Use of CGRP antagonist compounds for treatment of psoriasis

Abstract

The invention provides methods and compositions for treating, preventing and/or remedying psoriasis, based on compounds that have a calcitonin-related gene peptide (CGRP) antagonistic effect. Methods are also disclosed for identifying compounds with CGRP antagonist activity which thereby are suitable candidate compounds for treating psoriasis.

Claims

1. A method of systemic treatment of psoriasis in a subject in need of treatment, the method comprising subcutaneously injecting, to a localized site in the subject in need thereof, a therapeutically effective dose of CGRP 8-37 as the only active agent in a pharmaceutically acceptable formulation, the injection resulting in psoriasis treatment not localized to the site of injection.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1a and 1b: Show images that depict the scalp of a patient with Alopecia aerata and psoriasis.

(2) FIGS. 2a and 2b: Show Psoriasis pattern on legs of patients.

(3) FIG. 3 Shows Psoriasis lesions on a finger.

(4) FIG. 4: Is an image showing Herpes zoster lesions.

(5) FIG. 5: Shows Psoriasis lesions formed after skin injury.

(6) FIG. 6: Is an image showing pattern of Alopecia aerata on the skalp of a patient.

EXAMPLES

Example 1

Case Study

Possible Involvement of Neuropeptidergic Sensory Nerves in AA

(7) A recent study by R. Rossi et al. (Rossi, R. et al. Neuroreport, 8, 1135-1138 1997) indicated that patients with AA have lower basal blood flow. It was further shown that CGRP and SP (substance P) levels but not VIP (vasoactive intestinal peptide) are decreased in scalp biopsies of patients affected by AA. Reaction to stimuli is altered, such that a greater and more prolonged vasodilation in response to intradermal CGRP is observed in alopecic scalp than in controls. This is suggested by the authors of the study to indicate CGRP receptor hypersensitivity, due to a previous reduction in the amount of the neuropeptide present.

Example 2

Clinical Observation of a Patient with AA and Psoriasis

(8) A clinical observation of a Down's syndrome patient with AA and psoriasis showed that the patient had AA covering an area from one ear to the other through his occipital region. H is whole scalp was covered with psoriasis except for the area where he had AA (see FIGS. 1a and 1b). In those areas the scalp was clinically normal. The patient had psoriasis on his elbows and a strong family history of psoriasis.

(9) The observation strongly indicates that there is an inverse relationship between the two diseases, which has to my knowledge not been described before. In conjunction with the results of Example 1 that CGRP levels are lower in AA areas, this further supports the notion that CGRP is a causative agent in psoriasis.

Example 3

Clinical Observation of Psoriasis Patients Treated with UVB Therapy

(10) Patients receiving UVB treatment according to standard clinical practice were observed and interviewed. It was noticed that several patients experienced transient worsening of psoriasis after their first treatment sessions, in the very first days after initiating treatment, before they begin to get better. Worsening was defined as flare-up or increased size of existing lesions or appearance of new ones.

(11) Out of 95 patients interviewed, 38 said they had experienced worsening of their psoriasis. 21 got new lesions, most often lasting for 1 or 2 days. These lesions were often described as small, thin and red macules. 17 patients noticed a short worsening period of already existing psoriasis lesions. These symptoms were noted typically within 24-48 hours after first treatment. All patients, however, benefited from the treatment, i.e., received overall improvement of psoriasis over a longer time.

(12) I postulate that in the beginning of the treatment, increased CGRP is a normal reaction to UV radiation and heat trauma. (This has been observed experimentally in rats, see Gillardon et al. Neurosci. Lett. 1991 Apr. 1; 124(2):144-7) As the stimulus is ongoing, it is conceivably beneficial for the body to increase the specific defense mechanism and decrease cell turnover, by down-regulation of CGRP. In such a way the risk of mutation and skin cancer may be reduced. Thus, the increased CGRP levels in skin during beginning of UVB therapy enhances the patient's psoriasis symptoms, before the healing effect of the therapy sets in.

Example 4

Study of Psoriasis Pattern and Location

(13) Psoriasis lesions on a number of patients have been carefully studied to analyze patterns of the lesions. A hexagonal pattern can be observed on many patients, see FIGS. 2-3. Such pattern has not been described before. It is postulated that the pattern is a representation of neurological

Example 5

Herpes Zoster Pattern

(14) The pattern of Herpes Zoster lesions has been studied. It is noted that such patterns also show hexagonal pattern (FIG. 4). Herpes Zoster, a viral nerve infection, has a known neurological connection, and therefore the fact that hexagonal patterns are observed in both Herpes Zoster and psoriasis supports that such patterns are representations of neurological units.

Example 6

Psoriasis Lesions Formed after Skin Injury

(15) A psoriasis patient developed psoriatic lesions where his skin had been scratched or injured. It is frequently observed that lesions appear where the skin has been injured, this is called the Koebner's phenomenon. I observed that the lesions, showed a fine hexagonal pattern (see FIG. 5). It can thus be concluded that whereas the location of the straight-line lesions is caused by the injury to the skin, the finer structure-pattern comprising semi-circles or hexagons, is a strong indication of the disease's neural connection. It can further be observed in FIG. 5 that the sizes of the hexagons are interrelated such as e.g. the broader lines are comprised of hexagons that are comprised of the smaller hexagonal units of the finer lines. This propagation indicates that neural units of fixed size are activated in psoriasis. This has never been suggested before in the prior art.

