Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K38/00—Medicinal preparations containing peptides
  • A61K38/04—Peptides having up to 20 amino acids in a fully defined sequence; Derivatives thereof
  • A61K38/05—Dipeptides
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/33—Heterocyclic compounds
  • A61K31/395—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins
  • A61K31/495—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins having six-membered rings with two or more nitrogen atoms as the only ring heteroatoms, e.g. piperazine or tetrazines
  • A61K31/505—Pyrimidines; Hydrogenated pyrimidines, e.g. trimethoprim
  • A61K31/517—Pyrimidines; Hydrogenated pyrimidines, e.g. trimethoprim ortho- or peri-condensed with carbocyclic ring systems, e.g. quinazoline, perimidine
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P19/00—Drugs for skeletal disorders
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P19/00—Drugs for skeletal disorders
  • A61P19/02—Drugs for skeletal disorders for joint disorders, e.g. arthritis, arthrosis
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P29/00—Non-central analgesic, antipyretic or antiinflammatory agents, e.g. antirheumatic agents; Non-steroidal antiinflammatory drugs [NSAID]
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P35/00—Antineoplastic agents
  • A61P35/02—Antineoplastic agents specific for leukemia
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P37/00—Drugs for immunological or allergic disorders
  • A61P37/02—Immunomodulators
  • A61P37/06—Immunosuppressants, e.g. drugs for graft rejection
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K5/00—Peptides containing up to four amino acids in a fully defined sequence; Derivatives thereof
  • C07K5/02—Peptides containing up to four amino acids in a fully defined sequence; Derivatives thereof containing at least one abnormal peptide link
  • C07K5/0215—Peptides containing up to four amino acids in a fully defined sequence; Derivatives thereof containing at least one abnormal peptide link containing natural amino acids, forming a peptide bond via their side chain functional group, e.g. epsilon-Lys, gamma-Glu

Definitions

• This invention relates to the use of cyclopenta[g]quinazoline derivatives. More particularly it relates to cyclopenta[g]quinazoline derivatives for the treatment of rheumatoid arthritis (RA) and acute myeloid leukaemia (AML).
• RA rheumatoid arthritis
• AML acute myeloid leukaemia
• Cyclopenta[g]quinazoline derivatives showing a good level of activity both as regards their ability to inhibit thymidylate synthase (TS) and also as regards their anticancer activity against various cell lines have been developed.
• WO 94/11354 Al (British Technology Group Limited) discloses tricyclic compounds of formula:
• R 1 is hydrogen, amino, C 1 ⁇ alkyl, C 1 ⁇ alkoxy, C 1 ⁇ hydroxyalkyl or C 1 ⁇ fluoroalkyl;
• R 2 is hydrogen, C 1 ⁇ alkyl, C 3 _4 alkenyl, C 3 _ 4 alkynyl, C 2 - ⁇ hydroxyalkyl C 2 ⁇ halogenoalkyl or C 1- ⁇ cyanoalkyl;
• Ar is phenylene, thiophenediyl, thiazolediyl, pyridinediyl or pyrimidinediyl which may optionally bear one or two substituents selected from halogeno, hydroxy, amino, nitro, cyano, trifluoromethyl, C 1 ⁇ alkyl and C 1- ⁇ alkoxy; and
• R 3 is a group of one of the following formulae:
• R 3 is a iV-linked naturally-occurring amino acid selected from the group consisting of L-alanine, L-leucine, L-isoleucine, L- valine and L-phenylalanine.
• L-alanine L-leucine
• L-isoleucine L- valine
• L-phenylalanine L-phenylalanine.
• the L-Glu- ⁇ -D-Glu compound CB300638 also mentioned in Clinical Cancer Research, 5, November 1999 (Supplement) at #566 (Theti et al.) and Proceedings of the American Association for Cancer Research, 41, March 2000 at #33 (Jackman et al), as well as in J. Med. Chem., 2000, 43, 1910-1926, where it is disclosed on page 1923 as compound 7b.
