Randomised controlled study of orchidectomy vs long-acting D-Trp-6-LHRH microcapsules in advanced prostatic carcinoma

Luteinizing hormone-releasing hormone agonists versus orchiectomy in the treatment of prostate cancer: A systematic review

Background

Orchiectomy has been replaced by medication represented by luteinizing hormone-releasing hormone (LHRH) agonist as the first-line therapy for androgen deprivation therapy (ADT). After the wide application of LHRH agonist, the side-effects of long-term ADT were noticed. It is time to reconsider the role of medication and surgeries in the treatment of prostate cancer.

Methods

Embase, Pubmed, Web of science and Cochrane library were searched for relevant trials. Quality of the studies and risk of bias were assessed by using the Newcastle-Ottawa Scale (NOS). Therapeutic and adverse effects, as well as long-term metabolic adverse effects were extracted from the selected studies. The data synthesized in meta-analyses were performed with R software (4.2.1). Risk ratio (RR) with its 95% confidence interval (CI) was calculated by combining outcome data including complete and partial response rate, progression rate, death rate and adverse effects such as hot flash and increase in pain. Descriptive analysis was performed among the prostate specific antigen (PSA), testosterone and metabolic adverse effects due to a lack of homogeneity of frailty measures.

Results

1,711 participants from 11 studies were included in our systematic review. 1,258 patients from six studies were included in the meta-analysis. Based on the meta-analysis, the therapeutic and adverse outcomes included overall response rate, complete response rate, partial response rate, stable rate, progression rate, death rate and hot flashes. No statistical significance was observed between LHRH agonists and orchiectomy. Compared with surgery, LHRH agonist elevated the risk of the increase in pain. In descriptive analysis, it was shown that the therapeutic effects between PSA and testosterone also showed no significant difference. Both groups had lipid and glucose metabolic disorders, and a few studies reported worse lipid metabolic performance in orchiectomy group and worse insulin resistance in LHRH agonist group.

Conclusion

We found that the therapeutic outcomes were similar between the two options. The results of lipid and glucose metabolic abnormality were controversial in existing studies. The direct comparison studies on metabolic adverse effects should be performed in the future. The therapeutic, metabolic, psychological and economical effects should be considered before applying ADT methods.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022365891.

Linking prostate cancer cell AR heterogeneity to distinct castration and enzalutamide responses

Expression of androgen receptor (AR) in prostate cancer (PCa) is heterogeneous but the functional significance of AR heterogeneity remains unclear. Screening ~200 castration-resistant PCa (CRPC) cores and whole-mount sections (from 89 patients) reveals 3 AR expression patterns: nuclear (nuc-AR), mixed nuclear/cytoplasmic (nuc/cyto-AR), and low/no expression (AR-/lo). Xenograft modeling demonstrates that AR+ CRPC is enzalutamide-sensitive but AR-/lo CRPC is resistant. Genome editing-derived AR+ and AR-knockout LNCaP cell clones exhibit distinct biological and tumorigenic properties and contrasting responses to enzalutamide. RNA-Seq and biochemical analyses, coupled with experimental combinatorial therapy, identify BCL-2 as a critical therapeutic target and provide proof-of-concept therapeutic regimens for both AR+/hi and AR-/lo CRPC. Our study links AR expression heterogeneity to distinct castration/enzalutamide responses and has important implications in understanding the cellular basis of prostate tumor responses to AR-targeting therapies and in facilitating development of novel therapeutics to target AR-/lo PCa cells/clones.

Adjuvant androgen deprivation therapy for prostate cancer treated with radiation therapy

Radiation therapy is a commonly used curative modality for prostate cancer. The addition of androgen deprivation therapy (ADT) increases the curative potential of prostate radiotherapy (RT) in multiple subsets of patients. In addition to having an independent cytotoxic effect, current evidence suggests that androgen deprivation synergistically works with radiation therapy by preventing DNA repair. Given the wide-ranging toxicities of this therapy, clinicians must judiciously choose which patients may benefit from ADT and also consider the appropriate length of treatment. With recent advances in RT delivery, higher doses of radiation are currently used when compared with the dose used in historic trials, leading to the unanswered question of how RT dose interacts with ADT. Current and future clinical studies are attempting to further define the appropriate indications and patient populations for which ADT represents a clinically appropriate addition to prostate RT.

Discovery of LHRH and development of LHRH analogs for prostate cancer treatment

The discovery, isolation, elucidation of structure, synthesis, and initial testing of the neuropeptide hypothalamic luteinizing hormone-releasing hormone (LHRH), which regulates reproduction, is briefly described. The design, synthesis, and experimental and clinical testing of agonistic analogs of LHRH is extensively reviewed focusing on the development of new methods for the treatment of prostate cancer. Subsequent development of antagonistic analogs of LHRH is then faithfully recounted with special emphasis on therapy of prostate cancer and BPH. The concepts of targeted therapy to peptide receptors on tumors are re-examined and the development of the cytotoxic analogs of LHRH and their status is reviewed. The endeavor to develop better therapies for prostate cancer, based on LHRH analogs, guided much of our work.

Luteinizing Hormone-Releasing Hormone Agonists are Superior to Subcapsular Orchiectomy in Lowering Testosterone Levels of Men with Prostate Cancer: Results from a Randomized Clinical Trial

PURPOSE

Recent evidence suggests that reaching the lowest achievable levels of testosterone with androgen deprivation therapy delays disease progression and increases overall survival in men with advanced prostate cancer. The aim of this analysis was to compare posttreatment serum testosterone levels between patients undergoing subcapsular orchiectomy and patients treated with the luteinizing hormone-releasing hormone agonist triptorelin.

