Articles

Optimal Testosterone Control and Eligard®

By: Bertr, Tombala lowast ">.tombal@fycl.ucl.ac.be"> and Richard Bergesb

Published online: 01 July 2007

Keywords: Eligard, Hormone therapy, Leuprolide, Luteinising hormone-releasing hormone agonist, Prostate cancer, Testosterone

Abstract Full Text Full Text PDF (474 KB)

Abstract

Objectives

This review paper discusses the importance of optimal testosterone control in prostate cancer (PCa) and the advantages of the luteinising hormone-releasing hormone (LHRH) agonist Eligard® in this respect.

Methods

During an expert meeting in Marbella, Spain, in October 2006, PCa experts discussed optimal testosterone control and the role of Eligard. An interactive voting on these topics was held among the delegates. This paper reports on this meeting.

Results

LHRH agonists should suppress testosterone levels to an extent equivalent to surgical castration. A significant proportion of patients on conventional LHRH agonists do not achieve surgical castration levels. In addition, a significant percentage of patients experience hormonal escape during treatment. Eligard uses a modern delivery system and offers 1-, 3- and 6-mo depot formulations. The Eligard 1-mo, 3-mo, and 6-mo formulations achieve testosterone levels ≤20ng/dl in up to 98% of patients. Injection-related and breakthrough testosterone escapes seldom occur. Eligard 6-mo formulation (45mg; Eligard 6) is the first LHRH agonist able to extend treatment for 6 mo. Eligard 6 allows flexible monitoring of patients because the need for visits solely to administer injections is removed. In addition, reducing the number of injections may help reduce psychological burden in patients who then are less often reminded of their condition.

Conclusions

Eligard provides optimal testosterone control in PCa patients, that is, achieves castration testosterone levels and is associated with a very low percentage of hormonal escapes. Eligard 6 offers flexibility in follow-up of patients and may help reduce emotional distress.

Take Home Message

The LHRH agonist Eligard provides optimal control of testosterone, that is, achieves and maintains testosterone levels equal to those obtained with orchidectomy. The 6-mo formulation offers flexible monitoring of the patient and may reduce emotional distress.

Keywords: Eligard, Hormone therapy, Leuprolide, Luteinising hormone-releasing hormone agonist, Prostate cancer, Testosterone.

1. Introduction

Prostate cancer (PCa) is a major health care problem, being a common cancer in American men [1]. The American Cancer Society (ACS) estimates that, during 2007, about 218,890 new cases of PCa will be diagnosed in the United States. Not only is PCa very common, it is also associated with a high mortality rate, being the second leading cause of cancer death. PCa accounts for about 10% of cancer-related deaths in men [1]. When diagnosed with PCa, the patient and his physician have to choose from a wide range of therapies. Depending on stage and grade of the tumour and patient's life expectancy, treatment can be deferred until symptoms appear (expectant management) or the patient can be treated with radical prostatectomy, radiotherapy, androgen-deprivation therapy, or a combination of these treatments. Androgen-deprivation therapy has been the gold standard systemic therapy for the last 30 yr [2] and [3]. If historically lowering the testosterone level was achieved by surgical castration or estrogen therapy, now luteinising hormone-releasing hormone (LHRH) agonists have become the standard of care for advanced, metastatic, and recurrent disease [4]. Since the testosterone deprivation is reversible upon treatment interruption, LHRH agonists are also increasingly used in earlier stages of the disease in neoadjuvant or adjuvant setting to radiotherapy or surgery [5]. During an expert meeting in Marbella, Spain, in October 2006, which was attended by around 135 European urologists, experts on PCa discussed the importance of optimal testosterone suppression in patients receiving hormone treatment for PCa and the advantages of the new formulation of leuprolide: Eligard® in terms of optimal testosterone control. The opinion of the delegates on several topics was gathered by means of interactive voting, and the results were commented on by the expert panel. This review paper documents the most relevant topics discussed during the meeting and discusses the results of the interactive voting.

