[0001] The present invention relates to pharmaceutical compositions of blood factors for
subcutaneous administration.
[0002] Typically, blood factors have been prepared as pharmaceutical compositions for intravenous
administration. The compositions have been based on the active protein, often conjugated
to a polymer such as polyethylene glycol (PEG) to improve the half-life in circulation.
Intravenous administration of PEGylated blood factors as therapeutic agents is therefore
well understood and widely accepted. Liposomal formulations of naked (i.e. unconjugated
and without modification) blood factors such as Factor VIII and Factor IX substances
are known also, see for example
WO 95/04524.
[0003] Pharmaceutical compositions comprising Factor VIII and liposomes modified by the
presence of polyethylene glycol are described in
WO 99/55306 in which the blood factor is not encapsulated in the liposome. However, the formulations
are prepared for intravenous administration. Additional formulations of other proteins
are described in
WO 2004/091723 where the proteins include blood clotting factors. The proteins are said to bind
to the liposomes in a non-covalent manner through interaction with the polyethylene
glycol present on the surface of the liposomes. However, the formulations of blood
clotting factors prepared according to the examples of this document are also for
intravenous administration.
[0004] Other examples of formulations of blood factors, Factor VIII and Factor Vlla, present
as a conjugate with PEG are shown in
WO 2011/135307 and
WO 2011/135308 respectively where the actual formulations prepared were for intravenous administration.
WO 2013/156488 also describes a dosage form of modified therapeutic agents, including blood factors
such as Factor VIII (FVIII) and Factor VIIa (FVIIa), for subcutaneous administration.
[0005] Factor VIII has also been found to be capable of association with PEGylated liposomes,
i.e. the blood factor is not encapsulated inside the liposome (
Baru et al Thromb. Haemost., 93, pages 1061-1068, (2005)). However, the compositions of FVIII were only prepared as formulations for intravenous
administration.
[0006] Further studies by
Peng et al in The AAPS Journal, 14(1), pages 25-42 (2011) disclose an alternative approach based on FVIII encapsulated in liposomes which
are subsequently PEGylated by passively adding PEG to the liposomes after preparation.
In one experiment in Peng
et al the liposomal formulation is administered subcutaneously (SC) to investigate immunogenicity
but there is no suggestion of a therapeutic purpose to this administration. In Peng
et al there is also a specific reference to the paper of Baru
et al (2005) and a statement that the approach of Baru
et al "exposed FVIII to plasma components such as proteases and IgGs". Liposomes prepared
according to the method of Baru
et al (2005) containing recombinant Factor VIII have been administered intravenously to
subjects (
Spira et al Blood, 108 (12), pages 3668-3673 (2012)).
[0007] Current methodologies for formulating blood factors for administration rely on intravenous
modes of administration. This is problematic since the patient inevitably receives
a large bolus injection of the active agent at several time points leading an uneven
therapeutic level of agent in the blood of the patient.
[0008] There is therefore a need for pharmaceutical composition of a blood factor which
can provide a safe and effective dosage.
[0009] According to the present invention there is provided a pharmaceutical composition
for subcutaneous administration comprising the blood factor Factor VIII and a colloidal
particle comprising approximately 0.5 to 20 mole percent of an amphipathic lipid derivatized
with a biocompatible hydrophilic polymer, wherein the blood factor is not encapsulated
in said colloidal particle. The composition is administered subcutaneously with repeated
subcutaneous administration of the pharmaceutical composition carried out before the
concentration of the pharmaceutical composition in the blood reduces to sub-therapeutic
levels.
[0010] The colloidal particles may be substantially neutral and the polymer may carry substantially
no net charge. The colloidal particles may have a mean particle diameter of between
about 0.03 to about 0.4 microns (µm), for example having a mean particle diameter
of approximately 0.1 microns (µm). A mean particle diameter in this range may increase
the circulation time of the particles
in vivo and prevent their adsorption by the reticuloendothelial system (RES).
[0011] The blood factor may be used in a lyophilised form when preparing the pharmaceutical
composition.
[0012] Where the composition comprises a fragment of a blood factor, the factor may suitably
be an active fragment thereof in which the fragment retains the biological activity,
or substantially the same biological activity as the native blood factor. For example,
one such active fragment is the B-domain truncated Factor VIII sequence shown in Figure
1.
[0013] It is further possible that the composition may comprise both the native blood factor
and a fragment thereof.
[0014] The pharmaceutical composition of the invention may also additionally comprise another
therapeutically active compound or molecule, e.g. an anti-inflammatory drug, analgesic
or antibiotic, or other pharmaceutically active agent which may promote or enhance
the activity of Factor VIIa,
[0015] Factor VII, Factor VIII, Factor IX, Factor X, Factor Xa, Factor XI, Factor V, Factor
XIII, von Willebrand's Factor (vWF), prothrombin or Protein C, or a fragment thereof,
such as for example another blood coagulation factor.
[0016] The terms Factor VIIa (FVlla) and Factor VII (FVII) are also used interchangeably
unless the context specifies otherwise. FVIII is used as an abbreviation for Factor
VIII, FIX is used as an abbreviation for Factor IX, and so on for all the blood factors
described herein
mutatis mutandis.
[0017] The blood coagulation (clotting) factor may be from any suitable source and may be
a recombinant protein produced by recombinant DNA technology using molecular biological
techniques or synthesised chemically or produced transgenically in the milk of a mammal,
or the factor may be isolated from natural sources (e.g. purified from blood plasma).
Suitably the factor is a mammalian blood clotting factor, such as a human blood clotting
factor. References to a blood clotting factor include a blood coagulation factor.
[0018] As discussed above, blood factors are all characterised
inter alia by the property of surface adhesion. This is a necessary feature of the coagulation
cascade which requires that enzymes and cofactors adhere to other participants in
the cascade, to the surface of platelets and to tissue at the site of injury. Indeed
it is particularly important that a blood clot remains at the site of injury and does
not drift to cause a dangerous thrombosis. This property presents a challenge in the
formulation of drug products, since blood factors such as VIIa, VIII and IX will adhere
excessively to any glass and plastic surfaces. In practical terms this is mitigated
by the extensive use of polysorbate (e.g. Tween
® 80).
[0019] The colloidal particles of the invention are typically in the form of lipid vesicles
or liposomes as are well known in the art. References to colloidal particles in the
present specification include liposomes and lipid vesicles unless the context specifies
otherwise.
[0020] In the colloidal particles, the amphipathic lipid may be a phospholipid from natural
or synthetic sources. The amphipathic lipid may comprise approximately 0.5 to about
20 mole percent (%) of the particles, for example approximately about 1 to 20%, or
about 1 to 6%, or about 3%.
