Gonadotropin-releasing hormone (GnRH) antibodies formation in hypogonadotropic azoospermic men treated with pulsatile GnRH--diagnosis and possible alternative treatment

The use of hormone stimulation in male infertility

Infertility affects 15% of couples worldwide and in approximately 50% of cases the cause is secondary to an abnormality of the sperm. However, treatment options for male infertility are limited and empirical use of hormone stimulation has been utilised. We review the contemporary data regarding the application of hormone stimulation to treat male infertility. There is strong evidence supporting the use of hormone stimulation in hypogonadotropic hypogonadism but there is inadequate evidence for all other indications.

Goserelin Ovarian Ablation Failure in Premenopausal Women With Breast Cancer

Breast cancer is the most prevalent cancer known worldwide in women. It is a heterogeneous, phenotypically diverse disease composed of several biologic subtypes that have distinct behavior and response to therapy. Hormone receptor-positive (i.e., estrogen [ER] and/or progesterone [PR] receptor-positive) breast cancers comprise the most common types of breast cancer, accounting for 75% of all cases. This makes endocrine therapy the standardized treatment for patients with ER+/PR+ breast cancer. Drugs that block estrogen receptors or that lower estrogen levels are the mainstay of treatment. High-risk patients benefit from the addition of ovarian function suppression (OFS)/ablation to either an aromatase inhibitor (AI) or tamoxifen. This case report discusses a 36-year-old premenopausal female who presented with an abnormal right breast lump in the upper outer quadrant of the right breast. Due to high suspicion of malignancy, a biopsy was performed which showed features of both lobular and ductal carcinoma with ER and PR positivity, HER 2 was negative. The patient underwent mastectomy with axillary lymph node removal due to concern for multifocal disease. No clinically relevant genetic mutations were present. Oncotype DX breast recurrence score was 16 and no chemotherapy was offered. Due to large tumor size, young age OFS with goserelin 3.6mg/28 days and letrozole 2.5 mg once daily was recommended. After 16 months of treatment, the patient developed a failure of goserelin-induced ovarian suppression. This case report highlights the possibility of the development of hormonal resistance after long-term use of goserelin.

Medical treatment of male infertility

The majority of male infertility is idiopathic. However, there are multiple known causes of male infertility, and some of these causes can be treated medically with high success rates. In cases of idiopathic or genetic causes of male infertility, medical management is typically empirical; in most instances medical therapy represents off-label use that is not specifically approved by the FDA. Understanding the hypothalamic-pituitary-gonadal (HPG) axis and the effect of estrogen excess is critical for the assessment and treatment of male infertility. The use of certain medical treatment has been associated with an increase in sperm production or motility, and primarily focuses on optimizing testosterone (T) production from the Leydig cells, increasing follicle-stimulating hormone (FSH) levels to stimulate Sertoli cells and spermatogenesis, and normalizing the T to estrogen ratio.

Factors affecting spermatogenesis upon gonadotropin-replacement therapy: a meta-analytic study

A meta-analysis was performed to systematically analyse the results of gonadotropin and GnRH therapy in inducing spermatogenesis in subjects with hypogonadotropic hypogonadism (HHG) and azoospermia. An extensive Medline and Embase search was performed including the following words: 'gonadotropins' or 'GnRH', 'infertility', 'hypogonadotropic', 'hypogonadism' and limited to studies in male humans. Overall, 44 and 16 studies were retrieved for gonadotropin and GnRH therapy, respectively. Of those, 43 and 16 considered the appearance of at least one spermatozoa in semen, whereas 26 and 10 considered sperm concentration upon gonadotropin and GnRH, respectively. The combination of the study results showed an overall success rate of 75% (69-81) and 75% (60-85) in achieving spermatogenesis, with a mean sperm concentration obtained of 5.92 (4.72-7.13) and 4.27 (1.80-6.74) million/mL for gonadotropin and GnRH therapy, respectively. The results upon gonadotropin were significantly worse in studies involving only subjects with a pre-pubertal onset HHG, as compared with studies involving a mixed population of pre- and post-pubertal onset [68% (58-77) vs. 84% (76-89), p = 0.011 and 3.37 (2.25-4.49) vs. 12.94 (8.00-17.88) million/mL, p < 0.0001; for dichotomous and continuous data, respectively]. A similar effect was observed also upon GnRH. No difference in terms of successful achievement of spermatogenesis and sperm concentration was found for different FSH preparations. Previous use of testosterone replacement therapy (TRT) did not affect the results obtained with gonadotropins. Finally, a higher success rate was found for subjects with lower levels of gonadotropins at the baseline and for those using both human chorionic gonadotropin and FSH. Gonadotropin therapy, even with urinary derivatives, is a suitable option in inducing/restoring fertility in azoospermic HHG subjects. Gonadotropins appear to be more efficacious in subjects with a pure secondary nature (low gonadotropins) and a post-pubertal onset of the disorder, whereas previous TRT does not affect outcome.

