Improved vaccines

Abstract

This disclosure provides improved solid dose vaccines (SDVs) comprising: (i) an immunogen; and (ii) at least one structural adjuvant which is a polysaccharide adjuvant. In some embodiments an SDV comprises a water soluble or water dispersible solid matrix comprising (i) an immunogen; and (ii) at least one structural adjuvant which is a polysaccharide adjuvant. In some embodiments the structural adjuvant may be selected from the group consisting of DEAE-dextran, inulin, chitosan and cyclodextrin. The SDVs may be used inter alia in methods of vaccinating a subject against a variety of diseases or conditions. Processes for preparing the SDVs are also disclosed.

Description

[0001] IMPROVED VACCINES

[0002] Field of the invention

[0003] The present disclosure relates to improved vaccine formulations. In particular, the disclosure relates to improved solid dose vaccine (SDV) formulations, SDVs prepared using them and methods relating thereto.

[0004] Background

[0005] Vaccination is used for the treatment or prophylaxis of large numbers of both infectious and endogenous diseases. Typical liquid vaccines include an immunogen, intended to elicit an immune response in the subject and typically, a diluent such as water and one or more excipients such as stabilisers. Many vaccines incorporate an adjuvant which enhances the immune response to otherwise poorly immunogenic antigens. The most commonly used adjuvants are those based on aluminium compounds such as aluminium hydroxide and aluminium phosphate. However, whilst these elicit a strong humoral response, they are relatively poor at eliciting cellular immune responses and commonly cause adverse local reactions at the injection site that may be long lasting.

[0006] A typical immunization involves injection of the vaccine, (usually intramuscularly) followed by a period of slow increase in the production of specific antibodies to the immunogen (seroconversion). After a period of time the level of specific antibodies wanes or stabilizes and a so-called booster dose is given, leading to further increase in antibody production. The slow initial production of antibodies can leave the subject vulnerable, e.g. to infection, during this period. One area where this issue is particularly important is when subjects are vaccinated against a current, locally prevalent disease agent, or during an epidemic where early production of antibodies at protective level is important, both for the subject and for reducing spread in the wider population.

[0007] The preparation of large quantities of immunogen can be a significant challenge in the large-scale preparation of vaccines. This is both time consuming, technically challenging and expensive. It would therefore be advantageous to provide vaccines that deliver effective immune responses with smaller quantities of immunogen.

[0008] Although there are a number of drawbacks related to these liquid formulations, (e.g. storage stability, difficulty in presenting some immunogens in aqueous environments, rapid degradation of immunogens in the body, adverse reactions in some patients to adjuvants and patient aversion to needles), there remains a very limited disclosure in the art relevant to alternative approaches. In some cases, solid dose vaccines (SDVs) are small, usually elongate bodies that are delivered to a position under the surface of the skin, at low velocity from a needle-free injector device. This approach requires a formulation which is adaptable to the presence of various immunogens as well as any necessary additional components such as adjuvants or other excipients, without compromising the required high mechanical strength necessary for delivering the SDV projectile through the skin.

[0009] W008102136 discloses solid dose forms having high compressive strength and suitable for percutaneous delivery. These formulations are suitable for the delivery of a variety of therapeutic agents including vaccines. WO2017 / 068351 discloses solid dose protein and peptide formulations particularly suitable for manufacture by extrusion and comprising carboxymethylcellulose. These solid dose formulations have high mechanical strength whilst tolerating the incorporation of high proportions of active ingredient. W02020 / 260882 describes SDV formulations of high mechanical strength, which are suitable for manufacture by tabletting processes, and which comprise dextran as a structural excipient. These formulations are suitable for delivering therapeutic and prophylactic agents, including vaccines. Devices for delivering these agents are disclosed in inter alia W02006 / 082439, WO2012 / 098356, WO2016 / 124903 and WO2021 / 123736.