2. Importance of optimal testosterone control

2.1. Defining castration testosterone levels

Since the studies of the Nobel Prize's laureate Charles Huggins nearly 60 yr ago, it has been known that PCa cells rely on critical level of androgens to grow and survive [2] and [3]. Following castration, testosterone levels are suppressed, and prostate size and prostate specific antigen (PSA) levels decrease. By depriving PCa cells of testosterone, apoptosis is induced and the tumour shrinks. The testosterone level at which apoptosis is triggered is not known. The main goal of castration is thus to achieve and maintain low testosterone levels. But to what level should testosterone be suppressed? Although there are currently no clinical data available to support the concept that a low castration testosterone level is associated with better clinical outcomes, “the lower the better” has been advocated [6]. Historically, castration testosterone levels achieved by orchidectomy were regarded as the reference level. This level was set at below 50ng/dl by the Food and Drug Administration (FDA) in the 1980s. However, methodology and sensitivity of assays used have improved considerably since then, and more recent studies measuring serum testosterone levels after orchidectomy, based on the modern technique of chemiluminescence, have reported castration testosterone levels of around 20ng/dl [7], [8], [9], [10], and [11]. Since there is general consensus that testosterone levels achieved and maintained with LHRH agonists should be equivalent to surgical castration, several experts have proposed that the castration testosterone levels should be redefined to 20ng/dl or less, instead of the conventional 50ng/dl [12].

2.2. Castration by surgery or LHRH agonist?

Surgical castration by means of bilateral orchidectomy has for many years been the gold standard of castration until Andrew Schally [13] characterized the structure of LHRH. His research led to the development of synthetic peptide agonists of LHRH that offered new and more convenient alternatives for suppressing testosterone. Long-acting microcapsulated delivery systems for these LHRH agonists were developed and designed to release a controlled dose of the peptide over 1–3 mo. Although surgery is the most rapid method to achieve castration, LHRH agonists may lead to less psychological distress and are a flexible, reversible, and noninvasive method of castration. In a US study, 147 patients with previously untreated stage D PCa were asked whether they would prefer surgical castration or a monthly injection with the LHRH agonist goserelin [14]. Of these patients, 115 (78%) chose goserelin, whereas only 32 (22%) chose orchidectomy. In the same study, quality of life (QoL), as measured by cancer-specific questionnaires, statistically significantly improved in patients treated with goserelin, whereas there was no change observed in patients treated with orchidectomy [14]. With regard to adverse events (AEs), it appears that no major differences exist between orchidectomy and LHRH agonists concerning the rates of cardiovascular AEs (oedema, chest pain), digestive AEs (appetite change, constipation), musculoskeletal pain, and lethargy [11]. The incidence of hot flushes may be somewhat higher with LHRH agonists compared with orchidectomy [11]. A study performed by Potosky [15] somewhat contradicts these favourable data for LHRH agonists. A total of 431 men with PCa were treated either with orchidectomy (n=132) or an LHRH agonist (leuprolide or goserelin; n=299). Patients treated with the LHRH agonist reported physical discomfort and worries more often because of PCa than patients treated with orchidectomy. In addition, they more frequently assessed their overall health as fair or poor than did patients treated with orchidectomy and were also less likely to consider themselves free of PCa after treatment. Thus, it seems that although patients prior to treatment prefer LHRH agonists over orchidectomy, once the treatment is given, patients treated with LHRH agonists have more physical discomfort and worry about cancer or its treatment than patients who undergo orchidectomy. The fact that administration of LHRH agonists requires regular visits to the physician, which reminds the patient that he has cancer, may explain this finding. This result leads to an argument for the development of formulations of LHRH agonists that act for longer periods than 1–3 mo. In this regard, we will discuss the benefits of a new 6-mo formulation of leuprolide, Eligard 6, later in this paper.

