Patent Publication Number: US-2015087720-A1

Title: Dosage Regimen of an S1P Receptor Agonist

Description:
The present invention relates to a dosage regimen of an S1P receptor modulator or agonist particularly in the course of the treatment of transplant patients or patients suffering from autoimmune diseases or disorders. 
     S1P receptor modulators or agonists are compounds which signal as agonists at one or more sphingosine-1 phosphate receptors, e.g. S1P1 to S1P8. Agonist binding to a S1P receptor may e.g. result in dissociation of intracellular heterotrimeric G-proteins into Gα-GTP and Gβγ-GTP, and/or increased phosphorylation of the agonist-occupied receptor and activation of downstream signaling pathways/kinases. 
     S1P receptor modulators or agonists are valuable compounds for the manufacture of medication for the treatment of various conditions in mammals, especially in human beings. For example, efficacy in transplantation has been demonstrated in rats (skin, heart, liver, small bowel), dogs (kidney), and monkeys (kidney) models. Combination experiments with cyclosporin A showed synergy in skin and heart transplantation models in rats and in monkey renal transplantation. S1P receptor agonists or modulators combined with everolimus prolong survival of cardiac (rat) and renal (monkey) allografts. Due to their immune-modulating potency, S1P receptor modulators or agonists are also useful for the treatment of inflammatory and autoimmune diseases. Further characteristics of S1P receptor agonists can be found in the following publications:
         Brinkmann V, Chen S, Feng L, et al (2001) FTY720 alters lymphocyte homing and protects allografts without inducing general immunosuppression. Transplant Proc; 33:530-531.   Brinkmann V, Pinschewer D, Feng L, et al (2001) FTY720: altered lymphocyte traffic results in allograft protection (review). Transplantation; 72:764-769.   Pinschewer D D, Ochsenbein A F, Odermatt B, et al (2000) FTY720 immunosuppression impairs effector T-cell peripheral homing without affecting induction, expansion, and memory. J Immunol; 164:5761.   Yanagawa Y, Sugahara K, Kataoka H, et al (1998) FTY720, a novel immunosuppressant, induces sequestration of circulating mature lymphocytes by acceleration of lymphocyte homing in rats. II. FTY720 prolongs skin allograft survival by by decreasing T cell infiltration into grafts but not cytokine production in vivo. J Immunol.; 160(11):5493-9.       

     It has now surprisingly been found that a specific dosage regimen, e.g. a loading dose, will provide further unexpected benefits. 
     The binding affinity of S1P receptor agonists or modulators to individual human S1P receptors may be determined in following assay: 
     S1P receptor agonist or modulator activities of compounds are tested on the human S1P receptors S1P 1 , S1P 2 , S1P 3 , S1P 4  and S1P 5 . Functional receptor activation is assessed by quantifying compound induced GTP [γ- 35 S] binding to membrane protein prepared from transfected CHO or RH7777 cells stably expressing the appropriate human S1P receptor. The assay technology used is SPA (scintillation proximity based assay). Briefly, DMSO dissolved compounds are serially diluted and added to SPA-bead (Amersham-Pharmacia) immobilised S1P receptor expressing membrane protein (10-20 μg/well) in the presence of 50 mM Hepes, 100 mM NaCl, 10 mM MgCl 2 , 10 μM GDP, 0.1% fat free BSA and 0.2 nM GTP [γ- 35 S] (1200 Ci/mmol). After incubation in 96 well microtiterplates at RT for 120 min, unbound GTP [γ- 35 S] is separated by a centrifugation step. Luminescence of SPA beads triggered by membrane bound GTP [γ- 35 S] is quantified with a TOPcount plate reader (Packard). EC 50 s are calculated using standard curve fitting software. In this assay, the S1P receptor modulators or agonists preferably have a binding affinity to S1P receptor &lt;50 nM. 
     Preferred S1P receptor agonists or modulators are e.g. compounds which in addition to their S1P binding properties also have accelerating lymphocyte homing properties, e.g. compounds which elicit a lymphopenia resulting from a re-distribution, preferably reversible, of lymphocytes from circulation to secondary lymphatic tissue, without evoking a generalized immunosuppression. Nave cells are sequestered; CD4 and CD8 T-cells and B-cells from the blood are stimulated to migrate into lymph nodes (LN) and Peyer&#39;s patches (PP). 
     The lymphocyte homing property may be measured in following Blood Lymphocyte Depletion assay: 
     A S1P receptor agonist or modulator or the vehicle is administered orally by gavage to rats. Tail blood for hematological monitoring is obtained on day 1 to give the baseline individual values, and at 2, 6, 24, 48 and 72 hours after application. In this assay, the S1P receptor agonist or modulator depletes peripheral blood lymphocytes, e.g. by 50%, when administered at a dose of e.g. &lt;20 mg/kg. S1P receptor modulators or agonists are typically sphingosine analogues, such as 2-substituted 2-amino- propane-1,3-diol or 2-amino-propanol derivatives, e. g, a compound comprising a group of formula X 
     
       
         
         
             
             
         
       
     
     wherein Z is H, C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, phenyl, phenyl substituted by OH, C 1-6 alkyl substituted by 1 to 3 substituents selected from the croup consisting of halogen, C 3-8  cycloalkyl, phenyl and phenyl substituted by OH, or CH 2 -R 4z , wherein R 4z  is OH, acyloxy or a residue of formula (a) 
     
       
         
         
             
             
         
