`AND THERAPEUTICS
`Volume 12, Number 4, 1996
`Mary Ann Liebert, Inc.
`
`The In Vitro and In Vivo Ocular
`Pharmacology of Olopatadine
`(AL-4943A), an Effective
`Anti-Allergic/Antihistaminic Agent
`J.M. YANNI, DJ. STEPHENS, S.T. MILLER, L.K. WEIMER,
`G. GRAFF, D. PARNELL, L.S. LANG, J.M. SPELLMAN,
`M.T. BRADY, and D.A. GAMACHE
`Allergy/Inflammation Research, Alcon Laboratories, Inc., Fort Worth, Texas
`
`ABSTRACT
`
`Olopatadine (AL-4943A; KW-4679)
`[(z)-ll-[3-(dimethylamino)propylidene]-6,ll-dihydro-
`dibenz[b,e]oxepine-2 acetic acid hydrochloride]
`is an anti-allergic agent which inhibits mast cell
`mediator release and possesses histamine H, receptor antagonist activity. Studies were conducted to
`characterize the in vitro and in vivo pharmacological profile of this drag relevant to its topical ocular
`use. AL-4943A inhibits histamine release in a concentration-dependent fashion (IC50 = 559 pM) from
`human conjunctival mast cell preparations in vitro. Histamine release was not stimulated by
`AL-4943A at concentrations as high as 10 mM.
`In contrast, ketotifen stimulated histamine release
`at concentrations slightly higher than effective inhibitory concentrations. AL-4943A did not display
`any in vitro cyclooxygenase or 5-lipoxygenase inhibition. Topical ocular application of AL-4943A
`effectively inhibits antigen- and histamine-stimulated conjunctivitis in guinea pigs. Passive
`anaphylaxis in guinea pig conjunctiva was attenuated by AL-4943A applied 30 min prior to
`topical ocular antigen challenge (ED50 values 0.0067% and 0.0170%, w/v,
`intravenous or
`respectively). Antihistaminic activity in vivo was demonstrated using a model of histamine-induced
`vascular permeability in guinea pig conjunctiva. AL-4943A applied topically from 5 min to 24 hrs
`prior
`to histamine challenge effectively and concentration-dependently inhibited the vascular
`permeability response, indicating the compound has an acceptable onset and a long duration of action.
`Drag concentrations 5-fold greater than those effective against histamine-stimulated conjunctival
`responses failed to inhibit vascular permeability responses induced with either serotonin or
`Platelet-Activating-Factor.
`These data indicate that
`the anti-histaminic effect observed with
`AL-4943A is specific. These anti-allergic/antihistaminic activities of AL-4943A observed in
`preclinical model systems have been confirmed in clinical trials in allergic patients.
`
`INTRODUCTION
`
`Olopatadine (AL-4943A; KW-4679)
`[(z)-ll-[3-(dimethylamino) propylidene]-6,ll-dihydro-
`dibenz-[b,e]oxepine-2 acetic acid hydrochloride] is an anti-allergic/antihistaminic agent synthesized
`(1) and under development by Kyowa Hakko Kogyo Co., Ltd., for the treatment of bronchial asthma,
`
`389
`
`APOTEX EX1005
`
`Page 1
`
`
`
`AL-4943A's anti-allergic efficacy following systemic
`allergie rhinitis and chronic urticaria.
`administration has been demonstrated in rat and guinea pig models of immediate hypersensitivity
`Inhibition of passive anaphylaxis persisted for 9 hrs following oral administration of
`(1,2,3).
`AL-4943A (3) indicating a prolonged duration of action.
`In vitro receptor binding studies have
`demonstrated the affinity of AL-4943A for the H,-histamine receptor (1,4,5). Additionally, these
`receptor and demonstrated a lack of
`studies have shown selectivity of AL-4943A for the H,
`significant interaction with alpha adrenergic, muscarinic, dopaminergic and numerous other receptors
`(5).
`the reported long duration of anti-allergic activity, coupled with selective
`Because of
`anti-histaminic activity, studies were undertaken to evaluate the utility of this compound for use in
`allergic conjunctivitis. AL-4943A's effects on human conjunctival mast cell mediator release, on
`cyclooxygenase and 5-lipoxygenase enzymes, and in models of allergen- and histamine-stimulated
`conjunctivitis following topical ocular administration were characterized. The results of those
`investigations are reported below.
`
`METHODS AND MATERIALS
`
`Inhibition of Histamine Release from RBL Rat Basophils
`
`RBL-2H3 is a rat basophilic leukemia cell
`line which secretes both histamine and serotonin
`upon degranulation. RBLs were passively sensitized overnight with IgE specific for dinitrophenol
`(DNP) tagged to bovine serum albumin according to Benacerraf and Levine (6). Cells were washed
`with PIPES buffer, and incubated for 15 min at 37°C with AL-4943A prior to challenge with antigen
`(DNP, 10 ng/ml). Supematants were analyzed for histamine content using a commercially available
`radioimmunoassay (RIA) system (AMAC, Inc., Westbrook, ME).