2.3. Do currently available LHRH agonists achieve and maintain castration levels?

Conventional LHRH agonists currently available on the market include leuprolide, buserelin, goserelin, and triptorelin, each available in depot formulations requiring monthly or 3-monthly injections. In light of the standard definition of ≤50ng/dl castration level, it appears that a significant proportion of patients on these LHRH agonists (2–13%) do not achieve this level [16], [17], and [18]. Even fewer patients on currently available LHRH agonists achieve the more stringent definition of ≤20ng/dl; 13–38% of patients on conventional LHRH agonists have testosterone levels above 20ng/dl [16], [17], [19], and [20].

Effective androgen-deprivation therapy should be able not only to achieve castration testosterone levels but also to maintain these low testosterone levels. During long-term LHRH therapy, hormonal escapes may occur. Injection-related testosterone escapes or mini flares are defined as rises in testosterone levels >50ng/dl within 12h after second or subsequent injection of the LHRH agonist [12]. These events occur in about 10% of patients on currently available LHRH agonists [18] and [21]. A rise in testosterone levels >50ng/dl that occurs at any time during long-term LHRH agonist therapy is called a breakthrough testosterone escape, and are reported in 4–13% of patients on currently available LHRH agonists [22], [23], and [24]. Hormonal escapes can have a serious impact on the patient's QoL, and can be associated with a temporary increase in tumour symptoms such as bone pain and spinal cord compression [6], [25], and [26].

In conclusion, surgical castration reduces testosterone levels to ≤20ng/dl and, to be consistent, we should expect that LHRH agonist therapy suppress testosterone levels to the same extent. However, many LHRH agonists do not achieve or maintain these castration testosterone levels, which may negatively affect health and QoL. There is a need for an improved LHRH agonist formulation that is able to achieve and maintain testosterone levels equal to those achieved with orchidectomy.

3. Eligard: advantages for optimal testosterone control

3.1. Eligard: an innovative second-generation delivery system

Eligard is a unique extended-release formulation of leuprolide that has been developed with the aim to provide optimal testosterone control, that is, to achieve and maintain castration levels in a larger proportion of patients than that achieved with the conventional formulations of LHRH agonists. Although the molecular structure of the different LHRH agonists is virtually the same, they differ in the delivery system used. Leuprolide, which uses a lyophylised microsphere drug depot delivery system, has been used for many years. Eligard uses a new delivery system: the Atrigel® delivery system, which consists of a biodegradable polymer of D,L-lactide-co-glycolide dissolved in N-methyl-2-pyrolidone [27]. After mixing of the polymer and leuprolide, the formulation is injected subcutaneously as a liquid and forms a solid depot within the body for slowly releasing the drug [27] and [28], enabling a continuous and sustained release of leuprolide over the delivery period. Compared with the microsphere depot, this delivery system also provides a release of a 2-fold higher dose of leuprolide and maintenance of testosterone suppression for an additional 14 d [29]. The superior Atrigel delivery system was used not only in 1- and 3-mo Eligard depot formulations but also led to the development of a unique 6-mo Eligard depot formulation (45mg; Eligard 6) [30], [31], and [32]. Eligard 6 is the first commercially available LHRH agonist that extends treatment to once every 6 mo [33]. As has been discussed before, extending treatment and thereby reducing the number of visits to the physician may be of benefit for the patient, leading to less emotional distress. Patients do not have to visit the physician as frequently and are therefore not reminded as often that they have PCa. Moreover, Eligard 6 will allow more freedom in arranging follow-up visits, removing the need for visits purely to administer injections [33]. Eligard 6 thus offers convenience and increased patient comfort as a consequence of a decreased number of injections [33].

