Compositions and methods for treating psoriasis

Abstract

Novel isohexides and pharmaceutical compositions containing the same as well as methods of using the same in the treatment of psoriasis.

Description

This application (i) I, especially the dianhydrohexitol di-(methylfumarate)s, most especially Isosorbide di-(methylfumarate) (IDMF), has surprisingly been found to provide a marked effect in ameliorating, reducing and/or reversing or otherwise treating the effects and/or manifestation of psoriasis as well as other disease manifesting similar symptoms and/or sharing common gene expression profiles, at least with respect to those genes that appear to be disease related. While not intending to be bound by theory or mechanisms, it is believed that these compounds, especially IDMF, is capable of modulating key genes/proteins responsible for chronic inflammation in psoriasis involving numerous immune axes, particularly various arms of the T-lymphocyte axis, and elevated oxidative stress, impaired antioxidant responses and barrier dysfunction.

While these compounds are effective individually, the compounds of the present teaching may be, and are preferably and/or beneficially, used in combination with each other, e.g., combinations of two or more compounds meeting Formula (I) above, and/or in combination with other pharmacologically active compounds, particularly compounds that similarly reduce, ameliorate, inhibit or otherwise address or treat symptoms and/or conditions associated with the diseases to be addressed by the compounds of the present teaching. Such combinations of compounds and actives provide further surprising results in terms of their pharmacological activity, especially with respect to the treatment of psoriasis and other diseases which manifest and/or have common effects on gene expression profiles. Such other pharmaceutical actives may be selected to treat the same disease or symptoms as the compounds of formula (I) or a different disease or symptom. Alternate drugs useful for treating psoriasis which may be combined with the compounds of formula (I) or into which compounds of Formula (I) may be incorporated include, but are not limited to, etanercept, adalimumab, triamcinolone, cortisone, infliximab, golimumab, di- or mono-alkyl fumarates, and retinoids. Most especially, as noted above, the compounds of formula (I) are used in combination with compounds of Formulae II and III, may be, and preferably are, incorporated into various pharmaceutical compositions for administration to a patient. These additional actives may be combined together and the combination of actives administered as a single pharmaceutical composition or administered independently, in concurrent or sequentially administered pharmaceutical compositions.

Thus, in accordance with yet another aspect of the teaching of the present disclosure there are provided pharmaceutical compositions and methods of treatment comprising a combination of two or more compounds according to formula (I) above as well as combinations of at least one compound of formula (I) above and one or more other suitable pharmaceutical active. Such combinations of active compounds and their application or administration is found to have improved and/or synergistic performance, particularly with respect to the treatment of psoriasis and diseases which manifest similar symptoms and/or common gene expression profiles. For example, one preferred class of other pharmaceutical actives is those compounds that are capable of activating granular-layer activating genes, more specifically, skin aspartic proteases (SASPase) and filaggrin. In this regard, it has been reported that <5% of patients with psoriasis have filaggrin (FLG) mutations and 80% of psoriasis patients have FLG deficiency in their skin (U Huffmeier et al, J Invest Dermatol, 127:1367-370, 2006). Research demonstrates that SASPase activity is indispensable for processing profilaggrin and maintaining the texture and hydration of the SC (EMBO Mol Med, 3(6):320-33, 2011). Additionally, Bernard et al have identified SASPase in the granular layer of human epidermis (J Invest Dermatol, 125:156-159m 2005). Thus, the presence of such compounds or actives in the compositions according to the present teaching leads to reinforcement and/or enhancement in the skin barrier function and stimulation of epidermal regeneration and differentiation.

Among the preferred active compounds that may be used in combination with the compounds of formula (I) are those of Formula II and/or Formula III:

##STR00007##
wherein R₃ and R₄, which may be the same or different, are independently selected from straight chain or branched; saturated or unsaturated alkyl groups having from 4 to 30 carbon atoms, preferably from 6 to 22 carbon atoms, most preferably from 8 to 18 carbon, said carbon number including the carbonyl carbon atom in the case of structure (II), provided that when R₃ and R₄ are different, one of R₃ or R₄ may also be hydrogen or a straight chain or branched; saturated or unsaturated alkyl group of from 1 to 4, preferably 1 to 3, carbon atoms. These compounds and their manufacture are disclosed in, e.g., U.S. Pat. No. 8,496,917B2, which is incorporated herein by reference. Like the compounds of the present disclosure, i.e., formula (I), compounds of Formula II and III are based upon reaction products of the dianhydrohexitols V, VI and VII, most notably V, and various long chain halides and/or sulfates and acids and/or esters, respectively. These long chain precursors, especially the acids and, are derived from vegetable oils which typically contain these types of acids as triglycerides. Oftentimes vegetable oils contain 60% or more of the higher acid esters: exemplary sources include Salicornia oil, Safflower oil, Evening primrose oil, poppy seed oil, Grape seed oil. Sunflower oil, Barberry fig seed oil, Hemp oil and Corn oil.

In yet another preferred embodiment of the present teaching preferred pharmaceutical compositions of the present teaching comprise at least one compound of formula (I) in combination with one or more compounds of formula (II) wherein R₃ and R₄ have from 8 to 18 carbon atoms, more preferably 16 to 18 carbon atoms. Most especially, the compounds of formula II are those wherein R₃ and R₄ are both C17 species, namely the di-linoleate esters (two unsaturation), the di-oleate esters (one unsaturation) and/or the di-stearate esters (no unsaturation); both C15 species, especially, the di-palmitate esters (no unsaturation); or the C8 species, especially the di-caprylate esters, or combinations of two or more of the foregoing.