• WO 95/30673 Al (British Technology Group Limited) discloses cyclopenta- [g]quinazolines of formula:
• R 1 is hydrogen, amino, C 1 ⁇ alkyl, C ⁇ - A alkoxy, C 1- ⁇ hydroxyalkyl or d_ 4 fluoroalkyl;
• R 2 is hydrogen, C 1 ⁇ alkyl, C 3- ⁇ alkenyl, C 3 _ 4 alkynyl, C 2 ⁇ hydroxyalkyl, C 2-4 halogenoalkyl or d_ 4 cyanoalkyl;
• Ar 1 is phenylene, thiophenediyl, thiazolediyl, pyridinediyl or pyrimidinediyl which may optionally bear one or two substituents selected from halogeno, hydroxy, amino, nitro, cyano, trifluoromethyl, C 1- ⁇ alkyl and C 1 ⁇ alkoxy; and
• R 3 is a group of one of the following formulae:
• ⁇ -FR membrane-associated folate-
• binding protein is a glycosylphosphatidylinositol anchored cell membrane protein that has very high affinity for folic acid and the more biologically relevant reduced- -folates (Kd ⁇ 0.1 nM).
• the mechanism of folate internalization is receptor-mediated endocytosis.
• the ⁇ -FR is overexpressed in many carcinomas, particularly those of ovarian origin where it is overexpressed highly and homogeneously in 90% of cases; see Cancer Res. 51, 5329-5338, 1991 (Campbell et al, 1991).
• high ⁇ -FR expression has been linked to aggressive, platinum resistant disease and poor prognosis— see Int. J. Cancer 74, 193-198, 1997 and Int. J.
• FR- ⁇ is normally found in placenta tissues and in hematopoietic cells, where it is expressed in the myelomonocytic lineage and is particularly elevated during neutrophil maturation or during monocyte or macrophage activation.
• the FR- ⁇ expressed on normal hematopoietic cells unlike that on activated macrophages for example, is nonfunctional in that it cannot bind and internalize folate.
• FR- ⁇ is expressed on malignant cells from patients with chronic myelogenous leukaemia (CML), and on malignant cells from approximately 70% of patients with AML.
• CML chronic myelogenous leukaemia
• WO 03/072091 -Al uses the discovery that expression of FR- ⁇ is increased in malignant cells from myeloid leukaemia patients by FR- ⁇ inducers.
• the FR- ⁇ expressed in myeloid leukaemia cells preferably AML cells, is functional in that it binds and internalizes folate, unlike the FR- ⁇ expressed in the majority of normal hematopoietic cells which is nonfunctional.
• Such functional FR- ⁇ is a target for folate-conjugated therapeutics.
• the present invention comprises a cyclopenta[g-]- quinazoline derivative, containing an L-Glu- ⁇ -D-Glu dipeptide group, of formula (I):
• R 1 is amino, C 1 ⁇ alkyl, C 1- ⁇ hydroxyalkyl, C 1 ⁇ 4 fluoroalkyl or methoxy-C ⁇ - -alkyl;
• R 2 is Ci- 4 alkyl, C 3 - 4 alkenyl, C 3 ⁇ alkynyl, C 2 _ 4 hydroxyalkyl C 2- ⁇ halogeno- alkyl or C 1 ⁇ cyanoalkyl;
• Ar is phenylene, thiophenediyl, thiazolediyl, pyridinediyl or pyrimidinediyl which may optionally bear one or two substituents selected from halogeno, hydroxy, amino, nitro, cyano, trifluoromethyl, C 1 ⁇ 4 alkyl and C 1 ⁇ 4 alkoxy.
• the compound (I) optionally being in the form of a pharmaceutically accept- able salt or ester; for the treatment of rheumatoid arthritis or acute myeloid leukaemia.
• alkyl, alkenyl and alkynyl include both straight and branched chain groups but references to individual alkyl groups, such as propyl, are specific for the straight chain group only.
• An analogous convention applies to other generic terms.
• the numbering system used for the cyclop enta[g]quin- azoline nucleus is the conventional one as shown below:
• Amino-acid residues are designated herein in the standard manner ⁇ Pure and
• ⁇ -glutamyl denotes the radical H 2 NCH(CO 2 H)CH 2 CH 2 CO- or -NHCH(CO 2 H)CH 2 CH 2 CO- according to the context, the carbon atoms in these radicals being numbered from the carbon atom of the ⁇ -carboxyl group as position 1.
• a cyclopenta[g]quinazoline of the invention contains at least three asymmetric carbon atoms [present at the point of attachment of the group — N(R 2 )- to the tricyclic ring system and at the ⁇ -carbon atoms of the group L-Glu- ⁇ - D-GIu] and can therefore exist in racemic and optically active forms.