`
`Histamine Release from Human Conjunctival Mast Cells
`
`Human conjunctival tissue was obtained from organ/tissue donors. Upper and lower palpebral
`conjunctivas were aseptically collected within 8 hrs of death (average time 4.5 hrs) and transported
`in Dexsol® corneal preservation medium (Chiron Ophthalmics, hvine, CA). Conjunctival tissue was
`weighed and placed into a glass 20 ml screw-cap bottle containing culture medium (RPMI 1640)
`supplemented with heat inactivated fetal bovine serum (20%), L-glutamine (2 mM), penicillin (100
`units/ml), streptomycin (100 mg/ml), amphotericin B (2.5 mg/ml), and HEPES (10 mM). Tissues and
`medium were transferred to sterile petri dishes for overnight equilibration at 37° C prior to enzymatic
`digestion.
`Modification of a previously reported method for obtaining monodispersed cell suspensions
`containing mast cells (7) was employed using human conjunctival
`tissue. Briefly, tissues were
`transferred to Tyrode's buffer (in mM: 137 NaCl, 2.7 KC1, 0.35 NaH2P04, 1.8 CaCl2, 0.98 MgCl2,
`11.9 NaHC03, 5.5 glucose) containing 0.1% gelatin (TGCM) for enzymatic treatment. Tissues were
`incubated with 200 U each of collagenase (Type IV) and hyaluronidase (Type I-S) per gram of tissue
`for 30 min at 37° C. Following enzyme digestion, tissues were washed with an equal volume of
`TGCM over Nitex® filter cloth (Tetko, Briarcliff Manor, NY). Two digestions, completed as
`described above, were followed by additional digestion steps using 2000 U each of collagenase and
`hyaluronidase per gram of tissue for 30 min at 37° C.
`The filtrate obtained from each digestion was centrifuged (825 g, 7 min), and pelleted cells were
`resuspended in calcium/magnesium free Tyrode's buffer (TG). Pooled cells from all digestions were
`centrifuged (825 g, 30 min) over a 1.058 g/L Percoll® cushion. Mast cell enriched cell pellets were
`resuspended and washed in TG buffer. Viability and number of mast cells were determined by vital
`dye (trypan blue) exclusion and toluidine blue O staining of the harvested cell suspensions. Cell
`suspensions containing 5000 mast cells were added to TGCM containing tubes. The cells were
`
`390
`
`Page 2
`
`
`
`treated with test compound 15 min prior to challenge with anti-human IgE (10 pg/ml). The final
`volume per reaction tube was 1.0 ml. The release reaction was terminated by the addition of ice-cold
`TGCM and centrifugation (500 g, 7 min). Supernatants were collected and stored at -20° C until
`histamine analysis (described above).
`
`Inhibition of Cyclooxygenase In vitro
`
`Inhibition of cyclooxygenase activity from sheep vesicular glands by AL-4943A was assayed
`as follows: Lipid-depleted sheep vesicular gland microsomal powder (10 mg) was homogenized in
`ice-cold 50 mM phosphate buffer (pH 7.4) supplemented with 1 % Tween-20, 2 pM hematin, and 5
`mM diethyldifhiocarbamic acid. The solubilized microsomal preparation (10 pg) was added to the
`incubation chamber containing 3.0 ml 50 mM phosphate buffer (pH 7.4), 0.5 mM phenol, and 0.5 pM
`hematin and pre-equilibrated to 30° C. AL-4943A, dissolved in dimethyl sulfoxide (DMSO), was
`added to the incubation chamber. The mixture was stirred for 2 min before initiating the reaction by
`the addition of 30 pi of a freshly prepared aqueous solution of 10 mM ammonium arachidonate.
`Indomethacin, also in DMSO (s 30 pi), served as reference compound. Cyclooxygenase activity was
`determined polarographically by monitoring the rate of oxygen consumption, due to the conversion
`of arachidonic acid to prostaglandin H2 (8).
`
`Inhibition of 5-HETE and LTB^ Formation In vitro
`
`The potency of AL-4943A to suppress 5-hydroxy eicosatetraenoic acid (5-HETE) and
`leukotriene B4 (LTB4) formation was investigated in calcium ionophore (A23187)-stimulated neutrophils
`isolated from rabbit peripheral blood. Neutrophils from peripheral blood were isolated by standard
`procedures. Briefly, heparinized/calcium chelated blood was obtained from five New Zealand Albino
`rabbits by heart puncture. Red cells were removed at 4°C by dextran sedimentation (9). White cells,
`contained in the supernatant fraction, were sedimented by centrifugation and contaminating red cells
`removed by hypotonie lysis. The white cell pellet obtained following hypotonie red cell
`lysis and
`centrifugation was resuspended in Dulbecco's phosphate buffered saline (Ca27Mg2+-free). The cell
`suspension was layered onto a 60% Histopaque-1083/40% Histopaque-1119 cushion. The neutrophil
`pellet at the bottom of the tube following centrifugation was washed and resuspended in 1/25 the
`original blood volume. Aliquots of the cell suspension were pretreated for 5 min at 37° C with either
`carrier (DMSO) or test article dissolved in DMSO.
