l A
`
`
`
`i Bi_oavailabi1ity of Higher Dose Methotrexate
`Comparing Oral and Subcutaneous Administration in
`Patients with Rheumatoid Arthritis
`
`MONIQUE HOEKSTRA, CEES I-IAAGSMA, CEES NEEF, JCIHANNES FROOST, ANTONIUS KNUIF,
`and MART van tic LAAR
`
`A3573-‘ICT3 Ollivufiive. To dcturminc tho bioavailability of l]lglJ.E!' oral dorms of mothottcztutc (MTPC) in adult
`patients with rheumatoid :u'thIiti5: (RAJ.
`Methods. A phnrmaccltinctic analysis was performed in 15 patients with RA taldng it stable dose of
`T.\*I'I‘2~.’." (2 E5 mg wcoldy). Separated by 2 weeks, :1 phnmmcckinetic analysis was pcrfonned in crush
`pationl aflcr oral and subcutaneous administration of the sumo dean of MTX. MI’); scrum cocoon»
`nations were maasumcl by z: fluoreaccnce polarization immunoassay. Phannacukjnctic: analysis: was
`pcrformcrl with an iterative: 2~—stetgc Bayesian population procedure, obtaining population and indi«
`vidual. pliarmacckinrztic parameters.
`Rcmlm. Tho mcdinn M1132 do!-to wins 30 mg weakly (range .2540 mg). A 2~com_pa.ttmcnt modcl boat
`dcscrihcd the serum MFR conccntmtion Vernon time curvcs. The moan hioavnilahilily after oral
`MTX was 0.l54(r:1ngo 0.2l««»0.9l:'i) compamd to subcutaneous: ndminimtmtion. Thorn was a rttntjsticnlly
`significant diffcrcnco in that hionvnilnbillty of the R ndrninintrzttion rogimcntl
`floncluxinn. Elioavailnlrrility BTW! higltczr oral dose of MTX in adult pnticnts with RA. is highly vnr.i«
`nb1¢.‘a.nd on nvcragc two-thircln that of this subcutaneous aclministmtlon. To impmvo cffi.<:acy of
`MIKE»: at dosages of 2.5 mg wccldy or morn, :1 change: to parcnternl adndnitttration should hr: commit!»
`cred. (J lthoumntol 20€lI4:3J.:lS45——8)
`
`my Indexing Tamar.‘
`METHOTREXATE
`
`PHARMACDKJNEWC5
`
`REIEUMATOID ARTHRITIS
`
`Mcthotrmcate: (i'vITK)iis commonly used in weekly tingle-
`dose: regimens in the theattnont cf‘ rlicumatoid arthritis (RA).
`A rIosc«cl’fcct rolationj war: cctnblichcd For clones of 'l.5~2‘5
`mg per wank”. In clinical trials in RA. the MTX close in
`lncrcnscd up to 25 mgitvccldy, until efficacy is rcnchcd. It is
`not clccr whcthot‘ cvcii higher oral doses of MTX are more
`cffcctivc. Efficucy of high intravenous doses of MTX
`(4{l~«500 mg/mi),
`in Q patients: with refractory RA, was
`dcscribcd in several 9.thtiics3‘5_
`The hioavrrilahilityl of oral MTX could he a limiting
`factor for its czfficacy. Qra] MTX in absorbed in the proximal
`intestine by El spccithtransport mechanism. and a rclation
`between dose and ab5orpti,on of oral MTX was observed in
`2 clinical studies”. lPharm-acokinctic studios in adult
`
`
`patients with RA show comparable bioavailnlizility oi’ oral
`and parcntcrnl MTK in doses up to 25 mg weekly”. In
`these oludicn rhc mean rclativr: bionvailahility of oral M'I‘ll{,
`compared to intramutcular adnilnisuntion. ranged from 035
`to 1.0. In other atlldifisi using 15 mg MTX and 10 mglmi
`I\-'ITX. bionvailability of oral compared to intravenous l\-TTX
`was 0.67 and 0.70, rcspcctivcl.y“"3. In 3 comparison of 25
`mg MTX. the mean bioawnilahility after oral administration
`was 73% compared to the intravenous route”. Despite the
`in1prcssi_r_m given by a few rmclics”-”‘, it is not certain that the
`bioavailnhility of intravenous, inrramuccillar, and subcuta-
`neous IVITX is strictly comparable.