Generally speaking, pharmaceutical compositions provided by the present disclosure comprise a therapeutically effective amount of a compound of Formula (I) and one or more pharmaceutically acceptable vehicles. Of course these compositions may include other actives and conventional ingredients of pharmaceutical compositions, all of which are well known in the art. The selection of the pharmaceutically acceptable vehicles as well as other conventional ingredients depends, to a large extent, upon the mode of administration and the symptoms of the disease to be addressed. For example, in the case of topically applied pharmaceutical compositions, these compositions may optionally include an effective amount of one or more skin protective and/or treatment ingredients such as antioxidants, sunscreens, vitamins, anti-inflammatory agents, self-tanning agents, moisturizers, emollients, humectants, compatible solutes and the like, and mixtures thereof, in their conventional amounts. These compositions may also include other ingredients that have no or little bearing upon the intended end-use or application of the pharmaceutical composition, but aid in the preparation thereof, such as solubilizers, surfactants, etc.

Similarly, the final form of the pharmaceutical compositions and their method of manufacture also depend, in part, upon the mode of mode of administration. For example, the pharmaceutical compositions comprising a compound of Formula (I) may be manufactured by means of conventional mixing, dissolving, granulating, dragee-making, levigating, emulsifying, encapsulating, entrapping, or lyophilizing processes. Pharmaceutical compositions may be formulated in a conventional manner using one or more physiologically acceptable carriers, diluents, excipients, or auxiliaries, which facilitate processing of compounds of Formula (I), or crystalline forms thereof and one or more pharmaceutically acceptable vehicles into formulations that can be used pharmaceutically. Pharmaceutical compositions provided by the present disclosure may take the form of solutions, suspensions, emulsions, tablets, pills, pellets, capsules, capsules containing liquids, powders, creams, lotions, gels, sustained-release formulations, suppositories, emulsions, aerosols, sprays, suspensions, or any other form suitable for administration to a patient.

The pharmaceutical compositions provided by the present disclosure may be formulated in a unit dosage form. A unit dosage form refers to a physically discrete unit suitable as a unitary dose for patients undergoing treatment, with each unit containing a predetermined quantity of a compound of Formula (I) calculated to produce an intended therapeutic effect. A unit dosage form may be for a single daily dose, for administration 2 times per day, or one of multiple daily doses, e.g., 3 or more times per day. When multiple daily doses are used, a unit dosage form may be the same or different for each dose. One or more dosage forms may comprise a dose, which may be administered to a patient at a single point in time or during a time interval.

The pharmaceutical compositions comprising a compound of Formula (I) may be formulated for immediate release or for delayed or controlled release. In this latter regard, certain embodiments, e.g., an orally administered product, may be adapted for controlled release. Controlled delivery technologies can improve the absorption of a drug in a particular region, or regions, of the gastrointestinal tract. Controlled drug delivery systems may be designed to deliver a drug in such a way that the drug level is maintained within a therapeutically effective window and effective and safe blood levels are maintained for a period as long as the system continues to deliver the drug with a particular release profile in the gastrointestinal tract. Controlled drug delivery may produce substantially constant blood levels of a drug over a period of time as compared to fluctuations observed with immediate release dosage forms. For some drugs, maintaining a constant blood and tissue concentration of the drug throughout the course of therapy is the most desirable mode of treatment as immediate release of drugs oftentimes causes blood levels to peak above that level required to elicit a desired response. This results in waste of the drug and/or may cause or exacerbate toxic side effects. In contrast, the controlled delivery of a drug can result in optimum therapy; not only reducing the frequency of dosing, but also reducing the severity of side effects. Examples of controlled release dosage forms include dissolution controlled systems, diffusion controlled systems, ion exchange resins, osmotically controlled systems, erodable matrix systems, pH independent formulations, and gastric retention systems.

As noted, the compounds of formula (I), more appropriately, the pharmaceutical compositions comprising compounds of formula (I), may be administered through any conventional method. The specific mode of application or administration is, in part, dependent upon the form of the pharmaceutical composition, the primary purpose or target of its application (e.g., the application may be oral if intending to address the disease generally or topically if intending to address primarily a topical symptom of the disease. Suitable modes of administration include, for example, intradermal, intramuscular, intraperitoneal, intravenous, subcutaneous, intranasal, epidural, oral, sublingual, intracerebral, intravaginal, transdermal, rectal, inhalation, or topical. Especially preferred modes of administration are oral, topical or those methods that involve absorption through epithelial or mucous linings (e.g., oral mucosa, rectal, and intestinal mucosa, etc.). Furthermore, again, depending in part upon the form and primary purpose or target of the administration, the pharmaceutical compositions of the present disclosure may be administered systemically or locally. Finally, the form of the pharmaceutical composition and its delivery system may also vary depending upon the parameters already noted. For example, orally administered pharmaceutical compositions of the present teaching may be in encapsulated form, e.g., encapsulated in liposomes, or as microparticles, microcapsules, capsules, etc. Similarly, topically applied pharmaceutical compositions of the present teachings may be applied as a liquid, cream, gel, spray, lotion, etc.