[0021] Suitable examples of such amphipathic lipids include phosphatidylethanolamine (PE),
a carbamate-linked uncharged lipopolymer or aminopropanediol distearoyl (DS), or mixtures
thereof. A suitable example of phosphatidyl ethanolamine (PE) may be 1,2-distearoyl-sn-glycero-3-phosphoethanol-amine
(DSPE). The purpose of the biocompatible hydrophilic polymer is to sterically stabilize
the SUVs, thus preventing fusion of the vesicles
in vitro, and allowing the vesicles to escape adsorption by the RES
in vivo.
[0022] The colloidal particles may further comprise a second amphipathic lipid obtained
from either natural or synthetic sources. The second amphipathic lipid may be phosphatidylcholine
(PC). A suitable example of phosphatidyl choline (PC) may be palmitoyl- oleoyl phosphatidyl
choline (POPC).
[0023] In such an embodiment, the pharmaceutical composition may be composed of colloidal
particles which comprise palmitoyl- oleoyl phosphatidyl choline (POPC) and 1,2-distearoyl-sn-glycero-3-phosphoethanol-amine
(DSPE) in a ratio (POPC:DSPE) of from 85 to 99:15 to 1. In some cases, the ratio of
POPC:DSPE may be from 90 to 99:10 to 1. In one embodiment, the ratio of POPC:DSPE
may be 97:3.
[0024] In an alternative embodiment, the pharmaceutical composition of the invention may
be supplemented with cholesterol.
[0025] The biocompatible polymer may have a molecular weight of between about 500 to about
5000 Daltons, for example approximately 2000 Daltons.
[0026] The biocompatible hydrophilic polymer used according to the invention may be selected
from the group consisting of polyalkylethers, polylactic acids and polyglycolic acids.
The biocompatible hydrophilic polymer may be polyethylene glycol (PEG). The polyethylene
glycol as used in the compositions of the invention may have a molecular weight of
between about 500 to about 5000 Daltons, for example it may have a molecular weight
of approximately 1000, 2000, or 3000 Daltons. In one embodiment the molecule weight
of the PEG may be 2000 Daltons. The polyethylene glycol may be branched or unbranched.
[0027] An example of a suitable derivatized amphipathic lipid may be 1,2-distearoyl-sn-glycero-3-phosphoethanol-amine-N-[poly-(ethyleneglycol)].
If the PEG has a molecular weight of 2000 Daltons, the derivatized amphipathic lipid
may be described as 1,2-distearoyl-sn-glycero-3-phosphoethanol-amine-N-[poly-(ethyleneglycol)-2000]
(DSPE-PEG 2000).
[0028] The pharmaceutical composition may comprise any suitable excipient, buffer and/or
adjuvant. Examples of such excipient, buffer and/or adjuvants, include phosphate buffered
saline (PBS), potassium phosphate, sodium phosphate and/or sodium citrate. Other biological
buffers can include PIPES, MOPS etc.
[0029] Suitable pH values for the pharmaceutical composition include any generally acceptable
pH values for administration
in vivo, such as for example pH 5.0 to pH 9.0, suitably from pH 6.8 to pH 7.2, or pH 7.0.
[0030] The present inventors have surprisingly found that formulations of blood factors
in association with colloidal particles (liposomes) derivatized with a biocompatible
polymer can be successfully administered subcutaneously and achieve a therapeutically
effective dose of blood factor to a subject suffering from haemophilia. Suitably,
the biocompatible polymer is polyethylene glycol.
[0031] In the examples of the present invention the PEG is incorporated into the liposome
during vesicle formation, before association with the blood factor. It is believed
that specific amino acid sequences on the blood factor may bind non-covalently to
carbamate functions of the PEG molecules on the outside of the liposomes.
[0032] Although there is a reference in Peng
et al (2011) to the administration of the liposomal FVIII to mice subcutaneously (SQ) it
is quite clear that this was only done to look at relative immunogenicity and was
not considered as a viable treatment option. To highlight this, the authors clearly
state at the top of page 41 that "FVIII-PI/PEG was given intravenously, the clinical
route of administration for FVIII." In other words, Peng
et al does not disclose or even suggest subcutaneous administration as a viable treatment
option. Further, the authors in Peng
et al (2011) also state on page 40 that their approach is "distinctively different" to
that of Baru
et al (2005). The most recent publications in the field therefore present mutually exclusive
and different alternatives to the present invention.
[0033] As discussed above, the liposome does not encapsulate the blood factor(s) so that
smaller sized liposomes may be used if desired which have a longer half-life
in vivo, since they are not removed by the reticuloendothelial system (RES). The activity
of the formulated blood factors is not impaired as shown in the Examples with full
activity found
in vitro and immediately after injection
in vivo.
[0034] The blood factors interact non-covalently with the polymer chains on the external
surface of the liposomes, and no chemical reaction is carried out to activate the
polymer chains, unlike the composition disclosed in
EP-A-0689428. The nature of the interaction between the blood factor and the liposome derivatized
with a biocompatible hydrophilic polymer may be by any non-covalent mechanism, such
as ionic interactions, hydrophobic interactions, hydrogen bonds and Van der Waals
attractions (
Arakawa, T. and Timasheff, S. N., Biochemistry 24: 6756- 6762 (1985);
Lee, J. C. and Lee, L. L. Y., J. Biol. Chem. 226: 625-631 (1981)). An example of such a polymer is polyethylene glycol (PEG).
[0035] A variety of known coupling reactions may be used for preparing vesicle forming lipids
derivatized with hydrophilic polymers. For example, a polymer (such as PEG) may be
derivatized to a lipid such as phosphatidylethanolamine (PE) through a cyanuric chloride
group. Alternatively, a capped PEG may be activated with a carbonyl diimidazole coupling
reagent, to form an activated imidazole compound. A carbamate-linked compound may
be prepared by reacting the terminal hydroxyl of MPEG (methoxyPEG) with p-nitrophenyl
chloroformate to yield a p-nitrophenyl carbonate. This product is then reacted with
1-amino-2,3-propanediol to yield the intermediate carbamate. The hydroxyl groups of
the diol are acylated to yield the final product. A similar synthesis, using glycerol
in place of 1-amino-2, 3-propanediol, can be used to produce a carbonate-linked product,
as described in
WO 01/05873. Other reactions are well known and are described, e.g. in
US 5,013,556.
[0036] Colloidal particles (liposomes) can be classified according to various parameters.
For example, when the size and number of lamellae (structural parameters) are used
as the parameters then three major types of liposomes can be described: Multilamellar
vesicles (MLV), small unilamellar vesicles (SUV) and large unilamellar vesicles (LW).
[0037] MLV are the species which form spontaneously on hydration of dried phospholipids
above their gel to liquid crystalline phase transition temperature (T
m). The size of the MLVs is heterogeneous and their structure resembles an onion skin
of alternating, concentric aqueous and lipid layers.