`Pharmacokinctic studios in patients with malignant
`diseases haw: shown that the absorption of higlicr dcscoof
`MTX (2 25 mg wcclrlyl is incomplete‘-'5'“. The relative
`hinavaiilahility of 40 rngfml oral MTX in Fl: study in children
`with acute Iymphohlastic lculcemia was 42%;
`in adult
`patients with solid tumors using 15 mglmz MTX this was
`57%”“7. Another study in 15 children” showed a. decreased
`absorption of oral MTX at doses :» 12 mglmi. However, the
`results: of pharmacokinetic studies in disorders other than
`RA, and even more so in children, cannot be extrapolated to
`adult pationts with RA.
`Although a clear. relation between pharmacokinctic para:
`meters and cfficacy has not been dcn-mnstratcd in‘1l3.A,
`it
`seems lilszcly that
`improvcmcnt of the bioavai]ahI,l1ty of
`MTX will load to better cfficncy, given that dose—ct‘fcct rela-
`
`
`F."tmi tire‘ JfJupa.='l1r:r_:ni‘ ofK&r:i¢4matolug}‘, and the Department rJfCI;'n.El:'a{
`Phamra-rology, Mcdisch Spccrmm Zlwmr.-r, Em-shade; and the ,Dc-pammenr
`rJ_l”Pf:arntaca.l:inerr'cs am‘ Dnlig Dr.-livery, Urrr't=er.u'ry Conn: jicr .F"hurmr:It’.‘;v.
`Gmningcn. The Netherlands.
`M. Hoglln-rm, MD, Riummatalogisr; CJ. Hangman MD, RIteuma:'o!ogz'st.-
`M.:'l.FJ'. van de Lam: MD, Rhnumaralogisr. Department r>_fRhe'unIal0log_}'.
`Mndi.n-:1: Spcctmm Manic.’ 112'. Ncefi PFID, Hospital Phammctm A..f.H.
`Karo): Phamrac-euziml Analyst. Department of Clinical Phannacclogy.
`Medtrch Sprcrmm 2'lvente.' .l.H. Pmcsl. PHD, Pltammcrlfl-'. Dffldfllfleflf flf
`Phamacokinrrics and Drug Deliwrja. Urtt"w:r3r'l}r Cenrrofar Phamacu
`-fld4'n=.t.s reprint mqnerr: to Dr. M‘. tram-ira, Depar-mtenr of
`Rh:-nmaioraggi. Mada-ch Sperm-um In.-euro, PO Box 50000. ‘.7500 EA
`-E'rr.rchea'e. The Netherlands. E-mail.‘ m.h-avclcsrra@ziarkrnhui.r-rm-:.nr
`-'$'ubm:'rmd May 22, 2003; ruirision acccprcd tJr:>‘ober2?, 200.3.
`
`Haclcrrrtr. or or‘: mmvnllcbilinv of M‘.‘l‘?l'
`
`
`
`Page 1 of 3
`Page 1 of 3
`
`M5
`
`ANTARES Exhibit 1004
`
`ANTARES Exhibit 1004
`
`

`
`lion‘-2' This idea is supported by n study in patients with
`psoriasis in which a relation was found bctwccn the area
`under the curve of the time. versus .MTX concentration and
`a decrease in the Psoriasis Activity and Severity Index
`{PASI)"-‘.
`
`The bioavailability of higher MTX doses can be
`improved by parenteral adrm'nistraxion.'1"o study this option,
`W5 Ptnfonned a crossover pliaunncokinetic study in adult
`patients with RA. comparing the bioavailahiiity of oral and
`subcutaneous MTX at doses 3 25 mg wee.l:ly..
`
`tr.-nion (Cm) were eoictilntcd from use model parameters for cash paticm,
`-3'-'d'rr'.rt:'-:dn' anolv.ri.v. To compare the values of the phsrrnnookinotic pnr-“um.
`turn nftlle oral and subculnncotm route of mlminisrrstion. 3 s.i;mi:ri.i-nnl; [N
`was empl-.oyea,1.A Znsidetl p Vnllle -r 0.05 was cnnsidnrcrl sl'gniEir_'nnt..
`
`RESULTS
`
`Fifteen patients with RA were studied. fa.ti.ent charnotcris.