       
     
     wherein Z 1  is a direct bond or O, preferably O; 
     each of R 5z  and R 6z , independently, is H, or C 1-4 alkyl optionally substituted by 1, 2 or 3 halogen atoms; 
     R 1z  OH, acyloxy or a residue of formula (a); and each of R 2z  and R 3z  independently, is H, C 1-4 alkyl or acyl. 
     Group of formula X is a functional group attached as a terminal group to a moiety which may be hydrophilic or lipophilic and comprise one or more aliphatic, alicyclic, aromatic and/or heterocyclic residues, to the extent that the resulting molecule wherein at least one of Z and R 1z  is or comprises a residue of formula (a), signals as an agonist at one of more sphingosine-1-phosphate receptor. 
     Examples of appropriate S1P receptor agonists or modulators are, for example: 
     Compounds as disclosed in EP627406A1, e.g. a compound of formula I 
     
       
         
         
             
             
         
       
     
     wherein R 1  is a straight- or branched (C 12-22 ) chain 
     which may have in the chain a bond or a hetero atom selected from a double bond, a triple bond, O, S, NR 6 , wherein R 6  is H, C 1-4 alkyl, aryl-C 1-4 alkyl, acyl or (C 1-4 alkoxy)carbonyl, and carbonyl, and/or
         which may have as a substituent C 1-4 alkoxy, C 2-4 alkenyloxy, C 2-4 alkynyloxy, arylC 1-4 alkyl-oxy, acyl, C 1-4 alkylamino, C 1-4 alkylthio, acylamino, (C 1-4 alkoxy)carbonyl, (C 1-4 alkoxy)-carbonylamino, acyloxy, (C 1-4 alkyl)carbamoyl, nitro, halogen, amino, hydroxyimino, hydroxy or carboxy; or       

     R 1  is 
     a phenylalkyl wherein alkyl is a straight- or branched (C 6-20 )carbon chain; or 
     a phenylalkyl wherein alkyl is a straight- or branched (C 1-30 )carbon chain wherein said phenylalkyl is substituted by 
     a straight- or branched (C 6-20 )carbon chain optionally substituted by halogen, 
     a straight- or branched (C 6-20 )alkoxy chain optionally substitued by halogen, 
     a straight- or branched (C 6-20 )alkenyloxy, 
     phenyl-C 1-14 alkoxy, halophenyl-C 1-4 alkoxy, phenyl-C 1-4 phenoxy-C 1-4 alkoxy or phenoxy-C 1-4 alkyl, 
     cycloalkylalkyl substituted by C 6-20 alkyl, 
     heteroarylalkyl substituted by C 6-20 alkyl, 
     heterocyclic C 6-20 alkyl or 
     heterocyclic alkyl substituted by C 2-20 alkyl, 
     and wherein 
     the alkyl moiety may have 
     in the carbon chain, a bond or a heteroatom selected from a double bond, a triple bond, O, S, sulfinyl, sulfonyl, or NR 6 , wherein R 6  is as defined above, and 
     as a substituent C 1-4 alkoxy, C 2-4 alkenyloxy, C 2-4 alkynyloxy, arylC 1-4 alkyloxy, acyl, C 1-4 alkyl-amino, C 1-4 alkylthio, acylamino, (C 1-4 alkoxy)carbonyl, (C 1-4 alkoxy)carbonylamino, acyloxy, (C 1-4 alkyl)carbamoyl, nitro, halogen, amino, hydroxy or carboxy, and 
     each of R 2 , R 3 , R 4  and R 5 , independently, is H, C 1-4  alkyl or acyl or a pharmaceutically acceptable salt or hydrate thereof; 
     Compounds as disclosed in EP 1002792A1, e.g. a compound of formula II 
     
       
         
         
             
             
         
       
     
     wherein m is 1 to 9 and each of R′ 2 , R′ 3 , R′ 4  and R′ 5 , independently, is H, C 1-6 alkyl or acyl, or a pharmaceutically acceptable salt or hydrate thereof; 
     Compounds as disclosed in EP0778263 A1, e.g. a compound of formula III 
     
       
         
         
             
             
         
       
     
     wherein W is H; C 1-6 alkyl, C 2-6 alkenyl or C 2-6 alkynyl; unsubstituted or by OH substituted phenyl; R″ 4 O(CH 2 ) n ; or C 1-6 alkyl substituted by 1 to 3 substituents selected from the group consisting of halogen, C 3-8 cycloalkyl, phenyl and phenyl substituted by OH; 
     X is H or unsubstituted or substituted straight chain alkyl having a number p of carbon atoms or unsubstituted or substituted straight chain alkoxy having a number (p-1) of carbon atoms, e.g. substituted by 1 to 3 substitutents selected from the group consisting of C 1-6 alkyl, OH, C 1-6 alkoxy, acyloxy, amino, C 1-6 alkylamino, acylamino, oxo, haloC 1-6 alkyl, halogen, unsubstituted phenyl and phenyl substituted by 1 to 3 substituents selected from the group consisting of C 1-6 alkyl, OH, C 1-6 alkoxy, acyl, acyloxy, amino, C 1-6 alkylamino, acylamino, haloC 1-6 alkyl and halogen; Y is H, C 1-6 alkyl, OH, C 1-6 alkoxy, acyl, acyloxy, amino, C 1-6 alkylamino, acylamino, haloC 1-6 alkyl or halogen, Z 2  is a single bond or a straight chain alkylene having a number or carbon atoms of q. 
     each of p and q, independently, is an integer of 1 to 20, with the proviso of 6≦p+q≦23, m′ is 1, 2 or 3, n is 2 or 3, 
     each of R″ 1 , R″ 2 , R″ 3  and R″ 4 , independently, is H, C 1-4 alkyl or acyl, 
     or a pharmaceutically acceptable salt or hydrate thereof, 
     Compounds as disclosed in WO02/18395, e.g. a compound of formula IVa or IVb 
     