[0010] There remains a need for solid formulations suitable for delivery through the skin, which tolerate incorporation of immunogenic components, that elicit an effective immune response in the subject when used in combination with a range of immunogens, including those with poor immunogenicity, or that require the use of an adjuvant.

[0011] Summary of the invention

[0012] The inventors have identified a group of compounds that can be incorporated into the structure of the solid dose form without compromising its deliverability, which have no (or limited) effect on structural strength, that can be simply incorporated into process workflows and that provide an improved immune response. These compounds are referred to herein as first excipients or structural adjuvants. A first aspect of the invention provides a solid dose vaccine comprising: (i) an immunogen; and (ii) at least one structural adjuvant which is a polysaccharide adjuvant. In some embodiments the structural adjuvant may be selected from the group consisting of DEAE-dextran, inulin, chitosan and cyclodextrin.

[0013] In some cases, SDVs are delivered to a position fully under the surface of the skin, typically at low velocity from a needle-free injector device. These dosage forms are usually small and / or elongate bodies. In some cases SDVs may be delivered parenterally and in still further cases the SDV is a microneedle array or patch. In some embodiments an SDV comprises a water soluble or water dispersible solid matrix comprising (i) an immunogen; and (ii) at least one structural adjuvant which is a polysaccharide adjuvant. In some embodiments the structural adjuvant may be selected from the group consisting of DEAE-dextran, inulin, chitosan and cyclodextrin.

[0014] The structural adjuvants are compounds that provide an improved immune response to the immunogen either individually or in combination with another of the structural adjuvants.

[0015] In some embodiments, for example, the structural adjuvant consists of DEAE-dextran and optionally at least one additional structural adjuvant selected from chitosan, inulin and cyclodextrin.

[0016] In some embodiments the structural adjuvant consists of chitosan and optionally at least one additional structural adjuvant selected from DEAE-dextran, inulin and cyclodextrin.

[0017] In some embodiments the structural adjuvant consists of inulin and optionally at least one additional structural adjuvant selected from DEAE-dextran, chitosan and cyclodextrin.

[0018] In some embodiments the structural adjuvant consists of cyclodextrin and optionally at least one additional structural adjuvant selected from DEAE-dextran, chitosan and inulin.

[0019] The term “cyclodextrin” as referred to herein, includes a-cyclodextrin, P-cyclodextrin and y- cyclodextrin as well as the hydroxyalkyl derivatives thereof, particularly the hydroxypropyl derivatives. Hydroxypropyl-beta-cyclodextrin is preferred.

[0020] In addition to an immunogen and one or more structural adjuvants (or first excipients), the SDV may additionally comprise one or more compounds from a second group of excipients, referred to herein as “structural excipients” or second excipients. Thus in some embodiments, an SDV comprises a water soluble or water dispersible solid matrix comprising (i) an immunogen; and (ii) at least one structural adjuvant which is a polysaccharide adjuvant. In some embodiments the polysaccharide adjuvant is selected from the group consisting of DEAE-dextran, inulin, chitosan and cyclodextrin and (iii) at least one structural excipient.

[0021] These compounds may be bulking agents but also inherently provide structural strength to the SDV. They may be combined with other components of the SDV without compromising the deliverability of the SDV, for example, without reducing the compressive strength below the level required for needle- free injection. Structural excipients are selected from dextran, carboxymethyl cellulose (CMC) and mixtures of the two, particularly dextran.

[0022] In some embodiments, the solid dose optionally comprises one or more additional adjuvants. However, whilst in some embodiments these additional adjuvants may include aluminium compounds such as alum. In some embodiments the solid dose may be free of aluminium containing compounds. A further aspect of the disclosure relates to a solid dose vaccine comprising: (i) an immunogen; and (ii) between 3.2% and 99.9wt% DEAE-dextran. In some embodiments, an SDV comprises a water soluble or water dispersible solid matrix comprising (i) an immunogen; and (ii) 3.2-99.9wt% DEAE-dextran. The SDV may additionally comprise one or more structural adjuvants selected from chitosan, inulin and cyclodextrin.