[0038] SUV are formed from MLV by sonication or other methods such as extrusion, high pressure
homogenisation or high shear mixing and are single layered. They are the smallest
species with a high surface-to-volume ratio and hence have the lowest capture volume
of aqueous space to weight of lipid.
[0040] As used herein the term "loading" means any kind of interaction of the biopolymeric
substances to be loaded, for example, an interaction such as encapsulation, adhesion
(to the inner or outer wall of the vesicle) or embedding in the wall with or without
extrusion of the biopolymeric substances.
[0041] As used herein and indicated above, the term "liposome" refers to colloidal particles
and is intended to include all spheres or vesicles of any amphipathic compounds which
may spontaneously or non-spontaneously vesiculate, for example phospholipids where
at least one acyl group replaced by a complex phosphoric acid ester. The liposomes
may be present in any physical state from the glassy state to liquid crystal. Most
triacylglycerides are suitable and the most common phospholipids suitable for use
in the present invention are the lecithins (also referred to as phosphatidylcholines
(PC)), which are mixtures of the diglycerides of stearic, palmitic, and oleic acids
linked to the choline ester of phosphoric acid. The lecithins are found in all animals
and plants such as eggs, soybeans, and animal tissues (brain, heart, and the like)
and can also be produced synthetically. The source of the phospholipid or its method
of synthesis are not critical, any naturally occurring or synthetic phosphatide can
be used.
[0042] Examples of specific phosphatides are L-a-(distearoyl) lecithin, L-a-(dipalmitoyl)
lecithin, L-a-phosphatide acid, L-a-(dilauroyl)-phosphatidic acid, L-a(dimyristoyl)
phosphatidic acid, L-a(dioleoyl)phosphatidic acid, DL-a (di- palmitoyl) phosphatidic
acid, L-a(distearoyl) phosphatidic acid, and the various types of L-a-phosphatidylcholines
prepared from brain, liver, egg yolk, heart, soybean and the like, or synthetically,
and salts thereof. Other suitable modifications include the controlled peroxidation
of the fatty acyl residue cross-linkers in the phosphatidylcholines (PC) and the zwitterionic
amphipathates which form micelles by themselves or when mixed with the PCs such as
alkyl analogues of PC.
[0043] The phospholipids can vary in purity and can also be hydrogenated either fully or
partially. Hydrogenation reduces the level of unwanted peroxidation, and modifies
and controls the gel to liquid/crystalline phase transition temperature (T
m) which effects packing and leakage.
[0044] The liposomes can be "tailored" to the requirements of any specific reservoir including
various biological fluids, maintains their stability without aggregation or chromatographic
separation, and remains well dispersed and suspended in the injected fluid. The fluidity
in situ changes due to the composition, temperature, salinity, bivalent ions and presence
of proteins. The liposome can be used with or without any other solvent or surfactant.
[0045] Generally suitable lipids may have an acyl chain composition which is characteristic,
at least with respect to transition temperature (T
m) of the acyl chain components in egg or soybean PC, i.e., one chain saturated and
one unsaturated or both being unsaturated. However, the possibility of using two saturated
chains is not excluded.
[0046] The liposomes may contain other lipid components, as long as these do not induce
instability and/or aggregation and/or chromatographic separation. This can be determined
by routine experimentation.
[0047] The biocompatible hydrophilic polymer may be physically attached to the surface of
the liposome, or inserted into the membrane of the liposome. The polymer may therefore
be covalently bound to the liposome.
[0048] A variety of methods for producing the modified liposomes which are unilamellar or
multilamellar are known and available (see Lichtenberg and Barenholz, (1988)):
- 1. A thin film of the phospholipid is hydrated with an aqueous medium followed by
mechanical shaking and/or ultrasonic irradiation and/or extrusion through a suitable
filter;
- 2. Dissolution of the phospholipid in a suitable organic solvent, mixing with an aqueous
medium followed by removal of the solvent;
- 3. Use of gas above its critical point (i.e., freons and other gases such as CO2 or mixtures of CO2 and other gaseous hydrocarbons) or
- 4. Preparing lipid detergent mixed micelles then lowering the concentration of the
detergents to a level below its critical concentration at which liposomes are formed.
[0049] In general, such methods produce liposomes with heterogeneous sizes from about 0.02
to 10 µm or greater. Since liposomes which are relatively small and well defined in
size are preferred for use in the present invention, a second processing step defined
as "liposome down-sizing" can be used for reducing the size and size heterogeneity
of liposome suspensions.
[0050] The liposome suspension may be sized to achieve a selective size distribution of
vesicles in a size range less than about 5 µm, for example < 0.4 µm. In one embodiment
of the invention, the colloidal particles have an average particle size diameter of
from about 0.03 to 0.4 microns (µm), suitably around 0.1 microns (µm).
[0051] Liposomes in this range can readily be sterilized by filtration through a suitable
filter. Smaller vesicles also show less of a tendency to aggregate on storage, thus
reducing potentially serious blockage or plugging problems when the liposome is injected
intravenously or subcutaneously. Finally, liposomes which have been sized down to
the submicron range show more uniform distribution.
[0052] Several techniques are available for reducing the sizes and size heterogeneity of
liposomes, in a manner suitable for the present invention. Ultrasonic irradiation
of a liposome suspension either by standard bath or probe sonication produces a progressive
size reduction down to small unilamellar vesicles (SUVs) between 0.02 and 0.08 µm
in size.
[0053] Homogenization is another method which relies on shearing energy to fragment large
liposomes into smaller ones. In a typical homogenization procedure the liposome suspension
is recirculated through a standard emulsion homogenizer until selected liposome sizes,
typically between about 0.1 and 0.5 µm are observed. In both methods, the particle
size distribution can be monitored by conventional laser-beam particle size determination.
[0054] Extrusion of liposomes through a small-pore polycarbonate filter or equivalent membrane
is also an effective method for reducing liposome sizes down to a relatively well-defined
size distribution whose average is in the range between about 0.02 and 5 µm, depending
on the pore size of the membrane.
[0055] Typically, the suspension is cycled through one or two stacked membranes several
times until the desired liposome size distribution is achieved. The liposome may be
extruded through successively smaller pore membranes to achieve a gradual reduction
in liposome size.
[0056] Centrifugation and molecular sieve chromatography are other methods which are available
for producing a liposome suspension with particle sizes below a selected threshold
less than 1 µm. These two respective methods involve preferential removal of large
liposomes, rather than conversion of large particles to smaller ones. Liposome yields
are correspondingly reduced.
[0057] The size-processed liposome suspension may be readily sterilized by passage through
a sterilizing membrane having a particle discrimination size of about 0.4 µm, such
as a conventional 0.45 µm depth membrane filter. The liposomes are stable in lyophilized
form and can be reconstituted shortly before use by taking up in water.
