Is calcitonin gene-related peptide (CGRP) the missing link in food histamine-induced migraine? A review of functional gut-to-trigeminovascular system connections.

Calcitonin gene-related peptide (CGRP) and histamine plasma concentrations increase during migraine attacks. Both mediators are potent vasodilators, and they have been shown to reciprocally contribute to the release of each other in the trigeminovascular system, possibly driving migraine development. A high-histamine-content diet triggers migraine in patients who have histamine degradation deficiency owing to diaminooxidase (DAO) gene mutations. Therefore, studying functional links between exogenous histamine and CGRP seems promising for the understanding of diet-induced migraine generation. Notably, there is a lack of knowledge about the interplay of the enteric nervous system and the spinal/trigeminal somatosensory system with regard to CGRP and histamine. Based on background evidence, we propose that a functional interconnection between exogenous histamine and CGRP contributes to migraine development.

Combined analytical assays for the characterization of drugs binding to human IgE: Applicability to omalizumab-bearing biosimilar candidates assessment.

Analytical and functional comparison is key for substantiating the level of convergence (essential sameness) or divergence between versions or variants of a given biological medicine. Accordingly, an overlapping biological activity between products meant to be equal probably reflects a highly similar structure and anticipates a comparable pharmacodynamic behavior. We developed an orthogonal approach to compare the human IgE binding features of different lots and versions of Xolair® (omalizumab), an anti-human IgE monoclonal antibody. The IgE binding affinity and kinetics were measured by surface plasmon resonance. Ability to prevent mast cell activity was assessed in vitro and in vivo in mast cell-based models. The variability of monoclonal antibodies with identical amino acid sequences produced either in Chinese hamster ovarian cells or in human HEK293 cells, was compared. Monoclonal antibodies from the two sources exhibited slightly different human IgE binding and neutralizing features. A known variant exhibiting a three amino acid replacement in the Fab region had lower IgE binding affinity than the original omalizumab. The lower binding affinity translated into reduced IgE neutralizing capacity and, in turn, a difference in the ability to prevent mast cell activation in vitro and in vivo. The proposed set of analytical and functional assays was sensitive enough to detect Fab-linked differences between anti-IgE antibody versions exhibiting an identical aminoacid sequence. In addition to add value to the comparative assessment of biosimilar candidates bearing omalizumab, these methods can aid pre-assessments of new anti-IgE agents that aim to improve therapeutic performance.

Overlapping biosimilar and originator follitropin alfa preparations: How much closer can they get?

Unfounded skepticism relating to biosimilars, arising from the assertion that they are not molecularly identical to their original counterpart, fails to acknowledge that no biological medicine, including Gonal-f® (from Merck Serono) is identical to itself. Molecular differences between the biosimilar and the reference medicines are irrelevant and clinically undetectable as long as they are contained within the accepted variability for the original medicine. Accordingly, the minor differences in 'ongoing pregnancy rate' and 'live birth' rate reported in a recent meta-analysis of biosimilars of Gonal-f® from Chua et al. are probably driven by product-unrelated factors, notwithstanding the fact that of the four products under analysis, only Ovaleap® (from Theramex UK Ltd) and Bemfola® (from Gedeon Richter Plc) can unambiguously be considered to be biosimilars. The EU Biosimilars model has proven successful, but some healthcare professionals, building on highly arguable premises, voice a distrust in biosimilars. Only if such scientifically unfounded distrust is reverted, the full promise of rFSH alfa biosimilars for reproductive medicine patients is likely to be fulfilled.

Extrapolation: Experience gained from original biologics.