• this invention encompasses both racemic and optically active forms, it being a matter of common general knowledge how such optically active forms may be obtained by stereospecific synthesis or by separation of a mixture of isomeric compounds. It will be appreciated that one isomer may be of more interest than another owing to the nature of the activity which it exhibits or owing to superior physical properties, for example aqueous solubility.
• a cyclop enta[g]quinazoline of the formula (I) may exhibit the phenomenon of tautomerism and that the formulae shown in this specification represent only one of the possible tautomeric forms. It is also to be understood that certain cyclopenta[g]quinazolines of the formula (I) can exist in solvated as well as unsolvated forms such as, for example, hydrated forms.
• a suitable value for R 1 or R 2 when it is C 1- ⁇ alkyl, or for a C 1 - 4 alkyl substituent which may be present on Ar, is, for example, methyl, ethyl, propyl or isopropyl.
• a suitable value for a d_ 4 alkoxy substituent which may be present on Ar is, for example, methoxy, ethoxy, propoxy, isopropoxy or butoxy.
• a suitable value for a halogeno substituent which may be present on Ar is, for example, fluoro, chloro or bromo.
• a suitable value for R 2 when it is C 3 _ 4 alkenyl is, for example, prop-2-enyl, but-2-enyl, but-3-enyl or 2-methylprop-2-enyl; and when it is C 3 - 4 alkynyl is, for example, prop-2-ynyl or but-3-ynyl.
• R 2 when it is C 2- ⁇ hydroxyalkyl is, for example,
• a suitable value for Ar when it is phenylene is, for example, 1,3- or
• a suitable value for Ar when it is thiophenediyl is, for example, thio- phene-2,4-diyl or thiophene-2,5-diyl; when it is thiazolediyl is, for example thiazole-2,4-diyl or thiazole-2,5-diyl; when it is pyridinediyl is, for example, pyridine-2,4-diyl, pyridine-2,5-diyl, pyridine-2,6-diyl or pyridine-3,5-diyl; and when it is pyrimidinediyl is, for example, pyrimidine-2,4-diyl, pyrimidine-2,5-diyl or pyrimidine-4,6-diyl.
• Ar may carry one or two substituents.
• a preferred level of substitution in Ar, where substitution is present, is either two substituents or especially one substituent; and the one or two substituents may conveniently be at positions adjacent to the atom bonded to the group -CO-L-Glu- ⁇ -D-Glu, halogeno substituents such as fluoro being preferred.
• a suitable pharmaceutically acceptable salt form of a cyclopenta[g]- quinazoline of the invention is, for example, an acid addition salt with an inorganic or organic acid, for example hydrochloric, hydrobromic, trifluoroacetic or maleic acid; or an alkali metal, for example sodium, an alkaline earth metal, for example calcium, or ammonium, for example tetra(2-hydroxyethyl)ammonium, salt.
• a suitable pharmaceutically acceptable ester form of a cyclopenta[g]quin- azoline of the invention is, for example, an ester with an aliphatic alcohol of up to 6 carbon atoms, for example a methyl, ethyl or tert-butyl ester.
• the compound contains three carboxyl groups.
• a salt or ester may be mono-acid-di-salt or -ester, di-acid-mono-salt or -ester or even tri-salt or -ester.
• R 1 is C 1 - 4 alkyl or C 1 ⁇ hydroxyalkyl. More preferably R 1 is methyl or, especially, hydroxymethyl.
• R 2 is methyl, ethyl, propyl, prop-2-enyl, prop-2-ynyl, 2-hydroxy- ethyl, 2-fluoroethyl, 2-bromoethyl or 2-cyanoethyl. More preferably R is methyl or, especially, prop-2-ynyl.
• Ar is 1,4-phenylene which may optionally bear one or two sub- stituents selected from the group consisting of chloro and especially fluoro, thiophene-2,5-diyl, thiazole-2,5-diyl or pyridine-2,5-diyl.
• Ar is 1,4- phenylene or 1,4-phenylene having a 2-fluoro substituent as in 2,6-difluoro-l,4- -phenylene or especially 2-fluoro- 1,4-phenylene or is pyridine 2,5-diyl. Most preferably Ar is 1,4-phenylene or 2-fluoro- 1,4-phenylene.