[0058] Suitable lipids for forming liposomes are described above. Suitable examples include
but are not limited to phospholipids such as dimirystoylphosphatidylcholine (DMPC)
and/or dimirystoyl - phosphatidylglycerol (DMPG), egg and soybean derived phospholipids
as obtained after partial or complete purification, directly or followed by partial
or complete hydrogenation.
[0059] The following four methods are described in
WO 95/04524 and are generally suitable for the preparation of the colloidal particles (liposomes)
used in accordance with the present invention.
Method A
[0060]
- a) mixing amphipathic substances, such as lipids suitable for forming vesicles in
water-immiscible organic solvents
- b) removing of the solvent in presence of a solid support, alternatively, dried amphipathic
substances or mixtures thereof can be used in any form (powder, granular, etc.) directly,
- c) taking up the product of step b) into a solution of the biopolymeric substances
in a physiologically compatible solution
- d) adding an organic solvent having solubilizing or dispersing properties, as well
as
- e) drying the fraction obtained in step d) under conditions retaining the function
of the biopolymeric substances.
[0061] According to step a) of Method A amphipathic substances suitable for forming vesicles
as mentioned above are mixed in a water-immiscible organic solvent. The water-immiscible
organic solvent may be a polar-protic solvent such as fluorinated hydrocarbons, chlorinated
hydrocarbons and the like.
[0062] In step b) of the method of the invention the solvent is removed in presence of a
solid support. The solid support may be an inert organic or inorganic material having
a bead-like structure. The material of the inorganic support material may be glass
and the organic material can be Teflon
™ or other similar polymers.
[0063] The step c) of Method A of the invention is for taking up the product of step b)
into a solution of the substances to be encapsulated in a physiologically compatible
solution.
[0064] The physiological compatible solution may be equivalent to a sodium chloride solution
up to about 1.5 by weight. It is also possible to use other salts as long as they
are physiologically compatible e.g. as a cryoprotectant e.g., sugars and/or amino
acids. For example, lactose, sucrose or trehalose may be used as a cryoprotectant.
[0065] Optionally, between step a) and b) a step of virus inactivation, sterilizing, depyrogenating,
filtering the fraction or the like of step a) can be provided. This might be advantageous
in order to have a pharmaceutically acceptable solution at an early stage of the preparation.
[0066] The step d) of the Method A is adding an organic solvent having solubilizing or dispersing
properties.
[0067] The organic solvent may be an organic polar-protic solvent miscible with water. Lower
aliphatic alcohols having 1 to 5 carbon atoms in the alkyl chain can also be used,
such as tertiary butanol (tert-butanol). The amount of organic polar-protic solvent
miscible with water is strongly dependent on its interference with the substance to
be loaded to the liposomes. For example, if a protein is to be loaded the upper limit
is set by the amount of solvent by which the activity of the protein becomes affected.
This may strongly vary with the nature of the substance to be loaded. For example,
if the blood clotting factor comprises Factor IX then the amount of about of tert-butanol
is around 30%, whereas, for Factor VIII an amount of less than 10% of tert-butanol
is suitable (Factor VIII is much more sensitive to the impact of tert-butanol). The
percentage of tert-butanol in these examples is based on percent by volume calculated
for final concentration.
[0068] Optionally, subsequent to step d), virus inactivation sterilizing and/or portioning
of the fraction yielded after step d) can be carried out.
[0069] The step e) of the present invention is drying the fraction obtained in step d) under
conditions retaining the function of the substance to be loaded. One method for drying
the mixture is lyophilization. The lyophilization may be carried out in presence of
a cryoprotectant, for example, lactose or other saccharides or amino acids. Alternatively,
evaporation or spray-drying can be used.
[0070] The dried residue can then be taken up in an aqueous medium prior to use. After taking
up of the solid it forms a dispersion of the respective liposomes. The aqueous medium
may contain a saline solution and the dispersion formed can optionally be passed through
a suitable filter in order to down size the liposomes if necessary. Suitably, the
liposomes may have a size of 0.02 to 5 µm, for example in the range of < 0.4 µm.
[0071] The liposomes obtainable by the Method A show high loading of the blood factors.
[0072] The pharmaceutical compositions of the invention can also be an intermediate product
obtainable by isolation of either fraction of step c) or d) of the method A. Accordingly,
the formulation of the invention also comprises an aqueous dispersion obtainable after
taking up the product of step e) of method A in water in form of a dispersion (liposomes
in aqueous medium).
[0073] Alternatively, the pharmaceutical compositions of the invention are also obtainable
by the following methods which are referred to as Methods B, C, D and E.
Method B
[0074] This method comprises also the steps a), b) and c) of the Method A. However, step
d) and e) of Method A are omitted.
Method C
[0075] In Method C step d) of method A is replaced by a freeze and thaw cycle which has
to be repeated at least two times. This step is well-known in prior art to produce
liposomes.
Method D
[0076] Method D excludes the use of any osmotic component. In method D the steps of preparation
of vesicles, admixing and substantially salt free solution of the substances to be
loaded and co-drying of the fractions thus obtained is involved.
Method E
[0077] Method E is simpler than methods A - D described above. It requires dissolving the
compounds used for liposome preparation (lipids antioxidants, etc.) in a polar-protic
water miscible solvent such as tert.-butanol. This solution is then mixed with an
aqueous solution or dispersion containing the blood factor. The mixing is performed
at the optimum volume ratio required to maintain the biological and pharmacological
activity of the agent.
[0078] The mixture is then lyophilized in the presence or absence of cryoprotectant. Rehydration
is required before the use of the liposomal formulation. These liposomes are multilamellar,
their downsizing can be achieved by one of the methods described in
WO 95/04524.
[0079] The invention also includes methods of treatment of haemophilia A in a subject comprising
administering subcutaneously a pharmaceutical composition or dosage as defined herein
to a subject in need thereof. Such methods may include, a method of treatment of haemophilia
A in a subject wherein the patient has developed antibodies (i.e. inhibitors) to a
blood factor.
[0080] Blood clotting diseases or disorders may be characterised by a loss of function of
a blood clotting factor, or the generation of auto-antibodies. Examples of blood clotting
diseases include haemophilia, such as haemophilia A and haemophilia B.
[0081] The present invention therefore extends to a pharmaceutical composition as defined
above for use in the treatment of haemophilia A. Such pharmaceutical compositions
for use the treatment of haemophilia A may be used where the patient has developed
antibodies to said blood factor. Uses of the invention in accordance with this aspect
also include the use of a blood factor in the manufacture of a medicament as defined
above for use in the treatment of haemophilia A.
[0082] Factor VIIa can be used in the treatment of bleeding episodes in haemophilia A or
B, or in treatment of patients who have developed inhibitory antibodies against FVIII
or IX, respectively. Factor VIII can be used in the treatment of bleeding episodes
in patients with haemophilia A and Factor IX can be used in the treatment of patients
with haemophilia B.
