MY-T study: Symptom-based titration decisions when using testosterone nasal gel, Natesto®.

INTRODUCTION: Natesto®, testosterone nasal gel (TNG), is a testosterone therapy (TTh) indicated for adult male hypogonadism. This study allowed titration decisions to be based on physicians' assessment of patient symptoms. METHODS: Hypogonadal males on active topical testosterone therapy (TThE) or naive to any form of testosterone therapy (TThN) were treated with 22 mg TNG daily (11 mg twice daily) for 90 days. Titration was determined by the physician at day 90 wherein the dose was increased to 33 mg daily if symptoms were not properly managed. Total testosterone (TT) levels were collected at day 90 and 120 and the quantitative Androgen Deficiency in the Aging Male (qADAM) symptom questionnaire was administered on days 0, 30, 60, 90, and 120. RESULTS: At study endpoint, 77.0% of all patients were in the normal TT range. Mean qADAM scores increased from 30.8 at baseline to 35.5 (6.6) at day 90. Physician assessments resulted in 37% patients being up-titrated for an additional 30 days, however, qADAM scores did not change significantly at the higher dose. CONCLUSIONS: The majority of patients achieved the normal range of testosterone with TNG when physicians based their titration decision on an assessment of symptoms. Sexual function and energy-related symptoms were predictive of improvements resulting from treatment. These symptoms were the most relevant indicators for physicians in making decisions relating to titration.

Efficacy of Nasal Testosterone Gel (Natesto®) Stratified by Baseline Endogenous Testosterone Levels.

OBJECTIVE: Pharmacokinetic and efficacy data from a phase 3 testosterone nasal gel (TNG) study were stratified by baseline endogenous testosterone level in patients with testosterone deficiency. Total testosterone (TT), LH, and FSH levels, as well as erectile function, mood, and lean body mass for each group were compared. In a subset of patients with very low baseline endogenous testosterone levels (<100 ng/dL), we investigated whether TNG is a suitable treatment option. MATERIALS AND METHODS: Patients with testosterone deficiency (serum TT <300 ng/dL) were treated with TNG for 3 months, followed by safety extension periods of 90 and/or 180 days. Pharmacokinetic parameters were calculated from serum hormone levels on days 30 and 90, along with efficacy measurements, which were analyzed by comparison with baseline values. Baseline and/or predose TT values were used for patient stratification. RESULTS: Prestudy and predose endogenous testosterone concentrations correlated. The maximal concentration of TT was nearly identical across all cohorts at days 30 and 90, whereas the average concentration over 24 hours had a slight positive dependence relative to predose levels. LH levels remained in the normal range but were decreased more in patients with higher starting baseline levels. These findings indicate that TNG works with an active hypothalamic-pituitary-gonadal axis that responds to each dose of TNG throughout the treatment period. Patients with the lowest endogenous testosterone levels received maximum exposure impact from each TNG dose. Patients with severe testosterone deficiency had similar efficacy improvements as the remainder of the study population. CONCLUSION: All testosterone-deficient cohorts were successfully treated with TNG.

The My-T study: Patient satisfaction and preference comparing topical and nasal testosterone therapies.

INTRODUCTION: Natesto®, testosterone nasal gel (TNG) is an intranasal testosterone therapy (TTh) used to restore testosterone levels and improve symptoms of hypogonadism. Treatment requires application two (bid) or three (tid) times daily. The Treatment Satisfaction Questionnaire for Medication (TSQM) and a Patient Preference and Use (PPU) Questionnaire were used to obtain patient feedback on the use of TNG and compare to experience with topical TTh. METHODS: The study enrolled 24 TTh-naive (TThN) and 93 TTh-experienced (TThE) hypogonadal men. Treatment lasted up to 120 days, with titration at day 90 to determine the most appropriate dose for restoration of testosterone levels (11 mg bid or tid). Patient satisfaction and symptom changes were measured at days 0, 30, 60, 90, and 120. The PPU Questionnaire was performed at study entry and study completion. RESULTS: Symptoms improved from baseline (30.6) to day 90 (35.1) (p<0.0001; +15%), consistent with testosterone replacement. TNG increased scores for effectiveness (+20%), convenience (+30%), and global satisfaction (+3%) as compared to their previous topical TTh. TThE patients reported ease of use, convenience, efficacy/effectiveness, and travel friendliness as "likes" of TNG therapy. Overall, 67.2% of patients agreed or strongly agreed that they preferred TNG over topical TTh and 59% sought a prescription to continue treatment with TNG. CONCLUSIONS: Patients switching from topical TTh to TNG reported significant improvements in symptoms and patient satisfaction compared to their previous topical TTh. Patients also reported a significant improvement in convenience with TNG despite two to three times daily application. Preference, satisfaction, and convenience may translate to better treatment compliance.