`Immediately thereafter, CaCl2 was added to the
`cell suspension and cells stimulated by the addition of 5 pi of a mixture containing [1-14C]-
`arachidonic acid and calcium ionophore (A23187)
`in DMSO. The final concentrations of CaCl2,
`[l-14C]-arachidonic acid and calcium ionophore were 5.0 mM, 52 pM and 5.0 pM, respectively.
`After 3 min of incubation at 37° C, reactions were terminated by the addition of 2 volumes of acetone.
`Extraction and reversed phase (C18-5 p) HPLC analysis of [l-,4C]-labelled arachidonic acid metabo-
`lites were conducted as previously described by Graff and Anderson (10).
`
`Passive Anaphylaxis in Conjunctiva
`Guinea pigs or rats (5-8/group) were passively sensitized with anti-ovalbumin serum injected
`subconjunctivally in one eye. Twenty-four (24) hrs after passive sensitization, ovalbumin (OA) was
`administered either intravenously (i.v.) or topically onto the eye.
`The anti-allergic effect of AL-4943A following i.v. antigen administration was determined as
`follows: Thirty (30) min prior to i.v. antigen challenge, the animals received 20 pi of AL-4943A or
`saline applied topically to the eye. The animals were then challenged i.v. via the marginal ear vein
`1 mg:2.5
`or lateral tail vein with 1.0 ml of an OA:Evans Blue solution (100 pg:l mg, guinea pigs;
`mg, rats). Responses were quantitated as previously described by Yanni et al. (11).
`
`391
`
`Page 3
`
`
`
`For assessment of the allergic response following topical ocular antigen challenge, 20 pi of
`ovalbumin (1.0%, w/v) was administered to the sensitized eye 5 min after topical ocular application
`of AL-4943A or saline (20 pi). During dose response studies, the order of compound administration
`was randomized. Thirty (30) min later, the reaction was quantitated, using the following scoring
`scheme (maximum score per animal = 10):
`
`Congestion (refers to palpebral and bulbar conjunctiva)
`0- Normal
`Pink conjunctiva
`1
`Red conjunctiva
`2
`Dark red conjunctiva; petechiae present
`3
`
`-
`
`-
`
`-
`
`Swelling
`0- None
`Any swelling on lower lid only
`1
`Swelling upper and lower lid, lids partially closed
`2
`Lids everted, very swollen, lids at least half closed
`3
`4- Swelling of both lids and side of face
`
`-
`
`-
`
`-
`
`Discharge
`0- None
`Glazed, glassy appearance
`1
`Moist lids and surrounding hair
`2
`Moist lids and surrounding hair, thicker mucous-like
`3
`
`-
`
`-
`
`-
`
`Histamine-induced Vascular Permeability in Guinea Pig Conjunctiva
`
`Male Dunkin Hartley Viral Antibody Free outbred guinea pigs (Charles River Labs, Portage,
`MI), 250-350 grams, (6/group) were injected i.v. via the marginal ear vein with 1.0 ml of Evans Blue
`dye (1.0 mg/ml). Forty-five (45) min post dye injection, 20 pi of test compound or saline vehicle
`was applied topically onto one eye of each experimental animal. Thirty min following topical drag
`application, the guinea pigs were anesthetized and challenged subconjunctivally with histamine (300
`ng/10 pi). Responses were quantitated as previously described (11).
`All modifications of the pretreatment interval between compound administration and histamine
`challenge are noted in the Results section.
`
`Platelet Activating Factor
`Conjunctiva
`
`(PAF)- or Serotonin (5-HT)-induced Vascular Permeability in Rat
`
`Male Sprague Dawley rats (Harlan Sprague Dawley, Houston, TX), 125-200 grams, (6/group)
`were injected i.v. via the lateral tail vein with 1.0 ml Evans Blue dye (2.5 mg/ml). Approximately
`20 min post dye injection, 20 pi of test compound or vehicle was applied topically onto one eye of
`the experimental animal. Thirty (30) min later, each animal was anesthetized and challenged
`subconjunctivally with PAF (30 ng/10 pi) or 5-HT (100 ng/10 pi) in the treated eye. Thirty (30)
`min after challenge, the animals were killed, and responses were quantitated as noted for histamine.