Again as noted above, the compounds of formula (I) may be used as is, i.e., as 100% of the composition to be applied; however, the compounds of formula (I) are preferably incorporated into a pharmaceutical composition in which the compound(s) of formula account for from about 0.01 to about 99 weight percent of the pharmaceutical composition. Preferably, the compounds of formula (I) will comprise from about 0.5 to about 30 wt %, more preferably from about 0.5 to about 20 wt %, most preferably from about 1.0 to about 10 wt % of the pharmaceutical composition. Another factor playing into the concentration of the compounds of formula (I) in the pharmaceutical composition is the dose or rate of application of the compounds to the patient. Obviously, dosing itself depends upon a number of factors including the concentration and/or purity of the compounds of formula (I), the efficacy thereof, the individual to whom the pharmaceutical is to be administered, the mode of administration, the form in which the pharmaceutical composition is to be administered, the disease or symptom to be addressed, etc.

The foregoing factors as well as the application thereof in formulating the compositions of the present teaching are all as well known in the art whereby the final or actual concentration in the pharmaceutical composition and/or the dose can readily be determined based up simple dose-response testing and the like. For example, an appropriate oral dosage for a particular pharmaceutical composition containing one or more compounds of formula (I) will depend, at least in part, on the gastrointestinal absorption properties of the compound, the stability of the compound in the gastrointestinal tract, the pharmacokinetics of the compound and the intended therapeutic profile. An appropriate controlled release oral dosage and ultimate form of a pharmaceutical composition containing a particular compound of Formula (I) will also depend upon a number of factors. For example, gastric retention oral dosage forms may be appropriate for compounds absorbed primarily from the upper gastrointestinal tract, and sustained release oral dosage forms may be appropriate for compounds absorbed primarily from the lower gastrointestinal tract. Again, it is to be expected that certain compounds may be absorbed primarily from the small intestine whereas others are absorbed primarily through the large intestine. It is also to be appreciated that while it is generally accepted that compounds traverse the length of the small intestine in about 3 to 5 hours, there are compounds that are not easily absorbed by the small intestine or that do not dissolve readily. Thus, in these instances, the window for active agent absorption in the small intestine may be too short to provide a desired therapeutic effect in which case large intestinal absorption must be channeled and/or alternate routes of administration pursued.

Generally speaking, an appropriate dose of a compound of Formula (I), or pharmaceutical composition comprising a compound of Formula (I), may be determined according to any one of several well-established protocols including in-vitro and/or in-vivo assays and/or model studies as well as clinical trials. For example, animal studies involving mice, rats, dogs, and/or monkeys may be used to determine an appropriate dose of a pharmaceutical compound. Results from animal studies may be and typically are extrapolated to determine appropriate doses for use in other species, such as for example, humans.

As noted above, the compositions according to the present teaching may be designed for immediate infusion or application of the actives to the body or site of the symptom to be treated. However, it is also recognized that in certain instances the pharmaceutical compositions provided by the present disclosure may be, and are preferably, adapted to provide sustained or timed release of a compound of Formula (I): this is especially so and desirable for oral administration. Sustained release oral dosage forms are used to release drugs over a prolonged time period and are useful when it is desired that a drug or drug form be delivered to the lower gastrointestinal tract. Sustained release oral dosage forms include any oral dosage form that maintains therapeutic concentrations of a drug in a biological fluid such as the plasma, blood, cerebrospinal fluid, or in a tissue or organ for a prolonged time period. Sustained release oral dosage forms include diffusion-controlled systems such as reservoir devices and matrix devices, dissolution-controlled systems, osmotic systems, and erosion-controlled systems. Sustained release oral dosage forms and methods of preparing the same are well known in the art.

Following on the foregoing, the amount of a compound of Formula (I) contained in a dose may depend on the route of administration and whether the disease in a patient is effectively treated by acute, chronic, or a combination of acute and chronic administration. In any event, the administered dose is typically less than a toxic dose: though it may have significant adverse health effects, provided that the desired beneficial effect is also attained. Toxicity of the compositions described herein may be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., by determining the LD₅₀ (the dose lethal to 50% of the population) or the LD₁₀₀ (the dose lethal to 100% of the population). The dose ratio between toxic and therapeutic effect is the therapeutic index. In certain embodiments, a compound or metabolite thereof may exhibit a high therapeutic index. The data obtained from these cell culture assays and animal studies may be used in formulating a dosage range that is not toxic for use in humans. A dose of a compound of Formula (I) may be within a range of circulating concentrations in for example the blood, plasma, or central nervous system, that include the effective dose and that exhibits little or no toxicity. A dose may vary within this range depending upon the dosage form employed and the route of administration utilized. In certain embodiments, an escalating dose may be administered.

Where additional pharmaceutical actives are also present in the compositions according to the present teaching, the amount by which they are present and/or the dosage amount will typically be consistent with their conventional concentration and rates of application. For example, the compounds of formulae II and III will be present in an amount of from about 0.5 to about 30 wt %, more preferably from about 0.5 to about 20 wt %, most preferably from about 1.0 to about 10 wt % of the pharmaceutical composition. Of course, as noted, the combination of pharmaceutical actives with the compounds of formula (I) also provide enhanced performance and/or synergy whereby the amounts of each and/or the dose of each may be and is generally less than required for the use of the active compounds on their own.

Having described inventive compounds, process of making compounds, compositions, and treatment methods in general terms, attention is now directed to the following examples in which specific formulations and applications thereof are evaluated. In the foregoing and in the following examples, unless otherwise indicated, all temperatures are set forth in degrees Celsius and all parts and percentages are by weight. The disclosed embodiments are not intended to be limiting of the claims. To the contrary, the claims are intended to cover all alternatives, modifications, and equivalents.

