SCIENTIFIC DISCUSSION
`
`This module reflects the initial scientific discussion for the approval of Ventavis. For
`information on changes after approval please refer to module 8.
`
`1.
`
`Introduction
`
`Ventavis contains iloprost, (ZK 36374; 5-{(E)—(IS, SS, 6R, 7R)—7—hydroxy—6-[(E)-(3S, 4RS)—3-
`hydroxy-4—methyl-1—octen-6—inyl]-bi-cyclo[3.3.0]octan—3-ylidene}pentanoic acid), a chemically stable
`synthetic analogue of prostacyclin PGIZ. There are 6 stereogenic centers in the molecule. Iloprost is an
`approximately equal mixture of two diastereoisomers with the 4-methy1 group the hydroxy methyl
`octenyi in either the R or the S position; the other 5 stereogenic centers are pure R or S.
`
`OH
`
`'dH
`
`is marketed under the trade name Ilomedine in several
`An intravenous formulation of iloprost
`European member states and was authorised through national procedures. The approved indications
`include the treatment of thromboangiitis obliterans with ulcers or rest pain, severe inoperable
`peripheral arterial occlusive disease stages III-IV, and severe Raynaud’s phenomenon.
`
`VENTAVIS 10 ug/ml nebuliser solution in ampoules containing 2 ml of solution (i.e. 20 u g iloprost) is
`intended for administration via the inhalation route with a nebuliser.
`
`Pulmonary Arterial Hypertension (PAH) can occur without apparent cause (Primary Pulmonary
`Hypertension)(PPH) or be secondary to systemic disease, such as systemic sclerosis, CREST
`syndrome, mixed connective tissue disease (MCTD), HIV infection or be induced by drugs/toxins.
`Pulmonary hypertension may also be caused by chronic thromboemboiic occlusions of the pulmonary
`arteries.
`
`The pathogenesis involves vasoconstriction, vascular remodelling, and thrombosis in situ resulting in a
`progressive increase in pulmonary vascular resistances leading to increase pulmonary hypertension.
`Death is most closely associated with an increase in pulmonary artery pressure and right atrial pressure
`and a decrease in cardiac outth due to failure of the right side of the heart. Pulmonary hypertension is
`clinically defined as a mean pulmonary arterial pressure of more than 25 mini-lg at rest or 30 mmHg
`during exercise.
`
`The incidence of PPH amounts to 1 to 2 cases per million individuals per year. PPH and the following
`forms of SPH:
`connective tissue disease pulmonary hypertension, drug-induced pulmonary
`hypertension, portopulmonary hypertension, pulmonary hypertension associated with congenital heart
`disease and chrome thromboembolic pulmonary hypertension are estimated to "be affecting
`approximately 2.2 per 10,000 persons in the European Community.
`
`At the present time, the conventional therapy for patients with primary or secondary pulmonary
`arterial hypertension includes vasodilators,
`such as high doses of calcium—channel blockers,
`anticoagulants and oxygen. Epoprostenoi (prostacyclin) delivered via a portable pump system into an
`in dwelling central vein catheter has been shown to improve hemodynamic parameters and exercise
`capacity in patients with both PPH and secondary PAH (functional class 1H and IV), and it has been
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`shown to improve survival in patients with severe conditions. Phannacological tolerance with need for
`dose increments during long—term treatment is commonly observed.
`
`The severity of pulmonary hypertension is classified according to the WHO functional assessment
`1998 WHO World Symposium (modified after the NYHA functional assessment). Functional class is
`a predictor of survival. Patients who are in functional class II and III have a mean survival of 3.5 years
`compared with a mean survival of 6 months for those who are in functional class IV.
`
`Ventavis is indicated for treatment of patients with PPH, classified as NYHA fimctional class III, to
`improve exercise capacity and symptoms.