3.2. Optimal testosterone control with Eligard

In clinical trials, the 1-, 3- and 6-mo formulations of Eligard effectively suppressed testosterone levels. The mean testosterone levels after 6 mo of treatment with the 1-, and 3-mo formulations were 6.1ng/dl and 10.1ng/dl, respectively (Fig. 1) [30] and [32]. This level was 12.3ng/dl after 12-mo treatment with Eligard 6 (Fig. 1) [31]. Mean time to castration (50ng/dl) was about 20 d [30], [31], and [32]. The percentages of patients achieving castration testosterone levels of ≤50ng/dl and ≤20ng/dl were up to 99% and 98%, respectively [30], [31], and [32]. These data compare favourably with conventional LHRH agonist formulations (Fig 2 and Fig 3) [16], [17], [18], [19], and [20]. No injection-related testosterone escapes were observed with all three Eligard formulations, and the rate of breakthrough testosterone escapes was also very low: ≤1% with the Eligard 1, 3, and 6 formulation (Fig. 4) [30], [31], and [32].

gr1

Fig. 1 Eligard 1, 3, and 6 suppress testosterone levels below the castration level of 20ng/dl [33]. Reprinted from Sartor O, Eligard® 6: a new form of treatment for prostate cancer, Eur Urol Suppl 2006;5:905–10 with permission from the European Association of Urology.

gr2

Fig. 2 Eligard 1, 3, and 6 show an increased testosterone response rate, that is, a reduced percentage of patients not achieving castration testosterone levels of 50ng/dl compared with conventional formulations of LHRH agonists [16], [17], [18], [20], [23], [30], [31], [32], and [37].

gr3

Fig. 3 Eligard 1, 3, and 6 show an increased testosterone response rate, that is, a reduced percentage of patients not achieving castration testosterone levels of 20ng/dl compared with conventional formulations of LHRH agonists [16], [17], [19], [20], [30], [31], and [32].

gr4

Fig. 4 Eligard 1, 3, and 6 maintain low testosterone levels, that is, have a very low incidence of injection-related and breakthrough responses [30], [31], and [32].

3.3. Tolerability of Eligard

Eligard 1, 3, and 6 seem to have a tolerability similar to conventional leuprolide microsphere depot formulations [30], [31], [32], [34], [35], [36], and [37]. Most adverse events were related to testosterone suppression and are typical for LHRH agonists (eg, hot flushes, gynaecomastia, asthenia) (Table 1). Hot flushes were reported most frequently and were mainly mild or moderate in nature (Fig. 5) [30], [31], and [32].

Table 1 Eligard has a tolerability comparable to other LHRH agonists [30], [31], [32], [35], [36], [37], and [38]

General LHRH agonistsEligard
Hot flushes48–75%57–59%
Gynaecomastia4–16%1–4%
Asthenia6–15%6–17%
Testicular atrophy3–6%2–5%
Nausea0–13%0–3%

LHRH=luteinising hormone-releasing hormone.

gr5

Fig. 5 The majority of hot flushes reported during use of Eligard 1, 3, and 6 are of mild intensity [30], [31], and [32].

4. Interactive voting: testosterone monitoring and hormone therapy in clinical practice

An interactive voting session was held during the expert meeting in Marbella. When the delegates were asked if they currently measured testosterone levels before initiating hormone therapy, 37% answered “never,” 35% “in some cases,” and 28% “in most cases/always.” According to the PCa experts, it is important to measure testosterone levels before initiating hormone therapy because this allows monitoring of the efficacy of therapy. The majority of the delegates (75%) considered a testosterone level of ≤20ng/dl an appropriate castration level. When asked if the delegates measured testosterone levels to monitor treatment response after initiation of hormone therapy, 30% of the delegates indicated that they never measure testosterone levels. A total of 45% indicated that they assessed testosterone levels in case of a relevant PSA rise. It was discussed that it is indeed important to differentiate a PSA rise indicative of hormone resistance from that attributable to a breakthrough response. Six percent of respondents measured testosterone levels at least once during LHRH agonist therapy and 13% every 6 mo. The PCa experts concluded that it is important to measure testosterone levels at least once during LHRH agonist therapy to assess treatment efficacy in addition to measuring PSA. The measurement of testosterone should become part of clinical practice when evaluating the effects of hormonal therapy.