MATERIALS AND METHODS

In this randomized clinical trial we included 58 consecutive hormone naïve men diagnosed with advanced prostate cancer at Herlev and Gentofte University Hospital, Herlev, Denmark from September 2013 to March 2015. Followup was 48 weeks. Participants were randomly assigned 1:1 to subcapsular orchiectomy or triptorelin 22.5 mg given as 24-week depot injections. Androgen status was measured by liquid chromatography-tandem mass spectrometry prior to treatment and after 12, 24 and 48 weeks. Between group differences in achieved hormone levels were analyzed by longitudinal Tobit regression.

RESULTS

Triptorelin injections resulted in 29% lower testosterone levels (95% CI 17.2-41.7) compared to subcapsular orchiectomy (p <0.001). A significantly higher proportion of men receiving triptorelin had testosterone levels less than 20 ng/dl at 12 and 48 weeks compared to men undergoing orchiectomy (97% vs 79% and 100% vs 87%, respectively, p <0.05). There was no detectable difference in the adrenal androgen reduction between the treatment groups.

CONCLUSIONS

The use of 24-week depot triptorelin injections results in significantly lower testosterone levels compared to subcapsular orchiectomy. To our knowledge this is the first randomized study to demonstrate a difference in treatment effect between surgical and medical castration on testosterone levels.

Carriers for the tunable release of therapeutics: etymological classification and examples

Introduction Physiological processes at the molecular level take place at precise spatiotemporal scales, which vary from tissue to tissue and from one patient to another, implying the need for carriers that enable tunable release of therapeutics. Areas covered Classification of all drug release to intrinsic and extrinsic is proposed, followed by the etymological clarification of the term 'tunable' and its distinction from the term 'tailorable'. Tunability is defined as analogous to tuning a guitar string or a radio receiver to the right frequency using a single knob. It implies changing a structural parameter along a continuous quantitative scale and correlating it numerically with the release kinetics. Examples of tunable, tailorable and environmentally responsive carriers are given, along with the parameters used to achieve these levels of control. Expert opinion Interdependence of multiple variables defining the carrier microstructure obstructs the attempts to elucidate parameters that allow for the independent tuning of release kinetics. Learning from the tunability of nanostructured materials and superstructured metamaterials can be a fruitful source of inspiration in the quest for the new generation of tunable release carriers. The greater intersection of traditional materials sciences and pharmacokinetic perspectives could foster the development of more sophisticated mechanisms for tunable release.

Bench-to-bedside development of agonists and antagonists of luteinizing hormone-releasing hormone for treatment of advanced prostate cancer

BACKGROUND

Androgen deprivation therapy (ADT) has been the standard of care for treating patients with hormone-sensitive advanced prostate cancer (PCa) for 3 decades. The agonists of luteinizing hormone-releasing hormone (LHRH), also called gonadotropin-releasing hormone, are still the most frequently used form of medical ADT.

ADT AND LHRH ANALOGS

The application of agonists of LHRH has improved and modernized the treatment of advanced PCa; millions of patients have benefited from therapy with LHRH agonists as a preferred alternative to surgical castration, as the psychological effects and perpetuity of orchiectomy are undesirable for most men. Despite their efficacy, agonists of LHRH have several shortcomings, including initial surge in testosterone, producing exacerbation of clinical symptoms, and microsurges in testosterone that might occur after each administration. A new, alternate approach to ADT is emerging with the improvements in antagonists of LHRH. This class of LHRH analogues produces a direct and immediate blockade of pituitary LHRH receptors and leads to a more rapid suppression of testosterone without an initial surge or subsequent microsurges. Degarelix, a third-generation LHRH antagonist, is the only antagonist with a low histamine-releasing activity that is currently on the market for clinical use in advanced PCa with improved testosterone suppression, better control of follicle-stimulating hormone and prostate-specific antigen, and which offers a prolonged delay to progression and more favorable effects on serum alkaline phosphatase.

CONCLUSIONS

Although LHRH agonists are still the mainstay for treatment of advanced PCa, antagonists of LHRH offer an alternative as a pharmacological approach.

Antitumour activity of abiraterone and diethylstilboestrol when administered sequentially to men with castration-resistant prostate cancer

BACKGROUND

Abiraterone is a standard treatment for men with castration-resistant prostate cancer (CRPC). We evaluated the antitumour activity of abiraterone following the synthetic oestrogen diethylstilboestrol (DES).

METHODS

Castration-resistant prostate cancer patients treated with abiraterone were identified. Demographics, response variables and survival data were recorded.

RESULTS

Two-hundred and seventy-four patients received abiraterone, 114 (41.6%) after DES. Pre-chemotherapy abiraterone resulted in ≥50% PSA declines in 35/41 (85.4%) DES-naïve and 20/27 (74.1%) DES-treated patients. Post-docetaxel abiraterone resulted in ≥50% PSA declines in 40/113 (35.4%) DES-naïve and 23/81 (28.4%) DES-treated patients. Time to PSA progression was similar regardless of prior DES.

CONCLUSION

Abiraterone has important antitumour activity in men with CRPC even after DES exposure.

Goserelin and bicalutamide treatments alter the expression of microRNAs in the prostate

BACKGROUND

Although endocrine therapy has been used for decades, its influence on the expression of microRNAs (miRNAs) in clinical tissue specimens has not been analyzed. Moreover, the effects of the TMPRSS2:ERG fusion on the expression of miRNAs in hormone naïve and endocrine-treated prostate cancers are poorly understood.

METHODS

We used clinical material from a neoadjuvant trial consisting of 28 men treated with goserelin (n = 8), bicalutamide (n = 9), or no treatment (n = 11) for 3 months prior to radical prostatectomy. Freshly frozen specimens were used for microarray analysis of 723 human miRNAs. Specific miRNA expression in cancer, benign epithelium and stromal tissue compartments was predicted with an in silico Bayesian modeling tool.