Significance of neutralizing antibodies to interferon beta during treatment of multiple sclerosis: expert opinions based on the Proceedings of an International Consensus Conference

On August 30, 2002, an international panel of neurologists who specialize in the treatment of multiple sclerosis (MS) was convened in Paris (France) to discuss the issue of neutralizing antibodies (NAb) to interferon beta (IFN-beta) therapy in patients with MS. The goals of this meeting were to: (i) review the most recent clinical information on NAb, (ii) come to a consensus on the clinical relevance of NAb in the management of patients with MS receiving IFN-beta therapy, and (iii) establish a framework for the development of patient management guidelines based on scientific consensus. The meeting was chaired by Hans-Peter Hartung (Heinrich-Heine University, Düsseldorf, Germany) and Huub Schellekens (Utrecht University, Utrecht, the Netherlands). This article summarizes the opinions of the expert panel on a number of key issues raised at the meeting.

Immunogenicity of therapeutic proteins: clinical implications and future prospects

BACKGROUND

Therapeutic proteins have revolutionized the treatment of many diseases. In the near future, many more therapeutic proteins are likely to become available for an increasingly wide range of indications.

OBJECTIVES

This article reviews the incidence, causes, and consequences of formation of antibodies to therapeutic proteins and suggests ways to address issues surrounding immunogenicity.

METHODS

Searches of MEDLINE and EMBASE databases were performed, covering the period 1990 to May 2002. Search terms included immunogenicity, antibodies, and the names of specific therapeutic proteins and classes of therapeutic proteins. Bibliographies of retrieved articles were not searched.

RESULTS

All exogenous proteins, including therapeutic ones, have the potential to cause antibody formation. The reported incidence of antibody formation with therapeutic proteins varies widely between proteins and between studies (depending on the assay techniques used). The clinical consequences of antibody formation vary with the type of antibody present; for example, neutralizing antibodies are more likely to cause loss of efficacy than nonneutralizing antibodies. The immunogenicity of therapeutic proteins can be influenced by many factors, including the genetic background of the patient, the type of disease, the type of protein (human or nonhuman), the presence of conjugates or fragments, the route of administration, dose frequency, and duration of treatment. Manufacturing, handling, and storage can introduce contaminants, or alter the 3-dimensional structure of the protein via oxidation or aggregate formation. Various means have been suggested by which therapeutic proteins might be modified to reduce their immunogenicity, including PEGylation, site-specific mutagenesis, exon shuffling, and humanization of monoclonal antibodies. In the future, it may even be possible to predict the immunogenicity of new therapeutic proteins more accurately, using specifically designed animal models, including nonhuman primates and transgenic mice.

CONCLUSIONS

Scientists and clinicians are becoming increasingly aware of the importance of assessing the immunogenicity of new molecules as they are introduced, and of existing molecules whenever they are modified or their manufacturing process is changed. Immune responses to therapeutic proteins are usually only of clinical significance if they are associated with the development of treatment resistance. Although various means to reduce the immunogenicity of therapeutic proteins have been suggested, monitoring for antibodies during clinical trials and postmarketing surveillance remains an important issue for all therapeutic proteins.

Bioequivalence and the immunogenicity of biopharmaceuticals

The expiry of the first patents for recombinant-DNA-derived biopharmaceuticals will open the possibility of marketing generics, if they can be shown to be essentially similar to the innovator product. However, as shown by the problem of immunogenicity, the properties of biopharmaceuticals are dependent on many factors, including downstream processing and formulation. Products from different sources cannot be assumed to be bioequivalent, even if identical genes are expressed in the same host cells and similar production methods are used. Some of the influencing factors are still unknown, which makes it impossible to completely predict biological behaviour, such as immunogenicity, which can sometimes lead to serious side effects.