`
`The recommended dose regimen of Ventavis is 2.5 micrograms or 5.0 micrograms of inhaled iloprost
`(as delivered at
`the mouthpiece of the nebuliser). The dose per inhalation session should be
`administered 6 to 9 times per day according to the individual need and tolerability. The duration of
`treatment depends on clinical status and is left to physician’s discretion. Ventavis should only be
`initiated and monitored by a physician experienced in the treatment of pulmonary hypertension.
`
`2.
`
`Part 11: Chemical, Pharmaceutical And Biological Aspects
`
`Composition
`
`' Ventavis is an aqueous, clear, sterile, ready to use nebuliser solution for inhalation. It is an isotonic
`solution in dilute ethanol with a pH close to 8.0. Ventavis contains lOpg/ml of the active substance,
`iloprost, (as trometamol salt). 2 ml of the solution are supplied in single glass (type I) ampoules of '
`3 ml.
`
`Active substance
`
`is a synthetic analogue of the natural prostacyclin PGI'; , IUPAC name: 5- {(13)—
`Iloprost (INN),
`(1 8,5 S,6R,7R)—7-Hydroxy—6-[(E)—(3 S,4RS)—3 -hydroxy-4—methyi— l -octen—6—ynyl] -bicyclo [3 .3.0}oct—3-
`ylidene}-pentanoic acid . Iloprost is an oily substance, very slightly soluble in water. Due to its chiral
`centers, iloprost is an optically active diastereoisomeric mixture which also exhibits geometric (—2— E—)
`isomerism.
`
`The synthesis of Iloprost can be divided into three parts:
`-
`(1) the manufacture of the basic backbone bicyclo—octane (BCO).
`—
`(2) Addition of the side chain.
`—
`(3) Modification of the side chains.
`
`Particular attention is paid to isomeric/stereocherrncal control and the process involves optical
`resolution by preparative I-LPLC on a chirally—modified substrate,
`in order
`to obtain desired
`enantiomers. Chromatography is necessary at a number of stages and relevant diastereoisomers are
`separated by HPLC during the process.
`
`Iloprost possesses 6 asymmetrical carbon atoms of which 5 are common with the those in the natural
`prostacyclin. The configuration of the molecule is (therefore namely 88, 98, liR, 128 and 153. The
`methyl group at (316 causes two isomers to occur: 16R and 16S. Consequently, iloprost consists of
`two optically active diastereoisomers. Iloprost also contains two defined configurations of carbon-
`carbon double bonds, 5E and 13E — this stereo—specific formation is common in prostaglandin
`chemistry.
`.
`-
`The separated methyl diastereoisorners E(l6S) and E(16R) —iloprost are obtained as crystals and the
`isomer ratio has been determined. This ratio is [45/55 ] of [E(16S) / E(16R)] and has been shown to be
`unchanged since the pre—clinical and clinical development program began. Moreover, it was shown
`that there was no significant difference in the pharmacokinetic parameters of the E (16R)-iloprost, E
`(168)-iloprost and diastereoisomer mixture. Further data (i.v. infusion in dogs) demonstrated that the
`diastereoisomers do not undergo inter—conversion in viva.
`
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`The structure of Iloprost has been confirmed by IR, NMR, SM and X—ray spectroscopy as
`well as mechanistic arguments derived from the synthetic route. Solid state variables related
`to bioavailability are not relevant as the substance is administered in solution.
`
`Active substance specy’icaz‘ion
`
`The specification includes tests for identity, specific optical rotation, assay determination of identitifed
`and unidentified related substances by HPLC; Z- isomers are quantified separately. Levels of those
`related impurities, which are mentioned in the specification are qualified by animal toxicology studies.
`The isomer ratio E(16R):E(16S) is also checked.
`The level of residual solvents and catalysts are adequately discussed and are acceptable taking into
`account the small therapeutic quantities in which iloprost is administered. Batch analytical data
`indicate satisfactory compliance with the agreed specification and uniformity fiom batch to batch.
