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Pinto F, Calamo A, Totaro A, Sacco E, Volpe A, Racioppi M, D'Addessi A, Bassi P. Androgen-Deprivation Therapy in Prostate Cancer: Clinical Evidence and Future Perspectives. Urologia 2010. [DOI: 10.1177/039156031007700201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Androgens are involved in the development and progression of prostate cancer even if the mechanism is not well-recognized. For this reason androgen-deprivation therapy remains a milestone for the treatment of patients with advanced and metastatic disease and, in the last years, in conjunction with radiotherapy and surgery in locally advanced tumors. Alternative options, such as intermittent deprivation suppression, seem to be promising in terms of clinical benefits and toxicity profile. However, current therapies present side effects, such as testosterone surge with consequent clinical flare-up, metabolic syndrome and hormone-resistance, which develops after a variable number of years. Novel therapies such as LH-RH antagonists and prolonged depot LH-RH analogues have been developed in order to avoid clinical flare-up and testosterone microsurges. Novel androgen synthesis inhibitors, such as abiraterone acetate and MDV3100, have been recently discovered and tested as promising hormonal second-line agents in patients with castration-resistant prostate cancer. Finally, long-term side effects from androgen deprivation, such as osteoporosis, sarcopenic obesity and cardiovascular morbidity should be carefully monitored and properly treated.
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Affiliation(s)
- F. Pinto
- Urologia, Policlinico Universitario Agostino Gemelli, Università Cattolica del Sacro Cuore, Roma
| | - A. Calamo
- Urologia, Policlinico Universitario Agostino Gemelli, Università Cattolica del Sacro Cuore, Roma
| | - A. Totaro
- Urologia, Policlinico Universitario Agostino Gemelli, Università Cattolica del Sacro Cuore, Roma
| | - E. Sacco
- Urologia, Policlinico Universitario Agostino Gemelli, Università Cattolica del Sacro Cuore, Roma
| | - A. Volpe
- Urologia, Policlinico Universitario Agostino Gemelli, Università Cattolica del Sacro Cuore, Roma
| | - M. Racioppi
- Urologia, Policlinico Universitario Agostino Gemelli, Università Cattolica del Sacro Cuore, Roma
| | - A. D'Addessi
- Urologia, Policlinico Universitario Agostino Gemelli, Università Cattolica del Sacro Cuore, Roma
| | - P.F. Bassi
- Urologia, Policlinico Universitario Agostino Gemelli, Università Cattolica del Sacro Cuore, Roma
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Van Poppel H. Evaluation of degarelix in the management of prostate cancer. Cancer Manag Res 2010; 2:39-52. [PMID: 21188095 PMCID: PMC3004563 DOI: 10.2147/cmar.s8841] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Indexed: 11/23/2022] Open
Abstract
Medical castration using gonadotropin-releasing hormone (GnRH) receptor agonists currently provides the mainstay of androgen deprivation therapy for prostate cancer. Although effective, these agents only reduce testosterone levels after a delay of 14 to 21 days; they also cause an initial surge in testosterone that can stimulate the cancer and lead to exacerbation of symptoms ("clinical flare") in patients with advanced disease. Phase III trial data for the recently approved GnRH receptor blocker, degarelix, demonstrated that it is as effective and well tolerated as GnRH agonists. However, it has a pharmacological profile more closely matching orchiectomy, with an immediate onset of action and faster testosterone and PSA suppression, without a testosterone surge or microsurges following repeated injections. As a consequence, with this GnRH blocker, there is no risk of clinical flare and no need for concomitant antiandrogen flare protection. Degarelix therefore provides a useful addition to the hormonal armamentarium for prostate cancer and offers a valuable new treatment option for patients with hormone-sensitive advanced disease. Here, we review key preclinical and clinical data for degarelix, and look at patient-focused perspectives in the management of prostate cancer.