Hormone substitution in male hypogonadism

Male hypogonadism is characterised by androgen deficiency and infertility. Hypogonadism can be caused by disorders at the hypothalamic or pituitary level (hypogonadotropic forms) or by testicular dysfunction (hypergonadotropic forms). Testosterone substitution is necessary in all hypogonadal patients, because androgen deficiency causes slight anemia, changes in coagulation parameters, decreased bone density, muscle atrophy, regression of sexual function and alterations in mood and cognitive abilities. Androgen replacement comprises injectable forms of testosterone as well as implants, transdermal systems, sublingual, buccal and oral preparations. Transdermal systems provide the pharmacokinetic modality closest to natural diurnal variations in testosterone levels. New injectable forms of testosterone are currently under clinical evaluation (testosterone undecanoate, testosterone buciclate), allowing extended injection intervals. If patients with hypogonadotropic hypogonadism wish to father a child, spermatogenesis can be initiated and maintained by gonadotropin therapy (conventionally in the form of human chorionic gonadotropin (hCG) and human menopausal gonadotropin (hMG) or, more recently, purified or recombinant follicle stimulating hormone (FSH)). Apart from this option, patients with disorders at the hypothalamic level can be stimulated with pulsatile gonadotropin-releasing hormone (GnRH). Both treatment modalities have to be administered on average for 7-10 months until pregnancy is achieved. In individual cases, treatment may be necessary for up to 46 months. Testosterone treatment is interrupted for the time of GnRH of gonadotropin therapy, but resumed after cessation of this therapy.

Induction of testicular growth and spermatogenesis by pulsatile, intravenous administration of gonadotrophin-releasing hormone in patients with hypogonadotrophic hypogonadism

OBJECTIVE

To induce testicular growth including spermatogenesis, 38 patients with hypogonadotrophic hypogonadism were treated with long-term pulsatile GnRH administration.

PATIENTS

The group of patients comprised 17 individuals with idiopathic hypogonadotrophic hypogonadism, 11 with Kallmann's syndrome, four with multiple pituitary hormone deficiencies and six with a secondary hypogonadotrophic hypogonadism due to surgical removal of a brain tumour. Thirteen patients (seven with idiopathic hypogonadotrophic hypogonadism and six with Kallmann's syndrome) had undescended testes, of whom six had undergone surgery on both testes and four on one testis. Sixteen of the 17 had previously received androgen therapy and six others had received gonadotrophin treatment, of whom three had long-term treatment to induce testicular development, without success.

TREATMENT

GnRH was administered intravenously in a dose of 2-20 micrograms per pulse every 90 minutes. After GnRH discontinuation, hCG treatment was instituted, 1500-3000 IU (i.m.) twice weekly.

RESULTS

During treatment plasma levels of LH, FSH and testosterone increased. In 35 out of the 38 patients plasma testosterone levels increased into the normal adult range. In all patients testicular volume increased. Mean pretreatment testicular volume per patient group ranged from 2.4 to 4.8 ml and increased to 11.5-18.1 ml by the end of treatment. There was a significant difference in the achieved testicular volumes between the patients with Kallmann's syndrome and the brain tumour patients. GnRH treatment mean lasted between 46 and 75 weeks in the different groups. On hCG therapy, testicular development was either maintained or improved. Semen analysis revealed the presence of spermatogenesis in 31 out of the 38 patients (26 patients already on GnRH, and in another five patients on hCG therapy). All three patients pretreated with gonadotrophins as well as three patients with bilateral testicular surgery developed a detectable sperm count. In 19 adolescent patients with growth potential, an adequate height velocity was observed during GnRH treatment.

CONCLUSIONS

GnRH is a feasible way to induce testicular growth as well as spermatogenesis in hypogonadotrophic male patients, even in patients in whom gonadotrophin treatment has failed. After GnRH treatment, hCG alone can maintain or even improve testicular development, including spermatogenesis. GnRH treatment may also induce a physiological growth spurt in hypogonadotrophic adolescents.