Immunological perspective of self versus tumor antigens: insights from the RIP-gp model.

Self-reactive T cells in the body are controlled by mechanisms of peripheral tolerance that limit their activation and induction of immune pathology. Our understanding of these mechanisms has been advanced by the use of tissue-specific promoters to express neo-self-antigens. Here, we present findings using the RIP-gp (rat insulin promoter-glycoprotein) transgenic mouse, which expresses the lymphocytic choriomeningitis virus glycoprotein (LCMV-gp) specifically in the pancreatic ß islet cells. T cells responsive to this antigen remain ignorant of the LCMV-gp expressed by the islets, and breaking tolerance is dependent upon the maturation status of antigen-presenting cells, the avidity of the T-cell receptor ligation, and the level of major histocompatibility complex expression in the pancreas. Furthermore, decreased activity of Casitas B-lineage lymphoma b, a negative regulator of T-cell receptor signaling, can allow recognition and destruction of the pancreatic islets. This review discusses the roles of these factors in the context of anti-tissue responses, both in the setting of autoimmunity and in anti-tumor immunity.

Adjuvant IL-7 antagonizes multiple cellular and molecular inhibitory networks to enhance immunotherapies.

Identifying key factors that enhance immune responses is crucial for manipulating immunity to tumors. We show that after a vaccine-induced immune response, adjuvant interleukin-7 (IL-7) improves antitumor responses and survival in an animal model. The improved immune response is associated with increased IL-6 production and augmented T helper type 17 cell differentiation. Furthermore, IL-7 modulates the expression of two ubiquitin ligases: Casitas B-lineage lymphoma b (Cbl-b), a negative regulator of T cell activation, is repressed, and SMAD-specific E3 ubiquitin protein ligase-2 (Smurf2) is enhanced, which antagonizes transforming growth factor-beta signaling. Notably, we show that although short term IL-7 therapy potently enhances vaccine-mediated immunity, in the absence of vaccination it is inefficient in promoting antitumor immune responses, despite inducing homeostatic proliferation of T cells. The ability of adjuvant IL-7 to antagonize inhibitory networks at the cellular and molecular level has major implications for immunotherapy in the treatment of tumors.

Death pathways in T cell homeostasis and their role in autoimmune diabetes.

T cell apoptosis is a process necessary for central and peripheral tolerance. It ensures the proper removal of autoreactive T cells during thymic development as well as T cell homeostasis and the downregulation of immune responses against antigens in the periphery. Thus it is essential for the prevention of autoimmunity. Apoptotic pathways can be triggered by intrinsic (mitochondria-based) and extrinsic (receptor-based) stimuli. Both pathways involve a cascade of proteolytic enzymes called caspases whose activation commits the cell to death. In the periphery, autoreactive lymphocytes can be silenced by developmental arrest (anergy), or deleted by programmed cell death (apoptosis) through receptor-based activation-induced cell death (AICD). Central tolerance seems to rely more heavily on the mitochondria-based, T cell receptor (TCR)-stimulated apoptotic pathway, since thymocytes lacking the pro-apoptotic Bcl-2 family member Bim are resistant to TCR-induced apoptosis. Furthermore, defects in the intrinsic pathway of apoptosis may impair clonal deletion of autoreactive T cells. Several animal models exist in which impaired apoptosis results in autoimmunity. Here, we discuss data that suggest defects in T cell apoptosis in type 1 diabetes mellitus.

TCR affinity and negative regulation limit autoimmunity.