[0023] A further aspect of the disclosure relates to a method of eliciting an immune response towards an immunogen in a subject comprising delivering to the subject a solid dose vaccine as described herein comprising the immunogen. The SDV may be delivered by a variety of routes including by dermal, intradermal, transdermal, subcutaneous or intramuscular administration, but may also be delivered orally, mucosally or intraperitoneally.

[0024] A further aspect of the disclosure relates to a method of vaccinating a subject against an infection caused by organism comprising delivering to the subject a solid dose vaccine, comprising an immunogen of (or derived from) the organism.

[0025] A further aspect of the disclosure relates to a method of eliciting an immune response towards an immunogen in a subject comprising delivering to the subject a solid dose vaccine comprising the immunogen.

[0026] A further aspect of the disclosure relates to a method of vaccinating a subject against a cancer comprising delivering to the subject an SDV as described herein comprising an immunogen of the cancer. Such immunogens of the cancer include, for example, neo antigens.

[0027] A further aspect of the disclosure relates to a method of treating or preventing a condition, disease or disorder, said method comprising administering to a subject in need thereof, a therapeutically effective amount of an SDV as described herein

[0028] A further aspect of the disclosure relates to an SDV as described herein for use as a medicament, particularly as a vaccine, in the treatment or prevention of a condition, disease or disorder as described further herein.

[0029] A further aspect of the disclosure relates to an immunogen as described herein for use in vaccinating a subject in the treatment or prevention of a condition, disease or disorder; wherein the immunogen is delivered in the form of an SDV as described herein.

[0030] A further aspect of the disclosure relates to a solid dose vaccine as described herein for use in a method of needle-free vaccination.

[0031] A further aspect of the disclosure relates to a solid dose vaccine as described herein, for use in the vaccination of a subject against an infectious disease. A further aspect of the disclosure relates to a solid dose vaccine as described herein, for use in the vaccination of a subject against a cancer.

[0032] A further aspect of the disclosure relates to an immunogen as described herein for use in the manufacture of a medicament, particularly a vaccine, for use in the treatment or prevention of a condition, disease or disorder; wherein the immunogen is delivered in the form of an SDV as described herein.

[0033] A further aspect of the disclosure relates to SDVs as described herein for use in the manufacture of a medicament, particularly a vaccine, for use in the treatment or prevention of a condition, disease or disorder.

[0034] In a yet further aspect, the disclosure provides a process for the preparation of an SDV as disclosed herein, comprising combining (i) an immunogen; and (ii) one or more structural adjuvants which are polysaccharide adjuvants, as a powder; compressing the powder to form a body and drying the body to provide an SDV. In some embodiments the method comprises providing a water soluble or water dispersible solid matrix comprising (i) an immunogen; and (ii) at least one structural adjuvant which is a polysaccharide adjuvant as a powder; compressing the powder to form a body and drying the body to provide an SDV. In some embodiments the SDV has a compressive strength of at least 40MPa. In some embodiments the SDV has a compressive strength of at least 50, 60, 70 or 80MPa. In some embodiments the structural adjuvant is selected from the group consisting of DEAE-dextran, inulin, chitosan and cyclodextrin.

[0035] Detailed description of the invention

[0036] The SDV compositions of the present disclosure are suitable for delivering a variety of immunogens in order to elicit an immune response in a subject. The immunogen used in the SDV of this disclosure are not particularly limited and any immunogen suitable for eliciting an immune response in a subject can be used. The immunogen may be suitable for eliciting an antibody response a cellular immune response, or both an antibody and a cellular immune response, in a subject. Example immunogens include, but are not limited to, attenuated or inactivated organisms or immunogenic portions thereof, toxoids, purified immunogens (such as proteins, polysaccharides), recombinant proteins, viral or bacterial vectors, nucleic acids, conjugated immunogens and cancer neoimmunogens.