`ties are presented in Table l.A1i patients received folio acid
`supplementation in varying doses (54.5 mg weekly), bur
`not on the day of
`intake. Three patients concurrently
`used hycltoxychloroquine, one chloroquine, one sulfasa.
`lazine, and one aurothiom-slate. Low dose predrtisolone
`(E 10 mg daily‘; was used by 8 patients. and NSAID by 11
`patients.
`A 2-cornpartmeni model fitted significantly better to the
`data than a one~eon'1partrnent model {MC value -350 and
`-956 for the one» and 2-compartment model. respectively).
`The mean ‘bio.=.wailal3ility (F) was 0.64, with a rnthcr large
`range from 0.21 to (3.96. The pltarrnacoionctic parameters
`with paired statistical axialysis are shown in 'I‘abl.e 2. The
`AUC of oral MTX was significantly lower than the AUC of
`the subcutaneous route of administration (13 -e: 0.00.1). The
`fitted mean t'Ln1e—coneentration curves of oral and sub:-.uta—
`nsous administration are presented in Fignro 1.
`
`DISCUSSION
`
`The lnoavailability of oral MTX (:2 25 mg weekly) was
`highly vanable. and was significantly less emnpared to
`smbcutaneously administered MT}: in patients with RA. It
`varied between 0.2! and 0.96, with a mean of 0.64.
`In the design of our study comedication was continued,
`and patients were allowed to have breakfast at home before
`coming to the hospital. Because of the time between comed-
`icaiion, breaicfast. and MTX administration. an effect on
`MIX absorption is unl.ikr:ly. Further. the effect of food has
`been extensively atudiod and no effect on MTX absorption
`was foundii”.
`
`The majority of pharrnaeoltinotic studies in adult patients
`with RA have used low doses of MTX. In studies using
`MTX doses of 7.5 to so mg weekly. bionvailability after oral
`compared to parenteral. administration ranged from £1.67 to
`1.Cl"*‘3. Only one study compared 25 mg oral and intra-
`venous MTX, in 18 patients with rheumatic cl.i.sc.as-as". The
`oioavailability of oral MITX was 0.73. somewhat higher than
`what we found. but in our study most patients need higher
`
`MATERIALS AND METHODS
`Patients and MTX administration. Patients with RA. who were treats-.d with
`MIX in a stable (1: 3 months) dose of 2 25 mg wookly, oral or parenteral.
`were studied. Consecutive outpatients fulfilling those inclusion criteriit
`were invited to pznticipate. Th£:1|1lci.\lBl.i‘liCfi committee approved the study
`and written inforrnocl consent was -utltainetl From oacli patient.
`Baseline data wore gathered on diagnosis, age. sex. disease duration.
`dose, serum crnstinine. folio acid supplementation. and use of disease
`modifying antirlleutrlfitio drugs {D13-lA.RD),. nonsteroidai antiinllommatory
`dmgs {NSAJD}. and prednisolnne. Pharmacokinctios were studied twice in
`each patient with n 2—woelt interval: once with their regular MTX close by
`oral route of administration. and ones with the same dose oi‘ MTX by
`subcutaneous administration in random order. Folic acid supplementation
`was allowed. but not on the day of MTI'X intake. Leulcoponin, thrombo-
`eytopenia, and transnrninaso elevations were masons for exclusion.
`Patients were admitted in the hospital
`in the rooming. ‘They were
`nllnwed. to have breakfast at home. at least 1.5 hour hefovn: MIX intake.
`Comodication was continued during both sampling episodes. Dtnsr
`DMARD and prodnisonc were allowed. with stable doses throughout the
`shady. The concurrent medication was taken at least 1.5 hour before and
`more than 2 boon: after MTX intake. Urnl MT): was administered with
`wator. MTX was injected sxxbeutaneously in tho upper leg in .111 patients by
`the examinsr. Blood samples were drawn frum an indwelling catheter at
`Time. 0 iptoadminislrationl and at 0.35, 0.5, 0.75. L0. L25. L5, 2, 4. 6. ii.
`ll 24. and 48 h after axlntinistrntion of M'.l‘X. The blood samples were
`centrifuged and the serum stored at 40°12 until analysis.