       
         
         
             
             
         
       
     
     wherein X a  is O, S, NR 1S  or a group —(CH 2 ) na —, which group is unsubstituted or substituted by 1 to 4 halogen; n a  is 1 or 2, R 1S  is H or (C 1-4 alkyl, which alkyl is unsubstituted or substituted by halogen; R 1a  is H, OH, (C 1-4 )alkyl or O(C 1-4 )alkyl wherein alkyl is unsubstituted or substituted by 1 to 3 halogen; R 1b  is H, OH or (C 1-4 )alkyl, wherein alkyl is unsubstituted or substituted by halogen; each R 2a  is independently selected from H or (C 1-4 )alkyl, which alkyl is unsubstituted or substitued by halogen; R 3 , is H, OH, halogen or O(C 1-4 )alkyl wherein alkyl is unsubstituted or substituted by halogen; and R 3b  is H, OH, halogen, (C 1-4 )alkyl wherein alkyl is unsubstituted or substituted by hydroxy, or O(C 1-4 )alkyl wherein alkyl is unsubstituted or substituted by halogen; Y a  is —CH 2 —, —C(O)—, —CH(OH)—, —C(═NOH)—, O or S, and R 4a  is (C 4-14 )alkyl or (C 4-14 )alkenyl; 
     or a pharmaceutically acceptable salt or hydrate thereof; 
     Compounds as disclosed in WO 02/076995, e.g. a compound of formula V 
     
       
         
         
             
             
         
       
     
     wherein 
     m c  is 1, 2 or 3; 
     X c  is O or a direct bond; 
     R 1c  is H; C 1-6  alkyl optionally substituted by OH, acyl, halogen, C 3-10 cycloalkyl, phenyl or hydroxy-phenylene; C 2-6 alkenyl; C 2-6 alkynyl; or phenyl optionally substituted by OH; 
     R 2c  is 
     
       
         
         
             
             
         
       
         
         
           
             wherein R 5c  is H or C 1-4 alkyl optionally substituted by 1, 2 or 3 halogen atoms, and R 6c    
             is H or C 1-4 alkyl optionally substituted by halogen; 
           
         
       
    
     each of R 3c  and R 4c , independently, is H, C 1-4 alkyl optionally substituted by halogen, or acyl, and 
     R c  is C 13-20 alkyl which may optionally have in the chain an oxygen atom and which may optionally be substituted by nitro, halogen, amino, hydroxy or carboxy; or a residue of formula (a) 
     
       
         
         
             
             
         
       
         
         
           
             wherein R 7c  is H, C 1-4 alkyl or C 1-4 alkoxy, and R 8c  is substituted C 1-20 alkanoyl, phenylC 1-14 alkyl wherein the C 1-14 alkyl is optionally substituted by halogen or OH, cycloalkylC 1-14 alkoxy or phenylC 1-14 alkoxy wherein the cycloalkyl or phenyl ring is optionally substituted by halogen. C 1-4 alkyl and/or C 1-4 alkoxy, phenylC 1-14 alkoxy-C 1-4 alkyl, phenoxyC 1-14 alkoxy or phenoxyC 1-14 alkyl, 
           
         
       
    
     R c  being also a residue of formula (a) wherein R 8c  is C 1-14 alkoxy when R 1c  is C 1-4 alkyl, C 2-6 alkenyl or C 2-6 alkynyl, 
     or a compound of formula VI 
     
       
         
         
             
             
         
       
     
     wherein 
     n x  is 2, 3 or 4 
     R 3X  is H; C 1-6 alkyl optionally substituted by OH, acyl, halogen, cycloalkyl, phenyl or hydroxy-phenylene: C 2-6 alkenyl; C 2-6 alkynyl; or phenyl optionally substituted by OH; 
     R 2x  is H, C 1-4  alkyl or acyl 
     each of R 3X  and R 4x , independently is H, C 1-4 alkyl optionally substituted by halogen or acyl, 
     R 5x , is H, C 1-4 alkyl or C 1-4 alkoxy, and 
     R 6x  is C 1-20 alkanoyl substituted by cycloalkyl; cyloalkylC 1-14 alkoxy wherein the cycloalkyl ring is optionally substituted by halogen, C 1-4 alkyl and/or C 1-4 alkoxy; phenylC 1-14 alkoxy wherein the phenyl ring is optionally substituted by halogen, C 1-4 alkyl and/or C 1-4 alkoxy, 
     R 6x  being also C 4-14 alkoxy when R 1x  is C 2-4 alkyl substituted by OH, or pentyloxy or hexyloxy when R 1x  is C 1-4 akyl, 
     provided that R 6x  is other than phenyl-butylenoxy when either R 5x  is H or R 1x  is methyl, 
     or a pharmaceutically acceptable salt or hydrate thereof; 
     Compounds as disclosed in WO02/06268A1, e.g. a compound of formula VII 
     
       
         
         
             
             
         
       
     
     wherein each of R 1d  and R 2d , independently, is H or an amino-protecting group; 
     R 3d  is hydrogen, a hydroxy-protecting group or a residue of formula 
     
       
         
         
             
             
         
       
     