[0037] Whilst the SDV disclosed herein is suitable for presenting any immunogen, they are particularly useful for the presentation of immunogens that require the presence of an adjuvant in order to elicit an effective immune response, that is to say, an immune response that is effective in providing the treatment or prophylaxis for which it is administered, for example by eliciting the production of sufficient antibodies. Such immunogens include those comprising purified natural or recombinant proteins and polysaccharides. The quantity of immunogen incorporated into the SDV will vary dependent on a number of factors, including for example the immunogenicity of the immunogen. The SDVs described herein typically comprise between 1 nanogram and 1 milligram or between 10 nanograms and 100 or 500 micrograms of immunogen. The high levels of antibody response elicited using the presently described SDV compositions means that the amount of immunogen used can be considerably less than would be required for a typical non adjuvanted liquid based vaccine using the same immunogen and moreover considerably less than would be needed for a base (blank or control) SDV lacking the structural adjuvants described herein. In some embodiments the quantity of immunogen is less than 20% of that used in a base SDV providing the same level of antibody response. In some embodiments the quantity of immunogen is less than 50%, less than 40%, less than 30%, less than 20%, less than 10%, less than 5%, or even less than 2% of that used in a base SDV providing the same level of antibody response. The same level of antibody response means the same increase in total IgG or the same increase in IgG directed to the immunogen (as measured using the methods described herein) plus or minus 1 std. dev.

[0038] The SDV comprises one or more compounds from a group of “structural adjuvants”. These excipients have adjuvant properties, but can be incorporated into the SDV either individually or in combination with one or more of the other structural adjuvants. In some embodiments, they can be incorporated in sufficient quantity to provide an improved immune response without compromising the deliverability of the SDV, for example, without reducing the compressive strength below that required for deliverability. These compounds may be referred to herein as “structural adjuvants”.

[0039] The structural adjuvant, may be a polysaccharide with adjuvant properties, or combination of two or more polysaccharides, with adjuvant properties and in some embodiments may be selected from the group consisting of DEAE-dextran, inulin, chitosan and cyclodextrin. The structural adjuvant may be one or a combination of two or more of these, e.g. a combination of two, three, four or more of these compounds.

[0040] In some embodiments, the one or more structural adjuvants consists of chitosan. In some embodiments, the one or more structural adjuvants consists of chitosan and at least one additional structural adjuvant selected from DEAE-dextran, inulin and cyclodextrin. In some embodiments the one or more structural adjuvants consists of DEAE-dextran. In some embodiments the one or more structural adjuvants consists of DEAE-dextran and at least one additional structural adjuvant selected from cyclodextrin, inulin and chitosan. In some embodiments the one or more structural adjuvants consists of inulin. In some embodiments the one or more structural adjuvants consists of inulin and at least one additional structural adjuvant selected from cyclodextrin, DEAE-dextran and chitosan. In some embodiments the one or more structural adjuvants consists of cyclodextrin. In some embodiments the one or more structural adjuvants consists of cyclodextrin and at least one additional structural adjuvant selected from DEAE-dextran, inulin and chitosan. In some embodiments the one or more structural adjuvants consists of DEAE-dextran and inulin. In some embodiments the one or more structural adjuvant consists of DEAE-dextran and inulin and one or more of chitosan and cyclodextrin.

[0041] In some embodiments the one or more structural adjuvants is / are incorporated into the SDV at a rate sufficient to elicit an effective immune response, in combination with the immunogen.

[0042] In some embodiments the SDV comprises a total of at least 135pg, at least 210pg, at least 420pg, at least 630pg at least 840 pg or at least 1050pg of the one or more structural adjuvants and up to, and including 2900pg, 3360pg, 3570pg, 3780pg, 4150pg or 4195pg of the SDV. In some embodiments, for example the SDV may comprise between 210pg and 3570, 3780, 4150 or even 4195pg.