[0083] As used herein, the term "treatment" includes any regime that can benefit a human
or a non-human mammal. The treatment of "non-human mammals" extends to the treatment
of domestic mammals, including horses and companion animals (e.g. cats and dogs) and
farm/agricultural animals including members of the ovine, caprine, porcine, bovine
and equine families. The treatment may be in respect of any existing condition or
disorder, or may be prophylactic (preventive treatment). The treatment may be of an
inherited or an acquired disease. The treatment may be of an acute or chronic condition.
[0084] Levels of activity in the blood coagulation cascade may be measured by any suitable
assay, for example the Whole Blood Clotting Time (WBCT) test or the Activated Partial
Thromboplastin Time (APTT).
[0085] The Whole Blood Clotting Time (WBCT) test measures the time taken for whole blood
to form a clot in an external environment, usually a glass tube or dish.
[0086] The Activated Partial Thromboplastin Time (APTT) test measures a parameter of part
of the blood clotting pathway. It is abnormally elevated in haemophilia and by intravenous
heparin therapy. The APTT requires a few millilitres of blood from a vein. The APTT
time is a measure of one part of the clotting system known as the "intrinsic pathway".
The APTT value is the time in seconds for a specific clotting process to occur in
the laboratory test. This result is always compared to a "control" sample of normal
blood. If the test sample takes longer than the control sample, it indicates decreased
clotting function in the intrinsic pathway. General medical therapy usually aims for
a range of APTT of the order of 45 to 70 seconds, but the value may also be expressed
as a ratio of test to normal, for example 1.5 times normal. A high APTT in the absence
of heparin treatment can be due to haemophilia, which may require further testing.
[0087] The invention also provides a kit of parts comprising a pharmaceutical composition
of the invention, and an administration vehicle including an injectable solution for
subcutaneous administration, said kit suitably comprising instructions for use thereof.
[0088] The invention therefore may also suitable provide a dosage form of a pharmaceutical
composition of the invention. Such dosage forms may be provided as suitable containers
or vials containing the appropriate dose for a patient.
[0089] The pharmaceutical compositions for subcutaneous administration or dosage forms of
the invention may be administered alone or in conjunction with other compounds, such
as therapeutic compounds or molecules, e.g. anti-inflammatory drugs, analgesics or
antibiotics, or other pharmaceutically active agents which may promote or enhance
the activity of Factor VIIa, Factor VII, Factor VIII, Factor IX, Factor X, Factor
Xa, Factor XI, Factor V, Factor XIII, von Willebrand's Factor (vWF), prothrombin or
Protein C, or a fragment thereof, such as for example another blood coagulation factor.
Such administration with other compounds may be simultaneous, separate or sequential.
The components may be prepared in the form of a kit which may comprise instructions
as appropriate.
[0090] The pharmaceutical compositions of the invention allow for improved treatment of
diseases where a blood factor is administered to treat a patient suffering from haemophilia
A.
[0091] In one embodiment of the invention there is provided a pharmaceutical composition
for subcutaneous administration comprising a blood factor and a colloidal particle
comprising approximately 1-20 mole percent of an amphipathic lipid derivatized with
a biocompatible hydrophilic polymer, a pharmaceutically acceptable buffer, adjusted
to physiological pH suitable for subcutaneous administration, wherein the blood factor
is not encapsulated in said colloidal particle.
[0092] It is understood by the skilled person that the dosage of the medicament of the invention
is depending on the concentration of the effective biopolymeric substances as well
as their efficiency.
[0093] A dosage up to 2.000 mg/liposomes lipid per kg body weight can be administered to
patients wherein the active factors in the liposomes are loaded with an efficiency
of higher than 50% based on the total activity used for preparing the loaded liposomes.
[0094] Accordingly, in another aspect of the present invention, the volume of the formulation
for delivery into a patient may be no more than 2ml. Suitably, the delivery volume
may be 5µl, 10µl, 25µl, 50µl, 100µl, 250µl, 500µl, 750µl, or 1ml. In alternative embodiments
the volume of the formulation for delivery may be no more than 1.5ml, 2ml, 2.5ml,
3.0ml or 3.5ml.
[0095] It is important to note that the present invention allows for a higher concentration
of an active agent to be delivered in a single subcutaneous injection more safely
than by intravenous injection, since it is not delivered directly into the bloodstream
of the patient. This is particularly important when dealing with blood clotting factors,
since high concentration of blood clotting factors administered intravenously can
result in undesirable and dangerous blood clots in the patient.
[0096] Subcutaneous delivery allows the steady infusion of the active agent into the blood
stream via the lymphatic system, thus avoiding the effect of dangerous levels of an
active agent being delivered directly into the blood system. Therefore, since the
concentration of delivery of the agent into the blood stream is regulated by the lymph
system of the patient, a higher concentration may be delivered in a subcutaneous administration
dose, which allows for smaller volumes to be used than traditionally used with intravenous
delivery.
[0097] The formulations of the invention may be for administration at least once per day,
at least twice per day, about once per week, about twice per week, about once per
two weeks, or about once per month.
[0098] For certain therapeutic substances, a dosage regime of once per day will be sufficient,
but for others a more frequent dosage regime may be more appropriate or desirable,
where the amount delivered in each dosage administered subcutaneously may be reduced
relative to a standard intravenous dosage. So for example a formulation of the invention
may be administered once per day, twice per day (or more if required).
[0099] The present invention allows the prevention of the rapid rise and subsequent fall
(i.e. a "sawtooth") in the concentration of a therapeutic agent in the blood. The
present invention provides a more consistent, predictable concentration of the agent
in the blood of a patient over a longer period of time than is traditionally seen
with standard pharmaceutical formulations of the same agent when repeatedly delivered
intravenously.
[0100] A further benefit of the present invention is that it enables a higher dose of the
agent to be administered subcutaneously than may be safely administered intravenously.
This results in the provision of a longer duration of the therapeutic benefit than
could ordinarily and safely be achieved by higher dosing or more frequent dosing via
intravenous delivery. For example, in the case of blood factors, because the products
are being delivered via the thoracic duct into the subclavian vein, the method enables
a larger amount of product to be administered at a single time point as a single dose
subcutaneously than could be administered at a single time point intravenously into
a vein. Delivery of a high dose bolus into a vein may cause an undesirable thrombotic
event.
[0101] A further benefit of the present invention is that it enables the therapeutic agent
to be re-dosed at intervals to allow blood concentration of the agent to be maintained
at a consistent level, providing a sustained constant and predictable therapeutic
effect without the need to wait to re-dose until the concentration of the agent in
the blood falls to therapeutically irrelevant levels. In traditional practice, intravenous
re-dosing of blood clotting factors, with its immediate C
max and onset of action, is delayed until it has been estimated that the level of the
therapeutic has dropped to a level at which the addition of the C
max from the new injection will not reach a potentially thrombogenic level (i.e. reducing
the risk of an adverse event), but which means that the patient has reached an "unhealthy"
range of a level of an agent in his or her bloodstream. In other words, subsequent
doses of an agent are not normally given to the patient while "healthy levels", or
therapeutically effective levels, of the agent are still present in the bloodstream.