`
`Stability oftne active substance
`
`Prostaglandins in general are unstable substances. The stability of iloprost has been studied under
`forced degradation conditions, and for three batches, stability studies have been carried out in long
`term (at —18°C for three years) and under accelerated conditions (at +6°C I uncontrolled RH for 6
`months and at +25°C / 60% RH for lmonth). The samples used for long term and accelerated stability
`studies were stored in glass vials .
`
`These stressing conditions show that iloprost is sensitive to temperature, light and acid conditions as
`expected, and that the substance is not sensitive to alkalis and oxygen.
`ISB—Hydroxy-iloprost, 15—Oxo—iloprost, iloprost -ethyl~ and iloprost—isopropyl ester and the dimeric
`esters
`iloprost—1 l-iloprost
`ester and iloprost-IS-iloprost
`ester were identified as
`the main
`decomposition products.
`After 36 months storage at —18 °C the samples of iloprost show a time dependent tendency of a
`decrease of the content of iloprost accompanied by a minor increase of the main decomposition
`products iloprost -l l-iloprost ester and iloprost -15-iloprost ester. After longer storage periods, the
`decrease does not continue. Changes in other parameters such as appearance, isomer ratio E(4R)I'E(4S)
`and Z—isomers are not time—dependent .
`,
`At higher temperatures, +6 °C and +25 °C/6O % RH, iloprost decomposes significantly. The oily
`substance crystallizes and gets turbid, the amount of decomposition products increases, particularly
`the inner iloprost esters iloprost—1 l-iloprost ester and iloprost «ES-iloprost ester and the content of
`iloprost decreases, both below the specification limits. Isomer ratio and the amount of Z—isomer
`remain unchanged however.
`
`It is clear that iloprost is an unstable'substance and must be stored with care. A three years shelf— life
`with a re—test period of one year is acceptable when the active substance is stored sealed at w18° C and
`protected from light. (For stability of finished product: see below).
`
`Other ingredients
`
`The ingredients of the formulation are defined in the SPC. All are of PhEur standard and there are no
`significant risks in relation to TSE.
`
`Product development and finished product
`
`Product Development
`
`Development of the formulation is simple and is governed by the need to produce a sterile, isotonic
`solution suitable for nebulisation without the need for any extraneous excipients, which may have an
`adverse effect when given by the pulmonary route. The product can withstand terminal heat
`sterilisation.
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`In the overall development history, it should be noted that clinical trials were not performed with this
`product as intended for marketing. They were performed with solutions prepared from another,
`intravenous, product already—authorised, containing 20 ug iloprost / ml, diluted with isotonic saline
`(1:1) and nebulised for pulmonary administration The same amount of active substance would be
`administered in both cases; differences in safety profiles arising from different formulations and
`excipients used were regarded as not significant.
`
`Use with inhalation devices
`
`inhalation
`In vitro performance tests were performed with the product nebulised with different
`devices. The goal of those studies was to evaluate the performance characteristics of the different
`inhalation devices and to compare those with the device used in the clinical trials. On the basis of
`these investigations, relevant information has been included in the SPC to indicate which inhalation
`devices can be used since they met the experimental parameters.
`
`Manufacture ofthe Product
`
`In summary, the manufacturing process is: dissolution 'oftrometamol and sodium chloride in water for
`injection, a dissolution of Iloprost in ethanol and a mixing of the 2 phases, followed by a pH
`adjustment, a volume adjustment, and a filtration on a 0.22 pm filter. After filling of the solution, the
`ampoules are sealed and sterilized at 121°C for 20 min, and visually checked. Satisfactory in process
`controls are carried out: bulk pH, integrity of the filter membrane, yield, filled volume etc.
`
`Concerning the validation of the manufacturing process, the results are those of the validation of the
`intravenous solution, which is more concentrated. They indicate the good stability of the drug in
`ethanolic or unbuffered solution during 24 hours at room temperature. There are no adsorption losses
`of the drug during the process, and there is no significant degradation after one or two sterilisation
`cycles. The validation studies also Show that the bulk solution after filtration is essentially free of
`microorganisms prior to terminal sterilisation.