EXPERIMENTAL

Example 1

Synthesis of Isosorbide Di-(Methylfumarate)

To a suspension of isosorbide (50 g, 0.34 mol) in ethyl acetate (500 ml) was added monomethyl fumarate (97.5 g, 0.75 mol) followed by 4-dimethylaminopyridine (DMAP) (8.3 g, 0.06 mol). The reaction mixture was cooled to 0° C. (ice bath) and a solution of dicyclohexylcarbodiimide (DCC) (168 g, 0.75 mol) in ethyl acetate (800 ml) was added drop wise. The reaction mixture was then allowed to warm up to room temperature and stirred for 16 hrs. Precipitates were filtered and washed with Ethyl acetate (300 ml). The filtrate was concentrated under vacuum to give 176 g crude product. This crude product was shaken in hexane (1 L), filtered and the solid again washed with hexane (500 ml). This resultant solid product was dried and subsequently purified on a short path of silica gel using ethyl acetate/hexane (0 to 50%) to give 87 g of white solid. This solid was recrystallized in hot ethyl acetate (500 ml) to give a total of 60 g of pure isosorbide di-(methylfumarate)(“IDMF”), mp 106-108° C., with a purity of about 98.5% as determined by HPLC. Structure of IDMF was established by ¹HNMR and MS analyses.

TABLE 1
Topical formulations of IDMF at 2 and 5% level
		%	%
INCI name	Trade Name/Supplier	w/w	w/w
Phase A-1
Water (demineralized)		Qs	Qs
Disodium EDTA		0.10	0.10
Glycerin	Glycerin 99%/Ruger	2.00	2.00
Butylene Glycol	Butylene Glycol/Ruger	2.00	2.00
Phase A-2
Xanthan Gum	Rhodicare S/Rhodia	0.10	0.10
Acrylates/C10-30 Alkyl	Carbopol Ultrez 21/	0.25	0.25
Acrylate Crosspolymer	Lubrizol
Phase B
Caprylic/Capric	Myritol 318/Cognis	6.00	4.00
Triglycerides
Mineral Oil,	Fancol LAO/Elementis	2.00	2.00
Lanolin Alcohols
Oleth-10	Brij-10/Croda	0.50	0.50
Glyceryl Stearate,	Arlacel 165/Croda	2.50	2.50
PEG-100 Stearate
Dimethicone	DC, 200/100 CST/Dow	3.00	2.00
	Corning
Stearic Acid	Stearic Acid, NF/Spectrum	1.00	1.00
Cetyl Alcohol	Crodacol C-70/Croda	1.50	1.50
Phase C
Triethanolamine	Triethanolamine 99%	0.15	0.15
Phase D
Dimethyl Isosorbide	Arlasolve DMI/Croda	6.00	15.00
IDMF(Isosorbide	IDMF/Sytheon	2.00	5.00
di-methyl fumarate)
Phase E
Phenoxyethanol,	Euxyl 9010/Schulke	1.00	1.00
Ethylhexylglycerine
Total		100.00	100.00

Example 2

Topical Formulations of 2% and 5% IDMF

A topical pharmaceutical composition containing IDMF was prepare using the formula as presented in Table 1. The composition was prepared by preparing compositions A-1 and A-2 and then dispersing composition A-2 in A-1 while stirring and heating to 75° C. to form Phase A. Independently, the Phase B ingredients were combined and then heat to 75° C. Phase B was then added to Phase A with good mixing. Phase C was added to a premixed Phase D and the combination then added to the combined Phase A/B. The mixture was then homogenized at moderate speed while cooling to ˜40° C. A preservative was added and the composition stirred until a uniform, homogeneous composition attained. The final composition had a pH of 6.0 and a viscosity of 30,000-40,000 cps (sp 4, 5 rpm).

Example 3

Topical Formulations of 2% IDMF and 2% Isosorbide Dilinoleate

A second topical composition was prepare in accordance with the same procedure as that for the preparation of the topical composition of Example 2 with the exception that a combination of IDMF and isosorbide dilinoleate (formula III) was employed. The formulation of the composition is as presented in Table 2.

Example 4

Anti-Psoriatic Effects of IDMF in Psoriasiform Keratinocyte Cultures

Psoriasiform keratinocyte cultures were established by incubating epidermal keratinocyte progenitors from stratum basae (Zen-Bio, RTP, NC) with IL-17A/IL-22/TNFα (100 μg/ml; 100 μg/ml; 10 μg/ml) for 24 h. These cytokines have been reported to be key triggers in psoriasis (Y Tokura, T Mori, R Hino, Psoriasis and other Th17-mediated skin diseases. J UOEH, 32(4):317-328, 2010; A B Van Belle, M de Heusch, M M Lemaire, E Hendrickx, G Wamier, K Dunussi-Joannopoulos, L A Fouser, J C Renauld, L Dumoutier, IL-22 is required for imiquimod-induced psoriasiform skin inflammation in mice, J Immunol, 188(1):462-469, 2012; A Hänsel, C Günther, J Ingwersen, J Starke, M Schmitz, M Bachmann, M Meurer, E P Rieber, K Schäkel, Human slan (6-sulfo LacNAc) dendritic cells are inflammatory dermal dendritic cells in psoriasis and drive strong TH17/TH1 T-cell responses, J Allergy Clin Immunol, 127(3):787-794, 2011; Kim J, Krueger J G. The Immunopathogenesis of Psoriasis, Dermatol Clin, 33:13-23, 2015).