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Affiliation(s)
- Hendrik Van Poppel
- Department of Urology, University Hospitals Leuven, Campus Gasthuisberg, Leuven, Belgium
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Abstract
The growth of prostate cancer cells is hormone dependent in the majority of patients with the disease. Lowering testosterone either surgically or medically (usually with a gonadotropin releasing hormone (GnRH) agonist) is the standard of care in patients with metastatic prostate cancer. Degarelix is a new GnRH antagonist for the treatment of patients with prostate cancer. In contrast to GnRH agonists, the development of GnRH antagonists was hindered for a long time owing to histamine-releasing activity and lack of potency and water solubility. Recently, however, degarelix has been approved by the FDA for the treatment of advanced prostate cancer. This review summarizes the preclinical and clinical data available for degarelix and describes its potential role in the market of prostate cancer therapeutics.
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Affiliation(s)
- Christian Doehn
- Department of Urology, University of Lübeck Medical School, Ratzeburger Allee 160, Lübeck, Germany.
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Kapitulnik J, Pelkonen O, Gundert-Remy U, Dahl SG, Boobis AR. Effects of pharmaceuticals and other active chemicals at biological targets: mechanisms, interactions, and integration into PB-PK/PD models. Expert Opin Ther Targets 2009; 13:867-87. [DOI: 10.1517/14728220903018965] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Samant MP, Miller C, Hong DJ, Koerber SC, Croston G, Rivier CL, Rivier JE. Synthesis and biological activity of GnRH antagonists modified at position 3 with 3-(2-methoxy-5-pyridyl)-alanine*. ACTA ACUST UNITED AC 2008; 65:284-91. [PMID: 15705170 DOI: 10.1111/j.1399-3011.2005.00219.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Degarelix is a potent very long-acting GnRH antagonist after subcutaneous administration. In this paper, we describe the synthesis of two analogs of degarelix incorporating racemic 3-(2-methoxy-5-pyridyl)-alanine (2-OMe-5Pal, 5) at position 3. The two diastereomers were separated by reverse-phase high-performance liquid chromatography (RP-HPLC) and the absolute stereochemistry at position 3 in the peptides was determined by enzymatic digestion with proteinase K. These analogs were tested in vitro for their ability to antagonize the GnRH receptor and in vivo for duration of action in a castrated male rat assay. Analog 7 with D2-OMe-5Pal was potent in vitro (IC50 = 5.22 nM); however, analog 8 with L2-OMe-5Pal at position 3 in degarelix lost potency as an antagonist of the human GnRH receptor (IC50 = 36.95 nM). Both the analogs were found to be short-acting in vivo.
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Affiliation(s)
- M P Samant
- The Clayton Foundation Laboratories for Peptide Biology, The Salk Institute, La Jolla, CA 92037, USA
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Princivalle M, Broqua P, White R, Meyer J, Mayer G, Elliott L, Bjarnason K, Haigh R, Yea C. Rapid suppression of plasma testosterone levels and tumor growth in the dunning rat model treated with degarelix, a new gonadotropin-releasing hormone antagonist. J Pharmacol Exp Ther 2006; 320:1113-8. [PMID: 17179469 DOI: 10.1124/jpet.106.112326] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Degarelix (FE 200486) is a member of a new class of water-soluble (>50 mg/ml) gonadotropin-releasing hormone (GnRH) antagonists in clinical development for prostate cancer. Upon subcutaneous administration, degarelix forms a gel that results in a sustained release of the compound into the circulation, immediately blocking GnRH receptors in the pituitary and inducing a fast and sustained suppression of gonadotrophin secretion in rats and primates. One of the few animal models of prostate adenocarcinoma is the Dunning R-3327H rat carcinoma transplanted into Copenhagen rats. The growth of the Dunning tumor can be inhibited by various treatments reported to be effective in the clinic, such as GnRH superagonists, antiandrogens, 5-alphareductase inhibitors, tyrosine kinase inhibitors, and surgical castration. We report in this study that degarelix produces a fast and sustained suppression of the pituitary gonadal axis in rats and a similar inhibition of tumor growth compared with surgical castration in the Dunning R-3327H rat carcinoma model. First, degarelix as been compared with d-Trp(6)-luteinizing hormone-releasing hormone and surgical castration on a short-term study (2 months); and second, degarelix has been compared with leuprolide and surgical castration on a long-term study (12 months). In both studies, degarelix demonstrated a sustained inhibition of tumor growth at least comparable with surgical castration. These data provide a convincing profile of degarelix as a potential candidate for the clinical management of sex steroid-dependent pathologies, such as prostate cancer, where long-term reversible chemical castration is required.