`
`Compounds
`
`AL-4943A (Kyowa Hakko Kogyo Co., Ltd., Tokyo,
`Japan);
`levocabastine (Janssen
`Pharmaceutica, Beerse, Belgium); histamine dihydrochloride, ovalbumin, 5-hydroxytryptamine
`
`392
`
`Page 4
`
`
`
`hydrochloride, Percoll®, goat IgG, ketotifen fumarate, bovine serum albumin, dinitrofluorobenzene,
`cyproheptadine hydrochloride (Sigma Chemical Co., St. Louis, MO); Evans Blue dye (Aldrich
`Chemical Co., Milwaukee, WI); PAF (Biomol, Plymouth Meeting, PA); anti-human IgE (goat-derived
`IgG) (Cortex Biochem, San Leandro, CA).
`Immediately prior to in vivo use, all compounds were prepared as solutions or suspensions in
`in water) at the concentrations noted in the Results section. All solutions and
`saline (0.9% NaCl
`suspensions were prepared on a weight/volume basis to reflect the percentage of free acid or base for
`in vivo experiments.
`all
`
`Statistical Analyses
`
`Dunnett's t-test (12) was used to compare the mean of each treatment group with the mean of
`Linear regression was used to analyze dose response and calculate
`the vehicle control group.
`effective doses (ED50).
`
`RESULTS
`
`The anti-allergic activity of AL-4943A, defined as inhibitory activity on basophil and mast cell
`degranulation, was assessed in vitro. The addition of AL-4943A 15 min before antigen challenge to
`cultured RBL cells inhibited histamine release in a concentration dependent manner. The IC50 value
`was calculated to be 803 pM. When human conjunctival mast cells were treated with AL-4943A for
`15 min prior to anti-IgE challenge, histamine release was also significantly reduced in a concentration
`dependent fashion. The IC50 value obtained in human conjunctival mast cells was 559 + 277 pM.
`Dose response curves obtained using both cell types are presented in Figs. 1A and IB. The reference
`drag, ketotifen, examined in the human conjunctival mast cell also significantly inhibited histamine
`release. However, at concentrations 3 times greater than the maximally effective concentration,
`ketotifen caused a significant release of histamine from these cells (Fig.
`IB). Additional
`in vitro
`evaluations of AL-4943A for cyclooxygenase or 5-lipoxygenase activity failed to detect significant
`activity (data not presented).
`Anti-allergic activity noted in vitro was confirmed in vivo using two models of passive
`conjunctival anaphylaxis. Significant inhibition of i.v. antigen-stimulated allergic conjunctivitis was
`observed in both rats and guinea pigs when AL-4943A was applied topically onto the eye prior to
`antigen challenge. Significant concentration dependent inhibition was noted in both species (Table
`1). AL-4943A was more efficacious when evaluated in guinea pigs compared to rats (80% inhibition
`vs. 40% inhibition, respectively, at 0.1%).
`The anti-allergic activity observed following i.v. antigen challenge was further evaluated using
`topical ocular antigen challenge of passively sensitized guinea pigs. The application of AL-4943A
`onto the eye of sensitized animals 30 min, 4 hrs or 8 hrs before allergen instillation significantly
`attenuated the allergic response (Table 2). The ED50 values determined in these experiments were
`0.017%, 0.053% and 0.100%, respectively.
`When evaluated for topical ocular antihistaminic activity in vivo, AL-4943A potently inhibited
`histamine-induced vascular permeability in the conjunctiva. The compound was applied topically 5,
`15 or 30 min, 2, 4, 8 or 24 hrs prior to histamine injection. Concentration dependent inhibition was
`observed (Table 3). The ED50 values derived from these data are 0.019%, 0.004%, 0.002%, 0.0014%,
`0.0056%, 0.035% and 0.114%, respectively.
`The ability of AL-4943A to affect the response of the contralateral eye to histamine challenge
`following topical ocular administration was also assessed. AL-4943A or levocabastine (0.05%) was
`applied to one eye and histamine was subsequently injected subconjunctivally in the contralateral eye.
`The drags' effects were quantified as described above. AL-4943A (0.1%) applied 30 min before
`histamine challenge failed to decrease the response in the contralateral eye (197 + 40, vehicle vs. 199
`+ 39, AL-4943A treated) while inhibiting the response in the treated eye by 95%.
`In contrast,
`
`393
`
`Page 5
`
`
`
`levocabastine did significantly reduce the response in the untreated eye (28%). These results indicate
`a lack of systemic effect following topical administration of AL-4943A.
`The specificity of AL-4943A noted in histamine and antigen stimulated in vivo models was
`evaluated using conjunctival vascular permeability models induced by 5-HT and PAF. AL-4943A
`applied at a concentration (0.01%) and pretreatment
`interval (30 min) before challenge proven to
`prevent histamine-induced responses greater than 70 % failed to significantly inhibit the response in
`the conjunctiva to either 5-HT or PAF (Table 4).
`
`[A] RBL Cells
`
`AL-4943A
`
`-5.5
`
`-5.0
`
`-4.5
`-4.0
`Dose log(M)
`
`* p<0.05, Dunnett's t-test.