RESULTS

The expression of 52, 44, and 34 miRNAs was affected >1.4-fold by the endocrine treatment in the cancer, non-malignant epithelium, and stromal compartments, respectively. Of the 52 miRNAs, only 10 were equally affected by the two treatment modalities in the cancer compartment. Twenty-six of the 52 genes (50%) showed AR binding sites in their proximity in either VCaP or LNCaP cell lines. Forty-seven miRNAs were differentially expressed in TMPRSS2:ERG fusion positive compared with fusion negative cases. Endocrine treatment reduced the differences between fusion positive and negative cases.

CONCLUSIONS

Goserelin treatment and bicalutamide treatment mostly affected the expression of different miRNAs. The effect clearly varied in different tissue compartments. TMPRSS2:ERG fusion positive and negative cases showed differential expression of miRNAs, and the difference was diminished by androgen ablation.

Chemical castration and anti-androgens induce differential gene expression in prostate cancer

Endocrine therapy by castration or anti-androgens is the gold standard treatment for advanced prostate cancer. Although it has been used for decades, the molecular consequences of androgen deprivation are incompletely known and biomarkers of its resistance are lacking. In this study, we studied the molecular mechanisms of hormonal therapy by comparing the effect of bicalutamide (anti-androgen), goserelin (GnRH agonist) and no therapy, followed by radical prostatectomy. For this purpose, 28 men were randomly assigned to treatment groups. Freshly frozen specimens were used for gene expression profiling for all known protein-coding genes. An in silico Bayesian modelling tool was used to assess cancer-specific gene expression from heterogeneous tissue specimens. The expression of 128 genes was > two-fold reduced by the treatments. Only 16% of the altered genes were common in both treatment groups. Of the 128 genes, only 24 were directly androgen-regulated genes, according to re-analysis of previous data on gene expression, androgen receptor-binding sites and histone modifications in prostate cancer cell line models. The tumours containing TMPRSS2-ERG fusion showed higher gene expression of genes related to proliferation compared to the fusion-negative tumours in untreated cases. Interestingly, endocrine therapy reduced the expression of one-half of these genes and thus diminished the differences between the fusion-positive and -negative samples. This study reports the significantly different effects of an anti-androgen and a GnRH agonist on gene expression in prostate cancer cells. TMPRSS2-ERG fusion seems to bring many proliferation-related genes under androgen regulation.

Leuprorelin depot injection: patient considerations in the management of prostatic cancer

Hormone therapy is well established for treating patients with prostate cancer and remains the mainstay of the treatment of metastatic and locally advanced disease, this article reviews the rationale for its use, its different forms, and complications and controversies still surrounding some of its modalities. Availability of long-acting synthetic luteinizing hormone-releasing hormone (LHRH) agonists revolutionized the hormonal treatment of prostate cancer, and helped to avoid the emotional and psychological effects related to surgical castration. The depot formula has gained wide acceptance from both patients and physicians. This review emphasizes the newer, long-acting formula, leuprorelin (leuprolide acetate), especially the 6-month formula, its advantage over over shorter-acting depot products, and its potential to become a standard of care for patients eligible for androgen deprivation therapy.

Etude randomisée multicentrique comparant la castration médicale par triptoréline à la castration chirurgicale dans le traitement du cancer de la prostate localement avancé ou métastatique

OBJECTIVE

To report the results of a trial comparing the efficacy of triptorelin and surgical castration in the treatment of locally advanced or metastatic prostate cancer.

MATERIALS AND METHODS

80 patients with previously untreated locally advanced or metastatic prostate cancer prostate cancer were included in a one-year multicentre, randomized, prospective, open-label therapeutic trial. Patients either received a monthly injection of triptorelin (group 1; n = 40), or were treated by pulpectomy (group 2; n = 40). Patients were reviewed every 3 months, then every 6 months.

RESULTS

The mean age of the patients was 71.22 +/- 8.25 years. At 1 month, 38 patients were castrated (plasma testosterone < 0.5 mg/ml) in the pulpectomy group versus 35 in the triptorelin group. The mean follow-up was 38.8 +/- 26 months in the triptorelin group and 36.3 +/- 25 months in the pulpectomy group. On multivariate analysis, age, impaired performance status and PAP level (> 3.2 ng/ml) were predictive factors of a poor outcome. The median survival was 37.5 +/- 9 months in the triptorelin group and 33 +/- 3 months in the pulpectomy group. At 3 years, no significant difference in specific survival was observed between the 2 groups. At 8 years of follow-up, 63 patients had died.

CONCLUSION

This study demonstrates an equivalent specific survival between patients treated by triptorelin or surgical castration. Castration is rapidly obtained with triptorelin (< 2 months) and is maintained over time throughout the duration of treatment.

Vinorelbine, doxorubicin, and prednisone in androgen-independent prostate cancer

BACKGROUND

Ultimately, patients with metastatic prostate cancer progress on androgen ablation therapy. The investigation of new chemotherapeutic regimens for the treatment of androgen-independent prostate cancer (AIPC) is essential. The authors conducted a Phase II trial with vinorelbine, doxorubicin, and daily prednisone (NAP) to investigate the antitumor activity and palliative response of this regimen in patients with AIPC.

METHODS

Forty-six patients entered this Phase II combination chemotherapy trial. Patients were treated with both vinorelbine and doxorubicin at doses of 20 mg/m2 on Days 1, 8, and 15 every 28 days and prednisone 5 mg twice daily. Endpoints included prostate-specific antigen (PSA) response and palliation, as measured by the Functional Assessment of Cancer Therapy-Prostate (FACT-P) instrument, the Brief Pain Inventory Scale, and a narcotic analgesic log.