Biologicals undergo modifications throughout their commercial lifecycle. Major changes can unintentionally magnify their inherent physicochemical variability. Although trials comparing the pre- and the post-change versions have been requested occasionally, analytical comparison is the most sensitive approach to anticipating clinical equivalence. Therefore, it may be concluded, by means of 'extrapolation', that non-identical versions of a given biologic will behave equally in all indications. Despite the lessons learned with original biologics, there are still controversies around the approval of biosimilars through extrapolation. Here, a comprehensive analysis of scattered information allows for an account of cases of original biologic versions approved in some indications with no patient trials involved. Healthcare professionals can be reassured that inasmuch as extrapolation has proven valid for new versions of original biologics, the same holds for biosimilars.

In Vitro and In Vivo Validation of EP2-Receptor Agonism to Selectively Achieve Inhibition of Mast Cell Activity.

PURPOSE: Agonism of the prostaglandin E2 receptor, E-prostanoid receptor 2 (EP2), may represent an alternative protective mechanism in mast cell (MC)-mediated diseases. Previous studies have suggested that activation of the MC EP2 receptor prevents pathological changes in the murine models of allergic asthma. This work aimed to analytically validate the EP2 receptor on MCs as a therapeutic target. METHODS: Murine MC lines and primary cultures, and MCs bearing the human immunoglobulin E (IgE) receptor were subjected to IgE-mediated activation subsequent to incubation with selective EP2 agonists. Two molecularly unrelated agonists, butaprost and CP-533536, were tested either in vitro or in 2 in vivo models of allergy. RESULTS: The diverse range of MC populations was consistently inhibited through selective EP2 agonism in spite of exhibiting a heterogeneous phenotype. Such inhibition occurred in both mouse and human IgE (hIgE)-mediated activation. The use of molecularly unrelated selective EP2 agonists allowed for the confirmation of the specificity of this protective mechanism. This effect was further demonstrated in 2 in vivo murine models of allergy where MCs are a key to pathological changes: cutaneous anaphylaxis in a transgenic mouse model expressing the hIgE receptor and aeroallergen-induced murine model of asthma. CONCLUSIONS: Selective EP2 agonism is a powerful pharmacological strategy to prevent MCs from being activated through IgE-mediated mechanisms and from causing deleterious effects. The MC EP2 receptor may be an effective pharmacological target in allergic and other MC-mediated conditions.

Biosimilars: A Value Proposition.

Biosimilars are biological agents that effectively replicate original reference products. The main driver of their development is the promise of bringing competition into the marketplace, and consequently contributing to the sustainability of healthcare systems. By reducing financial barriers to biological therapies, biosimilars play a part in budgetary redistribution and, hence, in increasing patients' access to treatment. They also foster innovation and deliver other non-price-driven advantages. However, the market is such that harmonization of pricing of reference biologics and biosimilars may dissuade physicians from prescribing biosimilars and often creates an unfavorable market environment for the launch of biosimilars. Such dynamics result in a high cost by denying patients the full benefits and added value inherent in biosimilar agents. A more equitable offering of established original biologics and biosimilars is needed to ensure the viability of current healthcare services.

Biosimilars to recombinant human FSH medicines: comparable efficacy and safety to the original biologic.

Two recombinant follicle-stimulating hormone (rFSH)-bearing similar biological medicines (biosimilars) have been authorized by the European Commission. Biosimilar is a regulatory concept alluding to the evidence-based high-standard comparability studies needed to demonstrate its equivalence to a reference original biologic. Because biosimilar development represents a shift from the long-lasting existing paradigms, a thorough understanding of the science behind it will contribute to helping prescribers make informed treatment choices. Contrary to chemically-synthesized medicines, biologics are subject to an inherent molecular variability. From the experience with original biologics, regulatory authorities have accumulated a wealth of knowledge as to what minor batch-to-batch physicochemical variations may be therapeutically acceptable in a given product. Furthermore, in spite of analytically detectable differences, the two original rFSH-bearing medicines currently on the market share fundamentally the same therapeutic profile. Unlike those original medicines, a biosimilar of an rFSH product and the corresponding reference biologic share essentially the same active pharmaceutical ingredient. They are also administered via the same route, at the same dose, and for the same indications. This article revises the background evidence over which the biosimilarity principle has been built, and highlights the therapeutic potential for follitropin biosimilars in order to reassure physicians on their benefit.