However, the present invention enables re-dosing of the agent to occur while blood
levels of the agent are still in a therapeutic effective range. Thus the invention
provides for a more consistent therapeutic level of protein in the bloodstream that
is more ideally suited to prophylaxis. Due to the consistent delivery of the agent
into the bloodstream via the thoracic duct, the problem of increasing the agent in
the bloodstream to undesirably high levels is avoided.
[0102] The invention provides a formulation for subcutaneous administration to a subject
which enables the subject to receive a dosage form of a blood clotting factor sufficient
to maintain a whole blood clotting time in said subject of no more than 20 minutes,
in other words for administration of no more than once per month. Also provided is
a formulation of blood coagulation factor for subcutaneous administration no more
than once per month wherein the dosage form has a C
max of at least 10% and no more than 90% compared to an equivalent reference dosage form
when administered intravenously, for use in the treatment of a blood clotting disorder.
Suitably, the C
max is from 20% to 80%, or from 30% to 70%, or from 40% to 60%.
[0103] By "no more than" it is meant that the dosage form may be administered more frequently
than the time period specified, but it is not necessary to do so; the effect of the
subcutaneous administration of such a dosage form means that the effects are seen
for the duration of the time period. However, due to the lower and consistent C
max, more frequent dosing may occur without adverse effects to the patient.
[0104] Suitably, the dosage form of a blood clotting factor may be sufficient to maintain
a whole blood clotting time in said subject of less than 15 minutes, or suitably,
less than 12 minutes. In an embodiment, the dosage form of a blood clotting factor
is an at least once per week dosage form, or at least once per month, at least once
per two weeks, at least once per half week dosage form.
[0105] Also provided is a dosage formulation according to the invention, in which the dosage
of the blood clotting factor is of from 1 to 1000 IU/kg, or from 5 to 500 IU/kg, or
from 100 to 250 IU/kg, or from 25 to 50 IU/kg, or from 5 to 50 IU/kg.
[0106] The dosage form of the present invention comprising a blood clotting factor allows
for a less frequent dosing of the dosage form, which is still sufficient to maintain
the whole blood clotting time in a subject of no more than 20 minutes, or no more
than 15 minutes, or no more than 10 minutes. In one embodiment, the dosage form is
sufficient to maintain whole blood clotting time of less than 12 minutes. The dosage
form may provide a no more than once a fortnight, no more than once a week, no more
than twice a week, no more than once every three days, no more than once every 2 days,
no more than once a day or a more or less frequent dosage form.
[0107] It is important to note that one benefit of the present invention is that the dosage
form when the agent is a blood clotting factor, does not need to be administered to
the patient more frequently than these intervals in order to continue to maintain
whole blood clotting time in a healthy range, but it may be administered more frequently
in order to help to provide a "steady state" similar to that of a controlled release
formulation. A "normal" whole blood clotting time is generally considered by one skilled
in the art to be 10 to 12 minutes, and anything under 15 minutes is considered to
be healthy in a non-haemophiliac human. Once whole blood clotting time is over 20
minutes, it is considered to be in an unhealthy range. Between 15 and 20 minutes is
considered to indicate that although bleeding is under control, it is not normal.
[0108] In another embodiment the dosage form is administered less frequently than would
be predicted by the plasma half-life of a bolus intravenous injection. For example,
a bolus injection of modified Factor IX may be required once a week, whereas the same
agent delivered subcutaneously in accordance with the invention, may only be required
once per ten days, or less.
[0109] According to a further aspect of the invention, there is provided a dosage form of
a pharmaceutical composition of 25 to 50 IU/kg of a blood coagulation factor for subcutaneous
administration at the same or with less frequency than the blood coagulation factor
administered intravenously.
[0110] Formulations of the present invention are therefore able to maintain a normal value
for haemostasis of up to seven days in which a normal value is defined as a Whole
Blood Clotting Time (WBCT) of less than 15 minutes, suitably, about 12 minutes or
less.
[0111] The formulations of specific embodiments of the invention wherein the formulation
comprises a blood factor may comprise a dosage of from 25 to 50 IU/kg. In some embodiments
the dosage may be 25, 30, 35, 40, 45, or 50 IU/kg. The dosage may be from 25 IU/kg
to 30 IU/kg, 35 IU/kg to 40 IU/kg, or 40 IU/kg to 50 IU/kg.
[0112] The formulations of specific embodiments of the invention wherein the formulation
comprises a blood factor may alternatively comprise a dosage of from 5 to 50 IU/kg.
In some embodiments the dosage may be 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 IU/kg.
The dosage may be from 5 IU/kg to 10 IU/kg, 25 IU/kg to 30 IU/kg, 35 IU/kg to 40 IU/kg,
or 40 IU/kg to 50 IU/kg.
[0113] In one embodiment, when the dosage form is prepared as a dose of 150 IU/kg, the formulation
may be suitable for administration once every two weeks to a subject in need thereof.
Suitably, the formulation may be for administration no more than once every two weeks.
Alternatively, the dosage may be prepared as a dose of 100 IU/kg
[0114] According to an embodiment of the invention, a formulation of the invention comprising
a blood clotting factor can result in normal haemostasis being maintained for at least
one half of a week.
[0115] Dosage forms in accordance with the invention, when administered subcutaneously result
in lower amounts of the modified blood coagulation (clotting) factor being required
to achieve the same therapeutic end-point thus providing safer products for subjects
in need of treatment. In one embodiment half the adjusted dose of modified blood clotting
factor administered intravenously is sufficient to achieve normal haemostasis for
at least one week in subjects, particularly wherein the blood coagulation factor is
Factor VIII. A suitable value for normal haemostasis is a Whole Blood Clotting Time
(WBCT) of about 12 minutes, as described above.
[0116] Formulations of the invention may suitably comprise less than half the dose adjusted
therapeutically effective amount of a reference formulation formulated for intravenous
administration comprising the same modified blood coagulation factor in order to achieve
the same therapeutic effect.
[0117] The invention therefore also provides for a dosage form of a modified blood coagulation
factor for subcutaneous administration in which the dosage form comprises 50% of the
dose adjusted amount required for intravenous administration in order to achieve the
same duration of effective action.
[0118] A formulation suitable for subcutaneous administration may suitably be prepared as
an aqueous or substantially aqueous formulation. The formulation may comprise such
additional salts, preservatives and stabilisers and/or excipients or adjuvants as
required. The dosage forms of the invention may be provided as anhydrous powders ready
for extemporaneous formulation in a suitable aqueous medium.