RESULTS

The median follow-up for all 46 patients was 13.4 months. Fifty-two percent of patients had impaired performance status at baseline. One responding patient remained on NAP and was progression-free at 11.5 months. Thirty-nine patients progressed, 3 patients died prior to response assessment, and 3 patients refused therapy. The median overall survival was 57 weeks (95% confidence interval [95% CI], 36-76 weeks), and the median time to disease progression was 17 weeks (range, 11-24 weeks). The PSA response among the 36 patients who completed 3 cycles of NAP was 42% (95% CI, 26-59%). There was a statistically significant improvement in quality of life measured both by the FACT-General instrument (P = .03) and the FACT-P instrument (P = .0006) over the 3 months compared with baseline measurements. Pain medicine use also improved: The median morphine equivalents among patients who were taking pain medications at the time of study enrollment showed a substantial decline after 1 cycle of treatment that was maintained. Pain (as assessed by the Brief Pain Inventory) improved compared with baseline pain at the 2nd-month assessment (worst pain, P = .08; least pain, P = .02; and average pain, P = .003). Overall, the regimen was tolerated well. The most common side effects were mild fatigue and gastrointestinal complaints (all of which were Grade 1 or 2 [according to Version 2.0 of the Expanded Common Toxicity Criteria]). Seventeen patients (37%) experienced Grade 3 or 4 neutropenia. Five patients (11%) developed a cardiac ejection fraction of <50% during treatment and had doxorubicin discontinued. No patients developed clinical congestive heart failure.

CONCLUSIONS

The NAP combination produced substantive palliation and a moderate response rate in men with AIPC.

Luteinizing hormone-releasing hormone agonists in the treatment of prostate cancer: A review of their discovery, development, and place in therapy

BACKGROUND

Early identification of the biological activity of luteinizing hormone-releasing hormone (LHRH) paved the way for the synthesis of analogues with enhanced potency and biological properties. Early testing in animal models and humans provided insight into the potential clinical uses of these substances, and, within 10 years, LHRH-agonist therapy had become available for use in patients with advanced prostate cancer (PC). Over time, the role of LHRH-agonist therapy has expanded to include use as part of multimodal treatment regimens throughout the course of the disease.

OBJECTIVES

This article reviews the discovery and development of LHRH agonists and summarizes the clinical evidence for their efficacy in PC.

METHODS

Relevant clinical studies were identified through searches of the English-language literature indexed on MEDLINE through May 2006. The main search terms were prostate cancer and LHRH agonist.

RESULTS

Results of the initial therapeutic trials of sustained-release depot formulations of LHRH agonists in patients with PC were reported in the mid-1980s, indicating that these agents were effective and well tolerated in improving clinical symptoms and producing medical castration. Longer-term studies and subsequent meta-analyses of randomized controlled trials in patients with advanced PC found no significant differences in overall survival when single-therapy androgen suppression was achieved through the use of LHRH-agonist therapy or orchiectomy. Randomized trials have reported significant improvements in disease-free and overall survival in patients with locally advanced or high-grade PC treated with LHRH agonists in addition to radiotherapy. Several prospective randomized trials have reported decreases in rates of positive surgical margins with short-term (6 weeks to 4 months) neoadjuvant LHRH-agonist therapy in patients with stage T1 to T3a PC undergoing prostatectomy. Definitive comparisons of immediate and delayed treatment in patients with biochemical relapse have not been reported. However, the results of several studies suggest that immediate LHRH-agonist therapy (or orchiectomy) may improve the course of disease progression and survival. The risks of long-term treatment (eg, osteoporosis; fracture; anabolic loss of muscle mass, with a tendency toward weight gain) must be considered carefully in patients who are likely to receive chronic LHRH-agonist therapy. Intermittent schedules have been developed to reduce the adverse effects associated with LHRH-agonist therapy; some reports support sparing effects on bone and muscle mass and relative improvements in toxicities during off-therapy periods, whereas others have documented continuing decreases in bone mineral density (BMD), with the rate of bone loss highest during the early cycles of therapy. Bisphosphonate therapy has been shown to increase BMD in patients with PC and may therefore be beneficial when overt symptoms of osteopenia or osteoporosis are present.

CONCLUSIONS

LHRH-agonist therapy has been the mainstay of treatment for advanced PC for >20 years. Clinical evidence supports expanding use of these agents at an earlier stage of disease and as part of multimodal regimens that include radiotherapy. There is a need for further study of the efficacy of adjuvant LHRH-agonist therapy along with prostatectomy, in patients with biochemical failure, in intermittent regimens, and in conjunction with cytotoxic therapies in late-stage disease.

Strategies to improve plasma half life time of peptide and protein drugs

Due to the obvious advantages of long-acting peptide and protein drugs, strategies to prolong plasma half life time of such compounds are highly on demand. Short plasma half life times are commonly due to fast renal clearance as well as to enzymatic degradation occurring during systemic circulation. Modifications of the peptide/protein can lead to prolonged plasma half life times. By shortening the overall amino acid amount of somatostatin and replacing L: -analogue amino acids with D: -amino acids, plasma half life time of the derivate octreotide was 1.5 hours in comparison to only few minutes of somatostatin. A PEG(2,40 K) conjugate of INF-alpha-2b exhibited a 330-fold prolonged plasma half life time compared to the native protein. It was the aim of this review to provide an overview of possible strategies to prolong plasma half life time such as modification of N- and C-terminus or PEGylation as well as methods to evaluate the effectiveness of drug modifications. Furthermore, fundamental data about most important proteolytic enzymes of human blood, liver and kidney as well as their cleavage specificity and inhibitors for them are provided in order to predict enzymatic cleavage of peptide and protein drugs during systemic circulation.