TABLE 2
2% IDMF and 2% Isosorbide dilinoleate
		%
INCI name	Trade Name/Supplier	w/w
Phase A
Water (demineralized)		Qs
Disodium EDTA		0.10
Glycerin	Glycerin 99%/Ruger	2.00
Butylene Glycol	Butylene Glycol/Ruger	2.00
Phase A-1
Xanthan Gum	Rhodicare S/Rhodia	0.10
Acrylates/C10-30 Alkyl	Carbopol Ultrez 21/	0.25
Acrylate Crosspolymer	Lubrizol
Phase B
Caprylic/Capric	Myritol 318/Cognis	4.00
Triglycerides
Isosorbide dilinoleate	HydrasSynol IDL/Sytheon	2.00
Mineral Oil,	Fancol LAO/Elementis	2.00
Lanolin Alcohols
Oleth-10	Brij-10/Croda	0.50
Glyceryl Stearate,	Arlacel 165/Croda	2.50
PEG-100 Stearate
Dimethicone	DC, 200/100 CST/Dow	3.00
	Corning
Stearic Acid	Stearic Acid, NF/Spectrum	1.00
Cetyl Alcohol	Crodacol C-70/Croda	1.50
Phase C
Triethanolamine	Triethanolamine 99%	0.15
Phase D
Dimethyl Isosorbide	Arlasolve DMI/Croda	6.00
IDMF(Isosorbide	IDMF/Sytheon	2.00
di-methyl fumarate)
Phase E
Phenoxyethanol,	Euxyl 9010/Schulke	1.00
Ethylhexylglycerine
Total		100.00

In our keratinocyte system, IL-17A/IL-22/TNFα triggered the modulation of expression of genes, such as DEFB4A (18.9 fold), HPGD (−84.5 fold), CXCL3 (3.3 fold) and IL8 (40.7 fold), known to be implicated in psoriasis (M Simanski, F Rademacher, L Schroder, H M Schumacher, R Glaser, J Harder, IL-17A and IFN-γ synergisticall induce RNase 7 expression via STAT3 in primary keratinocytes, PLoS One, 2013; 8(3):e59531, 2013; O Arican, M Aral, S Sasmaz, P Ciragil, Serum levels of TNF-alpha, IFN-gamma, IL-6, IL-8, IL-12, IL-17, and IL-18 in patients with active psoriasis and correlation with disease severity, Mediators Inflamm, (5):273-279, 2005; K Ikai, Psoriasis and the arachidonic acid cascade, J Dermatol Sci, 21(3):135-146, 1999; K Guilloteau, I Paris, N Pedretti, K Boniface, F Juchaux, V Huguier, G Guillet, F X Bernard, J C Lecron, F Morel, Skin Inflammation Induced by the Synergistic Action of IL-17A, IL-22, Oncostatin M, IL-1{alpha}, and TNF-{alpha} Recapitulates Some Features of Psoriasis, J Immunol, 184(9): 5263-5270, 2010; A B Van Belle, M de Heusch, M M Lemaire, E Hendrickx, G Wamier, K Dunussi-Joannopoulos, L A Fouser, J C Renauld, L Dumoutier, IL022 is required for imiquimod-induced psoriasiform skin inflammation in mice, J Immunol, 188(1)462-469, 2012). IL-17A/IL-22/TNFα also caused psoriasiform morphological alterations in these cells (Compare FIG. 1A—non-cytokine treated to FIG. 1B—cytokine treated). These morphological changes result in senescent “fried egg” cells (see arrows in FIG. 1B) which are reminiscent of the senescence-associated secretory phenotype (SASP).

After 24 h of cytokine treatment, the IDMF test materials were added to cells and further incubation with IL-17A/IL-22/TNFα was pursued for another 24 h. At the end of the experiment total RNA was extracted from keratinocytes and quantified using DNA microarrays. DNA microarray quantification clearly showed a general anti-cytokine effect of IDMF, with significant inhibition of TNFα/IFNγ/IL-17 responses, while the antioxidant pathways, especially those related to glutathione, were upregulated, demonstrating the mechanism of action typical for DMF. In addition, the study demonstrated that a number of genes were down regulated by IDMF. These genes have enrichment for NFκB and STAT1 binding sites in their upstream region, adding more evidence for the TNFα/IFNγ/IL-17-targeting mechanism of IDMF.

Table 3 presents the data pertaining to the psoriasis-relevant biological processes most significantly down-regulated by 1 μg/ml IDMF in psoriasiform keratinocytes, as revealed by DNA microarray approach. Table 4 presents the data pertaining to the psoriasis-relevant biological processes most significantly up-regulated by 1 μg/ml IDMF in psoriasiform keratinocytes, as revealed by DNA microarray approach. Note the down regulation of inflammatory responses, with the emphasis on interferon-γ (complete with its downstream inhibition of ICAM1—see Table 4), and the up-regulation of pathways appears to involve redox homeostasis and glutathione synthesis processes, which are the hallmarks of the DMF mechanism of action.

TABLE 3
Psoriasis-relevant pathways in psoriasiform
keratinocytes decreased by IDMF (1 μg/ml)
	p-
GOBPID	value	Term
GO:0002685	0.000	regulation of leukocyte migration
GO:0090023	0.000	positive regulation of neutrophil chemotaxis
GO:0006955	0.000	immune response
GO:0060333	0.002	interferon-gamma-mediated signaling pathway
GO:0060337	0.002	type I interferon-mediated signaling pathway
GO:0034340	0.002	response to type I interferon
GO:2000145	0.002	regulation of cell motility
GO:0030335	0.004	positive regulation of cell migration
GO:0034341	0.005	response to interferon-gamma
GO:0006954	0.007	inflammatory response
GO:0071347	0.012	cellular response to interleukin-1
GO:0032680	0.017	regulation of tumor necrosis factor production
GO:0071706	0.019	tumor necrosis factor superfamily cytokine
		production
GO:0071345	0.019	cellular response to cytokine stimulus
GO:0071356	0.024	cellular response to tumor necrosis factor
GO:0002697	0.026	regulation of immune effector process
GO:0002684	0.028	positive regulation of immune system process
GO:0002285	0.029	lymphocyte activation involved in immune response
GO:0001819	0.033	positive regulation of cytokine production
GO:0045321	0.035	leukocyte activation
GO:0017015	0.046	regulation of TGFβ receptor signaling pathway