Biosimilar: what it is not.

A biosimilar is a high quality biological medicine shown to be in essence the same as an original product. The European Medicines Agency (EMA) paved the way in the regulatory arena by creating a safeguarding framework for the development of biosimilars. Biosimilar is thus a regulatory term that alludes to the evidence-based studies required to demonstrate such very high similarity. They are therefore not innovative products but the pathway laid down by the EMA for their approval represented a new paradigm. This has brought some confusion and has cast doubts among healthcare professionals about the scientific evidence behind their authorization. Many papers have been published to clarify the concept, and to reassure those professionals, but misconceptions frequently still arise. Unfortunately, this prevents biosimilars from deploying their full therapeutic added value. This paper is intended to approach those misconceptions from a new angle, by explaining what a biosimilar is not…and why. A biosimilar is neither a generic, nor an original product. It is not a biobetter or a 'stand-alone'. Therefore, it should not be managed as such therapeutically, commercially or from a healthcare policy viewpoint. The EMA's criteria were acknowledged by other agencies, but a significant regulatory gap with a vast majority of regulatory bodies still remains. This leaves room for the so-called non-original biologics (NOB), i.e. non-biosimilar biologics, to be launched in many regions. Raising awareness of what a biosimilar is and what it is not, will generate trust in biosimilars among healthcare professionals and will ultimately benefit patients.

The PGE2-EP2-mast cell axis: an antiasthma mechanism.

Despite the fact that cyclooxygenase and its products, prostaglandins, have been traditionally associated with the development of inflammation, PGE2 was implicated early on as potentially beneficial in asthma. During the 1970s and 1980s, several studies reported the bronchodilator effect of PGE2 in asthma patients. In parallel, it was being shown to exert an inhibitory effect on mast cells in vitro. In spite of this, data supporting the beneficial role for PGE2 in asthma were scarce and sometimes controversial. Many years later, in vitro and in vivo studies suggested a range of biological activities attributable to PGE2, others than the ability to relax smooth muscle, that potentially explained some of the observed positive effects in asthma. The identification and cloning of the four PGE2 receptors made available new tools with which to fine-tune investigation of the anti-inflammatory, pro-inflammatory, immunoregulatory, and bronchodilation mechanisms of PGE2. Among these, several suggested involvement of mast cells, a cell population known to play a fundamental role in acute and chronic asthma. Indeed, it has been shown that PGE2 prevents human and murine MC activity in vitro through activation of the EP2 receptor, and also that both exogenously administered and endogenous PGE2 inhibit airway MC activity in vivo in mouse models of asthma (likely through an EP2-mediated mechanism as well). In the last few years, we have furthered into the functional connection between PGE2-induced mast cells inhibition and attenuated damage, in asthma and allergy models. The validity of the findings supporting a beneficial effect of PGE2 in different asthma phases, the direct effect of PGE2 on mast cells populations, and the functional implications of the PGE2-MC interaction on airway function are some of the topics addressed in this review, under the assumption that increased understanding of the PGE2-EP2-mast cell axis will likely lead to the discovery of novel antiasthma targets.

Prostaglandin E2 prevents hyperosmolar-induced human mast cell activation through prostanoid receptors EP2 and EP4.