Immunohistochemical demonstration of gonadotropin-releasing hormone receptors in prostate carcinoma

The antiandrogen and gonadotropin-releasing hormone (Gn-RH) analogue treatment of prostate carcinoma is based on decreased proliferative and increased apoptotic activity of tumor cells, induced by androgen ablation. Gn-RH analogues decrease the serum level of androgens by breaking the pituitary-gonadal axis, but increasing evidence points to the direct effect of Gn-RH analogues on tumor cells. Immunohistochemical demonstration of Gn-RH receptors recently became possible. Cryostat and paraffin sections of prostate biopsy samples of 10 untreated patients with prostate carcinoma (T2-T3, Gleason score 5-8) were investigated for Gn-RH receptors (Gn-RHR) and androgen receptors, respectively, using the immunoperoxidase method. Membrane bound, focal Gn-RHR positivity was found in 5 samples. Nuclear androgen receptor positivity appeared in 7 samples. No correlation between Gn-RHR and androgen receptor positivity was found, neither receptor status and tumor-nodes-metastasis stage nor Gleason score could be related to each other. Correlation between Gn-RHR positivity and response to luteinizing hormone-releasing hormone analogue treatment will be investigated further.

Pharmacodynamic Equivalence of a Decapeptyl 3-Month SR Formulation with the 28-Day SR Formulation in Patients with Advanced Prostate Cancer

AIMS

The objective of the study was to assess the pharmacodynamic equivalence of LHRH analogue triptorelin 3-month and 28-day SR formulations.

METHODS

Patients with documented locally advanced or metastatic prostate cancer were randomized to receive one injection of the 3-month formulation (n = 63) or three injections at 28-day intervals of the 28-day formulation (n = 68). Group-chemical castration rates defined as the percentage of patients reaching a testosterone plasma level </=0.5 ng/ml were compared at D84 (i.e., 3 x 28 days). Testosterone, LH and triptorelin plasma profiles, and change from baseline in plasma PSA were assessed over 3 months (from baseline to D91).

RESULTS

Chemical castration rates were 98 and 96% in the 3-month and 28-day formulation groups, respectively, with confidence interval (two-sided 94.2% CI) of [-8.1%; 9.6%]. Median times to reach chemical castration were 18.8 and 18.5 days (p = 0.86, log rank), respectively. Ratios for mean peak plasma levels and AUC(91) of the two formulations for both testosterone and LH fell within the [0.80; 1.25] equivalence interval. Mean PSA decreases from baseline at D91 were 91.0 and 91.7%, respectively (p = 0.73).

CONCLUSION

Treatments with the two triptorelin formulations over 3 months are pharmacologically equivalent.

The antitumour effect of the somatostatin analogue TT-232 depends on the treatment regimen

The somatostatin analogue TT-232, containing a five residue ring structure, has a strong antitumour activity both in vitro and in vivo. This peptide has no effect on growth hormone (GH) release, but exhibits a remarkable tyrosine kinase inhibitory effect and induced apoptosis. We studied the effect of TT-232 in different routes of administration and treatment schedules on various types of mouse tumour models. The infusion treatment with inserted Alzet osmotic minipumps proved to be superior to both twice daily subcutaneous (s.c.) or intravenous (i.v.) injections in a 2 weeks period. In the case of S-180 tumour the infusion treatment resulted in 77-100% tumour growth inhibition and in 40-60% of mice long-term and tumour-free survivors. With the P-388sc tumour the infusion of TT-232 resulted in 20-40% of animals long-term and tumour-free survivors and in 76-100% tumour growth inhibition. In the very aggressive Colon-26 (C-26) and MXT, the TT-232 treatment resulted in 71-75% tumour growth inhibition and increased survival time by about 50%.

A phase II trial with new triptorelin sustained release formulations in prostatic carcinoma

OBJECTIVES

The objectives were to assess if a single intramuscular (i.m.) injection of the GnRH agonist triptorelin, as pamoate Sustained Release (RS) 11.25 mg, was able to induce pharmacological castration and to maintain the plasma testosterone levels in the castrate range (< 1.735 nmol/l) up to 3 months in prostatic carcinoma.

METHODS

Two different formulations of triptorelin pamoate 11.25 mg were assessed in 2 groups of 10 patients suffering from prostatic carcinoma. Each patient received one i.m. injection of triptorelin pamoate SR 11.25 mg. Triptorelin and testosterone levels were measured over 3 months. Pain, micturition difficulties, performance status, local and general tolerance, and the occurrence of adverse events were evaluated.

RESULTS

Both formulations were able to induce castration levels (<1.735 nmol/l) of testosterone within 3 to 4 weeks post-injection, and to maintain levels below 1.735 nmol/l till the end of 3rd month. The bioavailability of one formulation (DLGSD-3-95-21) tended to be greater. This may explain the quicker onset of castration and the slight better maintenance of low testosterone levels during the 3rd month observed with this formulation. In terms of clinical end-points, the local tolerance of both formulations was excellent. No serious adverse events were recorded except transient hot flushes in 2 cases and slight bone pain in one.

CONCLUSION

Triptorelin pamoate 11.25 mg given in microgranules is a 3-month sustained-release administration form which appears to be safe and effective in advanced prostatic carcinoma. Based on the findings of this study, the formulation with greater bioavailability (DLGSD-3-95-21) was selected as formulation of choice to be used for clinical treatments and further clinical investigation.