Based on these findings, it appears that genes decreased by IDMF correlate significantly with genes increased in psoriatic cells and skin, which inversely correlate with genes increased by anti-psoriatic drugs in patients, confirming the anti-psoriatic potential of IDMF. For example, using enrichment statistic value based on equation (8) from A A Philippakis publication (A A Philippakis, B W Busser, S S Gisselbrecht, F S He, B Estrada, A M Michelson, M L Bulyk, Expression-guided in silico evaluation of candidate cis regulatory codes for Drosophila muscle founder cells, PLoS Comput, Biol, 2(5): e53, 2006), it was found that genes strongly decreased by IDMF were strongly elevated in cultured keratinocytes following treatment with the combination TNFα/IFNγ (GSE accession number 20297), with TNFα/IL-17A, IFNγ (GSE12109; GSE7216), IL1 (GSE9120) or TNFα (GSE24767; GSE36287; GSE32975). Similar strong correlation (stat.>200, p<10⁻⁸) was found between genes decreased by IDMF and those increased in psoriatic (GSE6710; GSE9120; GSE36387; GSE11903; GSE30999), carcinoma (GSE2503), actinic keratosis (GSE2503), dermatomyositic (GSE32245) and atopic (GSE5667) vs. normal skin. There was a strong positive correlation between genes induced by the anti-inflammatory IL13 and IDMF (GSE36287; stat. 154, p<10⁻⁷).

TABLE 4
Psoriasis-relevant pathways in psoriasiform
keratinocytes increased by IDMF (1 μg/ml)
	p-
GOBPID	value	Term
GO:0006693	0.000	prostaglandin metabolic process
GO:0045454	0.004	cell redox homeostasis
GO:0006749	0.005	glutathione metabolic process
GO:0006749	0.005	glutathione metabolic process
GO:0072593	0.010	reactive oxygen species metabolic process
GO:0042592	0.010	homeostatic process
GO:0006750	0.012	glutathione biosynthetic process
GO:0006968	0.033	cellular defense response
GO:1901687	0.033	glutathione derivative biosynthetic process
GO:1901687	0.033	glutathione derivative biosynthetic process
GO:0006879	0.034	cellular iron ion homeostasis
GO:0002065	0.039	columnar/cuboidal epithelial cell differentiation
GO:0050931	0.040	pigment cell differentiation
GO:0032755	0.043	positive regulation of interleukin-6 production

Furthermore, genes decreased by IDMF tend to be strongly decreased in psoriasis lesions of patients treated with etanercept (GSE11903; stat. −204, p<10⁻⁵), efalizumab (GSE30768; stat. −141; p=0.001) or the anti-IL17A biologic LY2439821 (GSE31652; (stat. −193, p<10⁻⁴). Overall, there were over 200 significant (stat.>0.05/<−0.05; p<0.05) gene expression correlations in favor of the anti-psoriatic and anti-dermatitis activity of IDMF. It was especially encouraging to see an anti-dermatitis response for a compound derived from a skin-sensitizing parent molecule (notwithstanding the obvious limitations of a keratinocyte culture model). On the downside, IDMF seemed to hinder a defense response pathway, because genes decreased by IDMF also show enrichment for an IRF site in the upstream regions (also ISRE), and these same genes tend to be induced in keratinocytes by the poly(I:C) treatment. Polyinosinic:polycytidylic acid (usually abbreviated poly I:C) is an immunostimulant and is an adjuvant used for antitumor treatment and vaccines because of its prominent effects on CD8 T cells and NK cells. Poly(I:C) binds TLR3 and this interaction is thought to be central for driving cell-mediated immune responses (J Immunology, 181(11):7670-7680, 2008). Interestingly, IDMF has retained at least some of the biocidal effect of DMF, possibly partially compensating for the decrease of the defense response pathway.

Furthermore, as shown in Table 5 IDMF appears to suppress interferon-controlled pathways in psoriasiform keratinocytes by repressing multiple genes (last column) with significant enrichment/overrepresentation of STAT1 and NFKB motifs (first column) in their upstream region (1 kb). Induction of IFN-mediated pathways associated with STAT1 binding sites is a robust signature in psoriatic lesions. Enrichment of motifs was calculated using semiparametric generalized additive logistic models.

TABLE 5
Effect of IDMF on interferon controlled pathways
				Z	P	Predicted STAT1/NFKB targets
Motif	Motif ID	Estimate	SE	stat	value	down-regutated by IDMF
NFKB|GGGRAWTYCC	NF_	0.90	0.29	3.14	0.0016	RHCG|MMP9|GBP1|KCTD11|PLA
	kappaB_					T|NFKBIZ|COBLL1|IL1R2|BPGM|I
	disc1					L36G|IL23A
STAT1|RGAAANYGAAA	J9365	1.28	0.43	3.01	0.0026	DDX60|MX2|OAS2
CT|MA0137
STAT1|GRAANNGAAAS	STAT_disc3	1.21	0.31	3.95	7.77E−05	IFI44L|MX2|DDX60|SAMD9L|GBP
						1|OAS2
NFKB|GGGACTTYCCA|	M00208	1.52	0.39	3.86	0.0000	LTBP1|SLCO4A1|PLAT|ABCA1|N
M00208						FKBIZ|PDZK1IP1|IL36G
STAT1|TTTCC|M00496	M00496	0.050	0.03	2.01	0.0449	SLC6A14|IL36G|IFI44L|IL36RN|L
						NX1|BPGM|SPINK6|DDX60|OAS2
						|IL1R2|CAPND2|CD200|GBP1|NF
						KBIZ|EDN1|KRT75|ICAM1|(. . .)