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Affiliation(s)
- Marc Princivalle
- Ferring Research Ltd., Chilworth Science Park, 1 Venture Rd., Southampton SO16 7NP, UK.
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Tornøe CW, Agersø H, Senderovitz T, Nielsen HA, Madsen H, Karlsson MO, Jonsson EN. Population pharmacokinetic/pharmacodynamic (PK/PD) modelling of the hypothalamic-pituitary-gonadal axis following treatment with GnRH analogues. Br J Clin Pharmacol 2006; 63:648-64. [PMID: 17096678 PMCID: PMC2000597 DOI: 10.1111/j.1365-2125.2006.02820.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
AIMS To develop a population pharmacokinetic/pharmacodynamic (PK/PD) model of the hypothalamic-pituitary-gonadal (HPG) axis describing the changes in luteinizing hormone (LH) and testosterone concentrations following treatment with the gonadotropin-releasing hormone (GnRH) agonist triptorelin and the GnRH receptor blocker degarelix. METHODS Fifty-eight healthy subjects received single subcutaneous or intramuscular injections of 3.75 mg of triptorelin and 170 prostate cancer patients received multiple subcutaneous doses of degarelix of between 120 and 320 mg. All subjects were pooled for the population PK/PD data analysis. A systematic population PK/PD model-building framework using stochastic differential equations was applied to the data to identify nonlinear dynamic dependencies and to deconvolve the functional feedback interactions of the HPG axis. RESULTS In our final PK/PD model of the HPG axis, the half-life of LH was estimated to be 1.3 h and that of testosterone 7.69 h, which corresponds well with literature values. The estimated potency of LH with respect to testosterone secretion was 5.18 IU l(-1), with a maximal stimulation of 77.5 times basal testosterone production. The estimated maximal triptorelin stimulation of the basal LH pool release was 1330 times above basal concentrations, with a potency of 0.047 ng ml(-1). The LH pool release was decreased by a maximum of 94.2% by degarelix with an estimated potency of 1.49 ng ml(-1). CONCLUSIONS Our model of the HPG axis was able to account for the different dynamic responses observed after administration of both GnRH agonists and GnRH receptor blockers, suggesting that the model adequately characterizes the underlying physiology of the endocrine system.
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Jadhav PR, Agersø H, Tornøe CW, Gobburu JVS. Semi-mechanistic pharmacodynamic modeling for degarelix, a novel gonadotropin releasing hormone (GnRH) blocker. J Pharmacokinet Pharmacodyn 2006; 33:609-34. [PMID: 16967346 DOI: 10.1007/s10928-006-9025-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2006] [Accepted: 06/05/2006] [Indexed: 11/24/2022]
Abstract
An integrated semi-mechanistic pharmacodynamic (PD) model describing the relationship between luteinizing hormone (LH) and testosterone (T) after short-term administration of degarelix was developed. Data from three clinical studies involving, intravenous (IV) and subcutaneous (SC) dosing, in healthy male subjects were available. Degarelix pharmacokinetic (PK) data from all studies were modeled simultaneously. One intravenous study was used to develop the PD model and the two other studies (IV and SC dosing) were used to qualify the model. Degarelix PK follows a two-compartment model and exhibits flip-flop kinetics after subcutaneous dosing. Based on physiological mechanism, the gonadotropin releasing hormone (GnRH) time course was described using a pulsatile release model. A precursor-dependent pool model was used to describe the kinetics of LH in the pituitary and plasma compartment. In males, LH regulates T production in leydig cells. Degarelix inhibits the release of LH from the pool compartment to the plasma compartment leading to decreased T production. The plasma half-life of LH (2.6-3.3 hr) and T (2.7 hr) match well with the literature reports. The proposed PD model reasonably described the time course of LH and T including the LH rebound for short-term studies. The model predicted the time course of LH and T for the second IV and SC dosing studies very well. However, the long term simulations from the final model did not match with literature reports. A modification is suggested based on the physiological understanding of the system. The proposed novel modification to precursor models can be of general use for predicting long term responses.