BACKGROUND: Mast cells play a critical role in allergic and inflammatory diseases, including exercise-induced bronchoconstriction (EIB) in asthma. The mechanism underlying EIB is probably related to increased airway fluid osmolarity that activates mast cells to the release inflammatory mediators. These mediators then act on bronchial smooth muscle to cause bronchoconstriction. In parallel, protective substances such as prostaglandin E2 (PGE2) are probably also released and could explain the refractory period observed in patients with EIB. OBJECTIVE: This study aimed to evaluate the protective effect of PGE2 on osmotically activated mast cells, as a model of exercise-induced bronchoconstriction. METHODS: We used LAD2, HMC-1, CD34-positive, and human lung mast cell lines. Cells underwent a mannitol challenge, and the effects of PGE2 and prostanoid receptor (EP) antagonists for EP(1-4) were assayed on the activated mast cells. Beta-hexosaminidase release, protein phosphorylation, and calcium mobilization were assessed. RESULTS: Mannitol both induced mast cell degranulation and activated phosphatidyl inositide 3-kinase and mitogen-activated protein kinase (MAPK) pathways, thereby causing de novo eicosanoid and cytokine synthesis. The addition of PGE2 significantly reduced mannitol-induced degranulation through EP(2) and EP(4) receptors, as measured by beta-hexosaminidase release, and consequently calcium influx. Extracellular-signal-regulated kinase 1/2, c-Jun N-terminal kinase, and p38 phosphorylation were diminished when compared with mannitol activation alone. CONCLUSIONS: Our data show a protective role for the PGE2 receptors EP(2) and EP(4) following osmotic changes, through the reduction of human mast cell activity caused by calcium influx impairment and MAP kinase inhibition.

Locally administered prostaglandin E2 prevents aeroallergen-induced airway sensitization in mice through immunomodulatory mechanisms.

Prostaglandin E2 attenuates airway pathology in asthmatic patients and exerts a protective effect in antigen-sensitized mice when administered systemically. We aimed to establish the consequences of intranasal PGE2 administration on airway reactivity to aeroallergens in mice and reveal the underlying immunoinflammatory mechanisms. PGE2 was administered either daily during a 10-day exposure to house dust mite (HDM) extracts or for limited intervals. Airway hyperreactivity was measured by whole-body and invasive plethysmography. The phenotypes of lung immune cells and cytokine production were analysed by flow cytometry and ELISA, respectively. Airway hyperreactivity was sustainably reduced only when PGE2 administration was restricted to the initial 5 days of exposure to HDM. Lung inflammation, IL-4 production, and airway mast cell activity were also prevented under this early short-term treatment with PGE2. Interestingly, a Th2 response was already committed on day 5 of exposure to HDM. This was paralleled by GM-CSF and osteopontin upregulation and a decreased number of plasmacytoid dendritic and T regulatory cells, as well as a trend towards reduced IL-10 expression. Local PGE2 administration prevented the increase of airway IL-13 and osteopontin and kept lung plasmacytoid dendritic cell counts close to baseline. GM-CSF and Tregs were unaffected by the treatment. These findings suggest that the protection provided by PGE2 is a result of the modulation of early lung immunomodulatory mechanisms, and possibly a shift in the balance of dendritic cells towards a tolerogenic profile.

E-prostanoid 2 receptors dampen mast cell degranulation via cAMP/PKA-mediated suppression of IgE-dependent signaling.

The experimental administration of PGE(2) for the treatment of asthma dampens clinical symptoms, and similar efficacy has been found in dust mite-induced hypersensitivity reactions in animal models. Here, we investigate the mechanism by which PGE(2) mediates suppression of MC degranulation. We find that the effect of PGE(2) on FcεRI-dependent MC degranulation varies from activating to suppressing, depending on the relative ratio of EP(2) to EP(3) expression on these cells with suppression evident only in cells having increased EP(2) to EP(3) expression. Consistent with a role for EP(2) in suppressing MC responses in vitro, we found that a selective EP(2) agonist, Butaprost, inhibited MC-mediated FcεRI-induced immediate hypersensitivity in a model of PCA. EP(2) engagement on MCs increased cAMP production and inhibited FcεRI-mediated calcium influx. In addition, it also decreased the extent of FcεRI-induced Fyn kinase activity, leading to decreased phosphorylation of key signaling molecules such as Gab2 and Akt. Treatment with an antagonist of cAMP or shRNA down-regulation of PKA (the principal intracellular target of cAMP) reversed the EP(2)-mediated inhibitory effect on MC degranulation and restored calcium influx and phosphorylation of Akt. Collectively, the findings demonstrate that EP(2) suppresses the Fyn-mediated signals that are central to FcεRI-dependent MC degranulation, suggesting that engagement of the EP(2) on MCs may be beneficial in dampening allergic responses.