• a preferred cyclopenta[g]quinazoline of the invention has the formula (I) wherein R 1 is C 1 ⁇ alkyl or C 1- ⁇ hydroxyalkyl, especially hydroxymethyl;
• R 2 is methyl, ethyl, propyl, prop-2-enyl, prop-2-ynyl, 2-hydroxyethyl, 2- fluoroethyl, 2-bromoethyl or 2-cyanoethyl;
• Ar is 1,4-phenylene which may optionally bear one or two substituents selected from the group consisting of chloro and especially fluoro, thiophene-2,5-diyl, thiazole-2,5-diyl or pyridine-2,5-diyl.
• a further preferred cyclopenta[g]quinazoline of the invention has the formula (I) wherein R 1 is methyl or hydroxymethyl;
• R 2 is methyl or prop-2-ynyl
• Ar is 1,4-phenylene or 1,4-phenylene having a 2-fluoro substituent as in 2,6-difluoro- 1,4-phenylene or especially 2-fluoro- 1,4-phenylene or is pyridine 2,5-diyl.
• An especially preferred cyclopenta[g]quinazoline of the invention has the formula (I) wherein R 1 is methyl or hydroxymethyl;
• R 2 is methyl or preferably prop-2-ynyl
• Ar is 1,4-phenylene or 2-fluoro- 1,4-phenylene.
• cyclopenta[g]quinazolines of the invention are: N- ⁇ N- ⁇ 4-[N-(2-methyl-4-oxo-3 ,4,7,8-tetrahydro-6/J-cyclopenta[g-]quinazolin-
• compo ⁇ nds of the present invention can exist as a mixture of stereoisomers it is preferred that they are resolved into one optically active isomeric form. Such a requirement complicates the synthesis of the compounds and it is preferred therefore that they contain as few asymmetric carbon atoms as possible con- sistent with achieving the desired activity.
• the cyclopenta[g]quinazolines of the present invention contain at least three asymmetric carbon atoms.
• that at the 6 position of the ring system preferably has the 6S orientation rather than the 6R orientation.
• the preferred compounds (I) described hereinbefore thus preferably have such a configuration at this asymmetric carbon atoms or less preferably are a mixture in which one or both of these asymmetric carbon atoms is unresolved.
• a cyclopenta[g-]quinazoline of the invention may be prepared by any process known to be applicable to the preparation of chemically-related compounds.
• a cyclopenta[g]quinazoline of the present invention may itself be active or may be a prodrug converted in vivo to an active compound.
• a cyclopenta[g]quin- azoline of the invention may be administered to a warm-blooded animal, including a human, in the form of a pharmaceutical composition which comprises the cyclopenta- [g]quinazoline in association with a pharmaceutically acceptable diluent or carrier.
• the composition may be in a form suitable for oral use, for example a tablet, capsule, aqueous or oily solution, suspension or emulsion; for topical use, for example a cream, ointment, gel or aqueous or oily solution or suspension; for nasal use, for example a snuff, nasal spray or nasal drops; for vaginal or rectal use, for example a suppository; for administration by inhalation, for example as a finely divided pow- der such as a dry powder, a microcrystalline form or a liquid aerosol; for sub-lingual or buccal use, for example a tablet or capsule; or for parenteral use (including intravenous, subcutaneous, intramuscular, intravascular or infusion use), for example a sterile aqueous or oily solution, emulsion or suspension.
• parenteral use including intravenous, subcutaneous, intramuscular, intravascular or infusion use
• compositions may be prepared in a conventional manner using conventional excipients.
• the cyclopenta[g]quinazoline will normally be administered to a warmblooded animal at a dose within a range of 50-25000, particularly 50-5000, mg per square metre body area of the animal, i.e. approximately 1500, particularly 1—100, mg/kg.
• dosages outside this range may be employed and, in particular, where the preferred mode of administration involving subcutaneous infusion is used then the dose range may be increased to 1-1000 mg/kg.
• a daily dose in the range 10-250 mg/kg is employed, particularly 30-150 mg/kg.
• the daily dose will necessarily be varied depending upon the host treated, the particular route of administration and the severity of the illness being treated. Accordingly, the optimum dosage may be determined by the practitioner who is treating any particular patient.
• the present invention also includes a method for treating rheumatoid arthritis or acute myeloid leukaemia in a patient in need of such treatment which comprises administering to said patient an effective amount of a cyclopentafg-jquin- azoline derivative as defined hereinbefore.