     R 4d  is C 1-4 alkyl; 
     n d  is an integer of 1 to 6; 
     X d  is ethylene, vinylene, ethynylene, a group having a formula—D—CH 2 — (wherein D is carbonyl, —CH(OH)—, O, S or N), aryl or aryl substituted by up to three substitutents selected from group a as defined hereinafter; 
     Y d  is single bond, C 1-10 alkylene, C 1-10 alkylene which is substituted by up to three substitutents selected from groups a and b, C 1-10 alkylene having O or S in the middle or end of the carbon chain, or C 1-10  alkylene having O or S in the middle or end of the carbon chain which is substituted by up to three substituents selected from groups a and b; 
     R 5d  is hydrogen, C 3-6 cycloalkyl, aryl, heterocyclic group, C 3-6 cycloalkyl substituted by up to three substituents selected from groups a and b, aryl substituted by up to three substituents selected from groups a and b, or heterocyclic group substituted by up to three substituents selected from groups a and b; 
     each of R 6d  and R 7d , independently, is H or a substituent selected from group a; 
     each of R 8d  and R 9d , independently, is H or C 1-4 alkyl optionally substituted by halogen; 
     &lt;group a&gt; is halogen, lower alkyl, halogeno lower alkyl, lower alkoxy, lower alkylthio, carboxyl, lower alkoxycarbonyl, hydroxy, lower aliphatic acyl, amino, mono-lower alkylamino, di-C 1-4 alkylamino, acylamino, cyano or nitro; and 
     &lt;group b&gt; is C 3-6 cycloalkyl, aryl or heterocyclic group, each being optionally substituted by up to three substituents selected from group a; 
     with the proviso that when R 5d  is hydrogen, Y d  is a either a single bond or linear C 1-10  alkylene, or a pharmacologically acceptable salt, ester or hydrate thereof; 
     Compounds as disclosed in JP-14316985 (JP2002316985), e.g. a compound of formula VIII 
     
       
         
         
             
             
         
       
     
     wherein R 1e ,R 2e ,R 3e ,R 4e R 5e ,R 6e ,R 7e , n e , X e  and Y e  are as disclosed in JP-14316985; 
     or a pharmacologically acceptable salt, ester or hydrate thereof; 
     Compounds as disclosed in WO 03/29184 and WO 03/29205, e.g. compounds of formula IX 
     
       
         
         
             
             
         
       
     
     wherein X f  is O, S, SO or SO 2    
     R 1f  is halogen, trihalomethyl, OH, C 1-7 alkyl, C 1-4 alkoxy, trifluoromethoxy, phenoxy, cyclohexylmethyloxy, pyridylmethoxy, cinnamyloxy, naphthylmethoxy, phenoxymethyl, CH 2 —OH, CH 2 —CH 2 —OH, C 1-4 alkylthio, C 1-4 alkylsulflnyl, C 1-4 alkylsulfonyl, benzylthio, acetyl, nitro or cyano, or phenyl, phenylC 1-4 alkyl or phenyl-C 1-4 alkoxy each phenyl group thereof being optionally substituted by halogen, CF 3 , C 1-4 alkyl or C 1-4 alkoxy; 
     R 2f  is H, halogen, trihalomethyl, C 1-4 alkoxy, phenethyl or benzyloxy; 
     R 3f  H, halogen, CF 3 , OH, C 1-7 alkyl, C 1-4 alkoxy, benzyloxy or C 1-4 alkoxymethyl: each of R 4f  and R 5f , independently is H or a residue of formula 
     
       
         
         
             
             
         
       
     
     wherein each of R 8f  and R 9f , independently, is H or C 1-4 alkyl optionally substituted by halogen; and 
     n f  is an integer from 1 to 4; 
     e.g. 2-amino-2-[4-(3-benzyloxyphenoxy)-2-chlorophenyl]ethyl-1,3-propane-diol, 2-amino-2-[4-(benzyloxyphenylthio)-2- chlorophenyl]ethyl-1,3-propane-diol, 2-amino-2-[4-(3-benzyloxyphenoxy)-2-chlorophenyl]propyl-1,3-propane-diol or 2-amino-2[4-(benzyloxyphenyithio)-2-chlorophenyl]propyl-1,3-propane-diol, 
     or a pharmacological salt, solvate or hydrate thereof; 
     -Compounds as disclosed in WO03/062252A1, e.g. a compound of formula X 
     
       
         
         
             
             
         
       
     
     wherein 
     Ar is phenyl or naphthyl; each of m g  and n g  independently is 0 or 1; A is selected from COOH, PO 3 H 2 , PO 2 N,SO 3 H, PO(C 1-3 alkyl)OH and 1H-tetrazol-5-yl; each of R 1g  and R 2g  independently is H, halogen, OH, COON or C 1-4 alkyl optionally substituted by halogen; R 3g  is H or C 1-4 alkyl optionally substituted by halogen or OH; each R 4g  independently is halogen, or optionally halogen substituted C 1-4 alkyl or C 1-3 alkoxy; and each of R g  and M has one of the significances as indicated for B and C, respectively, in WO03/062252A1; 
     or a pharmacologically acceptable salt, solvate or hydrate thereof; 
     Compounds as disclosed in WO 03/062248A2, e.g. a compound of formula XI 
     
       
         
         
             
             
         
       
     
     wherein Ar is phenyl or naphthyl; n is 2,3 or 4; A is COOH, 1H-tetrazol-5-yl, PO 3 1-1 2 , PO 2 H 2 , —SO 3 N or PO(R 5h )OH wherein R 5h  is selected from C 1-4 alkyl, hydroxyC 1-4 alkyl, phenyl, —CO—C 1-3 alkoxy and —CH(OH)-phenyl wherein said phenyl or phenyl moiety is opitonally substituted; each of R 1h  and R 2h  independently is H, halogen, OH, COOH, or optionally halogeno substituted C 1-6 alkyl or phenyl; R 3h  is H or C 1-4 alkyl optionally substituted by halogen and/OH; each R 4h  independently is halogeno, OH, COOH, C 1-4 alkyl, S(O) 0, 1 or 2 C 1-3 alkyl, C 1-3 alkoxy, C 3-6 cycloalkoxy, aryl or aralkoxy, wherein the alkyl portions may optionally be substituted by 1-3 halogens; and each of R h  and M has one of the significances as indicated for B and C, respectively, in WO03/062248A2; or a pharmacologically acceptable salt, solvate or hydrate thereof; 
     Compounds as disclosed in WO 04/103306A, WO 05/000833, WO 05/103309 or WO 05/113330, e.g. compounds of formula XIIa or XIIb 
     