Liposomal Doxorubicin for the Treatment of Hormone-Refractory Prostate Cancer

There is a pressing need for new agents to treat hormone-refractory prostate cancer (HRPC). Doxorubicin has shown modest activity in this setting, but its use is limited by its toxicities. Liposomal encapsulation of doxorubicin appears to promote enhanced tumor accumulation in some tumor types, and toxicity appears to be reduced. A phase II trial of liposomal doxorubicin was therefore conducted in patients with HRPC. Fourteen patients with progressive HRPC were treated. For the first dose only, patients were randomized to receive either doxorubicin 50 mg/m2 or liposomal doxorubicin 50 mg/m2 in order to evaluate exploratory pharmacokinetics. For all subsequent cycles, all patients received liposomal doxorubicin 50 mg/m2. Response to therapy was assessed with serial measurements of serum prostate-specific antigen (PSA) and sequential imaging studies. All 14 patients were evaluable for response and toxicity. Two patients (14%) had declines in serum PSA of > or = 50%. The first patient had a baseline PSA of 34.7 ng/mL and a nadir of 17.0 ng/mL. The second patient had a baseline PSA of 5580.0 ng/mL and a nadir of 200.7 ng/mL. The latter of these 2 patients had an unambiguous improvement in bone scan and a reduction in pain. Treatment was well tolerated overall. One patient was removed from treatment after the development of a grade 3 infusion reaction with the first cycle of liposomal doxorubicin. Neutropenia was the most common toxicity; in only 1 case was it grade 3, and no cases of grade 4 were seen. Doxorubicin plasma concentrations were best fit by a linear, two-compartment model. Liposomal doxorubicin plasma concentrations were best fit by a linear, one-compartment model. Treatment with liposomal doxorubicin was well tolerated overall. While monotherapy with liposomal doxorubicin has only modest activity in the treatment of HRPC, it may be of interest to study this agent as part of combination chemotherapy.

Differential effects of vitamin D on normal human prostate epithelial and stromal cells in primary culture

OBJECTIVES

Because epidemiologic evidence has demonstrated that vitamin D may play a role in the etiology of prostate cancer, we tested the inhibitory effect of the biologically active form of vitamin D (1,25-D) on the cell proliferation of human prostate epithelial and stromal cells in a chemically defined situation in the presence and absence of dihydrotestosterone (DHT). We also tested the effect of 1,25-D in castrated rats in the presence and absence of flutamide, an androgen receptor blocker.

METHODS

Prostate stromal and epithelial cells were isolated from freshly collected human prostatectomy specimens, and cell proliferation was measured with the MTT assay. Immunohistochemistry was performed to detect the presence of 1,25-D receptors, androgen receptors, smooth muscle actin, and E-cadherin. For in vivo analysis of 1,25-D, male Sprague-Dawley rats were castrated, then treated with either 1,25-D, 1,25-D with flutamide, or vehicle control.

RESULTS

Incubation of primary cultures of prostate epithelial cells with 1,25-D at a concentration of 10(-8) M reduced cell proliferation by 40% of controls. The inhibition of growth by 1,25-D was maintained in the presence of DHT. Conversely, the effect of a similar dose of 1,25-D on stromal cell exposure was increased proliferation. In vivo, 1,25-D increased the prostatic weight of castrated rats that had serum testosterone levels below the detectable limit. The addition of flutamide did not alter this effect.

CONCLUSIONS

These results confirm that vitamin D may be an effective antiproliferative agent of epithelial cells in prostate cancer therapy and support in vivo studies performed in the normal rat prostate.

Treatment of prostate cancer

Prostate cancer is the leading cause of cancer death among older men in western countries. However, controversy surrounds many issues related to this disease, particularly its most appropriate treatment, with a wide spectrum of opinions ranging from watchful waiting to aggressive therapy. Patients with newly diagnosed prostate cancer, as well as their doctors, will have to make difficult decisions regarding treatment of this disease. In this article we discuss the current available treatment options and some novel therapeutic approaches to tackling the patient with prostate cancer.

The changing role of surgery in the diagnosis and treatment of cancer

Many changes have occurred in the surgical treatment of the cancer patient. For many tumors, surgery has been modified or eliminated. These changes are due to the realization that, for some cancers, more extensive surgical procedures are not more beneficial, to improvements in radiation therapy and chemotherapy, to the availability of better noninvasive or less invasive diagnostic and therapeutic techniques, and to improved surgical equipment (such as videoscopic surgery).

Use of a GnRH agonist to suppress testosterone in wild male Hawaiian monk seals (Monachus schauinslandi)

A gonadotropin-releasing hormone (GnRH) agonist, d-Trp6-LHRH, was evaluated for its effectiveness in reducing circulating testosterone concentrations in wild Hawaiian monk seals (Monachus schauinslandi). Twenty-eight adult male seals were randomly divided into three groups: 10 were captured and treated with 7.5 mg of the GnRH agonist, 9 were captured but did not receive the agonist, and 9 were captured near the end of the study to serve as handling controls. Blood samples were taken from all 28 seals. From 14 to 58 days after initial capture, 8 of the treated seals and 8 of the untreated seals were recaptured and a second sample of blood was taken. For comparison, blood was also collected from 4 captive adult male seals during the same months as the field study. In the treated group, the agonist induced a significant decline in mean circulating testosterone concentrations, from 1.01 ng/ml (first sample) to 0.21 ng/ml (second sample, taken approximately 38 days later). In the untreated group, mean testosterone concentrations of the first and second samples were statistically indistinguishable (1.11 vs 1.16 ng/ml). The mean concentration of the untreated group (second sample) was also indistinguishable from the mean concentration of seals in the control group (1.16 vs 0.82 ng/ml). Also, mean testosterone concentration in the initial samples from the four captive seals was not statistically different from that of untreated wild seals (1.38 vs 1.11 ng/ml). These results suggest that (1) the GnRH agonist suppresses the production of testosterone in wild adult male Hawaiian monk seals, (2) a single handling of adult male seals does not affect their testosterone levels, and (3) testosterone concentrations in captive male seals appear to be consistent with concentrations in wild seals. Further evaluation of this GnRH agonist is necessary before it is used in the management of this endangered species, but these results suggest it may be a useful tool for reducing mortality of monk seals from adult male aggression related to reproduction and mating behavior.

Management of metastatic prostate cancer

Metastatic prostate cancer remains an incurable disease. However, palliative treatment based on hormonal manipulation can effectively control symptoms and prolong life. The development of progressive "hormone-refractory disease" requires a multidisciplinary approach, with the involvement of general practitioners, urologists, radiation oncologists, medical oncologists and palliative care physicians. Some of the newer therapies, such as chemotherapy, have proved successful in improving the quality of life for many patients, and modern palliative care techniques can provide good symptom control.