Example 7

Study of Alopecia Greata Pattern

(16) FIGS. 6a and 6b of the scalp of a patient with Alopecia greata (AA) reveals that Alopecia spots display non-circular forms resembling hexagonal shape. In light of the discussion herein regarding the relationship between AA and psoriasis, the indication that AA also shows patterns indicative of neural factors further support the notion of psoriasis being a neurological disorder.

Example 8

Case Study

Topical Immunotherapy for Alopecia areata

(17) Orecchia et al. (Orecchia, G. et al. Dermatologica 1990, 180, 57-59) describe treatment of AA with SABDE (squaric acid dibutylester), a topical sensitizer. A patient who received the treatment developed psoriasis at the same spot where he got hair regrowth. Hairs on the psoriatic plaques were the last to fall off when the disease progressively worsened after treatment, to Alopecia Universalis.

(18) As discussed in the detailed description, to activate keratinocytes from hair follicles which act as reserve cells, CGRP can turn the hair in resting phase (telogen phase) into active phase (anagen phase). When the body is exposed to antigen in very small quantities (as topical immunotherapy) CGRP is released to stop the process of delayed type hypersensitivity (DTH) to evolve. I believe that is the reason why SABDE and DPCP are effective in treatment of Alopecia Aerata. This mechanism involving CGRP as a down-regulator of DTH and actor in early wound healing which is able to turn hair follicles from telogen to anagen phase explains why there is an inverse relationship between psoriasis and AA, as demonstrated in the Example 1.

Example 9

Lotion for Treating Psoriasis

(19) A lotion for treatment and/or prevention of psoriasis by topical administration may be prepared as follows:

(20) A suitable compound is selected, from those disclosed in the description or a compound identified with the method of Example 10 percent lotion is prepared as follows: about 0.1 to 0.5 g of the compound is dissolved in ethanol (6 ml), and the solution is admixed with a water-in-oil lotion (95 g) prepared from mineral oil, cottonseed oil, isopropyl palmitate and water with a surfactant such as sorbitan sesquioleate. The ingredients in the water-in-oil lotion are present for example in 10:10:5:70:5 parts by weight respectively.

Example 10

Screening for Antagonistic Compounds

(21) A method is described in WO 98/56779 to screen for compounds that hinder the CGRP receptor from binding CGRP. Thus, the method will identify compounds that are likely to be useful for the current invention.

(22) Briefly, the selected test compounds are assayed for the inhibition of [.sup.125I] CGRP (from Amersham, Chicago, Ill.). SK-N-MC cells (American Type Culture Collection, Rockville, Md.) are grown in Minimum Essential Medium (MEM) containing fetal calf serum (10%). Cells are grown in T-150 flasks or Costar multiwell plates and maintained at 37 C. in a 90% humidified incubator with an atmosphere of 5% CO.sub.2 and 95% air.

(23) The cells are homogenized in 5 mM Tris-HCl pH 7:4, 10 mM Na-EDTA and the homogenate centrifuged at 48,000 g for 20 min at 4 C. The pellet is re-suspended in 20 mL Na-HEPES pH 7.4, 10 mM MgCl.sub.2 and recentrifuged. The membrane pellets are re-suspended in the same buffer and stored frozen at 70 C. The protein concentration is measured by the Pierce BCA method using BSA (Bovine serum albumin) as a standard.

(24) The [.sup.125I]CGRP receptor binding assay is performed using a buffer of 20.mM Na-HEPES pH 7.4, 10 mM MgCl12, 0.05% BSA and 0.1 mg/mL bacitracin. The membranes (50 g/mL) are incubated with various concentrations (such as in the range of about 1 M and 1 mM) of the test compounds and 40 pM [.sup.125I]CGRP in a total volume of 500 L for 60 min at 25 C. The reaction is terminated by addition of 2 mL ice-cold 0.9% NaCl, followed by rapid filtration through Skatron Filtermates pre-soaked in 0.5% polyethylenimine (PEI). The filters are rinsed twice with 2 mL of cold 0.9% NaCl and the radioactivity counted in a gamma counter. The binding data is analyzed with conventional ligand-binding calculations and programs, such as the LIGAND 2 program.

Example 11

Measurement of CGRP in Edges Surrounding Psoriasis Lesions

(25) Laser Doppler blood flow measurement was used to measure blood flow in normal skin surrounding psoriasis lesions to determine the location of the active edge of psoriasis lesions. It is known that psoriasis lesions grow directionally, i.e., have a growing or active edge (see, Cunliff et al. J. Invest. Dennatol. 1989, 92(6):782-5). CGRP levels were measured in both the active edge and the inactive (opposite) edge in two subjects having psoriasis lesions. Initial results indicate that CGRP levels are increased in the active edge as compared to the inactive edge. The experiment was conducted by the use of microdialysis equipment for tissue fluid sampling with a 15 kDa cutoff probe; both the active and inactive edge were sampled for a total of 165 min. each sample to obtain a volume of 165 L in each sample. Neuropeptide CGRP concentration was measured with ELISA. Tissue biopsies from the sampled skin locations were taken after the tissue fluid sampling. At the active edge increased blood flow was observed indicated by increased capillary blood vessels indicated by increased number of capillary loops in the papillary dermis, which also were dilated. No epidermal hyperplasia or T-cell activation were found.

(26) The results strongly indicate that increased concentration in CGRP level in the skin is a very early event in the development of psoriasis. This supports that failure in regulating the GCRP level (i.e. an enhanced CGRP level) could be a causative factor in the psoriasis disease.