitumour responses. Various forms of immunotherapy are currently being explored clinically, with the most common being cancer vaccines (dendritic-cell, viral, and whole tumour cell-based) and immune checkpoint inhibition. This review will discuss recent clinical developments of immune-based therapies for prostate cancer that have reached the phase III clinical trial stage. A perspective of how immunotherapy could be best employed within current treatment regimes to achieve most clinical benefits is also provided.

scholarly journals Metastatic Castration-Resistant Prostate Cancer: Critical Review of Enzalutamide

2013 ◽  
Vol 7 ◽  
pp. CMO.S11670 ◽  
Author(s):  
Joelle El-Amm ◽  
Nihar Patel ◽  
Ashley Freeman ◽  
Jeanny B. Aragon-Ching
Keyword(s):  
Prostate Cancer ◽  
Clinical Trials ◽  
Survival Benefit ◽  
First Generation ◽  
Phase Iii ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Castrate Resistant Prostate Cancer ◽  
Castrate Resistant ◽  
Overall Survival Benefit

Enzalutamide, previously known as MDV300, is an oral, second-generation androgen receptor (AR) signaling inhibitor or antagonist that was approved by the Food and Drug Administration in 2012 for the treatment of metastatic castrate-resistant prostate cancer (mCRPC) postdocetaxel. Preclinical studies have demonstrated impressive affinity to the AR compared to the first-generation AR inhibitors. The landmark Phase III AFFIRM trial demonstrated improved overall survival benefit compared to placebo in addition to improvement in all tested parameters. Enzalutamide is currently being studied in several trials prechemotherapy and in earlier settings of prostate cancer. This review will discuss the mechanism of action of enzalutamide, its pharmacokinetics, the preclinical and clinical trials that led to its approval, the ongoing clinical trials, its safety and efficacy, as well as patterns of resistance, and discusses its place in therapy within the context of several recently approved agents for mCRPC.

scholarly journals Modern antiandrogenic therapy of patients with castration-resistant prostate cancer without metastases

2020 ◽  
pp. 84-88
Author(s):  
S. V. Popov
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Molecular Mechanisms ◽  
Combined Therapy ◽  
Tumor Therapy ◽  
Specific Antigen ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistance ◽  
Castrate Resistant Prostate Cancer ◽  
Castrate Resistant

The prevalence of prostate cancer continues to increase worldwide. The effectiveness of androgen deprivation therapy for advanced prostate cancer has a time limit, after which castration resistance and disease progression are formed. A part of patients with castrate-resistant prostate cancer has no metastases (according to standard imaging methods). The main goal of treatment of these patients is to prolong the time before metastasis formation. This article presents a review of the current understanding of the molecular mechanisms underlying the inhibition of androgen-receptor signaling with enzalutamide, a second-generation androgen receptor antagonist, and the results of clinical studies of its efficacy and safety in castrate-resistant prostate cancer without metastases. It was determined that enzalutamide stimulates the expression of a new class of genes that are not regulated by dihydrotestosterone. It was found that, in addition to inhibiting androgen receptors, enzalutamide can act as a partial transcriptional agonist. Enzalutamide therapy has been shown to reduce the risk of tumor progression and death in patients with non-metastatic castrate-resistant prostate cancer and is well tolerated. Treatment with this drug increases the time before metastases appear, before the first use of subsequent anti-tumor therapy is necessary, and the period before prostate-specific antigen levels have progressed. Study of mechanisms induced by enzalutamide – inhibition of prostate cancer cells growth and activation of genes contributing to cancer development by enzalutamide-related androgen receptor – can help to clarify possible ways of resistance formation to this drug and possibilities of its overcoming with combined therapy.

scholarly journals Targeting Bone Metastases in Metastatic Castration-Resistant Prostate Cancer

2016 ◽  
Vol 10s1 ◽  
pp. CMO.Ss30751 ◽  
Author(s):  
Joelle El-Amm ◽  
Jeanny B. Aragon-Ching
Keyword(s):  
Prostate Cancer ◽  
Zoledronic Acid ◽  
Castration Resistant Prostate Cancer ◽  
Bone Microenvironment ◽  
Skeletal Involvement ◽  
Radium 223 ◽  
The Us ◽  
Castrate Resistant Prostate Cancer ◽  
Skeletal Related Events ◽  
Castrate Resistant

Skeletal involvement in metastatic castrate-resistant prostate cancer (mCRPC) is common and results in significant morbidity and mortality. The interaction of prostate cancer with the bone microenvironment contributes to progression of cancer in the bone leading to skeletal-related events (SREs). Studies aimed at targeting the bone have been carried out over the recent years. Bisphosphonates are synthetic pyrophosphate analogs first investigated for their role in SRE prevention with zoledronic acid as the main bisphosphonate that is approved by the US Food and Drug Administration for retardation of skeletal events in men with metastatic prostate cancer. Denosumab is another bone-targeted agent against uncontrolled osteolysis and serves as a RANK ligand inhibitor, superior to zoledronic acid in delaying SREs. Radiopharmaceuticals have played a role in targeting the bone microenvironment mainly in pain palliation in mCRPC utilizing strontium or samarium in the remote past, but only radium-223 is the first radiopharmaceutical that has yielded improvement in overall survival. The combination and sequencing strategies of these agents is the subject of multiple ongoing trials to guide the best use of these emerging agents.

Application of a novel method weighing drug costs against survival in castrate-resistant prostate cancer cancer.

2013 ◽  
Vol 31 (31_suppl) ◽  
pp. 271-271
Author(s):  
Helmy M. Guirgis
Keyword(s):  
Prostate Cancer ◽  
Drug Costs ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Castrate Resistant Prostate Cancer ◽  
Previously Treated ◽  
Novel Method ◽  
Different Populations ◽  
Initial Survey ◽  
Castrate Resistant

271 Background: In the last few years, 5 new anticancer drugs have been introduced for the treatment of castration-resistant prostate cancer (CRPC). The objective was to apply a simplified methodology of weighing drug costs against overall survival (OS) in CRPC. Methods: Estimated cost in United Sates (US) dollars of an entire treatment course of an evaluated drug was divided by previously reported median OS gain over control. An initial survey of 45 drugs demonstrated that the maximal cost/OS/day gain was $757. Accordingly, a scale of crude scores was constructed with a 0% assigned to a cost/OS gain greater than $1,000 and 100% to a cost/OS gain of $1. Value scores were calculated after adjusting for quality of life (QoL), adverse events (AEs), and specialized administration and preparation (AP). Results: The lowest cost/OS gain and highest value score were demonstrated by generic docetaxel. Enzalutamide in previously-treated and abiraterone in chemo-naïve and treated patients x 6 months showed cost/OS gain lower than that of docetaxel but significantly higher than cabazitaxel. Pricing of sipuleucel-T based on cost of the entire course partly accounted for its highest cost/OS and lowest scores. Extending abiraterone and enzalutamide treatment to 12 months increased cost/OS gain and decreased scores. Conclusions: Methodology was proposed to weigh drug cost against OS/day gain with and without adjustment for QoL, AEs, and AP. Results in CRPC tend to support use of docetaxel, abiraterone, and enzalutamide rather than cabazitaxel and sipuleucel-T. Varying drug indications and different populations within the CRPC spectrum preclude direct drug comparison.

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