Subcutaneous administration of a depot gonadotropin-releasing hormone agonist induces profound reproductive axis suppression in women

OBJECTIVE

To compare the i.m. and s.c. routes of depot GnRH agonist administration.

DESIGN

Prospective, controlled pharmacokinetics study.

SETTING

Volunteers in an academic research environment.

PATIENT(S)

Forty women with benign gynecologic disorders.

INTERVENTION(S)

Triptorelin administration (3.75 mg) at 28-day intervals for 6 consecutive months. Twenty patients were treated with IM triptorelin, and 20 patients were treated with SC triptorelin.

MAIN OUTCOME MEASURE(S)

Assessment of side effects, GnRH test results, and triptorelin, LH, FSH, estradiol, and progesterone levels.

RESULT(S)

The occurrence of injection site redness and itching and of some hypoestrogenic side effects was increased significantly in the SC group. Plasma triptorelin levels were significantly higher in the IM group in the first month of treatment; thereafter, the pattern reversed, with a nonsignificant trend toward higher plasma triptorelin levels in the SC group. Serum LH, FSH, estradiol, and progesterone levels were low after the first month of treatment and did not differ between the two treatment groups. On day 196 (2 months after the last depot triptorelin injection), triptorelin was still measurable and gonadotropins and gonadal steroids were still suppressed. Spontaneous menses returned significantly later in the SC group than in the IM group.

CONCLUSION(S)

Subcutaneous triptorelin can be administered by the patient. Both IM and SC triptorelin administration are cliniclly effective, but they result in different triptorelin pharmacokinetics. Subcutaneous triptorelin is associated with more prolonged amenorrhea than is IM triptorelin, suggesting enhanced pituitary-ovarian suppression. These results suggest that SC triptorelin may allow lower drug dosage administration and/or longer administration intervals.

Rational use of agonists and antagonists of luteinizing hormone-releasing hormone (LH-RH) in the treatment of hormone-sensitive neoplasms and gynaecologic conditions

Analogues of luteinizing hormone-releasing hormone (LH-RH) have made possible new approaches to the treatment of some hormone-dependent cancers and diseases and conditions which result from inappropriate sex hormone levels. In the fields of both gynaecology and oncology, the development of sustained delivery depot systems has played a key role in the clinical use of LH-RH agonists and will be also essential for the LH-RH antagonists. Clinical results show that therapy with agonists of LH-RH is the preferred method of treatment for men with advanced prostate cancer. For prostate cancer and other indications, the new LH-RH antagonists such as Cetrorelix may offer an advantage based on the fact that they inhibit LH, FSH and sex-steroid secretion from the start of the administration and thus reduce the time of the onset of therapeutic effects. The use of antagonists would avoid the temporary clinical "flare-up" of the disease which can occur with the agonists in men with prostate cancer. The rapid shrinkage of the prostate and improvement in urinary symptoms obtained with Cetrorelix in men with benign prostatic hyperplasia (BHP) suggests that LH-RH antagonists offer a therapeutic alternative in patients who are considered poor surgical risks. Various experimental and clinical studies suggest that analogues of LH-RH might be useful for treatment of premenopausal women with oestrogen-dependent breast cancer. LH-RH antagonists such as Cetrorelix could be also considered for hormonal therapy of epithelial ovarian cancer which responds only marginally to the agonists, and for treatment of endometrial cancer. Many investigators have reported beneficial effects of LH-RH agonists in the treatment of patients with leiomyomas. LH-RH antagonists also appear to be promising for therapy of uterine leiomyomas, and in addition might be useful for treatment of endometriosis and polycystic ovarian disease (PCOD). LH-RH agonists have been employed in in vitro fertilization and embryo transfer (IVF-ET) programs to prevent a premature rise in LH and various results suggest that the use of antagonist Cetrorelix in assisted reproduction procedures, could be even more advantageous. For most of these indications, the use of sustained release depot preparations will be required.

Potentiating effect of buserelin acetate, an LHRH agonist, on the proliferation of ventral prostatic epithelial cells in testosterone-treated castrated rats

BACKGROUND

We used buserelin acetate ([D-Ser(But)6] LHRH ), an LHRH agonist and strong blocker of LH secretion, as a treatment for prostatic cancer. It is possible that this LHRH agonist has a proliferative effect on the prostate in addition to suppressing LH secretion. The purpose of this study was to examine the proliferative effect of LHRH agonist on rat prostatic epithelial cells.

METHODS

We determined the optimal dose of testosterone necessary to maintain a positive level of proliferating cell nuclear antigen (PCNA) in the ventral prostatic epithelial cells of castrated Wistar rats. Testosterone-treated rats then received various doses of buserelin acetate. Castrated rats without exogenous testosterone also received buserelin acetate. The PCNA positivity was determined by immunohistochemistry with anti-PCNA monoclonal antibody.

RESULTS

The optimal dose of testosterone enanthate was 4 mg at 0 and 28 days after castration. Administration of buserelin acetate on day 0 and 28 in doses of 0.16 mg to 1.28 mg significantly increased PCNA positivity in a dose-dependent manner. Administration of buserelin acetate to castrated rats without testosterone also increased PCNA positivity but there was no statistical significance.

CONCLUSIONS

Buserelin acetate has a potentiating effect on the proliferation of ventral prostatic epithelial cells of castrated rat in the presence of a physiological level of exogenous testosterone. This effect may slightly influence the result of hormonal therapy by LHRH agonist.

How is androgen-dependent metastatic prostate cancer best treated?