Example 5

Anti-Psoriatic Effects in Murine Tail Model of Psoriasis

The mouse tail test is a well-established animal model used for the development of FDA-approved anti-psoriasis drugs. Table 6 summarize the findings following 2 weeks of test material application on the tails, with the readout of improvement in stratum granulosum (StGrm) coverage +/− side effects. The benefits of IDMF consisted in significant extension of StGrm coverage and modest increase of epidermal thickness with no inflammation (as measured by the lack of leukocytic infiltrate), para-nor hyperkeratosis. The positive control Tazarotene (a retinoid approved for psoriasis) extended coverage too, but with a trade-off of adverse effects manifesting as substantial hyperkeratosis, spongiosis and wide-spread inflammation. Lack of inflammation with IDMF was a further confirmation of our in vitro results indicating absence of skin sensitization, an effect inherent to the parent molecule, DMF.

TABLE 6
Effect of IDMF on epidermal structure in mouse tail
model as compared with the Rx Tazarotene cream.
	Test Material
		IDMF (FIG. 2B)
	Control (FIG. 2A)	(2% in butylene	Tazorac (FIG. 2C)
	(no treatment)	glycol/glycerin)	(0.1% tazarotene)
Tail observations >	Normal tail epidermis (3-4	Increase of epidermal	Marked acanthosis (8
(StCr = stratum	layers thick, very limited	thickness (4-5 layers),	layers) with focal
corneum)	stratum granulosum	normal basketwave StCr,	spongiosis, lekocyte
(StGrm = Stratum	(StGrm).	no inflammatory infiltrate,	infiltrate, hyperkeratosis
Granulosum)		extended granular layer.	w/massive StGrm,
			widespread tail redness.
StGrm expansion	100 (p = 1)	134 (p < 0.0001)	485 (p < 0.0001)

FIGS. 2A, 2B and 2C are photomicrographs (40× magnification) of H&E-stained histologic sections of the mice tail skin sections characterized in Table 6 wherein FIG. 2A shows the tail section which has not been treated and FIGS. 2A and 2B show those sections that have been treated with IDMF (2% in DMI/glycerin) and Tazarotene cream (0.1% tazarotene), respectively. The arrow in each photomicrograph points to the StGrm (stratum granulosum), which, as noted, is minimal in the control.

Example 6

Human Fibroblast Model

The DMF-like mechanism of action of IDMF was further confirmed by PCR in TNF α-treated human dermal fibroblasts (HDF). Briefly, cells cultured in DMEM/5% FBS were challenged with TNF-alpha (10 ng/ml) for 24 h, afterward test materials were added in the same medium containing TNF-alpha and incubated with HDF for another 24 h. At the end of the incubation cells were lyzed and total RNA was extracted with NucleoSpin RNA II kit (Machery-Nagel; Bethlehem, Pa.). Purified total RNA was assessed at 260 nm and 280 nm with PERKIN ELMER MBA2000 UV/VIS spectrophotometer and the concentration of RNA was equalized across all samples. cDNA was synthesized with QuantiTect Reverse Transcription kit and gene products were quantified using RealTimePrimers (Elkins Park, Pa.) primer pairs and SYBR® Premix Ex Taq™ II (Tli RNase HPlus) mastermix (Takara, Japan), with BioRad iCycler iQ Detection System. Normalization to the expression of housekeeping genes was performed to calculate fold change relative to the water control. Genes were considered differentially expressed if the level of expression was reasonably high (<30 cycles to detect) and the modulation was ≥2 fold.

It was found that both DMF (5 μg/ml) and IDMF (1 μg/ml) significantly increased (>2× fold difference) NRF2 expression and decreased NFKB expression after only 24 hours of treatment. However, surprisingly, IDMF did not increase IL8 expression and actually decreased COX-2 expression (−2.4 fold), both of which are linked to skin sensitization, evidencing a lack of skin sensitization and supporting its utility as a topical treatment.

Example 7

Safety Studies

Example 7.1

Lack of Phototoxicity in 3T3 Model (OECD)

The 3T3 Neutral Red Uptake Phototoxicity Assay was based on the OECD Guideline for Testing of Chemicals: #423, with chlorpromazine and tazarotene as positive controls. The results show that IDMF is not phototoxic even at the maximum concentration required for testing (100 μg/ml), while tazarotene and chlorpromazine had PIF>6 technically validating the assay. This suggests that in contrast to other topical drugs, such as the anti-psoriatic retinoid tazarotene, IDMF has no radiation sensitivity and is believed to be compatible with anti-psoriatic phototherapy (PUVA).

Example 7.2

Lack of Mutagenicity in the AMES Genotoxicity Model

AMES genotoxicity testing, a standard protocol for the establishment of mutagenic potential of topical actives, was conducted using MOLTOX Salmonella Mutagenicity Assay with 2 strains (TA1535, TA1537) of S. typhimurium that contain different mutations of the genes involved in histidine synthesis. Table 7 shows that IDMF was not genotoxic including at the highest concentration required for testing (5 mg/ml). As a reference, it is to be appreciated that the values are expressed as percentage (%) of the number of mutant colonies spontaneously occurring in the water control: positive control was Sodium Azide (15 μg/ml) for TA1535 and ICR 191 Acridine (10 μg/ml) for TA1537.