• the compound will normally be administered at a dose within the range 5— 25000, particularly 5-500, mg per square metre body area of the animal, i.e. approximately 0.1-500, particularly 0.1—10, mg/kg. Where desired, however, dosages outside this range may be employed.
• Topical administration of a cyclopenta[g]quinazoline of the invention may be used.
• a daily dose in the range for example, of 0.1 to 10 mg/kg may be used.
• compositions containing the quinazolines may be formulated in unit dosage form, i.e. in the form of discrete portions each comprising a unit dose, or a multiple or sub-multiple of a unit dose, for example as a tablet or capsule.
• unit dosage form may, for example, contain an amount of the cyclopenta[g-]quinazoline in the range of 1-250 or 1-500 mg.
• A rabbit isotype staining
• B FR- ⁇ staining
• C macrophage staining
• D FR- ⁇
• E CD-68 (macrophages)
• F merge of D and E.
• nuclei are stained blue (Dapi-staining).
• PBLs Peripheral Blood Lymphocytes
• FR- ⁇ expression in these samples is shown as a percentage of the expression in CHO- ⁇ cells (Chinese Hamster Ovarian cells transfected with FR- ⁇ ; expression in these cells was set to 1.00).
• Figure 4 Relative binding affinities of FR- ⁇ (white bars) and FR- ⁇ (grey bars) for novel generation folate antagonists.
• FR- ⁇ and FR- ⁇ binding affinities of the drugs were determined by [ 3 H]-folic acid displacement of FRa expressing KB-cells and FR ⁇ transfected CHO- ⁇ cells as described in the Materials and Methods section.
• Binding affinities are presented as percentage relative of folic acid binding affinity.
• Figure 5 Growth inhibition of CHO/WT and CHO/FR- ⁇ cells by BGC 945 with or without 1 ⁇ M folic acid (A), CB300635 (B) and AG2034 (CYD) with or without supplementation of folic acid (1 ⁇ M) or leucovorin (20 nM). Results are the mean of 3 experiments (SD ⁇ 20%).
• Example 1 Exploitation of folate receptor- ⁇ as a potential delivery route for novel generation folate antagonists to activated macrophages in synovial tissue of rheumatoid arthritis patients
• MTX The folate antagonist methotrexate
• DMARD disease modifying antirheumatic drug
• RA rheumatoid arthritis
• DMARD disease modifying antirheumatic drug
• MTX use is obligate in most treatment strategies involving biological agents (anti-TNF ⁇ or -CD20 monoclonal antibodies.
• the first pivotal step in the cellular pharmacology of MTX is its cell entry which can be mediated by at least 3 different routes; the reduced folate carrier (RFC), membrane-associated folate receptors (MFR) or a proton-coupled (low pH) folate transporter (PCFT).
• the latter transporter is mainly involved in intestinal folate uptake.
• the other transport routes harbour physiological and pharmacological relevance for immune-competent cells by facilitating the uptake of natural reduced folate cofactors and folate antagonists like MTX.
• the RFC and MFR differ considerably in mechanism of (anti)folate uptake (transmembrane carrier vs.
• FR- ⁇ For MFR, three isoforms ( ⁇ , ⁇ and ⁇ ) have been identified.
• the ⁇ -isoform of MFR is overexpressed in specific, types of cancer (ovarian cancer) while the ⁇ -isoform is a secreted protein from haematopoietic cells.
• Selective expression of FR- ⁇ isoform has been described on activated macrophages in inflamed synovial fluid of RA patients and animal models of arthritis. Subsequently, FR- ⁇ was recognized as an attractive target for imaging of arthritis and therapeutically for selective antibody- guided or folate-conjugate guided delivery of toxins and other small / macro- molecules.
• targeting of FR with folate antagonists has only been explored on cancer cells / tissues overexpressing FRa.
• second generation of folate antagonists has been designed and clinically evaluated from a perspective to circumvent common mechanisms of resistance to MTX, including impaired transport via the RFC, defective polyglutamylation, increased activity of the target enzyme DHFR and/or enhanced drug efflux.
• second generation antifolates included compounds that were more efficiently transported via RFC, were more efficiently poly- glutamylated or independent of polyglutamylation, or target other key enzymes in folate metabolism other than DHFR, e.g. thymidylate synthase (TS) or glycinamide ribonucleotide transformylase.
• TS thymidylate synthase
• glycinamide ribonucleotide transformylase e.g. thymidylate synthase (TS) or glycinamide ribonucleotide transformylase.