A total of 94% of delegates more or less fully agreed with the statement “when initiating an LHRH agonist, my goal is to achieve “the lowest possible” level of testosterone” (Fig. 6). In addition, 82% of delegates indicated that the testosterone suppression achieved is important when choosing between LHRH agonist formulations (Fig. 6). The majority of the delegates (66%) also agreed that Eligard 6 offers practical advantages for selected PCa patients.

gr6

Fig. 6 The majority of delegates agreed with the statements “when initiating an LHRH agonist, my goal is to achieve ‘the lowest possible’ level of testosterone” ( fx1 ) and “the testosterone suppression achieved is important when choosing between LHRH agonist formulations” ( fx2 ).

5. Conclusions

Although there is no objective evidence that a low castration testosterone level is associated with better clinical outcomes, we can assume that efforts should be made to control testosterone in a method comparable to orchidectomy. LHRH agonists should achieve castration testosterone levels and maintain these levels throughout long-term therapy to avoid variations during treatment. Eligard 1, 3, and 6 formulations achieve and maintain castration testosterone levels equal to orchidectomy. The unique Eligard 6 formulation provides urologists with the liberty in follow-up frequency because they are no longer tied to the 3-monthly injection regime. In addition, this formulation may decrease the psychological burden for the patient.

Conflicts of interests

The first author is a paid consultant for Astellas, AstraZeneca, Ferring, Pfizer, Ipsen, and sanofi-aventis. The second author has nothing to disclose.