The principles of management of newly diagnosed metastatic prostate cancer have changed little since the time of Huggins and his colleagues. Modern clinicians have many more weapons in their therapeutic armamentarium than those pioneers, but little progress has been made in improving the survival of men with this disease. The results of androgen deprivation are comparable using any one of a number of different monotherapy approaches. The use of combined androgen blockade may improve survival in men with minimal disease but at considerable economic cost and with significant impairment of quality of life. The benefit of this therapy for men with more extensive disease is uncertain. New modalities such as intermittent androgen blockade or combination therapies are exciting, but unproven.

Goserelin versus orchiectomy in the treatment of advanced prostate cancer: final results of a randomized trial. Zoladex Prostate Study Group

OBJECTIVES

To compare the efficacy and safety of goserelin and orchiectomy in patients with stage D2 prostate cancer.

METHODS

A randomized, open, multicenter study was conducted in 283 patients. Patients were allocated to goserelin, 3.6 mg every 28 days or to orchiectomy. Study end points were endocrine response, objective response, time to treatment failure, survival, and tolerability. Objective response was based on modified criteria of the National Prostate Cancer Project.

RESULTS

Serum testosterone decreased from baseline to castrate levels by week 4 in each group and remained below castrate levels thereafter. Acid phosphatase and alkaline phosphatase concentrations also decreased in each group. The goserelin and orchiectomy groups had similar results for objective response (82% versus 77%) and had similar medial times to treatment failure (52 versus 53 weeks) and survival (119 versus 136 weeks). No significant interactions between treatments and prognostic factors were observed. Adjusting for baseline testosterone concentration had no effect on survival outcome. Race had no influence on outcome or efficacy end points. Common adverse events in both groups were pain, hot flushes, and lower urinary tract symptoms.

CONCLUSIONS

Goserelin is well tolerated and as effective as orchiectomy in patients with Stage D2 prostate cancer.

Hyperprolactinemia after treatment of long-acting gonadotropin-releasing hormone analogue Decapeptyl in girls with central precocious puberty

OBJECTIVE

To clarify the effects of prolonged treatment with long-acting GnRH analogue on serum PRL levels.

DESIGN

Blood PRL levels were measured at 9 A.M. every 28 days for a period of 6 months.

SETTING

Pediatric Endocrine Clinic, Hasharon Hospital, Petah Tiqva, Israel.

PATIENTS

Thirteen girls with idiopathic central precocious puberty.

RESULTS

Hyperprolactinemia developed in 5 of 13 girls after treatment with long-acting GnRH-a; mean blood PRL in all 13 girls rose significantly from 11.9 +/- 5.6 to 21.5 +/- 12.5 micrograms/L (mean +/- SD).

CONCLUSIONS

The mechanism of hyperprolactinemia in our patients is unclear. It may have resulted from a decline in the release of the hypothalamic PRL inhibitory factor. Clinically, transient hyperprolactinemia during long-acting GnRH-a treatment for central precocious puberty also may reflect a constant depression of LH secretion.

Reporting of assignment methods in clinical trials

A stratified random sample of the reports of 200 clinical trials, conducted in the 1980s, listed in the February 1991 issue of Controlled Clinical Trials, was reviewed. The four strata were small single-center trials (SST), small multicenter trials (SMT), large single-center trials (LST), and large multicenter trials (LMT). The description of the assignment method in the published reports of the results of the trials was classified into four categories: good description (G), provides details; fair description (F), describes some details; poor description (P), only states that randomization was used; and no description (N). The percentage of good and fair descriptions among the four strata were: [Tables: See Text] The proportion of G or F trials is slightly higher in the LST because one third used systematic rather than random assignment, which is easier to describe. Good descriptions usually require only two or three lines of text, and yet the description of the randomization method for most clinical trials is so poor that the reader cannot tell if randomization has been applied properly.

Safety, side effects and patient acceptance of the luteinizing hormone releasing hormone agonist leuprolide in treatment of benign prostatic hyperplasia

The luteinizing hormone releasing hormone agonist leuprolide was investigated in a double-blind, randomized, placebo-controlled study comprising 50 evaluable patients with moderate to severe symptoms resulting from benign prostatic hyperplasia. Patients received 3.75 mg. leuprolide depot or placebo as an injection every 28 days for 24 weeks. Hemoglobin level decreased by 0.8 gm/100 ml. (p = 0.0052) for patients receiving leuprolide. Mean testicular volume decreased by 28.9% (p < 0.001) compared to placebo. Of 26 patients receiving leuprolide 5 had a weight gain of more than 3 kg. Almost all patients receiving leuprolide experienced hot flushes. Breast changes, and loss of energy and vigor were not more pronounced than for patients receiving placebo. Erectile function and sexual activity were lost during treatment. Libido also decreased but was still partially retained. Despite this, patients receiving leuprolide were generally contented with their sexual life during treatment. Side effects were bothersome for some patients but were reversible. Of the patients in our study 73% expressed that they could repeat or continue treatment if that had been possible. The high cost of these drugs will limit their use for a benign condition, such as benign prostatic hyperplasia.

Association of goserelin and flutamide in the treatment of advanced prostatic carcinoma

From January 1987 to June 1990, 40 previously untreated patients, 60–85 years old (mean 76.7 years) with C and D stage (according to AUS) prostatic adenocarcinoma, were administered analogous LH-RH goserelin and the non-steroid antiandrogen flutamide. The patients were followed until June 1992. 9 patients died from the disease. The treatment was well tolerated in 68% of the cases (27 patients); in the other 13 patients, the administration of flutamide caused secondary effects (gastro-intestinal intolerance, alterations of hepatic function). The administration of goserelin did not cause any secondary effect. The local response (assessed by transrectal echography) was good and in 31 cases consisted of a regression of the initial area from 25 to 50%. The performance status improved in 16 patients. 12 patients had a remission of pain. In all the patients, from the third month of treatment, the testosteronemia remained under 0.8 ng/ml; the prostatic alkaline phosphatase and the prostatic specific antigen presented a good correlation with the clinical evolution of the disease.