`MT.-"i array. MTX serum concentrations were determined using a fluores-
`cence polarization immunoassay teelinique (M'I'XII: list no. 7312. "PBX-
`hblziott Diagnostic-s_. North Chicago. IL. USA)“. Tho lower detection limit
`was ll) pgil. At ll? ugil the coefficient of variation of the lost is 15%. The
`standard deviation (SD) oi‘ the test is described by the formula: SD .= 4.76
`+ I'.l.05*IC, where C >2 concentration.
`Pnormocnkinnric analysis. The MT}: concentration data of both adminis-
`uudons .fi'cvrn all patients were analysed sirnultanoouslfpr by an iterative 2m
`stage Bayesian analysis using the pmgnam MW\Phann. version 3.543%”.
`The nhannaookinefie model was 3. nnecompartment (parameters 1:4,. V,) or
`a Zrcornpartrnent model (parameters |r_._. V,, kn. km). with firm»-order
`absorption with a lax-tinne for oral, and a.ulrcnL-anac-‘cs adruitlistfafiflfl. with
`parmnerors F (blosvsilability). ls, [absorption rate constant). and TM (lag-
`time) for each route of adminristrntion. Since absolute bionvallahility cannot
`be -assessed \vitbnut an intravenous reference ndrriinistraiion. the analysis
`was performed assuming that lwinnvnilability of the subeutannous :iclm.inis—
`tration was soon. Measurement data. were woighted noemding to the reci-
`pmcal of their vafiance (115119). A lOg~l‘.Iui'l',r1sl distribution for the
`phmnncflkinetic population pannnctors was assurnod. Goodnesa«oi’~fit was
`evaluated from visual
`inspection of the measured and calculated ilatn
`points. The choice between :2 une~ nnd 2-cornpanrnent model was tassod on
`Alcailnrs Information Criterion (.nlC2)'*"‘.
`MEX clenmnw (CL), 1.-olumo of distribution (Vi. elimination iIalI'.”—lii'd:
`(W2). and for men route ofodminisontion the area under the oonoentmlion-dmc
`profile (AUC). tin-to to maximum concentration WM}. and maximum r:o'nl:r:n—
`
`
`Tobie 1, Patient charzaoterirtlos in re 15: 11 women. 4 men}.
`
`
`
` Median Range
`
`3i»-':'
`6‘!
`Age. yrs
`2-42
`7
`Disc.-we duration. yrs
`63-4 I II?
`75
`Weight. kg
`57-124
`80
`Creatininc clearance. mlfmin
`15-40
`30
`Dose. mg weekly
`0.21-0.57
`9.40
`Dons. rngflcg
`_&_&m
`
`645
`
`The Jonmal of R.hnunmtoi-my 2004'.‘ 3! :4
`
`Page 2 of 3
`Page 2 of 3
`
`

`
`jrg.-'«.l-E‘ 2. Pltnfinaeokinetic pnrtlmetets of oral -.t11cI sttlmutztnctous route oi".-tdminislrtttinrt {n = I5). Signed-mnk_ test. p vulut: r. 0.05 islsignitim.-1nI:.
`
` .-'-\.UC Lagdime ks Trw Cm“ V I V k I2 R21 kt‘. CL t‘/n cl
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Stthctutanwui
`
`0:111
`
`,,,......
`'3
`
`0.36
`.2466
`(0.18)
`[7353
`0.06
`3736
`(0.05)
`[373]
`—..-..—_......._,..,,,w,,,,,,,,.
`0.001
`wt: 0.001
`
`594
`I .2
`0.87
`(208)
`(0.3)
`(0.29)
`5 I 9
`1 .7
`0.35
`(I42)
`(0.3)
`(0.10)
`—n—«———-u——a.——.—__——_-—.¢—......p.—m...,,..m.....,....,w..,..
`as 0.00]
`0.001
`0.30
`
`91”:
`(2.0)
`
`34.5
`(3.1)
`
`0.31
`(0.31)
`
`l.l.55
`(0.04)
`
`0,83
`£0.11.)