[0119] Suitably such dosage forms can be formulated as buffered aqueous formulations. Suitable
buffer solutions may include, but are not limited to amino acids (for example histidine),
salts of inorganic acids and alkali metals or alkaline earth metals, (for example
sodium salts, magnesium salts, potassium salts, lithium salts or calcium salts - exemplified
as sodium chloride, sodium phosphate or sodium citrate). Other components such as
detergents or emulsifiers (for example, Tween 80
® or any other form of Tween
®) may be present and stabilisers (for example benzamidine or a benzamidine derivative).
Excipients such as sugars, (for example sucrose) may also be present. Suitable values
for pH are physiological pH, e.g. pH 6.8 to 7.4 or pH 7.0. Liquid dosage forms may
be prepared ready for use in such administration vehicles.
[0120] In one particular embodiment of the invention, there is provided a pharmaceutical
composition for subcutaneous administration as follows:
- 50mM sodium citrate
- pH 7.0
- 100mM phospholipids - 97:3 molar ratio of palmitoyl- oleoyl phosphatidyl choline (POPC)
and 1,2- distearoyl-sn-glycero-3phosphoethanol-amine-N-[poly-(ethyleneglycol)-2000]
(DSPE-PEG 2000).
- Lyophilised rFVIII (Helixate NexGen)
[0121] The invention will now be further described by way of reference to the following
examples which are present for the purposes of illustration only and are not be taken
as limitations to the invention.
Example 1: Synthesis of liposomes
[0122] Mixed lipids were prepared from palmitoyl- oleoyl phosphatidyl choline (POPC) and
1,2- distearoyl-sn-glycero-3-phosphoethanol-amine-N-[poly-(ethyleneglycol)-2000] derivatized
with PEG-2000 (PEG with molecular weight 2000 Daltons) (DSPE-PEG 2000), as follows:
Molecular weight of POPC: 760.08g/mol
Molecular weight of DSPE-2kPEG: 2789.5g/mol
[0123] The final preparation had a concentration of 100mM phospholipids. A 15% w/v mixture
of lipids was made with a 97:3 molar ratio of POPC:DSPE-2kPEG. The following were
weighed and mixed:
2.04g POPC
0.232g DSPE-2kPEG
14.9mL tert-butanol (melted in a 35°C water bath), all placed in a 100mL Schott bottle.
[0124] The mixture was maintained at 35°C in a water bath and stirred intermittently until
all solids had dissolved/dispersed. The final material was a clear colourless mixture.
The mixture was frozen at - 80°C overnight.
[0125] The operation was maintained in a fume hood to allow containment during the post-use
clean-up of dried/condensed solvent. The Christ Alpha 1-2 LD freeze-drier and vacuum
pump were warmed up for 20 minutes, and the frozen lipid/solvent mixture was removed
from -80°C storage and dried overnight.
[0126] The dried lipids were recovered from the drier the following morning. They appeared
as a dry crystalline cake. A 100mM lipid solution was required for further processing.
The quantities of lipid present calculate through as around 82µmoles of DSPE-2kPEG
and 2.69mmoles of POPC; so around 2.77mmoles of lipids. Thus 27.7mL of diluent was
required. 27.7mL of 50mM sodium citrate buffer was added to the dried lipids, and
the resulting mixture was stirred and heated to around 35°C. After around 120 minutes,
a white emulsion with no obvious large solids resulted. This was subjected to extrusion
as below.
[0127] A Sartorius 47mm stainless steel pressure filtration housing was assembled and wrapped
with a water jacket (wrapped tubing fed via a thermocirculator) maintained at 35°C.
The housing was fitted with a polycarbonate track-etched membrane (details below),
covered by a glass-fibre prefilter (Whatman GF/D). The emulsion was poured into the
housing and extruded under 4 bar nitrogen gas, with the filtrate collected into 50mL
tubes. The duration of each extrusion was timed and noted.
[0128] The filtration sequence was: 0.8µm, 0.4µm, 0.2µm, 0.2µm, 0.1µm and 0.1µm (i.e. single
passes through the larger filters and two passes through the smaller 0.2 and 0.1µm
filters), with the filtrate warmed back to 35°C between passes. The liposomes were
extruded, with tabulated data is below:
Table 1
| Pore size (µm) |
Duration |
Recovery (g) |
| 0.8 |
<4 sec |
28.19 |
| 0.4 |
<4 sec |
26.91 |
| 0.2 |
50 sec |
23.76 |
| 0.2 |
22 sec |
21.77 |
| 0.1 |
12 minutes |
20.18 |
| 0.1 |
4 minutes |
19.47 |
[0129] The resulting extruded lipids were stored at +5°C. 15mL of 'Extruded Liposomes' were
removed from the chilled stock and dispensed into a sterile 50mL tube within a MicroBiological
Safety Cabinet. The size of the extruded liposomes was analysed using an ALV5000 photon
correlation spectrometer. The average radius was determined to be 75.40 ± 0.86nm and
the average peak width 22.21 ± 3.86nm, giving an average diameter of 150.80nm and
polydispersity index of 0.087.
Example 2: Pharmacokinetics/Pharmacodynamics of recombinant human FVIII reconstituted
with PEGylated liposomes in haemophilia A dogs following subcutaneous administration
[0130] A dog with haemophilia A (identified as dog number "1") received subcutaneous doses
of PEGylated liposomes associated with Factor VIII (PEGLip FVIII SQ), as follows:
The objectives of this study were to determine the PK and PD in a haemophilia A dog
of full-length rFVIII reconstituted in PEGylated liposomes administered subcutaneously
(SQ).
Full-length rFVIII
[0131] Lyophilised, full-length rFVlll (Helixate NexGen, Lot 270LR8WB) was used as the test
article.
PEGylated Liposome formulation
[0132] PEGylated Liposomes in citrate buffer were produced in accordance with Example 1
above according to the method of Baru
et al. (2005). The Liposome formulation had the following composition; 50mM sodium citrate
pH 7.0 containing 100mM phospholipids; comprising a 97:3 molar ratio mixture of palmitoyl-oleoylphosphatidylcholine
(POPC) and 1,2-distearoyl-sn-glycero-3-phosphoethanol-amine-N-[poly-(ethyleneglycol)-2000]
(DSPE-PEG 2000).
[0133] The experimental test subject dog was from the haemophilia A colony housed at the
University of Alabama Medical School. All dogs have congenital severe haemophilia
A. The test subject weighed 16.4kg and was naive to human proteins.
[0134] Prior to dosing, the dog was tested to verify normal health status, including complete
blood chemistry, serum chemistry profile fibrinogen, fibrinogen derived peptides (FDPs),
thrombin time and urinary analysis
[0135] The design of this study was a single SQ dose feasibility trial in a single individual.