[0043] The structural adjuvants may be used individually, as the sole structural adjuvant, or as a combination of any two or more structural adjuvants.

[0044] In some embodiments, when used individually, the SDV comprises a minimum of 3.2wt% 5wt%, 10wt% or 15wt% DEAE-dextran and up to 90, 99 or even 99.9wt%. In some embodiments, when used individually, the SDV comprises a minimum of 135 pig. 21 Opg. 420pg or 630pg DEAE-dextran and up to 3780pg, 4150pg or even 4195pg.

[0045] In some embodiments, when used individually, the SDV comprises a minimum of 23.8wt% or 25wt% cyclodextrin. In some embodiments the total proportion of cyclodextrin does not exceed 14wt% of the SDV. In some embodiments, when used individually, the SDV comprises a minimum of lOOOpg or 1050pg cyclodextrin. In some embodiments the total amount of cyclodextrin does not exceed 588pg.

[0046] In some embodiments, when used individually, the SDV comprises a minimum of 14.3wt%, 15wt% or 20wt% inulin. In some embodiments, when used individually, the SDV comprises a minimum of 601 pg, 630pg or 840pg of inulin.

[0047] In some embodiments, when used individually, the SDV comprises a minimum of 6.8wt%, 10wt% or 25wt% chitosan. In some embodiments the SDV comprises less than 11.5% chitosan. In some embodiments, when used individually, the SDV comprises a minimum of 286pg, 420pg or 1050pg of chitosan. In some embodiments the SDV comprises less than 483 g chitosan..

[0048] The structural adjuvants described herein provide an improved immune response, that is to say they provide a greater antibody response to antigens than the equivalent SDV with no structural adjuvant (for example an SDV comprising a dextran structural excipient, but no structural adjuvant also referred to as a base SDV). The table below gives the minimum quantity (determined experimentally - see below) of each structural adjuvant, when used on its own, that is required to provide an immune response greater than the base SDV. Therefore, in some embodiments an SDV may comprise a structural adjuvant, where the structural adjuvant consists of DEAE-dextran at a minimum rate of 4.5wt%; or cyclodextrin at a minimum rate of 23.8wt%; or inulin at a minimum rate of 14.3wt%; or chitosan at a minimum rate of 22.5wt%. In some embodiments an SDV may comprise a structural adjuvant, where the structural adjuvant consists of DEAE-dextran at a minimum rate of 189pg; or cyclodextrin at a minimum rate of 1 OOOpg; or inulin at a minimum rate of 600pg or chitosan at a minimum rate of 945pg.

[0049] Table 1

[0050] In some embodiments an SDV may comprise a structural adjuvant, where the structural adjuvant consists of DEAE-dextran at a minimum rate of 3 ,2wt%; or cyclodextrin at a minimum rate of 23.8wt% or chitosan at a minimum rate of 22.5wt%. In some embodiments an SDV may comprise a structural adjuvant, where the structural adjuvant consists of DEAE-dextran at a minimum rate of 134pg; or cyclodextrin at a minimum rate of lOOOpg or chitosan at a minimum rate of 945pg. Such compositions may be suitable for use in a priming dose, for example.

[0051] In some embodiments an SDV may comprise a structural adjuvant, where the structural adjuvant consists of DEAE-dextran at a minimum rate of 4.5 wt%; or cyclodextrin at a minimum rate of 23.8wt%; or inulin at a minimum rate of 14.3 wt%; or chitosan at a minimum rate of 6.8wt%; In some embodiments the structural adjuvant consists of DEAE-dextran at a minimum rate of 189pg; or cyclodextrin at a minimum rate of lOOOpg; or inulin at a minimum rate of 600pg; or chitosan at a minimum rate of 286pg. Such compositions are suitable for use in a boosting dose for example.