`
`Product Specification
`
`At release, the product is examined for appearance of the solution, pH value, extractable volume,
`identification of iloprost and trometamol, sterility. The assay of iloprost and determination of
`impurities are performed by validated HPLC methods.
`Batch analytical data show good product uniformity.
`Identical specifications are applied at release and end of shelfiife.
`The limits for degradation products are based on results generated in the stability studies.
`
`Stability of the product
`
`Stability studies have been carried out on three batches under ICH conditions. The batches meet the
`specification after 6 months' storage at + 40 °C/75% RH and after 18 months‘ storage at + 25 00"60%
`RH and 30 °C/70% RH.
`All three batches exhibit no significant changes on storage compared to the results at start.
`In general, the results support the shelf—life and storage conditions as defined in the SPC.
`
`I
`
`Discussion on chemicai, pharmaceutical and biological aspects
`
`The synthetic control and purity of iloprost active substance has been well-described, in particular the
`isomeric control during synthesis and general purity aspects as reflected in the active substance
`specification. As expected, this prostanoid is intrinsically unstable and must be stored fiozen at low
`temperature. Furthermore, the chosen manufacturing process and the specification for the finished
`product will allow a good quality of this medicinal product. Stability of the product has also been
`shown to be satisfactory when due allowance is made for the unstable nature of the active substance.
`The compatibility of this product with commercially—available nebulisation devices available in the
`EU is addressed in the Clinical section below and in the SPC.
`In general, the information provided in the Chemical and Pharmaceutical documentation suggests this
`is a product that should have satisfactory and uniform quality characteristics from batch to batch.
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`At the time of the opinion, there was an unresolved minor pharmaceutical issue on the validation of
`the manufacturing process having no impact on the benefib’risk balance of the product. The applicant
`committed to resolve this by means of a post-opinion Follow—Up Measure within an agreed timeframe.
`
`3.
`
`Part III: Toxico-pharmacological aspects
`
`Pharmacodynamics
`
`In vitro Studies
`
`Iloprost is a raceme mixture of E-4R— and 1348- diastereoisomers; it binds with high affinity both to
`prostacyclin ([P—) receptors and to the EPl -subtype of prostaglandin B receptors. Binding of iloprost to
`IP-receptors activates adenylate cyclase and increases intracellular cyclic AMP concentration. This
`iloprost-induced rise of CAMP alters gene expression of IP-receptors.
`Human pulmonary vascuiar tissue was shown to respond to iloprost with vasorelaxation and this was
`also seen, but to a lesser extent, in human pulmonary artery preparations from patients with pulmonary
`hypertension, However,
`in isolated normoxic-perfused rat lung iloprost did not lower pulmonary
`artery pressure, but
`it potently inhibited hypoxia-induced vasoconstriction. These differences are
`presumably due to variations of the expression of functional IP—receptors.
`,
`In vitra, iloprost was shown to dilate blood vessels harm a number of species pre-contracted with a
`variety of vasoconstrictors (histamine, noradrenaline, angiotensine II). The E—4S-isomer of iloprost
`has a potency in vitro of approximately 3 times that of iloprost, whereas the E—4R—isomer is about 4
`times less potent than iloprost.
`_
`_
`Iloprost
`is a common pathway inhibitor of platelet activation, acting via binding to platelet IP-
`receptors and has been shown to inhibit aggregation in vitro of platelets from several species (human,
`dog, cat, rat, cattle and monkey), with IC5o concentrations ranging ficorn 0.06 rig/ml (1.6 x lO'loM in
`humans) to 4.3 ng/ml (1.2 x lO‘SM in monkeys) With regard to inhibition of platetet aggregation in
`human platelet—rich—plasma (PRP), iloprost has a potency of approximately twice that of prostacyclin
`and 17 times that ofPGE1. Similarly to the vascular effects, the E-4S—isomer is approximately 1.5 to 2
`times as potent as iloprost in inhibiting platelet aggregation and the EAR-isomer 4 to 7 times less
`potent.