[0136] Full-length, recombinant human FVIII (Helixate NexGen, 2,000 IU) was reconstituted
with 13.3ml of PEGylated liposomal diluent. The reconstituted rFVIII was mixed gently
at ambient temperature for 5-10 min to allow the protein to adsorb to the liposomes
before use. Once reconstituted, the suspension had a FVIII activity of 150 IU/ml.
[0137] The test individual was dosed SQ at 100 IU/kg. Calculation of the volume of drug
to be administered was carried out according to the following equation:

Where:
- a is the target dose (100 IU/kg)
- b is the weight of the dog (kg)
- c is the rFVIII activity (150 IU/ml)
[0138] Following dosing, the test animal was observed for clinical signs. Unexpected toxicities
were screened for by performing CBC and serum chemistry tests at 48hr and 5 days post-dose.
Fibrinogen, FDPs and the thrombin time (TT) were evaluated to test for increased thrombosis
risk.
[0139] Blood samples (5 ml) were taken from the dog dosed SQ at the following times points
after administration:
Pre-drug administration and at 0.5, 1, 2, 4, 8, 12, 24, 36, 48, 60, 72, 84, 96, 108
and 120 hours post-dose.
[0140] Whole blood (non-citrated; 1 ml) was used for the whole blood clotting assay and
the activated clotting time assay. The remaining 4ml blood samples were transferred
into tubes containing 0.109M tri-sodium citrate anticoagulant (9:1 v/v) on ice.
[0141] The activated Partial Thromboplastin Time (aPTT), Activated Clot Time (ACT) and Thromboelastogram
(TEG) assays were conducted on the citrated whole blood.
[0142] Plasma was prepared by centrifugation of the remaining citrated blood and the resulting
plasma samples were stored in aliquots of approximately 100 µl at -80°C.
Assays
(i) Non-citrated whole blood: Whole blood clotting assay
[0143] Blood samples were divided between 2 vacutubes, (2 X 0.5 ml) and observed carefully
with periodic and judicious levelling of the tube until a clot was determined by interruption
of flow in the fully horizontal position. The quality of the clot was observed by
holding the tube in the fully inverted position. The whole blood clotting time was
recorded as the mean of the total time from sample extraction until visual observation
of blood clot for both samples and the quality of the clot in the inverted position
was be noted.
(ii) Citrated whole blood: Thromboelastogram (TEG) assay
[0144] TEG was performed with re-calcified citrated whole blood using a Hemostasis Analyzer
Model 5000 (Haemoscope Corporation) thromboelastograph according to the manufacturers'
recommendations. Briefly, 1 ml of citrated whole blood was placed in a commercially
available (Teg
®Hemostasis System Kaolin, Haemonetics) vial containing kaolin. Mixing was ensured
by gentle inversion of the kaolin-containing vials 5 times. Pins and cups were placed
in the TEG analyzer in accordance with the standard procedure recommended by the manufacturer.
Each standard TEG cup was placed in the 37° C pre-warmed instrument holder and was
filled with 20 µl of calcium chloride (0.2 M). Then, 340 µl of kaolin-activated citrated
whole blood was added for a total volume of 360 µl.
(iii) Activated Clotting Time (ACT) and activated Partial Thromboplastin Time (aPTT)
[0145] The ACT and aPTT tests were carried out using a Haemachron Jr coagulation analyzer
(International Technidyne Corps.) according to the manufacturer's instructions.
(iv) Plasma: FVIII activity assay (Chromogenic)
[0146] FVIII plasma activity was determined using the Coatest Assay (Dia Pharma, West Chester
,OH). Plasma samples were diluted 1:20 to 1:80 with assay diluent and assayed according
to the manufacturer's instructions. Standard curves were established using normal
hemostasis reference plasma (american diagnostica inc, Stamford, CT) and the purified
PEG-FVIII protein.
(v) Plasma: FVIII ELISA
[0147] The concentration of FVIII antigen in plasma samples will be determined by ELISA
using the Visulize FVIII antigen kit from Affinity Biologicals (Ancaster, Ontario,
Canada) according to the manufacturer's instructions.
(vi) Plasma: Immunogenicity
[0148] Bethesda assays were conducted on 1:4, 1:10 and 1:20 dilutions of test plasma into
FVIII deficient human plasma. Equal volumes of the diluted test plasma and normal
human reference plasma were incubated at 37°C for 2 hours and the Bethesda titre determined
using the aPTT assay and a normal human plasma standard curve as described above.
Table 2
| Dog Number |
1 |
| Dog weight (kg) |
16.4 |
| Dose (IU/kg) |
100 |
| rFVIII batch number |
Lot 270LR8WB |
| Volume of PEGLip diluent used (ml) |
13.3ml |
| Volume administered (ml) |
10.93 |
[0149] Results of the study are shown in Table 3.
Table 3
| Date (dd/mm/yy) |
Time (hh:mm) |
Time post-dose (h) |
WBCT 1 (min) |
WBCT 2 (min) |
WBCT average (min) |
ACT-LR (sec) |
aPTT-cit (sec) |
TEG (r:min) |
FVIII activity) (IU/ml) |
[FVIII] (ELISA) (% normal) |
Bethesda assay (U) |
| |
|
|
|
|
|
|
|
|
|
|
|
| 26/11/2013 |
|
0 |
22 |
34 |
28 |
367 |
189.1 |
|
ND |
ND |
|
| 03/04/2014 |
|
0 |
28 |
28 |
28 |
347 |
300 |
60 |
0 |
ND |
ND |
| 08/04/2014 |
12:00pm |
0.50 |
20 |
22 |
21 |
332 |
300 |
|
|
1 |
|
| |
12:30pm |
1.00 |
10 |
10.5 |
10.25 |
270 |
158.1 |
30.2 |
0.6 |
2.1 |
|
| |
1:30pm |
2.00 |
8.5 |
10 |
9.25 |
193 |
129.8 |
21.9 |
1.4 |
4 |
|
| |
3:25pm |
4.00 |
10 |
12 |
11 |
211 |
126.2 |
15.6 |
1.9 |
4.3 |
|
| |
7:35pm |
8.00 |
7 |
8 |
7.5 |
200 |
99.4 |
21.9 |
1.4 |
5.2 |
|
| |
10:45pm |
11.25 |
9.5 |
10.5 |
10 |
207 |
94.7 |
20.9 |
2.1 |
5.4 |
|
| 09/04/2014 |
11:15am |
23.75 |
12 |
12 |
12 |
213 |
178.4 |
18.1 |
|
3.5 |
|
| |
5:05pm |
29.50 |
12 |
15 |
13.5 |
273 |
140.8 |
22.6 |
0.4 |
3.1 |
|
| 10/04/2014 |
12:00pm |
48.00 |
18 |
18 |
18 |
326 |
156.1 |
60 |
|
3.1 |
|
| 11/04/2014 |
09:40 |
70.16 |
26 |
24 |
25 |
305 |
387.7 |
60 |
|
2.4 |
ND |