[0052] When used as a combination of structural adjuvants, the quantities are not so limited and the SDV may comprise any combination of structural adjuvants that provides sufficient immune response for the purpose sought. For example in some embodiments the structural adjuvant consists of a combination of two or more of DEAE-dextran, chitosan, cyclodextrin and inulin and at least 10% of the total weight of the structural adjuvant is DEAE-dextran, or at least 10% of the total weight of the structural adjuvant is inulin, or at least 10% of the total weight of structural adjuvant is cyclodextrin or at least 10% of the total weight of structural adjuvant is chitosan.

[0053] In some embodiments DEAE-dextran may act as both the structural adjuvant and the structural excipient, i.e. as both structural adjuvant and second excipient, thus in some embodiments a solid dose vaccine may comprise: (i) an immunogen; and (ii) between 3.2% and 99.9wt% DEAE-dextran by dry weight; and optionally one or more structural adjuvants selected from chitosan, inulin and cyclodextrin as described further herein.

[0054] In some embodiments a solid dose vaccine may comprise: (i) an immunogen; and (ii) between 134pg and 4196pg of DEAE-dextran; and optionally one or more structural adjuvants selected from chitosan, inulin and cyclodextrin as described further herein.

[0055] In each case, the proportions of structural adjuvant may be limited if necessary, as described further below, in order to provide SDVs having a required compressive strength, for example in the case of needle free delivery where this is desirable. In some embodiments, the compressive strength of the SDV can be increased by decreasing the size and / or increasing the size uniformity of the particles of the structural adjuvant powders as detailed further below. In some embodiments therefore the powdered structural adjuvant is sized to pass through a 400pm, 300pm, 200pm, 100pm, 50pm sieve for example. 200pm powders provide good compressive strength. In some embodiments spray drying of structural excipients can increase the compressive strength further.

[0056] Strength of the base SDV may be provided by compacted structural excipients such as dextran as described further below. Structural adjuvants are able to replace some or even all of the structural excipients without reducing the structural strength below that required. In some embodiments, the SDVs of the present disclosure have sufficient compressive strength to penetrate the skin of a human or animal. The force required varies somewhat depending on the skin thickness as well as other properties such as age, location on the body and the level of keratinization. In some embodiments SDVs of the present invention are able to withstand a pressure force of at least 40MPa, at least 50MPa at least 60MPa at least 70MPa or at least 80 MPa, in some embodiments the SDV may withstand a compressive force of at least lOOMPa, at least 120MPa, at least 130MPa, or at least 140MPa.

[0057] Whilst some structural adjuvants have no or minimal effect on the compressive strength (for example DEAE-dextran) others tend to increase the structural strength (e .g . inulin) and yet others have a negative effect (cyclodextrin, chitosan). Nevertheless, these excipients may be used individually or in combination to provide an improved immune response either by limiting the quantities of each according to the level of compressive strength required or by improving the physical characteristics of the powders to increase the compressive strength of the SDVs For example, in some embodiments the following limitations (Table 2a) may be applied to the structural adjuvants (when used alone) to provide an SDV having a compressive strength of at least 80MPa:

[0058] Thus, by way of example only, an SDV having a compressive strength of at least 80MPa, may comprise a structural adjuvant, where the structural adjuvant consists of DEAE-dextran; or consists of inulin (optionally at a rate of greater than 0.6 wt%), or consists of cyclodextrin at a rate of less than or equal to 1 lwt% or consists of chitosan at a rate of less than or equal to 8.25wt%. The proportion of DEAE- dextran does not affect compressive strength. Inulin positively affects compressive strength.

[0059] Table 2a

[0060] By way of a further example only, an SDV having a compressive strength of at least 60MPa, may comprise a structural adjuvant consisting of DEAE-dextran; or consisting of inulin or consisting of cyclodextrin at a rate of less than or equal to 24wt% or consisting of chitosan less than or equal to 18.4wt%.