• Folic acid was obtained from Sigma Chem. Co, St. Louis, MO, L-leucovorin from Merck Eprova, Schaffhausen, Switzerland, methotrexate from Pharmachemie, Haarlem, Netherlands and Pemetrexed / ALIMTA ® (Eli Lilly) via the VUmc pharmacy department.
• the following folate antagonist drugs were obtained from the indicated companies / institutions; Raltitrexed I Tomudex ® / ZD 1694 (AstraZeneca, UK), PT523 and PT644 (Dr. A.
• Wild type Chinese Hamster Ovary (CHO-WT) cells CHO cells transfected with FR- ⁇ (CHO-FR- ⁇ ) and human nasopharyngeal epidermoid KB cells, expressing FR- ⁇ (American Type Culture Collection, Manassas, VA) were grown in folic-acid- free RPMI 1640 medium (Gibco, Grand Island, NY), supplemented with 10% foetal calf serum, 2 mM L-glutamine, 0.15 mg/ml proline and 100 units/ml penicillin and streptomycin.
• [ 3 H]folic acid binding capacities of CHO-FR- ⁇ and KB cells were 0.5- 1 pmol/10 6 cells and 20 ⁇ -0 pmol/10 6 cells, respectively.
• Human monocytic- macrophage THPl cells (American Type Culture Collection, Manassas, VA) were grown in RPMI 1640 medium (Gibco, Grand Island, NY) containing 2.2 ⁇ M folic acid, supplemented with 10% foetal calf serum, 2 mM L-glutamine, 0.15 mg/ml proline and 100 units/ml penicillin and streptomycin.
• AU cell lines were kept at 37 °C in a humidified atmosphere containing 5% CO 2 .
• synovial tissue samples In this study we analysed synovial tissue biopsies derived from the knee joints of 15 RA-patients with active disease before treatment and after 4 months of treatment with MTX (starting dose of MTX: 7,5 mg/week; increasing stepwise to 15 mg/week over 12 weeks). Active disease was defined as > 6 swollen or tender joints and levels of moderate or worse on the physician's and patient's assessments of disease activity (Disease Activity Score-28; DAS-28). AU patients had at least 1 clinically involved knee joint. Low dose prednisone ( ⁇ 10 mg/day) and concomitant stable doses of nonsteroidal anti-inflammatory drug (NSAID) treatment were allowed. None of the patients ever used MTX before enrolling the study.
• NSAID nonsteroidal anti-inflammatory drug
• Macrophages and T-cells were stained with 3A5 (dilution 1: 100) and anti-CD3-PE (dilution 1: 25; Dako, Glostrap, Denmark) monoclonal antibodies (isotype control: mouse immunoglobulin), respectively.
• Biotinylated swine anti-rabbit IgG (Dako; dilution 1:200) and rabbit anti-mouse IgG (Dako; dilution 1:300) were used as secondary antibodies.
• Colour development was performed using 0.4 mg/ml AEC (aminoethyl carbazole). After counterstaining with haematoxylin, slides were mounted.
• CD68 was detected by goat-anti-mouse biotinylated antibodies (dilution 1:100; Dako,
• Vectashield containing 1 ⁇ g/ml DAPI (for staining of nuclei) (Vector Laboratories Inc., Burlingame, CA). Cells were examined using a fluorescence microscope (Leica
• Peripheral blood mononuclear cells were isolated from freshly obtained blood samples by gradient centrifugation (35 minutes at 400 x g) on Ficoll-Paque Plus (Amersham Pharmacia Biotechnologies, UK). After centrifugation the interphase was carefully collected and washed 3 times using Phosphate Buffered Salt solution (PBS) supplemented with 1% BSA. The lymphocyte fraction was counted and resuspended in IMDM culture medium (hivitrogen, Breda, Netherlands) which contained 10%
• RNA extraction or macrophage differentiation by culturing the monocytes for 7 days in the presence of 10 ng/ml Macrophage Colony Stimulating Factor (M-CSF)
• Peripheral blood lymphocytes (PBLs) remaining in suspension after monocyte adherence were collected for RNA isolation or used for T-cell activation by incubating them at a density of 1 x 10 6 cells/ml with monoclonal anti-CD28 (5 ⁇ g/ml, CLB-CD28/1, Sanquin, Amsterdam, Netherlands) and anti-CD3 (1 ⁇ g/ml, CLB- T3/4.E, Sanquin, Netherlands) in goat anti-mouse (Dako, Glostrup, Denmark) coated 24 well plates. After 48 hours stimulation, activated T-cells were harvested for RNA isolation and the activation status was determined by measuring CD25 expression using flow-cytometry (FACScalibur, Becton & Dickinson). FR- ⁇ mRNA expression in synovial tissue and peripheral blood cells of RA-patients
• RT-PCR Real-time reverse transcription-PCR
• the reverse transcription step was carried out using Taqman Reverse Tran- script Reagents from Applied Biosystems (Foster City, CA), following the protocol of the manufacturer. Briefly, 400 ng of total RNA was mixed with random hexamer primers (50 ⁇ mol/L), RNase inhibitor (1 unit/ ⁇ L), MultiScribe reverse transcriptase (5 units/ ⁇ L), and deoxynucleoside triphosphates mix (2.5 mmol/L each) in reverse transcriptase buffer. The 10- ⁇ L reaction mixture was first incubated at 25 0 C for 10 minutes, then at 48 °C for 30 minutes and finally at 95 °C for 5 minutes.