`in vitra, iloprost was shown to reduce the LPS-induced upnregulation of pro—inflammatory
`Further,
`tumour necrosis factor and in human and animal monocytic ceIls and monocytic/macrophage cell
`lines.
`
`In vivo studies
`
`For technical reasons, most in viva data have been obtained using intravenous administration of
`iloprost. The summary of pharmacodynamic studies performed by the intravenous route in support of
`the Ilomedin application is presented. There are no phannacodynamic animal studies using inhaled
`iloprOst, since the intravenous and oral studies have demonstrated that its inhibitory action on platelet
`aggregation and vasodilatation is due to iloprost binding to the P612 receptors.
`The pharmacodynamic properties of iloprost are those expected for a prostacyclin analogue.
`Iloprost has shown vasodilatory effect on pulmonary and systemic blood vessels in various animal
`species, with variations presumably depending on the distribution of functional IP-receptors. In
`pulmonary hypertension animal models,
`iloprost
`treatment
`leads in _v:'va to an improvement or
`normalisation of pulmonary haemodynamics by reduction in vascular resistance and consequently in
`arterial blood pressure. Leukocyte adhesion to damaged endothelium in viva, and leukocyte
`accumulation in tissue following injury is
`reduced by iloprost.
`Iloprost has shown platelet
`antiaggregatory and antithrombotic effects,
`favorable effects on microvascular perfusion and
`microvascular integrity and inhibition of leukocyte-vessel wall interactions. Iloprost is characterized
`as a common pathway inhibitor of aggregation of human platelets and from varying animal species,
`probably by increasing the endogenous fibrinolytic potential in viva. Moreover, iloprost is able to
`inhibit the procoagulant activity of monocytic cells stimulated with LPS, TNFOL or IL-IB.
`Continuous administration of iloprost does not seem to result in loss of vasodilator response, although
`less of the platelet inhibitory effect of the compound on continuous exposure has been shown. With
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`regard to antithrombotic effects, somewhat reduced efficacy to platelet inhibition was seen following-
`continuous intravenous infusion for 9 days. Development of tachyphylaxis to the anti-platelet effect
`can be avoided by discontinuous treatment.
`
`Pharmacodynamic drug interactions
`
`Iloprost has been tested in combination with a number of other cardiovascular drugs. No major
`unexpected interactions were found.
`In animal studies, combinations of iloprost with other vasodilator principles resulted in most cases in
`sub-additive or additive systemic blood pressure lowering effects. An exception to this was the
`markedly super—additive effect on blood pressure seen with the combination of a moderately
`hypotensive dose of an ACE inhibitor
`(captopril) with a non—hypotensive dose of iloprost.
`Pretreatment with dexamethasone attenuated the blood pressure lowering effect of iloprost, but had no
`influence on the antiplatelet effect. Iloprost did not influence the positive inotropic response to the
`cardiac glycoside ouabain.
`1
`With regard to the effects on platelets and coagulation, synergistic inhibition ofplatelet aggregation in
`vitro was
`seen for combinations of iloprost with acetylsalicylic acid NO— donors or
`the
`phosphodiesterase inhibitor piroximone. Combination with anticoagulants such as heparin may result
`in increased bleeding time. Under certain conditions, combination of iloprost with tissue plasminogen
`activator has been shown to reduce plasma t—PA concentration, and may therefore reduce thrombolytic
`efficacy.
`
`General and safety pharmacology programme
`
`Effects of iloprost have been studied on the central and autonomic nervous system and on the cardiac,
`respiratory, renal, gastrointestinal and female reproductive systems. The results of these studies
`performed in animals and in vitro can be summarized as follows:
`.