References

  • [1] http://www.cancer.org/docroot/CRI/content/CRI_2_4_1X_What_are_the_key_statistics_for_prostate_cancer_36.asp?rnav=cri. Accessed at 2007.
  • [2] C. Huggins, C.V. Hodges. Studies on prostatic cancer. I. The effect of castration, of estrogen and of androgen injection on serum phosphatase in metastatic carcinoma of the prostate. Cancer Res. 1941;1:293-297
  • [3] C. Huggins, R. Stevens, C.V. Hodges. Studies on prostate cancer. II. The effect of castration on advanced carcinoma of the prostate gland. Arch Surg. 1941;43:209-223 Crossref.
  • [4] L. Boccon-Gibod. Optimising hormone therapy in advanced disease. Eur Urol Suppl. 2005;4(8):21-29 Abstract, Full-text, PDF, Crossref.
  • [5] L. Klotz. Optimising hormone therapy in localised and early disease. Eur Urol Suppl. 2005;4(8):12-20 Abstract, Full-text, PDF, Crossref.
  • [6] M.G. Oefelein, M.I. Resnick. Effective testosterone suppression for patients with prostate cancer: is there a best castration?. Urology. 2003;62:207-213 Crossref.
  • [7] A.V. Kaisary, C.J. Tyrrell, W.B. Peeling, K. Griffiths. Comparison of LHRH analogue (Zoladex) with orchiectomy in patients with metastatic prostatic carcinoma. Br J Urol. 1991;67:502-508 Crossref.
  • [8] B.J. Lin, K.K. Chen, M.T. Chen, L.S. Chang. The time for serum testosterone to reach castrate level after bilateral orchiectomy or oral estrogen in the management of metastatic prostatic cancer. Urology. 1994;43:834-837 Crossref.
  • [9] M.G. Oefelein, A. Feng, M.J. Scolieri, D. Ricchiutti, M.I. Resnick. Reassessment of the definition of castrate levels of testosterone: implications for clinical decision making. Urology. 2000;56:1021-1024 Crossref.
  • [10] H.F. Rohl, H.P. Beuke. Effect of orchidectomy on serum concentrations of testosterone and dihydrotestosterone in patients with prostatic cancer. Scand J Urol Nephrol. 1992;26:11-14 Crossref.
  • [11] N.J. Vogelzang, G.W. Chodak, M.S. Soloway, et al. Goserelin versus orchiectomy in the treatment of advanced prostate cancer: final results of a randomized trial. Zoladex Prostate Study Group. Urology. 1995;46:220-226 Crossref.
  • [12] A. Zlotta, F.M.J. Debruyne. Expert opinion on optimal testosterone control in prostate cancer. Eur Urol Suppl. 2005;4(8):37-41 Abstract, Full-text, PDF, Crossref.
  • [13] A.V. Schally, A.J. Kastin, A. Arimura. Hypothalamic follicle-stimulating hormone (FSH) and luteinizing hormone (LH)-regulating hormone: structure, physiology, and clinical studies. Fertil Steril. 1971;22:703-721
  • [14] B.R. Cassileth, M.S. Soloway, N.J. Vogelzang, et al. Quality of life and psychosocial status in stage D prostate cancer. Zoladex Prostate Cancer Study Group. Qual Life Res. 1992;1:323-329
  • [15] A.L. Potosky, K. Knopf, L.X. Clegg, et al. Quality-of-life outcomes after primary androgen deprivation therapy: results from the Prostate Cancer Outcomes Study. J Clin Oncol. 2001;19:3750-3757
  • [16] J. Morote, S. Esquena, J.M. Abascal, et al. Failure to maintain a suppressed level of serum testosterone during long-acting depot luteinizing hormone-releasing hormone agonist therapy in patients with advanced prostate cancer. Urol Int. 2006;77:135-138 Crossref.
  • [17] M.G. Oefelein, R. Cornum. Failure to achieve castrate levels of testosterone during luteinizing hormone releasing hormone agonist therapy: the case for monitoring serum testosterone and a treatment decision algorithm. J Urol. 2000;164:726-729
  • [18] M.F. Sarosdy, P.F. Schellhammer, M.S. Soloway, et al. Endocrine effects, efficacy and tolerability of a 10.8-mg depot formulation of goserelin acetate administered every 13 weeks to patients with advanced prostate cancer. BJU Int. 1999;83:801-806
  • [19] J. Kawakami, A. Morales. A comprehensive hormonal evaluation in patients with cancer of the prostate on androgen suppression with LHRH agonists. J Urol. 2002;167(Suppl):288 (abstract no. 1135)
  • [20] D. McLeod, N. Zinner, K. Tomera, et al. A phase 3, multicenter, open-label, randomized study of abarelix versus leuprolide acetate in men with prostate cancer. Urology. 2001;58:756-761 Crossref.