• the subsequent real-time PCR step for FR- ⁇ was carried out in the presence of 12.5 ⁇ L of PCR Mastermix (Applied Biosystems), 0.5 ⁇ L each of forward and reverse primer (CTGGCTCCTTGGCTG-AGTTC, ' GCCCAGCCTGGTTATCCA), and 0.5 ⁇ L of Taqman probe ( ⁇ FAM-TCCTCCCAGACTACCTGCCCTCAGC- TAMERA).
• the primers and the Taqman probe for control GAPDH gene were purchased from Applied Biosystems.
• the PCR conditions were 2 minutes at 50 °C, then 10 minutes at 95 °C, followed by 40 cycles of 15 seconds each at 95 0 C, and finally 1 minute at 60 °C. Fluorescence data generated were monitored and recorded by the Gene Amp 5700 sequence detection system (Applied Biosystems). All samples were set up in triplicate and normalized to GAPDH values.
• Detached cells were suspended in ice-cold HEPES-buffered saline (140 mM NaCl, 20 mM HEPES, 6 mM KCl, 2 mM MgCl 2 , 6 mM D-glucose, pH 7.4 with NaOH) to a cell concentration of 3 x 10 6 and 1 x 10 6 cells/ml, respectively.
• HEPES-buffered saline 140 mM NaCl, 20 mM HEPES, 6 mM KCl, 2 mM MgCl 2 , 6 mM D-glucose, pH 7.4 with NaOH
• 3 x 10 6 and 1 x 10 6 cells/ml respectively.
• One ml of cell suspension was added to a series of Eppendorf tubes containing 100 pmol [ 3 H]-folic acid (specific radioactivity: 2,000 dpm/pmol) in the absence or presence of increasing concentrations of natural folate or folate antagonists.
• CHO-WT and CHO-FR ⁇ cells were seeded in individual wells of a 24- well tissue culture plate at a density of 1 x 10 4 /cm 2 . After 24 hours, 8 concentrations (with 2.5 -fold increments) of folate antagonist drags were added in the absence or presence (to block FR) of 1 ⁇ M folic acid. After 72 hours incubation, cells were harvested by trypsinization and counted for cell viability as described before. See MoI. Pharmacol. 1999; 55(4): 761-769 (Jansen et al).
• FR- ⁇ mRNA levels were determined by PCR analysis in synovial tissue biopsies as com- pared to those in peripheral blood cells of RA-patients, including lymphocytes, ex vivo activated T-cells, and peripheral blood monocytes and ex vivo monocyte-derived macrophages. FR- ⁇ mRNA levels were presented relative to CHO-FR- ⁇ cells (set at
• Binding affinities of FRa for selected folate antagonists were previously reported by Westerhof et al. but to what extent they overlap ' or differ for the FR- ⁇ isoform has not been established. To this end, binding affinities by FR- ⁇ versus FRa for a series of folate-based inhibitors of DHFR, TS and GARTFase were determined and shown in Figure 4. With respect to folic acid, both FR- ⁇ and FRa displayed a rather low affinity for the group of folate antagonist inhibitors of DHFR. Binding affinity of FR- ⁇ for MTX is approximately 50-fold lower than for folic acid.
• PT523 The binding affinity for PT523 is markedly lower than for MTX (0.3% of folic acid) while PT644, the 5-methyl analogue of PT523, showed an affinity comparable to MTX.