`-
`Iloprost showed limited direct positive inotropic or chronotropic effects in cardiac tissue in vitro
`that probably do not influence its cardiovascular effects in vivo. The compound improved the
`circulatory shock provoked by ovalbumin injection in cats, which had previously undergone
`passive pre—sensitisation.
`No effects on cardiac action potential, no pro—arrhythmic effects in vitro and in vivo in rats and
`mice.
`
`o
`
`0
`
`0'
`0
`
`Symptoms of depression (probably due to exaggerated pharmacological effects, cg. peripheral
`vasodilatation and hypotension) and, at high doses, of CNS/autonomic stimulation in rats.
`No deleterious effects on respiratory function in vitro and in vivo in rabbits.
`Decreased urine flow and sodium excretion at hypotensive doses, which is rapidly reversed on
`cessation of administration in rats.
`
`0
`
`0
`
`Contractile effects on isolated ileum, little effect or decreased motility and antidiarrhoeio’anti-
`enteropooling effects (depending on model system) in vivo in rats and rabbits.
`Uterine contractile (guinea—pig) or biphasic (human) effects in vitro. No effect on uterine
`pressure and motility in vivo in anaesthetized rabbits, induction of abortion at near—lethal doses
`in guinea pigs.
`None of the studies on the effects of iloprost in various organ systems indicate a potential of the
`compound to induce serious adverse effects in the therapeutic dose range.
`'
`
`Pharmacokinetics
`
`Preclinical pharmacokinetic data are mainly based on conventional routes of drug administration, i.e.
`the intravenous, oral and subcutaneous routes. The pharmacokinetics of pharmacological to subtoxic
`doses of iloprost was studied in rodents (rat, mouse and rabbit) and non-rodent species (cat, dog and
`cynomolgus monkey).
`The pharmacokinetics of iloprost is characterized by very rapid and presumably complete absorption
`from the gastrointestinal tract in the rat, dog and cynomolgus monkey. The bioavailability of orally
`administered drug was approximately 10% of the dose in all species studied (rat, mouse, dog,
`monkey), including humans. The disposition half-life of unchanged iloprost was below 15 min in the
`rat, monkey and dog and about 0.5 h in the cat and in humans.
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`'
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`
`
`
`Following administration, it rapidly distributes into organs and tissues (with minor passage across the
`blood—brain and blood-placenta barriers) and is extensively biotransformed prior to excretion
`(preferentially via the kidney).
`,
`The pharmacokinetics of iloprost was further studied after inhalative daily administration in rats.
`iloprost serum concentrations rapidly increased reaching Cum 1 “[02 hours after start of inhalation. At
`the doses used (3.6 to 43.7 rig/kg), average Cmax and AUCM were several times those observed in men
`given 5 ug iloprost by inhalation. No important differences were observed in Cam and AUCM between
`sexes and between treatment days. The systemic exposure increased sub—proportionally with
`increasing the dose (3.6 to 43.7 rig/kg) and proportionally with prolonging the inhalation period (from
`135 to 240 min).
`_
`Iloprost isomers exhibited a similar pharmacokinetic behaviour in rats. No conversion of 4R to 43
`iloprost (and vice versa) occurred. The relevant half-life of labelled compounds in plasma was similar
`(0.7 h) in all animal species studied (rat, monkey, dog, mouse and cat). Distribution of 3H-active
`substances into tissues and organs was very rapid. However, concentrations were very low except for
`the liver, kidneys, muscle and stomach. In rabbit foetuses, concentrations of labelled compounds were
`1/200 as compared to maternal plasma.
`'
`Iloprost was totally metabolised in all species studied and the biodegradation products were excreted
`mainly with the urine. Main biotransformation pathways of iloprost were B-oxidation of the upper
`side-chain and hydroxylation at position 17.