       
         
         
             
             
         
       
     
     wherein 
     A k  is COOR 5k , OPO(OR 5k ) 2 , PO(OR 5k ) 2 , SO 2 OR 5k , POR 5k OR 5k  or 1H-tetrazol-5-yl, R 5k  being H or C 1-6 alkyl; 
     W k  is a bond, C 1-3 alkylene or C 2-3 alkenylene; 
     Y k  is C 6-10 aryl or C 3-9 heteroaryl, optionally substituted by 1 to 3 radicals selected from halogene, OH, NO 2 , C 1-6 alkyl, C 1-6 alkoxy; halo-substituted C 1-6 alkyl and halo-substituted C 1-6 alkoxy; 
     Z k  is a heterocyclic group as indicated in WO 04/103306A, e.g. azetidine; 
     R 1k  is C 6-10 aryl or C 3-9 heteroaryl, optionally substituted by C 1-6 alkyl, C 6-10 aryl, C 6-10 arylC 1-4 alkyl, 
     C 3-6 heteroaryl, C 3-9 heteroarylC 1-4 alkyl, C 3-8 cycloalkyl, C 3-8 cycloalkylC 1-4 alkyl, 
     C 3-8 heterocycloalkyl or C 3-8 heterocycloalkylC 1-4 alkyl; wherein any aryl, heteroaryl, cycloalkyl or heterocycloalkyl of R 1k  may be substituted by 1 to 5 groups selected from halogen, C 1-6 alkyl, C 1-6 alkoxy and halo substituted-C 1-6 alkyl or -C 1-6 alkoxy; 
     R 2k  is H, C 1-6 alkyl, halo substituted C 1-6 alkyl, C 2-6 alkenyl or C 2-6 alkynyl: and 
     each of R 1k  or R 4k , independently, is H, halogen, OH, C 1-6 alkyl, C 1-6 alkoxy or halo substituted C 1-6 alkyl or C 1-6 alkoxy; 
     and the N-oxide derivatives thereof or prodrugs thereof, 
     or a pharmacologically acceptable salt, solvate or hydrate thereof. 
     According to a further embodiment of the invention, a S1P receptor agonist or modulator for use in a combination of the invention may also be a selective S1P1 receptor, e.g. a compound which possesses a selectivity for the S1P1 receptor over the S1P3 receptor of at least 20 fold, e.g. 100, 500, 1000 or 2000 fold, as measured by the ratio of EC 50  for the S1P1 receptor to the EC 50  for the S1P3 receptor as evaluated in a  35 S-GTPγS binding assay, said compound having an EC 50  for binding to the S1P1 receptor of 100 nM or less as evaluated by the  35 S-GTPγS binding assay. Representative S1P1 receptor agonists or modulators are e.g. the compounds listed in WO 03/061567, the contents of which being incorporated herein by reference, for instance a compound of formula XIII or XIV 
     
       
         
         
             
             
         
       
     
     When the compounds of formulae I to XIV have one or more asymmetric centers in the molecule, the present invention is to be understood as embracing the various optical isomers, as well as racemates, diastereoisomers and mixtures thereof are embraced. Compounds of formula III or IVb, when the carbon atom bearing the amino group is asymmetric, have preferably the R-configuration at this carbon atom. 
     The compounds of formulae I to XIV may exist in free or salt form. Examples of pharmaceutically acceptable salts of the compounds of the formulae I to XIV include salts with inorganic acids, such as hydrochloride, hydrobromide and sulfate, salts with organic acids, such as acetate, fumarate, maleate, benzoate, citrate, malate, methanesulfonate and benzenesulfonate salts, or, when appropriate, salts with metals such as sodium, potassium, calcium and aluminium, salts with amines, such as triethylamine and salts with dibasic amino acids, such as lysine. The compounds and salts of the combination of the present invention encompass hydrate and solvate forms. 
     Acyl as indicated above may be a residue R y —CO— wherein R y  is C 1-6 alkyl, C 3-6 cycloalkyl, phenyl or phenyl-C 1-4 alkyl. Unless otherwise stated, alkyl, alkoxy, alkenyl or alkynyl may be straight or branched. 
     Aryl may be phenyl or naphthyl, preferably phenyl. 
     When in the compounds of formula 1 the carbon chain as R 1  is substituted, it is preferably substituted by halogen, nitro, amino, hydroxy or carboxy. When the carbon chain is interrupted by an optionally substituted phenylene, the carbon chain is preferably unsubstituted. When the phenylene moiety is substituted, it is preferably substituted by halogen, nitro, amino, methoxy, hydroxy or carboxy. 
     Preferred compounds of formula I are those wherein R 1  is C 13-20 alkyl, optionally substituted by nitro, halogen, amino, hydroxy or carboxy, and, more preferably those wherein R 1  is phenylalkyl substituted by C 6-14 -alkyl chain optionally substituted by halogen and the alkyl moiety is a C 1-6 alkyl optionally substituted by hydroxy. More preferably, R 1  is phenyl-C 1-6 olkyl substituted on the phenyl by a straight or branched, preferably straight, C 6-14 alkyl chain. The C 6-14 alkyl chain may be in ortho, meta or para, preferably in para. 
     Preferably each of R 2  to R 5  is H. 
     In the above formula of VII “heterocyclic group” represents a 5- to 7 membered heterocyclic group having 1 to 3 heteroatoms selected from S, O and N. Examples of such heterocyclic groups include the heteroaryl groups indicated above, and heterocyclic compounds corresponding to partially or completely hydrogenated heteroaryl groups, e.g. furyl, thienyl, pyrrolyl, azepinyl, pyrazolyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, 1,2,3-oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyranyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, tetrahydropyranyl, morpholinyl, thiomorpholinyl, pyrrolidinyl, pyrrolyl, imidazolidinyl, pyrazolidinyl, piperidinyl, piperazinyl, oxazolidinyl, isoxazolidinyl, thiazolidinyl or pyrazolidinyl. Preferred heterocyclic groups are 5-or 6-membered heteroaryl groups and the most preferred heteocyclic group is a morpholinyl, thiomorpholinyl or piperidinyl group. 
     A preferred compound of formula I is 2-amino-2-tetradecyl-1,3-propanediol. A particularly preferred S1P receptor agonist of formula 1 is FTY720, i.e. 2-amino-2-[2-(4-octylphenyl) ethyl]propane-1,3-diol in free form or in a pharmaceutically acceptable salt form (referred to hereinafter as Compound A), e.g. the hydrochloride, as shown: 
     