`-3.5
`
`-3.0
`
`-2.5
`
`[ B ] Human Conjunctival Tissue Mast Cells
`
`ketotifen
`
`100
`
`80
`
`60
`
`40
`
`20
`
`-20
`
`o
`
`JD
`JZ
`c
`
`vP
`
`100
`
`80
`
`60
`
`o 40
`
`-Q
`ÏE 20
`
`0
`
`-20-
`
`-40-
`
`-60
`
`* p<0.05, Dunnett's t-test.
`-1-1-1-1-T—
`-1-1-1—
`-5.0
`-3.5
`-5.5
`-2.0
`-4.5
`-4.0
`-3.0
`-2.5
`Dose log(M)
`FIGURE 1. AL-4943A's Inhibition of Histamine Release from RBL Cells (A) and Human
`Conjunctival Tissue Mast Cells (B).
`
`394
`
`Page 6
`
`
`
`TABLE 1
`
`Effect of AL-4943A on Passive Anaphylaxis in Rat or Guinea Pig Conjunctiva
`Following Intravenous Antigen Challenge"
`Permeability
`Cone.
`% Change
`(%, w/v)
`Score
`(x ± S.D.)
`
`Compound
`
`Regression
`Analysis
`
`Species
`
`Rat
`
`NaCl
`
`AL-4943A
`
`Guinea
`Pig
`
`NaCl
`
`AL-4943A
`
`0.9
`1.0
`0.1
`0.01
`
`0.9
`
`0.1
`0.01
`0.001
`
`308 ± 48
`147 + 30*
`185 ±37*
`266 +49
`
`506±124
`102 ±76 *
`264 ±161*
`334+133
`
`-52
`-40
`-14
`
`-80
`-48
`-34
`
`y = -53x+ 144
`slope t = p < 0.0001
`r = 0.821
`
`y = -116x-0.48
`slope t = p < 0.0054
`r = 0.975
`
`* p < 0.05, Dunnett's t test
`a Interval between compound administration and antigen challenge: rat 20 min; guinea pig 30 min.
`
`TABLE 2
`
`Effect of AL-4943A on Passive Anaphylaxis in Guinea Pig Conjunctiva
`Following Topical Ocular Antigen Challenge
`
`Compound Pre-
`treatment
`Interval
`
`NaCl
`
`AL-4943A
`
`30 min
`
`NaCl
`AL-4943A
`
`4 hr
`
`NaCl
`AL-4943A
`
`8 hr
`
`p < 0.05, Dunnett's t test
`
`Cone.
`(%, w/v)
`
`Score
`(x+S.D.)
`
`Change
`
`ED50
`(%, w/v)
`
`Regression
`Analysis
`
`-53
`-61
`-45
`-35
`
`-67
`-53
`-42
`-26
`
`-77
`-41
`-25
`-19
`
`0.0170
`
`y = -1.08x+2.17
`t slope = p < 0.020
`r = 0.542
`
`0.0529
`
`y = -0.98x + 2.32
`t slope = p < 0.0018
`r = 0.602
`
`0.100
`
`y - -1.37x + 2.17
`t slope = p < 0.0001
`r = 0.856
`
`0.9
`1.0
`0.1
`0.01
`0.001
`
`0.9
`1.0
`0.1
`0.01
`0.001
`
`0.9
`
`1.0
`0.1
`0.01
`0.001
`
`8.2 ± 1.3
`3.8 ±0.8*
`3.2 ± 1.3*
`4.5 ± 1.1 *
`5.3 + 2.0 *
`
`7.2 ± 1.0
`2.3 + 1.5 *
`3.3 ± 1.5*
`4.2 ± 2.0 *
`5.3 ±1.2
`
`7.2 ± 1.7
`1.7 ±0.8*
`4.2 ± 0.8 *
`5.4 ±1.1*
`5.8 ±0.8
`
`395
`
`Page 7
`
`
`
`TABLE 3
`
`The Effect of AL-4943A on Histamine-induced Vascular Permeability in Guinea Pigs
`Compound
`Permeability
`Pre-
`ED50
`Cone.
`%
`Change
`(%, w/v)
`(%)
`Score
`treatment
`Interval
`(x±S.D.)