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Affiliation(s)
- Pravin R Jadhav
- Pharmacometrics, Office of Clinical Pharmacology and Biopharmaceutics, Center for Drug Evaluation and Research, 10903 New Hampshire Avenue, Building 21, Silver Spring, MD 20993, USA
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Tornøe CW, Overgaard RV, Agersø H, Nielsen HA, Madsen H, Jonsson EN. Stochastic Differential Equations in NONMEM®: Implementation, Application, and Comparison with Ordinary Differential Equations. Pharm Res 2005; 22:1247-58. [PMID: 16078134 DOI: 10.1007/s11095-005-5269-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2004] [Accepted: 03/16/2005] [Indexed: 10/25/2022]
Abstract
PURPOSE The objective of the present analysis was to explore the use of stochastic differential equations (SDEs) in population pharmacokinetic/pharmacodynamic (PK/PD) modeling. METHODS The intra-individual variability in nonlinear mixed-effects models based on SDEs is decomposed into two types of noise: a measurement and a system noise term. The measurement noise represents uncorrelated error due to, for example, assay error while the system noise accounts for structural misspecifications, approximations of the dynamical model, and true random physiological fluctuations. Since the system noise accounts for model misspecifications, the SDEs provide a diagnostic tool for model appropriateness. The focus of the article is on the implementation of the Extended Kalman Filter (EKF) in NONMEM for parameter estimation in SDE models. RESULTS Various applications of SDEs in population PK/PD modeling are illustrated through a systematic model development example using clinical PK data of the gonadotropin releasing hormone (GnRH) antagonist degarelix. The dynamic noise estimates were used to track variations in model parameters and systematically build an absorption model for subcutaneously administered degarelix. CONCLUSIONS The EKF-based algorithm was successfully implemented in NONMEM for parameter estimation in population PK/PD models described by systems of SDEs. The example indicated that it was possible to pinpoint structural model deficiencies, and that valuable information may be obtained by tracking unexplained variations in parameters.
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Affiliation(s)
- Christoffer W Tornøe
- Experimental Medicine, Ferring Pharmaceuticals A/S, DK-2300, Copenhagen S, Denmark.
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Tornøe CW, Agersø H, Nielsen HA, Madsen H, Jonsson EN. Pharmacokinetic/Pharmacodynamic Modellingof GnRH Antagonist Degarelix: A Comparisonof the Non-linear Mixed-Effects Programs NONMEM and NLME. J Pharmacokinet Pharmacodyn 2005; 31:441-61. [PMID: 16222784 DOI: 10.1007/s10928-005-5911-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In this paper, the two non-linear mixed-effects programs NONMEM and NLME were compared for their use in population pharmacokinetic/pharmacodynamic (PK/PD) modelling. We have described the first-order conditional estimation (FOCE) method as implemented in NONMEM and the alternating algorithm in NLME proposed by Lindstrom and Bates. The two programs were tested using clinical PK/PD data of a new gonadotropin-releasing hormone (GnRH) antagonist degarelix currently being developed for prostate cancer treatment. The pharmacokinetics of intravenous administered degarelix was analysed using a three compartment model while the pharmacodynamics was analysed using a turnover model with a pool compartment. The results indicated that the two algorithms produce consistent parameter estimates. The bias and precision of the two algorithms were further investigated using a parametric bootstrap procedure which showed that NONMEM produced more accurate results than NLME together with the nlmeODE package for this specific study.
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Affiliation(s)
- Christoffer W Tornøe
- Experimental Medicine, Ferring Pharmaceuticals A/S, Kay Fiskers Plads 11, DK 2300, Copenhagen S, Denmark.
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