Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2000-10-18
2002-07-23
Dees, Jose G. (Department: 1615)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Heterocyclic carbon compounds containing a hetero ring...
C514S863000, C514S826000
Reexamination Certificate
active
06423703
ABSTRACT:
The presents invention relates to the domain of chemistry and more particularly to that of human or veterinary therapeutic chemistry.
The present invention especially concerns the use of porphyrin for the production of a medicine lowering the number of eosinophils.
In fact, many illnesses or pathologies are connected with hypereosinophilia; amongst them, bronchial asthma can be particularly cited.
The morbidity of this illness remains significant. In France the number of people affected by asthma is calculated at 2.5 million, and the number of deaths directly attributable to asthma is 2000 per year (cf. Epidemiological study of the European Community Respiratory Health Survey). The prevalence of asthma thus remains worrying, whatever is the age and geographical location of the population studied, The treatment of chronic asthma—apart from acute attacks—is mainly dominated by the use of &bgr;2-stimulants and corticosteroids administered by inhalation. Antihistamines are only marginally used today. Each category of medicines causes a different type of effect:
The &bgr;-stimulant agents essentially cause the relaxation of the smooth bronchial muscles: they also reduce the liberation of mediators. These substances including adrenaline, isoproterenol as well as more selective substances of the &bgr;2 receptors (bronchial tubes) than the &bgr;1 receptors (heart). After inhalation, the &bgr;2 (&bgr;2-adrenergic) substances act very quickly (in several minutes) but are only active for several hours.
The principle mode of action of theophylline is the relaxation of the smooth bronchial muscle. It inhibits the delayed phase of allergy and inhibits the liberation of inflammation mediators by mastocytes. Many authors consider that it is currently the most effective maintenance treatment for asthma. One of its major drawbacks however, is its narrow therapeutic margin.
Corticosteroids inhibit the migration of granulocytes towards the sites of allergic reaction, and prevent the liberation of inflammation mediators. In particular, when they are administered in aerosols, they inhibit the delayed phase of the allergy (but not the immediate phase) and the resulting bronchial hyperactivity. Although they are very effective, the systematic administration of corticosteroids has to be reserved for difficult cases because of their secondary effects. Inhaled steroids are used for maintenance treatment but not for acute asthma attacks.
Sodium cromoglycate and nedocromil are used as a preventive measure. They inhibit the liberation of mediators and reduce bronchial hyperactivity. Cromoglycate appears to be most effective in children and certain adults, for the maintenance treatment.
Subcutaneous specific desensitisation has been used for almost a hundred years; however the way it works is still not completely understood. The injection of allergens must be carried out under medical supervision. The results of desensitisation are controversial and only appear to improve the condition of a fraction of asthmatic people.
Anti-leukotrienes are currently the cutting edge in the domain of new therapies for asthma. The leukotrienes are synthesised by the inflammation cells. They play a role in the recruitment of inflammation cells and in bronchoconstriction. A number of molecules capable of inhibiting the effect of leukotrienes are currently being developed. Two of them, zafirlukast and pranlukast, are antagonists of the leukotriene receptors, but their use remains limited to moderate cases of asthma.
The importance of phosphodiesterases inhibitors, the main one being theophylline, is currently being rediscovered. The developed drugs currently attempt to inhibit more specifically phosphodiesterase of type IV, preponderantly present in the inflammation cells (eosinophils, lymphocytes) and the smooth bronchial muscles. The second-generation theophyllines are better able to be tolerated than theophylline itself, whose therapeutic margin remains narrow.
Furthermore, monoclonal antibodies directed against IL-5 are developed in the aim of controlling hypereosinophilia and the bronchial hyperreactivity of asthma. Even so, anti-IgE monoclonal antibodies are developed in the aim of blocking the IgE responsible for the sensitisation of the allergy cells. However, the effectiveness of these products in human asthma still has to be proven.
Asthma has been defined as “a chronic inflammatory illness of the airways, responsible for attacks of wheezing, a reduction of the MEVS (Maximum exhalation volume per second) and bronchial hyperreactivity” (NIH workshop report, January 1995). Bronchial hyperreactivity is the tendency that the bronchial tubes in asthmatics have to contract under the influence of a number of irritant or pharmacological stimuli, which are without effect in a healthy subject.
The most spectacular characteristic of the histopathology of asthma is the very large infiltration of eosinophils, macrophages and lymphocytes into the bronchial mucous membranes. Eosinophils appear to be the key cells responsible for lesions of the bronchial mucous membranes and bronchial hyperreactivity, although the precise mechanism of these phenomena is still being discussed.
Recent studies have compared asthmatics with healthy volunteers by using the broncho-alveolar wash technique and carrying out bronchial biopsies. A high number of eosinophils, both in the bronchial mucous membranes and in the broncho-alveolar wash fluid, is characteristic of asthma. Blood hypereosinophilia and the presence of eosinophils in the sputum, are characteristic of asthma; the level of eosinophils in the blood is correlated to the level of bronchial hyperreactivity.
After their differentiation and maturation in the bone marrow, the mature eosinophils are liberated into the blood circulation and go on to their main location in the tissues. The life span of the eosinophils in the tissues is unknown, but it is estimated at at least several days and it is probably dependent on the presence of cytokines like IL-5, IL-3 or GM-CSF. In some tissues (Skin, lung), the eosinophils are physiologically rare, but they can migrate to these tissues where they display their cytotoxic function and liberate inflammation mediators in response to a suitable stimulus [Texeira et al, 1995, Tr. Pharmacol. Sc. 16:418-423].
Eosinophils contribute to the physiopathology of allergic illnesses, particularly in the skin, the lungs, the nasal and ocular mucous membranes [Corrigan et al, 1992, Immunol. Today 13:501-506].
The accumulation in the tissues of eosinophils during allergic illnesses can prove to be disastrous; in fact, the granular proteins of the eosinophils are cytotoxic for the bronchial epithelial cells and also have many effects on the mastocytes, the epithelial cells, the macrophages and the T cells. Many works stress the link between the number of eosinophils, their state of activation and the severity of the asthma, both in man and animals (Bousquet et al, 1990, N Engl. J. Med. 323:1033-1039; Roisman et al, 1995, J. Clin. Invest. 96:12-21).
However despite the progress made in the course of the last few years, in the understanding of the mechanisms of allergy in general and asthma in particular, the most used medicines today belong to therapeutic classes which have been available for decades and the new molecules on the market continue to be based on old concepts.
According to the present invention, the proposed medicine is based on a different concept, that of preventing the accumulation of eosinophils in the tissues by pharmacologically acting on their life span. In fact, having the possibility of pharmacologically modulating the life span of the eosinophils is essential as it affects the potential of the eosinophil to liberate mediators, to exert its cytotoxicity or to functionally co-operate with other cells. Cytokine IL-5 appears to play a very important role in the survival in vivo of the eosinophils. It is however pharmacologically worthwhile to inhibit the effects of IL-5 and other factors for the survival of the eosinophils. This pharma
Francis Beauvais
Joly Francine
Bierman, Muserlian and Lucas
Dees Jos,e G.
Gollamudi Sharmila S.
Sephra S.A.R.L.
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