`
`8.4
`(2.2)
`
`2.9
`(0.5)
`
`Ill
`
`values an: mean [standard deviation). NJ‘-T: area under curve (045 hours=}in1t~ugIl:lsg-time in hours; Ira: absorption rate constant; Tm; time to maximum
`concentration (hours); Cm“: maximum coneentmtion (pg/I); V1: volume of dintvil:-utiotzt of first eornpattmentg V-, volume of cl'1st.ritmtion (liter); K12; rate
`constant of transport between comnartmertt 1 and 2', lull: rate constant of transport between cnmpeltmcnt 2 and 1'. Ice: elimination rate constant: CL: total
`bqcly clearance (literlhnutjt ti/2 cl: half-lire of elimination rjtottrsl.
`
`§
`
`sa-8
`
`Sfrxzmteennafientzoiezngals‘§§
`
`
`
`time in hours:
`
`I-‘igrms J’. Plnsmtt concentration-time curves of oral (or) and subcutaneous
`fSc)TI:IEI‘]1mI‘ext‘t|t'.‘:. Values are menus.
`
`closes than 25 mg.
`When we compare our data to other studies using higher
`dose IVITX (iv 25 mg), only phamtaeoklnctie studies in
`patients with malignancies are available. In these studies
`wide variability in MTX absorption was observed, and
`therefore split-dose regimens have been tried. to improve
`bioavailability”. A comparable investigation is the study by
`Freernat1—Narrod, er al. Doses of 15 mg/mi (25-35 mg) were
`used in adults with solid tumors. Eighteen patients received
`this dose by both oral and intramuscular adtninistratifim. The
`mean cumulative AUG up to 24 11 was higher with the intra-
`muscular route. and the mean oral bioavailahility was
`0.5'i'”'.
`
`effect. Decreasing l:pioavailnbi..lit_v with an increasing close
`favors an absorption limitation. The number of patients in
`our study with different MTX doses was too small to draw
`conclusions about «ll. dose-biotwsilahility relation. However.
`there is a positive relation between the subcutaneous AUC
`and the close of MTN (linear regression; R’ as 0.33, p m
`0.03]. whereas the oral AUG does not increase with no
`increasing dose. Plentilten. er of studied 21 RA patients on
`more oeeasi.ons. They found a decreasing hioavailsbillty
`with an.inc1"essing oral close, mean maximum dose being 1’?
`rngfwee-it‘. These results support the idea of an absorption
`llrnitntion of oral MTTX with an increasing dose. The finding
`of higher bionvailability of oral split high dose IWTK.
`compared to it single dose, in patients with solid tumors“
`supports it reduced hioavuilnbility due to an absorption limiw
`t.atl.ot1. However, to pursue this question for the MT): doses
`we use in RA, an additional. study is needed that directly
`compares :2 single-dose with 31 spliedose regimen.
`Although controlled trials studying the effect of higher
`doses of MTX are lacking, higher closing of MTX may be
`clinically useful. A dose escalation. study in 54 patients with
`RA concluded that increasing the intzramuscular MTX dose
`from 15 to 45 reg weekly did not result in improved disease
`controlzfi. However, the number of patients was small, and
`detailed data about baseline disease activity scores were not
`provided. In our opinion, additional controlled trials are
`needed to evaluate the effect of higher doses of MTX. which
`are in fact widely used in 1-heurnatolegy practice. In our
`observational study of it/.l'I‘}': use in 1022 RA patients, we
`found that 12% of the patients reached a maximum dose of
`E 25 mg weekly (maximum 40 mg weekl.y)=7.
`Our data suggest that closes between 2.5 and 40 mg M175
`per week. administerecl orally, result in liniited l:aioavail-
`ability. Bioavailability is enhanced by the subcutaneous
`route of administration, and this may increase efficacy.
`
`We analyzed the data assuming first-order absorption
`after a lag-time, which may be a simplification of the true
`absorption kinetics. In general a difference in AUC between
`oral and subcutaneous administration of medication could
`
`REFERENCES
`l. Furst DE. Kneltnlcc R. El-urmeister LF. Kchler J , Cat-gill I.
`Incmasinp; mcthetrcxste effect with increasing dose in the treatment
`cfrcaistant rheumatoid arthritis. J mteiimstol lil89:l6'.3l3-20.
`first-crass
`be due to either an absorption lhnitation or it
`5;. Saidemnn Iv. Meuann-cumin —- the retaticnsnip between dose and
`
`
`H'a:k.l'tm. at at: Biadvdilnbliity cf'MT‘X
`
`64.7
`
`an
`
`“
`
`Page 3 of 3
`Page 3 of 3