       
         
         
             
             
         
       
     
     A preferred compound of formula II is the one wherein each of R′ 2  to R′ 5  is H and m is 4, i.e. 2-amino-2-{2-[4-(1-oxo-5-phenylpentyl)phenyl]ethyl}propane-1,3-diol, in free form or in pharmaceutically acceptable salt form (referred to hereinafter as Compound B), e.g the hydrochloride. 
     A preferred compound of formula III is the one wherein W is CH 3 , each of R″ 1 , to R″ 3  is H, Z 2  is ethylene, X is heptyloxy and Y is H, i.e. 2-amino-4-(4-heptyloxyphenyl)-2-methyl-butanol, in free form or in pharmaceutically acceptable salt form (referred to hereinafter as Compound C), e.g. the hydrochloride. The R-enantiomer is particularly preferred. 
     A preferred compound of formula IVa is the FTY720-phosphate (R 2a  is H, R a , is OH, X a  is O, R 1a  and R 1b  are OH). A preferred compound of formula IVb is the Compound C-phosphate (R 2a  is H, R 3b  is OH, X a  is O, R 1a  and R 1b  are OH, Y a  is O and R 4a  is heptyl). A preferred compound of formula V is Compound B-phosphate. 
     A preferred compound of formula V is phosphoric acid mono-[(R)-2-amino-2-methyl-4-(4-pentyloxy-phenyl)-butyl]ester. 
     A preferred compound of formula VIII is (2R)-2-amino-4-[3-(4-cyclohexyloxybutyl)-benzo[b]thien-6-yl]-2-methylbutan-1-ol. 
     A preferred compound of formula XIIa is e.g. 1-{4-[1-(4-cyclohexyl-3-trifluoromethyl-benzyloxyimino)-ethyl]-2-ethyl-benzyl}-azetidine-3-carboxylic acid, or a prodrug thereof. 
    