TABLE 7
Mutagenicity Test
	Test Material	% CTR (TA1535)	% CTR (TA1537)
	H2O	100	100
	DMSO	100	100
	(+) CTR	2161	18574
	IDMF 5 mg/ml	18	13
	IDMF 1 mg/ml	64	30
	IDMF 200 μg/ml	68	91
	IDMF 40 μg/ml	89	117
	IDMF 8 μg/ml	96	83

Example 7.3

Lack of Skin Irritation and Sensitization in the Human RIPT

After observing beneficial anti-inflammatory activity in vitro, no inflammatory effect in the animal model and no genotoxicity, IDMF was further tested in the IRB-approved human repeat insult patch test (HRIPT) in 100 healthy adult volunteers to determine its skin irritation and sensitization potential. IDMF was formulated in a butylene glycol/glycerin base identical to the one used in animals and was tested at 2% and 5% by an independent lab (Cantor Research Laboratories, Inc., Blauvelt, N.Y., study #M-0106A and M-0106B). The test was performed accordingly to the protocol “Appraisal of the safety of Chemicals in Food, Drugs and Cosmetics” issued by FDA. It was found that on the skin sensitization/irritation scale 0-5, the IDMF formulation scored zero (0) in 100% of the participants. Interestingly, no flushing was observed with IDMF, while flushing is a key side effect of dimethyl fumarate (DMF). Therefore, the conclusion of the study was that the tested IDMF formulation was non-sensitizing and non-irritating.

The above findings and data clearly demonstrate that the novel derivative of the known anti-psoriasis drug DMF—IDMF—has DMF-like anti-psoriatic activity in vitro, and an anti-psoriatic activity in the mouse tail model, but appears to be devoid of the skin sensitization effects characteristic of its parent molecule. Accordingly, these finding show that IDMF and the related compounds as disclosed herein provide a new, powerful anti-psoriasis drug. It also demonstrates that these compositions may be applied or administered topically thereby also avoiding DMF's serious systemic side effects.

It should be noted that there are alternative ways of implementing the embodiments disclosed herein. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the claims are not to be limited to the details given herein, but may be modified within the scope and equivalents thereof. In following, from the foregoing description, various modifications and changes in the compositions and methods of this disclosure will occur to those skilled in the art and all such modifications are within the scope of the present teaching and are intended to be included therein.

Claims

1. A compound according to the general formula (I):

2. The compound of claim 1 wherein R₁ and R₂ are the same.

3. The compound of claim 1 wherein R₁ and R₂ are not the same.

4. A pharmaceutical composition comprising one or more compounds of claim 1 in a pharmaceutically acceptable vehicle formula (I)

5. The pharmaceutical composition of claim 4 wherein R₁ and R₂ are the same.

6. The pharmaceutical composition of claim 4 wherein R₁ and R₂ are not the same.

7. The pharmaceutical composition of claim 4 further comprising at least one other pharmaceutical active.

8. The pharmaceutical composition of claim 7 wherein the at least one other pharmaceutical active is one or more compounds corresponding to the formula II or formula III or at least one of each:

9. The pharmaceutical composition of claim 8 wherein the additional pharmaceutical active is of formula Ill and the alkyl groups of R₃ and R₄ have from 16 to 18 carbon atoms.

10. The pharmaceutical composition of claim 8 wherein the additional pharmaceutical active is isosorbide dilinoleate.

11. A method of therapeutically treating psoriasis comprising administering to the patient suffering therefrom an effective amount of a compound according to formula 1 (I)

12. The method of claim 11 wherein R₁ and R₂ are the same.

13. The method of claim 11 wherein R₁ and R₂ are not the same.

14. The method of claim 11 wherein the compound is a component of a pharmaceutical composition that is administered to the patient.

15. The method of claim 14 wherein the pharmaceutical composition is administered orally.

16. The method of claim 14 wherein the pharmaceutical composition is applied topically to those areas of the skin of a patient manifesting symptoms of psoriasis.

17. The method of claim 14 wherein the pharmaceutical composition further comprises at least one other pharmaceutical active.

18. The method of claim 17 wherein the at least one other pharmaceutical active is one or more compounds corresponding to the formulae II and/or III:

19. The method of claim 18 wherein the additional pharmaceutical active is of formula III and the alkyl groups of R₃ and R₄ have from 16 to 18 carbon atoms.

20. The method of claim 17 wherein the additional pharmaceutical active is isosorbide dilinoleate.

21. A method of delaying the onset of symptoms of psoriasis in persons predisposed to the disease comprising administering to said persons a therapeutically effective amount of a compound according to formula 1 (I)

22. The pharmaceutical composition of claim 4 wherein the one or more compounds according to the general formula (I) is or includes isosorbide di(methylfumarate)

23. The pharmaceutical composition of claim 4 wherein the one or more compounds according to the general formula (I) are isosorbides.

24. The method of claim 11 wherein the compound of according to he general formula (I) is isosorbide di-(methylfumarate)

25. The pharmaceutical composition of claim 4 wherein the one or more compounds according to the general formula (I) is the combination of isosorbide di-(methylfumarate) and isosorbide mono-(methylfumarate) each formed by the reaction of methyl fumarate and/or fumaric acid and isosorbide.