  • [21] R. Sharifi, R. Browneller. Serum testosterone suppression and potential for agonistic stimulation during chronic treatment with monthly and 3-month depot formulations of leuprolide acetate for advanced prostate cancer. J Urol. 2002;168:1001-1004
  • [22] D. Fontana, M. Mari, A. Martinelli, et al. 3-month formulation of goserelin acetate (‘Zoladex’ 10.8-mg depot) in advanced prostate cancer: results from an Italian, open, multicenter trial. Urol Int. 2003;70:316-320 Crossref.
  • [23] D. Jocham. Leuprorelin three-month depot in the treatment of advanced and metastatic prostate cancer: long-term follow-up results. Urol Int. 1998;60(Suppl 2):18-24 Crossref.
  • [24] M.S. Khan, A. O’Brien. An evaluation of pharmacokinetics and pharmacodynamics of leuprorelin acetate 3M-depot in patients with advanced and metastatic carcinoma of the prostate. Urol Int. 1998;60:33-40 Crossref.
  • [25] I. Popov, S. Jelic, D. Radosavljevic, Z. Nikolic-Tomasevic. Androgen level variations, clinical response to LHRH agonists and changes in the quality of life subscales in metastatic prostate cancer--speculations about possible role of the monoamine system. Neoplasma. 1997;44:308-313
  • [26] B. Tombal. Appropriate castration with luteinising hormone releasing hormone (LHRH) agonists: what is the optimal level of testosterone?. Eur Urol Suppl. 2005;4(5):14-19 Abstract, Full-text, PDF, Crossref.
  • [27] M.C. Cox, C.D. Scripture, W.D. Figg. Leuprolide acetate given by a subcutaneous extended-release injection: less of a pain?. Expert Rev Anticancer Ther. 2005;5:605-611 Crossref.
  • [28] H.B. Ravivarapu, K.L. Moyer, R.L. Dunn. Sustained activity and release of leuprolide acetate from an in situ forming polymeric implant. AAPS PharmSciTech. 2000;1:E1 Crossref.
  • [29] R. Perez-Marrero, R.C. Tyler. A subcutaneous delivery system for the extended release of leuprolide acetate for the treatment of prostate cancer. Expert Opin Pharmacother. 2004;5:447-457 Crossref.
  • [30] F.M. Chu, M. Jayson, M.K. Dineen, R. Perez, R. Harkaway, R.C. Tyler. A clinical study of 22.5mg. LA-2550: a new subcutaneous depot delivery system for leuprolide acetate for the treatment of prostate cancer. J Urol. 2002;168:1199-1203
  • [31] E.D. Crawford, O. Sartor, F. Chu, R. Perez, G. Karlin, J.S. Garrett. A 12-month clinical study of LA-2585 (45.0mg): a new 6-month subcutaneous delivery system for leuprolide acetate for the treatment of prostate cancer. J Urol. 2006;175:533-536 Crossref.
  • [32] R. Perez-Marreno, F.M. Chu, D. Gleason, E. Loizides, B. Wachs, R.C. Tyler. A six-month, open-label study assessing a new formulation of leuprolide 7.5mg for suppression of testosterone in patients with prostate cancer. Clin Ther. 2002;24:1902-1914 Crossref.
  • [33] O. Sartor. Eligard® 6: A new form of treatment for prostate cancer. Eur Urol Suppl. 2006;5:905-910 Abstract, Full-text, PDF, Crossref.
  • [34] J.E. Fowler. Use of Duros® leuprolide implant in patients with prostate cancer: efficacy and safety results from two long-term phase I/II and II studies. The Viadur Study Group. J Urol. 2000;163(Suppl 4):262-263
  • [35] M. Rizzo, T. Mazzei, E. Mini, R. Bartoletti, P. Periti. Leuprorelin acetate depot in advanced prostatic cancer: a phase II multicentre trial. J Int Med Res. 1990;18(Suppl 1):114-125
  • [36] R. Sharifi, R.C. Bruskewitz, M.C. Gittleman, S.D. Graham, P.B. Hudson, B. Stein. Leuprolide acetate 22.5mg 12-week depot formulation in the treatment of patients with advanced prostate cancer. Clin Ther. 1996;18:647-657 Crossref.
  • [37] H.W. Wechsel, M. Zerbib, F. Pagano, M.J. Coptcoat. Randomized open labelled comparative study of the efficacy, safety and tolerability of leuprorelin acetate 1M and 3M depot in patients with advanced prostatic cancer. Eur Urol. 1996;30(Suppl 1):7-14
  • [38] J.E. Fowler, J.E. Gottesman, C.F. Reid, G.L. Andriole, M.S. Soloway. Safety and efficacy of an implantable leuprolide delivery system in patients with advanced prostate cancer. J Urol. 2000;164:730-734

Footnotes

a Cliniques Universitaires Saint-Luc, UCL, Brussels, Belgium

b PAN-Klinik am Neumarkt, Cologne, Germany

lowast Corresponding author. Cliniques Universitaires Saint-Luc UCL, Avenue Hippocrate 10, 1200 Brussels, Belgium. Tel. +32 2 764 550 40; Fax: +32 2 764 55 80.