    
     According to the invention, it provides the use of an S1P receptor modulator or agonist in the manufacture of a medication, whereby said medication is administered in such a way that during the initial 3 to 6 days, preferably 4 or 5 days, most preferred 4 days, of treatment the dosage of said S1P receptor modulator or agonist is raised so that in total the R-fold (R being the accumulation factor) standard daily dosage of said S1P receptor modulator or agonist is administered and thereafter the treatment is continued with the standard or a lower daily dosage of said S1P receptor modulator or agonist. 
     Preferred medications comprise medication for transplant patients providing prolonged survival rates, in particular prolonged allograft survival rates especially for renal, heart, lung or liver transplants, or for patients suffering from autoimmune diseases, e.g. multiple sclerosis, lupus nephritis, rheumatoid arthritis, inflammatory bowel diseases or psoriasis. 
     In view of the normally prolonged taking of the medication, the standard daily dosage (also called maintenance dose) refers to the dosage of an S1P receptor modulator or agonist necessary for a steady-state trough blood level of the medication or its active metabolite(s) providing effective treatment. Said dosage is dependent on the accumulation factor (R). By blood level is meant the concentration of a drug in blood at any time. Trough blood level corresponds to a pre-dose blood level. Steady-state means whether the trough or blood level is stable over time. Steady-state trough blood levels may be assessed, for example, by obtaining a pre-dose blood sample anytime after month 1 The accumulation factor (R) is calculated on the ratio of the steady-state trough to the trough just before the second dose. 
     Preferably, the dosage of the S1P receptor modulator or agonist during the initial 3 to 6 days, of treatment is increased stepwise. Thereafter the treatment is continued with the maintenance therapy with the standard daily dosage or with a lower daily dosage. When the treatment is continued at a lower daily dosage, it may be e.g. about 1/50 to ½ preferably 1/50 to 1/10, of the standard daily dosage of the S1P receptor modulator or agonist. 
     Preferably, the total dosage of said S1P receptor modulator or agonist during the initial 3 to 6 days, preferably 4 or 5 days, most preferred 4 days, of treatment is increased incrementally from 3- to 21-fold, more preferred from 4 to 12-fold, particularly about 10-fold, the standard daily dosage of said S1P receptor modulator or agonist. For example, the loading dose may be 1; 1.5-2; 2-3; and 3-4 fold the standard daily dosage, on day 1, 2, 3 and 4, respectively. 
     According to a preferred embodiment of the invention, the highest loading regimen dose instalment on the last day of the loading regimen, e.g. on day 4, is 4× the maintenance dose of the S1P receptor modulator or agonist. The instalment doses on days 1, 2 and 3 of the loading regimen may be e.g. about ¼; ½; and ¾ of the highest instalment dose of the S1P receptor modulator or agonist, 
     A particularly preferred dosage of the S1P receptor modulator or agonist, e.g. the preferred S1P receptor modulator FTY720, is e.g. 2-5, 5-10, 10-15 and 15-20 mg, e.g. a regimen of 2.5 mg/5 mg/7.5 mg/10 mg or 5 mg/10 mg/15 mg/20 mg, respectively, during the initial period of 4 days. Thereafter the treatment is continued with the maintenance therapy, e.g. a daily dosage of 2.5 mg or 5 mg, or at a lower daily dosage, e.g. 0.1 to 0.5 mg. 
     In a further embodiment of the invention, a preferred loading regimen of a S1P receptor agonist or modulator, e.g. the preferred S1P receptor modulator FTY720, may also be e.g. 0.5 mg/1 mg/1.5 mg/2 mg during the initial period of 4 days. Thereafter the treatment is continued with the maintenance therapy, e.g. a daily dosage of 0.5 mg. 
     In a series of further specific or alternative embodiments, the present invention also provides:
         1.1 The use of a S1P receptor modulator or agonist, e.g. FTY720, in the manufacture of a medication, whereby said medication is administered in such a way to a subject that a steady-state of the S1P receptor modulator or agonist blood levels is attained in less than a week.
           The steady-state attained is such that the subject is sufficiently immunosuppressed, e.g. it shows no signs or symptoms of acute graft rejection or relapse or rebound of the autoimmune disease. During the initial 3 to 6 days, preferably 4 or 5 days, most preferred 4 days, of treatment the daily dosage of the S1P receptor modulator or agonist is raised stepwise up to 3- to 21-fold the standard daily dosage of said S1P receptor modulator or agonist and thereafter the treatment is continued with the standard daily dosage of said S1P receptor modulator or agonist.   
           1.2 The use of a S1P receptor modulator or agonist, e.g. FTY720, in the manufacture of a medication, whereby said medication is administered in such a way to a subject that a steady-state of the S1P receptor modulator or agonist blood levels is attained in less than a week, and thereafter the treatment is continued at a dosage lower than the standard daily dosage.   1.3. The use of a S1P receptor modulator or agonist, e.g. FTY720, in the manufacture of a medication, whereby said medication is administered in such a way that during the initial 4 days of treatment the dosage of the S1P receptor modulator or agonist is 1; 1.5-2; 2-3; and 3-4 fold the standard daily dosage, respectively, and thereafter the treatment is continued with the standard daily dosage of the S1P receptor modulator or agonist, or at a lower daily dosage.   1.4 The use of a S1P receptor modulator or agonist, e.g. FTY720, in the manufacture of a medication, whereby said medication is administered in such a way that during the initial 4 days of treatment the dosage of the S1P receptor modulator or agonist is ¼; ½; and ¾ of the highest instalment dose of the S1P receptor modulator or agonist; and 4× the maintenance dose of the S1P receptor modulator or agonist, respectively, and thereafter the treatment is continued with the maintenance dose or optionally with a lower daily dosage of the S1P receptor modulator or agonist.   1.5 The use of an S1P receptor modulator or agonist, e.g. FTY720, in the manufacture of a medication, whereby said medication is administered in such a way that during the initial 3 to 6 days, preferably 4 or 5 days, most preferred 4 days, of treatment the dosage of said S1P receptor modulator or agonist is raised so that in total the R-fold standard daily dosage of said S1P receptor modulator or agonist is administered and thereafter the treatment is continued with the standard daily dosage of said S1P receptor agonist or at a lower daily dosage.   1.6 The use of an S1P receptor modulator or agonist, e.g. FTY720, in the manufacture of a medication, whereby said medication is administered, after a loading regimen, at a daily dosage which is lower than the standard daily dosage.   1.7 The use of FTY720 in the manufacture of a medication, whereby said medication is administered, after a loading regimen, at a daily dosage of 0.1 to 0.5 mg.   2. A method for inhibiting graft rejection or treating an autoimmune disease in a subject in need thereof, comprising administering to the subject a S1P receptor modulator or agonist, e.g. FTY720, in such a pharmaceutically effective amount that a steady-state of the S1P receptor modulator or agonist blood levels is attained in the subject in less than a week. Thereafter the treatment is continued with the standard daily dosage of said S1P receptor modulator or agonist or at a lower daily dosage   2.1 A method for producing a steady-state of S1P receptor modulator or agonist blood levels in a subject in less than a week comprising administering during the initial 3 to 6 days, preferably 4 or 5 days, most preferred 4 days, an incremental daily dosage of up 3- to 21-fold the standard daily dosage of said S1P receptor modulator or agonist.   2.2 In a treatment method with a S1P receptor modulator or agonist, e.g. FTY720, the improvement being that the S1P receptor modulator or agonist is administered in such a way that during the initial 3 to 6 days, preferably 4 or 5 days, most preferred 4 days, of treatment the dosage is raised so that in total the R-fold standard daily dosage is administered. Thereafter the treatment is continued with the standard effective daily dosage or at a lower daily dosage.   2.3 A method for providing prolonged transplant survival rates in a subject, whereby an       