`
`Regression
`Analysis
`
`NaCl
`AL-4943A
`
`5 min
`
`NaCl
`AL-4943A
`
`15 min
`
`NaCl
`AL-4943A
`
`30 min
`
`AL-4943A
`
`2 hr
`
`NaCl
`
`4 hr
`
`AL-4943A
`
`NaCl
`AL-4943A
`
`8 hr
`
`NaCl
`AL-4943A
`
`24 hr
`
`p < 0.05, Dunnett's t test
`
`0.9
`0.3
`0.03
`0.003
`
`0.9
`0.1
`0.03
`0.01
`0.001
`0.0001
`0.00001
`
`0.9
`0.1
`0.01
`0.001
`0.0001
`
`0.1
`0.01
`0.001
`0.0001
`
`0.9
`1.0
`0.1
`0.01
`0.001
`
`0.9
`1.0
`0.1
`0.01
`0.001
`
`0.9
`1.0
`0.1
`0.01
`
`324 ±59
`94 ±65*
`165 ± 74 *
`197 + 56 *
`
`431 ±91
`98 ±87*
`180 ± 40 *
`238 ± 49 *
`240 ± 43 *
`302 ±55*
`370 + 73
`
`228 ±25
`15 ±15*
`69 ±33*
`125 ±36*
`195 + 53
`
`17±3*
`146 ±87*
`201 + 105 *
`342 + 66
`
`423 ± 47
`5 + 8*
`66 ±76*
`263 ± 49 *
`240 + 69 *
`
`374 ±45
`10 + 8*
`152 ±33*
`247 ± 29 *
`389 + 59
`
`347 + 27
`12 ±18*
`231 ±35*
`302 + 69
`
`396
`
`-71
`-49
`-39
`
`-77
`-5 8
`-45
`-44
`-30
`-14
`
`-94
`-70
`-45
`-15
`
`-96
`-66
`-52
`-19
`
`-99
`-84
`-38
`-43
`
`-97
`-60
`-34
`4
`
`-96
`-33
`-13
`
`0.019
`
`0.004
`
`y = -52x+73
`slope t - p < 0.013
`r = 0.571
`
`y = -59x + 73
`slope t = p < 0.0001
`r = 0.814
`
`0.002
`
`y = -61x
`56
`slope t = p < 0.0001
`r = 0.888
`
`-
`
`0.0014
`
`y = -103x
`82
`slope t = p < 0.0001
`r= 0.850
`
`-
`
`0.0056
`
`y = -90x+8
`slope t = p < 0.0001
`r= 0.826
`
`0.035
`
`y = -123x+ 14
`slope t = p < 0.0001
`r = 0.969
`
`0.114
`
`y = -145x+36
`slope t = p < 0.0001
`r = 0.909
`
`Page 8
`
`
`
`TABLE 4
`
`The Effect of AL-4943A on Serotonin- and
`Platelet Activating Factor-induced Vascular Permeability
`Permeability
`Compound
`Cone.
`Score
`(%, w/v)
`(x±S.D.)
`
`% Change
`
`NaCl
`AL-4943A
`cyproheptidine
`
`0.9
`0.01
`0.01
`
`0.9
`0.01
`
`385 ±59
`304 ±57
`118 ±52*
`
`409 ±74
`404 ±49
`
`-21
`-69
`
`-1
`
`Stimulus
`
`Serotonin
`
`PAF
`
`NaCl
`AL-4943A
`
`* p < 0.05, Dunnett's t test
`
`DISCUSSION
`
`The mast cell has long been considered to play a primary role in the pathogenesis of immediate
`hypersensitivity reactions. One therapeutic approach used in ocular allergic disease involves the use
`of mast cell stabilizers (13). Human conjunctival tissue is estimated to contain as many as 10,000
`mast cells per mm3 (14). Drags developed as mast cell stabilizers for the treatment of asthma have
`been available for topical use in allergic conjunctivitis. Recently,
`the concept of mast cell
`heterogeneity has been illustrated and accepted (15,16). Mast cells from different species and from
`different tissues within the same animal differ with respect to their morphological, cytochemical, and
`functional properties.
`Importantly,
`the mast cell populations also differ in their responses to
`pharmacological agents (14,17). These findings suggest that efficacious anti-allergic drugs for treating
`conjunctivitis should have demonstrated efficacy on the target cell, the human conjunctival mast cell.
`Data presented clearly demonstrate AL-4943A's concentration dependent inhibition of human
`conjunctival mast cell histamine release. Greater than 90% inhibition was achieved without observable
`histamine release due to cytotoxicity. AL-4943A, at concentrations 10 times greater than the
`maximally effective concentration, inhibited histamine release by greater than 90%. These data are
`in contrast to those obtained with ketotifen. Although ketotifen is more potent than AL-4943A at
`inhibiting mast cell mediator release, it causes pro-inflammatory mediator release at concentrations
`only 3 times greater than the maximally effective concentration. These data indicate that AL-4943A
`affords a larger safety margin than does ketotifen.
`The relevance of AL-4943A's effect on mast cells based upon the potency (IC50= 559 pM)
`becomes apparent when the molar concentration is converted to percentage weight/volume (559 pM
`= 209 pg/ml = 0.0209%, w/v). Because the conjunctiva is the target
`tissue for this compound,
`penetration and transport into the eye do not confound drug delivery. For these reasons, and because
`of the efficacy observed following topical ocular administration, the potency on human conjunctival
`mast cells appears acceptable.
`Anti-allergic activity observed in vitro was confirmed in vivo using models of passive
`anaphylaxis. Concentration dependent inhibition was noted following topical ocular administration
`of AL-4943A prior to antigen challenge. Significant activity was noted 8 hrs after administration of
`AL-4943A. The rat did not appear to be as responsive as the guinea pig to drag treatment. This can
`be partially explained by the two species' relative reactivity to the major vasoactive amines released
`
`397
`
`Page 9
`
`
`
`(18,19,20) and the activity of
`
`from activated mast cells (rat/serotonin; guinea pig/histamine)
`AL-4943A on histamine H, receptors (1,4,5).