Medicamentos derivados de la biotecnología: ¿qué son? una perspectiva farmacológica e histórica / Biotechnology-derived drugs: what are they?: pharmacological and historical perspective

Los biológicos, es decir, medicamentos obtenidos de organismos vivos, no son nuevos. La historia proporciona varios ejemplos de extractos animales o humanos que se utilizan para prevenir o tratar enfermedades humanas. En consecuencia, los médicos han estado conscientes, por siglos, del valor terapéutico de nuestras propias moléculas. La dificultad radicó, muchas veces, en cómo obtener estos compuestos propios o similares a los propios. La biotecnología, una tecnología mediante la cual organismos vivos manipulados se utilizan para generar productos útiles tales como fármacos, proporcionó una respuesta revolucionaria. Sabemos cómo crear genéticamente por ingeniería bacterias, levaduras, células de insectos o mamíferos para sintetizar moléculas humanas, las llamadas proteínas terapéuticas recombinantes humanas. Los anticuerpos monoclonales murinos y humanizados contra antígenos humanos también son productos biotecnológicos. El número de fármaco s biotecnológicos que se están comercializando, y aquéllos que se utilizan en ensayos clínicos o que están a la espera de autorización, está creciendo de manera exponencial. Actualmente, aún estamos en los inicios de una nueva era en farmacoterapia, cuyo final es imposible de ver. Los farmacólogos deben seguir el ritmo de estos cambios y desarrollar nuevas habilidades. Probablemente, incluso tengan que desafiar antiguas suposiciones, con la finalidad de investigar nuevas moléculas. Utilizando un enfoque fácil y entendible, este artículo de revisión vuelve a tratar bio-conceptos y da énfasis a la dimensión real del desafío.

Activity of the cyclooxygenase 2-prostaglandin-E prostanoid receptor pathway in mice exposed to house dust mite aeroallergens, and impact of exogenous prostaglandin E2.

BACKGROUND: Prostaglandin E2 (PGE2), experimentally administered to asthma patients or assayed in murine models, improves allergen-driven airway inflammation. The mechanisms are unknown, but fluctuations of the endogenous cyclooxygenase (COX)-2/prostaglandin/E prostanoid (EP) receptor pathway activity likely contribute to the clinical outcome. We analyzed the activity of the pathway in mice sensitized to aeroallergens, and then studied its modulation under exogenous PGE2. METHODS: Mice were exposed to house dust mite (HDM) aeroallergens, a model that enable us to mimic the development of allergic asthma in humans, and were then treated with either subcutaneous PGE2 or the selective EP1/3 receptor agonist sulprostone. Simultaneously with airway responsiveness and inflammation, lung COX-2 and EP receptor mRNA expression were assessed. Levels of PGE2, PGI2, PGD2 were also determined in bronchoalveolar lavage fluid. RESULTS: HDM-induced airway hyperreactivity and inflammation were accompanied by increased COX-2 mRNA production. In parallel, airway PGE2 and PGI2, but not PGD2, were upregulated, and the EP2 receptor showed overexpression. Subcutaneous PGE2 attenuated aeroallergen-driven airway eosinophilic inflammation and reduced endogenous PGE2 and PGI2 production. Sulprostone had neither an effect on airway responsiveness or inflammation nor diminished allergen-induced COX-2 and PGE2 overexpression. Finally, lung EP2 receptor levels remained high in mice treated with PGE2, but not in those treated with sulprostone. CONCLUSION: The lung COX-2/PGE2/EP2 receptor pathway is upregulated in HDM-exposed mice, possibly as an effort to attenuate allergen-induced airway inflammation. Exogenous PGE2 downregulates its endogenous counterpart but maintains EP2 overexpression, a phenomenon that might be required for administered PGE2 to exert its protective effect.