• FR- ⁇ exhibits a good binding affinity for all tested folate-based TS inhibitors, but binding affinities of FR- ⁇ for pemetrexed, raltitrexed and BGC 9331 were markedly lower (16-30 fold) than for FRa. Retention of a high binding affinity of FR- ⁇ was observed for the TS inhibitors CB300635 (161% of folic acid) and (6RS)- BGC 945 (89% of folic acid) and (6S)-BGC 945 (46% of folic acid).
• FR- ⁇ also exhibited a proficient binding affinity for the GARTFase inhibitors DDATHF (27% of folic acid) and AG2034 (54% of folic acid) even though FRa binding affinities for these compounds were 2.5-fold higher. Together, these results demonstrate a broad differential in binding affinities of FR- ⁇ for folate antagonists, among which several folate antagonists revealed a markedly higher binding affinity than for MTX.
• Folate antagonist induced growth inhibition of FR- ⁇ expressing cells To investigate whether the folate antagonists used in the current study would all convey a potential growth inhibitory effects against macrophage-like type of cells, this parameter was investigated for human monocytic-macrophage THPl cells (Table 1). Consistent with RFC as the dominant transport route in THPl cells, potent growth inhibitory effects were observed for all folate antagonists, except CB300635 and BGC 945, two compounds that have a poor affinity for RFC.
• THPl cell line model is FR-negative (in contrast to activated synovial macrophage)
• three folate antagonists for which FR- ⁇ displayed the highest binding affinity were evaluated for their potency to target FR- ⁇ by provoking cell growth inhibition of CHO-FR- ⁇ cells.
• BGC 945 Against CHO/WT cells, BGC 945 only induced growth inhibition at extracellular concentrations > 1000 nM ( Figure 5A). Remarkably, growth inhibition of CHO/FR- ⁇ cells was induced at markedly lower concentrations (10-50 nM) of BGC 945. The addition of folic acid to these cell cultures completely abrogated the activity of BGC 945, consistent with a blockade of FR.
• MTX is the anchor-drug in many therapeutic regimens for RA treatment
• delineation of genetic, biochemical and metabolic parameters that could assist in predicting and/or improving the therapeutic response to MTX have received con- siderable recent interest.
• This study focused specifically on the role of cell membrane transport of MTX, which, in activated synovial macrophages, is mediated predominantly by the folate receptor ⁇ isoform.
• FRs and the constitutively expressed RFC differ considerably, a better understanding of the properties of FR- ⁇ may facilitate a better therapeutic window by selective targeting of FR- ⁇ over RFC.
• FR- ⁇ expression primarily co-localized with macrophages in the intimal lining layer and the synovial sublining of RA patients and may therefore be an attractive target for folate antagonists.
• FR- ⁇ In addition to folate-based TS inhibitors, FR- ⁇ also exhibited moderate to high binding affinities for folate-based GARTFase inhibitors (AG2034 and DDATHF) which classifies them as folate antagonist drugs that can be transported both via RFC and FR.
• AG2034 and DDATHF folate-based GARTFase inhibitors
• FR- ⁇ -transfected CHO cells were used as a model system to evaluate the efficiency of FR- ⁇ -mediated cellular uptake of folate antagonists by conveying antiproliferative effects.
• This cell line mo . del may be clinically representative, based on [ 3 H]-folic acid binding levels and FR- ⁇ mRNA levels that are compatible with FR- ⁇ mRNA levels in synovial tissue of RA patients (Fig. 4).
• the largest differential in activity between control (RFC-expressing) CHO cells and FR- ⁇ transfected cells was observed for BGC 945, consistent with a poor affinity for transport via RFC and a high FR- ⁇ binding affinity.
• FR- ⁇ mediated uptake of BGC 945 could be inhibited by blocking of the receptor with excess folic acid, implying that circulating natural folates in synovial tissue / plasma could attenuate the potential activity of BGC 945 in vivo either by receptor occupancy / competition or by receptor down-regulation.
• Table 3 shows the structures of the following compounds of the invention:
• Maize starch paste (5% w/v paste) 2.25
• Citric acid 0.38% w/v
• the above formulations may be prepared by conventional procedures well known in the pharmaceutical art.
• the tablets (a) to (c) may be enteric coated by conventional means, for example with a coating of cellulose acetate phthalate.

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