`The reported in vitro histamine H[
`receptor antagonism was observed in vivo as well.
`AL-4943A applied topically onto the eye from 5 min to 24 hrs before histamine challenge
`significantly attenuated the vascular permeability response. A comparison of ED50 values obtained
`in our laboratory at time intervals from 15 min to 4 hrs after dosing indicate that AL-4943A is
`equipotent to levocabastine (15 min ED50s: 0.004%, AL-4943A vs. 0.0072%, levocabastine; 4 hr:
`0.0056%, AL-4943A vs. 0.0080%,
`levocabastine). These results are consistent with the similar
`affinities of the two compounds observed in radioligand binding studies (5). Assessment of activity
`at 24 hrs following compound administration demonstrates AL-4943A's long duration of action.
`These in vivo results are supported by the data obtained in ex vivo experiments in which AL-4943A
`occupied 80% of lung histamine H, receptors within an hour of oral dosing, and approximately 50%
`of the receptors were still occupied 24 hrs later (4).
`AL-4943A's ability to inhibit vascular permeability responses in the conjunctiva is agonist
`specific. No significant reductions in vascular permeability responses induced with serotonin or PAF
`were observed with concentrations of AL-4943A which inhibit histamine stimulated responses by
`70%. The specificity and selectivity of AL-4943A has been further characterized utilizing in vitro
`radioligand binding methodology (5). Data obtained from those studies confirm a lack of interaction
`at adrenergic, dopaminergic and muscarinic receptors. This suggests that AL-4943A's side-effect
`In addition, when AL-4943A was applied to one eye in a concentration
`potential may be minimal.
`which inhibited the response of that eye by 95%, no effect could be observed in the contralateral eye.
`This indicates that the potential for developing side effects is further reduced by the lack of systemic
`effect noted following topical ocular administration. AL-4943A's lack of side effects has been
`confirmed in clinical trials.
`Pharmacological
`intervention in allergic conjunctivitis has been primarily through the use of
`histamine H, antagonists in combination with oc-adrenergic agonists (22). Recently, Berdy et al. (23)
`demonstrated that Ht antagonists effectively relieve pruritis, conjunctival injection, and erythema in
`human volunteers. The other primary approach in managing ocular allergic diseases has been the use
`of mast cell stabilizers (24).
`The data presented demonstrate that AL-4943A combines both of these activities in one
`selective, topically effective, anti-allergic/antihistaminic agent. The compound possesses a rapid onset
`and long duration of action in preclinical models of allergic ocular disease. The anti-allergic and
`human conjunctival mast cell stabilizing activity of AL-4943A, coupled with its selective
`antihistaminic activity, suggests that the compound has potential utility when used prophylactically
`This affords distinct advantages over other agents currently used for the
`and therapeutically.
`treatment of ocular allergic diseases. Clinical trials with a topical ocular formulation of AL-4943A
`have been completed, and a New Drag Application (NDA) has been filed.
`
`REFERENCES
`
`1.
`
`2.
`
`3.
`
`4.
`
`Ohshima, E., Otaki, S., Sato, H., Kumazawa, T., Obase, H., Ishii, A., Ishii, H., Ohmori, K.,
`and Hirayama, N. Synthesis and antiallergic activity of 1 l-(aminoalkylidene)-6,l 1-dihydrodi-
`benz[b,e]oxepin derivatives. J. Med. Chem., 35:2074-2084, 1992.
`Inhibitory effect of KW-4679 on allergic models in
`Ishii, H., Kitamura, S., and Ohmori, K.
`rats. Jpn. J. Pharmacol, 55 (Suppl 1):375P, 1991.
`
`Ishii, H., Manabe, H., Sasaki, Y., Satoh, H., Tamura, T., and Ohmori, K. Pharmacological
`properties of a new antiallergic agent KW-4679. Jpn. J. Pharmacol, 46 (Suppl 1):284P, 1988.
`Ishii, A., and Kase, H. Effect of KW-4679, a novel antiallergic agent, on
`Nonaka, H.,
`histamine H, receptor. Jpn. J. Pharmacol, 61 (Suppl 1):87P, 1993.
`
`398
`
`Page 10
`
`
`
`5.
`
`6.
`
`7.
`
`8.
`
`9.
`
`10.
`
`11.
`
`12.
`
`13.
`
`14.
`
`15.
`
`16.
`
`17.
`
`Sharif, N.A., Xu, S.X., and Yarini, J.M. Olopatadine (AL-4943A): Ligand binding and
`functional studies on a novel, long acting H,-selective histamine antagonist/anti-allergic agent
`for use in allergic conjunctivitis. J. Ocular Pharmacol. Ther., in press.