[A cyclooxygenase-2 selective inhibitor worsens respiratory function and enhances mast cell activity in ovalbumin-sensitized mice]. / Un inhibidor selectivo de la ciclooxigenasa-2 empeora la función respiratoria y fomenta la actividad de los mastocitos en ratones sensibilizados a la ovalbúmina.

BACKGROUND: Cyclooxygenase (COX)-2 activity has been said to have a protective effect in asthmatic patients as a result of prostaglandin E(2) production. In order to elucidate the mechanisms involved, we evaluated the impact of selective inhibition of COX-2 with rofecoxib during ovalbumin challenge, assessing mast cell activity and airway response in a murine model of asthma. MATERIAL AND METHODS: Mice were sensitized to ovalbumin (10 microg injected intraperitoneally) and further challenged with 0.5% intranasal ovalbumin. Half the sensitized animals were treated orally with rofecoxib (15 mg/kg/d during the challenge phase). Lung function was measured by whole body plethysmography before and after exposure to ovalbumin. The severity of airway inflammation was evaluated by means of a scoring system. Finally, the serum level of mouse mast cell protease-1 was determined as an indicator of mucosal mast cell activity. RESULTS: Sensitized mice treated with rofecoxib exhibited 2.4-fold greater airway hyperresponsiveness than did vehicle-treated mice at a methacholine concentration of 100mg/ml. A clear trend toward worsening airway inflammation in the presence of rofecoxib was observed, although the difference between rofecoxib-treated and vehicle-treated animals was not significant. These changes were accompanied by a significant increase in mucosal mast cell activity. CONCLUSIONS: Selective pharmacological inhibition of COX-2 during the challenge phase worsens airway function in the ovalbumin -induced murine model of acute asthma. We suggest that this effect might be at least partially explained by the increase in airway mast cell activity.

Subcutaneous prostaglandin E(2) restrains airway mast cell activity in vivo and reduces lung eosinophilia and Th(2) cytokine overproduction in house dust mite-sensitive mice.

BACKGROUND: Prostaglandin (PG) E(2) is thought to exert protective effects in the lungs. Accordingly, aerosolized PGE(2) prevents the experimentally induced airway response to allergen challenge in asthmatics. In vitro evidence indicating that functional PGE(2) receptors (EP) are expressed on human mast cells and that PGE(2) can alter cytokine production suggests that these phenomena may be involved in its beneficial effect in asthma. However, in vivo evidence is scarce. METHODS: We assessed the effects of exogenous PGE(2) and of the EP1/EP3 agonist sulprostone on the murine airway response to house dust mite (HDM) allergens, a model that accurately reproduces the spontaneous exposure of allergic asthma patients to aeroallergens. We also analyzed the in vivo impact of PGE(2) on production in the murine airway of mast cell protease (mMCP)-1, a specific marker of lung mast cell activity, and on local production of cytokines. RESULTS: Exogenous PGE(2), but not sulprostone, reduced eosinophilic infiltration in HDM-sensitized mice by half and led to a strong reduction in airway Th(2) cytokine expression. These anti- inflammatory effects were accompanied in vivo by a substantial reduction in HDM-induced upregulation of airway mMCP-1. Neither PGE(2) nor sulprostone had any effect on airway hyperresponsiveness to methacholine. CONCLUSIONS: Our results indicate that the anti-inflammatory effect of PGE(2) can be reproduced in vivo in HDM-sensitized mice and suggest that this protective effect is dependent in vivo on inhibition of the allergen-triggered proinflammatory activity of bronchial mast cells. Finally, the effect of PGE(2) is linked to reduced upregulation of airway Th(2) cytokines.