`
`Toxicology
`
`Preclinical safety tests included intravenous, subcutaneous and oral studies in rodent and non-rodent
`species. Since the systemic iloprost exposure after parenteral and oral administration exceeds the
`therapeutic inhalative dose levels in humans, it was considered that specific studies of its inhalatory
`toxicity are not crucial. Complementary studies were carried out primarily to ensure the comparability
`of the effects after inhalation to those observed after iloprost oral or intravenous administration
`(“bridging” studies). All studies were done according to GLP rules.
`
`Single dose toxicity
`
`Single dose toxicity studies were carried out in three rodent species (mouse, rat, and rabbit) and in
`monkey, by oral or intravenous administration. Any acute inhalation toxicity study could not be
`carried out because of technical
`impossibility to exceed 0,345 11g of Iloprost per air liter, a
`concentration that does not induce any adverse'effect in the animal, even after chronic treatment.
`
`Design and results (LDso) 0f systemic toxicity tests with a single intravenous (i.v.) and
`intragastric (i.g.) administration:
`
`
`
`10M
`
`amals
`her
`per dose and sex
` Species
`Dose (mg/kg)
`
`125 to 250
`
`0000
`
`
`Rat
`
`
`VRoute of Bdrm—“ration "
`’ thesto—vaand
`95% confidence limits
`(mg/kg)
`201 (179—244)
`000000-040
`
`i
`
`
`
`
`
`
`EV
`50 to 200 __ 119 (85-164)
`M: 128 (92—216)
`V
`
`65 to 200
`25t025
`
`SMISF
`3M/3F
`
`i
`
`.
`
`F: 144 (116—201)
`9.86.5460)
`
`
`
`V g
`
`40 to 100
`40 to 100
`
`
`M a male, F = female, iv. = intravenous, Lg; : intragastric
`
`The values of LDso are much higher than the human therapeutic doses corresponding to six to nine
`administrations per inhalation between five and ten minutes of 2,5 or 5 pg of Iloprost. These human
`therapeutic doses correspond to an intake of 30 to 45 ng/day of Iloprost i.e 0,5 to 0,75 ug/kg/day.
`
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`Clinical symptoms, which appeared right from low dose, are common to all species. Most of the
`clinical symptoms at high dose such as apathy, changes of posture, redness of the skin and the mucous
`membranes can be attributed to an exaggerated pharmacological activity of the compound
`(hypotensive and hemodynamic effects). The necrosis of the tail observed in surviving animals
`sacrificed at the end of the study is most probably due to local irritating properties of Iloprost at the
`high concentrations required for these studies.
`Based on the administered doses and the LDso obtained, in spite of the absence of animal data on the
`levels of exposure after inhalation, no special hazard is expected after the single administration of
`iloprost via inhalation.
`
`Repeated dose toxiéily
`
`Subacute toxicity studies were performed by the oral route in rats and monkeys (Macaca fascicularis)
`by repeated intragastric administration of Iicprost solution, and by the intravenous route in rats and
`monkeys (Macaca fascicularis) with repeated intravenous infusion over 3 hours and continuous
`intravenous infusion of Iloprost. -
`
`For the assessment of local and systemic toxicity of iloprost after inhalative administration, Wistar rats
`were exposed by inhalation to three target concentrations generated by nebulization of iloprost
`10
`pg/mL formulation (corresponding to target doses of 0.9, 3.6 and 10.8 rig/kg) and two concentrations
`of iloprost 2O ug/mL (corresponding to target doses of 0.9 and 24.6 pg/kg) daily for 135 minutes on
`seven days a week for 28 days. The selection of dose levels is based .on multiples of the maximum
`human therapeutic dose level of 0.9 ug/kg/day. The duration of exposure was selected to simulate the
`clinical treatment regimen of a maximum of 9 exposure cycles of 15 minutes duration daily.
`Afier 4 weeks inhalation in the rat with an amount considered as maximum. from a technical point of
`view,
`there was no difference in toxic effect (clinical, biological and histological) between the
`different concentrations of Iloprost during or after the exposure. Alter histological examination of the
`respiratory tract, no sign of local irritation was observed.