`
`Immunological specificity of delayed and immediate
`Benacerraf, B. and Levine, B.B.
`hypersensitivity reactions. J. Exp. Med., 115:1023-1035, 1962.
`
`Undem, B.J., Brendel, J.B., Hirth, T., Buckner, C.K., and Graziano, F.M. Comparative studies
`of mediator release from guinea pig lung mast cells and basophils. Am. Rev. Resp. Dis.,
`133:763-768, 1986.
`
`Cook, H.W., Ford, G., and Lands, W.E.M.
`Instrumental
`improvements for rapid, detailed
`kinetic studies of oxygenase activity. Anal. Biochem., 96:341-387, 1979.
`
`Skoog, W.A. and Beck, W.S. Studies on the fibrinogen, dextran, and phytohemagglutinin
`methods of isolating leukocytes. Blood, 11:436-454, 1956.
`
`Graff G. and Anderson, L.A.
`l-[4-[3-[4[bis(4-fluorophenyl) hydroxymethyl] -1-piperidinyl]-
`-3-methoxyphenyl] ethanone (AHR-5333): a selective human blood neutrophil
`propoxy]
`5-lipoxygenase inhibitor. Prostaglandins, 38:473-496, 1989.
`
`Yanni, J.M., Weimer, L.K., Glaser, R.K., Lang, L.S., Robertson, S.M., and Spellman, J.M.
`Effect of lodoxamide in in vitro and in vivo conjunctival immediate hypersensitivity responses
`in rats. Int. Arch. Allergy Immunol, 101:102-106, 1993.
`
`Dunnett, C.W. A multiple comparison procedure for comparing treatments with a control. J.
`Am. Stat. Assoc, 50:1096-1121, 1955.
`
`Abelson, M. and Schaefer, K. Conjunctivitis of allergic origin: Immunologie mechanisms and
`current approaches to therapy. Surv. Ophthalmol, 38 (Suppl): 115-132,1993.
`
`Irani, A., Butrus, S., Tabbara, K., and Schwartz, L. Human conjunctival mast cells: Distribu-
`tion of MC,- and MC^. in vernal conjunctivitis and giant papillary conjunctivitis. J. Allergy
`Clin. Immunol, 86:34-39, 1990.
`
`Katz, H., Stevens, R., and Austen, K. Heterogeneity of mammalian mast cells differentiated
`in vivo and in vitro. J. Allergy Clin. Immunol, 76:250-259, 1985.
`
`Irani, A., and Schwartz, L. Mast cell heterogeneity. Clin. Exp. Allergy, 19:143-155, 1989.
`
`Befus, A.D., Dyck, N., Goodacre, R., and Bienenstock, J. Mast cells from the human intestinal
`lamina propria: isolation, histochemical subtypes, and functional characterization. J. Immunol.,
`138:2604-2610, 1987.
`
`18.
`
`Rowley, D. and Benditt, E. 5-Hydroxytryptamine and histamine as mediators of the vascular
`injury produced by agents which damage mast cells in rats. J. Exp. Med., 103:399-411, 1956.
`19. Maling, H.M., Webster, M.E., Williams, M.A., Saul, W., and Anderson, W. Jr.
`Inflammation
`induced by histamine, serotonin, bradykinin and compound 48/80 in the rat: Antagonists and
`mechanisms of action. / Pharmacol. Exp. Ther., 191:300-310, 1974.
`
`20.
`
`Rithche, D., Sierchio, J., Capetola, R., and Rosenthale, M. SRSA-mediated bronchospasm by
`pharmacologie modification of lung anaphylaxis in vivo. Agents Actions, 11:396-401,1981.
`
`399
`
`Page 11
`
`
`
`21.
`
`22.
`
`23.
`
`24.
`
`Yanni, J.M., Stephens, DJ., Parnell, D.W., and Spellman, J.M. Preclinical efficacy of
`emedastine, a superior histamine H[ antagonist for topical ocular use. J. Ocular Pharmacol,
`10:665-675, 1994.
`
`Abelson, M., Allansmith, M., and Friedlander, M. Effects of topically applied ocular
`decongestant and antihistamine. Am. J. Ophthalmol, 90:254-257, 1980.
`
`Berdy, G., Abelson, M., George, M., Smith, L., and Giovanoni, R. Allergic conjunctivitis: A
`survey of new antihistamines. J. Ocular Pharmacol, 7:313-324, 1991.
`
`Abelson, M. and Schaefer, K. Conjunctivitis of allergic origin: Immunologie mechanisms and
`current approaches to therapy. Surv. Ophthalmol, 38 (Suppl): 115-132, 1993.
`
`Received: October 20, 1995
`Accepted for Publication: February 15, 1996
`
`Reprint requests: John M. Yanni, Ph.D.
`Alcon Laboratories, Inc.
`6201 South Freeway
`Fort Worth, TX 76134-2099
`U.S.A.
`
`400
`
`Page 12