Autoimmune diseases are often mediated by self-reactive T cells, which must be activated to cause immunopathology. One mechanism, known as molecular mimicry, proposes that self-reactive T cells may be activated by pathogens expressing crossreactive ligands. Here we have developed a model to investigate how the affinity of the T-cell receptor (TCR) for the activating agent influences autoimmunity. Our model shows that an approximately fivefold difference in the TCR affinity for the activating ligand results in a 50% reduction in the incidence of autoimmunity. A reduction in TCR-ligand affinity to approximately 20 times lower than normal does not induce autoimmunity despite the unexpected induction of cytotoxic T lymphocytes (CTLs) and insulitis. Furthermore, in the absence of a key negative regulatory molecule, Cbl-b, 100% of mice develop autoimmunity upon infection with viruses encoding the lower-affinity ligand. Therefore, autoimmune disease is sensitive both to the affinity of the activating ligand and to normal mechanisms that negatively regulate the immune response.

Induction of T cell development and establishment of T cell competence from embryonic stem cells differentiated in vitro.

Embryonic stem cells (ESCs) have the potential to serve as a renewable source of transplantable tissue-specific stem cells. However, the molecular cues necessary to direct the differentiation of ESCs toward specific cell lineages remain obscure. Here we report the successful induction of ESC differentiation into mature functional T lymphocytes with a simple in vitro coculture system. The directed differentiation of ESCs into T cells required the engagement of Notch receptors by Delta-like 1 ligand (DL1) expressed on the OP9-DL1 stromal cell line. We found a normal program of T cell differentiation in ESC-OP9-DL1 cell cocultures. ESC-derived T cell progenitors effectively reconstituted the T cell compartment of immunodeficient mice, enabling an effective response to a viral infection. These findings provide a powerful tool for the molecular analysis of T cell development and open new avenues for the development of immunotherapeutic approaches using defined sources of stem cells.

PKCtheta signals activation versus tolerance in vivo.

Understanding the pathways that signal T cell tolerance versus activation is key to regulating immunity. Previous studies have linked CD28 and protein kinase C-theta (PKCtheta) as a potential signaling pathway that influences T cell activation. Therefore, we have compared the responses of T cells deficient for CD28 and PKCtheta in vivo and in vitro. Here, we demonstrate that the absence of PKCtheta leads to the induction of T cell anergy, with a phenotype that is comparable to the absence of CD28. Further experiments examined whether PKCtheta triggered other CD28-dependent responses. Our data show that CD4 T cell-B cell cooperation is dependent on CD28 but not PKCtheta, whereas CD28 costimulatory signals that augment proliferation can be uncoupled from signals that regulate anergy. Therefore, PKCtheta relays a defined subset of CD28 signals during T cell activation and is critical for the induction of activation versus tolerance in vivo.

Novel insights in the regulation of the immune system: a report on the FASEB summer research conference on autoimmunity (June 14-19, 2003, Saxton's River, Vermont, USA).

The bi-annual FASEB autoimmunity conference organized last year by Betty Diamond and Stephen Miller brought together some 150 delegates studying various aspects of autoimmune diseases such as lupus, rheumatoid arthritis and autoimmune diabetes. The conference provided numerous insights into the latest research on autoimmunity and answered many basic research type questions that are important for understanding the complex nature of these diseases. Because some time has elapsed since the conference, data from a number of talks has already been published. Thus, I will present an overview of some of the most interesting and at the same time, still unpublished data on T cells presented at the conference. The balance between tolerance and immunity is controlled through a variety of mechanisms such as the presence or absence of co-stimulation or negative regulation of a T cell response. CD4+ CD25+ regulatory T cells were also a focus of interest. Talks that I will discuss focused on the role of molecules such as GITR, Foxp3 and B7 for the development and function of regulatory T cells and the importance of these molecules in the prevention of autoimmunity. As well, a novel form of CTLA-4 and the use of 4-1BB co-stimulation blockade for the control of autoimmunity will be discussed.

The B7 family member B7-H3 preferentially down-regulates T helper type 1-mediated immune responses.

We investigated the in vivo function of the B7 family member B7-H3 (also known as B7RP-2) by gene targeting. B7-H3 inhibited T cell proliferation mediated by antibody to T cell receptor or allogeneic antigen-presenting cells. B7-H3-deficient mice developed more severe airway inflammation than did wild-type mice in conditions in which T helper cells differentiated toward type 1 (T(H)1) rather than type 2 (T(H)2). B7-H3 expression was consistently enhanced by interferon-gamma but suppressed by interleukin 4 in dendritic cells. B7-H3-deficient mice developed experimental autoimmune encephalomyelitis several days earlier than their wild-type littermates, and accumulated higher concentrations of autoantibodies to DNA. Thus, B7-H3 is a negative regulator that preferentially affects T(H)1 responses.