`
`Summary of the reievant doses for evaluation of systemic tolerance of iloprost after inhalation
`or i.v. administration (subacute toxicity). '
`
`Multiple of the intended human
`dose“ on the basis of
`
`Doses which were tolerated
`without symptoms or with minor
`effects
`
`mike/day
`
`0.0226
`
`0.167
`
`Treatment regimen
`Species
`
`Inhalation for 135 minuteslday
`over 28 days
`Rat
`
`i.v. infusion over 3 hours/day
`(10-11 treatment days)
`
`Continuous i.v. infusion over
`
`
`
`0.2
`0.002
`
`1.11
`0011
`
`2222
`
`139 (9)
`222 (138)
`0.139 (0.09)
`0.2 (124)
`1.4 (1)
`22.2 (13.8)
`0.014 (0.009)
`0.02 (12.4)
`,
`Human therapeutic dose per inhalation session of 10 minutes: 5 pg/patient of 50 kg = 0.1 ug/kg/ 10 min session
`= 0.01 ug/kg/min. For 9 sessions of 10 minutes/day the total dose is 0.9 ug/kg.
`
`iloprost related alterations found in the subacute toxicity studies afier different routes of
`All
`administration in rodents and non-rodents are mainly attributed to thehemodynamic properties of
`iloprost. At very high exposure levels, the hemodynamic changes led to the death of experimental
`animals, however direct organ toxicity was not observed. Considering a single inhalation dose of 5
`ug/patient (= 0.1 rig/kg for a patient of 50 kg body weight for 10 minutes) administered up to 9 times a
`day as the intended mode of application, it can be concluded that on the basis of total administered
`dose/day and on the basis of dose/kg/min, many times higher dosages of iloprost were tolerated in rats
`after inhalation than after administration via the intravenous or .oral routes of administration- In
`8130
`.
`©EMEA 2004
`
`WATSON LABORATORIES, INC. , IPR2017-01622, Ex. 1039, p. 8 of 30
`
`WATSON LABORATORIES, INC. , IPR2017-01622, Ex. 1039, p. 8 of 30
`
`

`

`monkeys, which were more sensitive to iloprost, the doses that were tolerated without or with minor
`symptoms after parenteral and oral administration were in the same range or slightly above the dose
`levels of human inhalative therapeutic treatment.
`
`Chronic toxicity studies were carried out in rats and dogs by intravenous or sub cutaneous continuous
`infusion or oral administration of Iloprost over 6 months. A chronic inhalation toxicity study was
`conducted in rats overl26 weeks (periods of 135 or 240 min/day).
`
`Continuous infusion of Iloprost up to the highest dose of 347 ng/kg/min (0.5 mg/kg/day) over 26
`weeks in rats did not produce any organ-toxic effect, but slight effects related to the pharmacological
`profile of the compound. The mean plasma levels of Iloprost at the highest dose were for females
`3.5 ng/ml and for males 5.0 ng/ml. In dogs, continuous s.c. infiision of iloprost up to the highest dose
`of 67 ng/kg/min (0.097 mg/kg/day) over 26 weeks did not produce any organ—toxic damage, though
`adverse effects related to gastrointestinal motility could be observed transiently from the mid~dose
`(33-34 ng/kg/min; 0.049 mg/kg/day) leading to mean plasma levels of 0.9 ng/ml onwards. The mean
`plasma levels of Iloprost at the highest dose were 1.6 and 2.1 ng/ml in female and male animals,
`respectively.
`
`The daily inhalative administration of a nebulizing solution of Iloprost at a concentration of 20 rig/m1
`over 26 weeks in rats, with a maximum technically achievable'aerosol concentration which led to a
`maximum achievable dose of 48.7 rig/kg body weight, did not cause adverse effects. The technically
`possible maximum amount (0,4 ug/l air) corresponding to 0,203 ng/kg/min (h