     S1P receptor modulator or agonist is administered in such a way that during the initial 3 to 6 days, preferably 4 or 5 days, most preferred 4 days, of treatment the dosage is raised stepwise so that in total the R-fold standard daily dosage is administered and thereafter the treatment is continued with the standard daily dosage or at a lower daily dosage.
         2.4 A method for inhibiting graft rejection or treating an autoimmune disease in a subject in need thereof, comprising administering to the subject, after a loading regimen, a S1P receptor modulator or agonist, e.g. FTY720, at a daily dosage which is lower than the standard daily dosage.   2.5 A method for treating an autoimmune disease in a subject in need thereof, comprising administering to the subject, after a loading regimen, a daily dosage of FTY720 of about 0.1 to 0.5 mg.   3. A kit containing daily units of medication of an S1P receptor modulator or agonist, e.g. FTY720, of varying daily dosage, whereby the daily dosage of said S1P receptor modulator or agonist for the initial 3 to 6 days, preferably 4 or 5 days, most preferred 4 days, of treatment is incrementally increased so that the total amount present in the daily units corresponds to the R-fold standard daily dosage of said S1P receptor modulator or agonist for this initial time period.   3.1. A kit containing daily units of medication of an S1P receptor modulator or agonist, e.g. FTY720, of varying daily dosage, whereby the daily dosage of S1P receptor modulator or agonist for the initial 4 days of treatment is 1; 1.5-2; 2-3; and 3-4 fold the standard daily dosage, respectively. The kit may further comprise units for the standard daily dosage of the S1P receptor modulator or agonist, e.g. FTY720, or for the subsequent treatment with a lower daily dosage. The kit may also contain instructions for use.   3.2 A kit containing daily units of medication of an SI P receptor modulator or agonist, e.g. FTY720, of varying daily dosage, whereby the daily dosage of S1P receptor modulator or agonist for the initial 4 days of treatment is ¼; ½; and ¾ of the highest instalment dose of the S1P receptor modulator or agonist; and 4× the maintenance dose of the S1P receptor modulator or agonist, respectively. The kit may further comprise units for the standard daily dosage of the S1P receptor modulator or agonist, e.g. FTY720, or for the subsequent treatment with a lower daily dosage. The kit may also contain instructions for use.       

     The loading regimen of S1P receptor modulator or agonist which is administered to the subject according to the invention may be given either during the initial 3-6 days post-transplantation or may start even prior to the transplantation surgery, or at the beginning of an autoimmune disease therapy, or after an interruption of S1P receptor modulator or agonist therapy. 
     Utility of an S1P receptor modulator or agonist dosage regimen in treating diseases and conditions as hereinabove specified may be demonstrated in standard animal or clinical tests, e.g. in accordance with the methods described hereinafter. 
     2-Phase Loading Regimen-Study: 
     Initial baseline (Day-2): on Day-2, subjects enter the study center at least 12-hours prior to dosing for verification of inclusion/exclusion criteria and baseline assessments. 
     Placebo run-in (Day-1): On Day 1, subjects receive a single, placebo dose of FTY720 
     FTY720 treatment (Days 1-7): All subjects receive FTY720 once daily for 7 consecutive days as follows,
         Day 1: Subjects receive a single 5 mg FTY720 oral dose at the exact time the Day-1 dose was administered.   Days 2-4: Subject receive a single 10 mg FTY720 oral dose on Day 2, a single 15 mg FTY720 oral dose on Day 3, and a single 20 mg FTY720 oral dose on Day 4, in order to achieve the FTY720 steady-state concentration typically measured in patients on chronic dosing of FTY720 5 mg qd.   Day 5-7: Subjects receive single 5 mg FTY720 oral doses once daily.       

     Pharmacokinetic, pharmacodynamic and safety assessments are performed at specified times during the multiple-dose study. Subjects are released from the study center approximately 24 hours after the last drug administration on Day 7, after the safety evaluations have been completed (i.e., Day 8). 
     Analytes, Media and Methods: 
     FTY720 is measured in whole blood using LC/MS/MS (LLOQ=0.080 ng/mL) 
     PK evaluations: Noncompartmental analysis to derive tmax, Cmax, AUC(0-24) on day 1. Peak and trough concentrations are summarized from days 2 through 7 to estimate drug accumulation and attainment of steady state. 
     Lymphocyte Assessment 
     Blood samples for absolute lymphocyte counts is collected at screening, at initial baseline (Day-2), Day 1 (6h postdose), Day 3 (predose), Day 5 (predose) and Day 7 (predose), 
     The samples are analyzed for pharmacodynamics. 
     Above procedure may be repeated and the patients are then treated Day 5 and followings with a daily maintenance dose of 0.5 mg/kg. The patients have lower steady-state blood levels. 
     Above procedure may be repeated with following loading treatments:
         1. Day 1: Subjects receive a single 2.5 mg FTY720 oral dose at the exact time the Day-1 dose was administered.   Days 2-4: Subject receive a single 5 mg FTY720 oral dose on Day 2, a single 7.5 mg FTY720 oral dose on Day 3, and a single 10 mg FTY720 oral dose on Day 4, in order to achieve the FTY720 steady-state concentration typically measured in patients on chronic dosing of FTY720 2.5 mg qd.   Day 5-7 and following: Subjects receive single 2.5 mg FTY720 oral doses once daily.       

     2. Day 1: Subjects receive a single 1.25 mg FTY720 oral dose at the exact time the Day 1 dose was administered.
         Days 2-4: Subject receive a single 2.5 mg FTY720 oral dose on Day 2, a single 3.75 mg FTY720 oral dose on Day 3, and a single 5 mg FTY720 oral dose on Day 4, in order to achieve the FTY720 steady-state concentration typically measured in patients on chronic dosing of FTY720 1.25 mg qd.   Day 5-7 and following: Subjects receive single 1.25 mg FTY720 oral doses once daily.