[0061] By way of a further example only, an SDV having a compressive strength of at least 40MPa, may comprise a structural adjuvant consisting of DEAE-dextran; or consisting of inulin; or consisting of cyclodextrin at a rate of less than or equal to 38wt% or consisting of chitosan less than or equal to 28.4wt%.

[0062] In some embodiments, in each case the minimum proportions of structural adjuvant is determined by the quantity required to provide an enhanced immune response, for example, as laid out in Table 1 above .

[0063] In some embodiments, where necessary, compressive strength of SDVs comprising structural adjuvants can be increased by reducing particle size of the structural adjuvant powders, for example by grinding the powder, and / or by improving the particle size uniformity, for example by sieving or spray drying (see Example 5 below). In one embodiment it is possible to increase compressive strength by providing structural adjuvants having a particle size < 200pm (e.g. by passing them through a sieve). In some embodiments it is possible to increase compressive strength further by spray drying structural adjuvants. Table 2b gives the proportion of excipient required to provide compressive strength (CS) greater than or equal to 80MPa when used alone after sieving.

[0064] Table 2b

[0065] *DEAE-dextran, cyclodextrin and chitosan were ground and sieved through a 200um sieve prior to preparation of the SDV (see Example 5 below)

[0066] Thus, by way of example only, an SDV having a compressive strength of at least 80MPa, may comprise a structural adjuvant, where the structural adjuvant consists of DEAE-dextran; or consists of inulin (optionally at a rate of greater than 0.6wt%), or consists of cyclodextrin at a rate of less than or equal to 26.2wt% or consists of chitosan at a rate of less than or equal to 31 ,2wt%. The proportion of DEAE- dextran does not affect compressive strength. Inulin positively affects compressive strength.

[0067] Because inulin improves compressive strength of the SDV, in a further example, an SDV having a compressive strength of at least 80MPa, may comprise a structural adjuvant, where the structural adjuvant consists of cyclodextrin at a rate of less than or equal to 40.7wt% and inulin at a rate of greater than or equal to 10.6%.

[0068] By way of a further example only, an SDV having a compressive strength of at least 60MPa, may comprise a structural adjuvant consisting of DEAE-dextran; or consisting of inulin or consisting of cyclodextrin at a rate of less than or equal to 69wt% or consisting of chitosan less than or equal to 82.6wt%.

[0069] By way of a further example only, an SDV having a compressive strength of at least 45MPa, may comprise a structural adjuvant consisting of DEAE-dextran; or consisting of inulin; or consisting of cyclodextrin or consisting of chitosan.

[0070] In some embodiments the range of proportions of structural excipients required to provide a minimal improvement in immune response (Table 1) provides the lower end of the range of structural excipients (optionally expressed as absolute amounts), whilst the upper end of the range is provided by the level required provided a desired compressive strength (Table 2a / 2b) (optionally expressed as wt% of the SDV).

[0071] In some embodiments an SDV comprises 600mg DEAE-dextran; lOOOmg cyclodextrin; 750mg inulin and 850mg chitosan. In some embodiments an SDV comprises 14.3wt% DEAE dextran; 23.8 lwt% cyclodextrin; 17.86wt% inulin and 19.2wt% cyclodextrin. Each value may vary by + / - 10, + / -5% + / - 2% or + / -1%. In some embodiments, such SDVs provide a pre boost improvement in antibody titre of approximately 9.2 In units and a post boost antibody titre of approximately 13.5 In units, whilst having a compressive strength of approximately 80MPa

[0072] Compressive strength may be tested on a Shimadzu tensile testing machine AGS-X, for example. Tests are carried out by formulating the composition as a dosage form in the shape of a rod and applying a pressure force to the dosage form. The force is increased until the dosage form breaks. The instrument records the pressure force necessary to crush the dosage form. This parameter is termed the compressive strength and should be understood as the breaking strength under compression. The tests are carried out on substantially dry dosage forms with a diameter of approximately 0.85mm and a length of approximately 2 mm.

[0073] In addition to an immunogen and one or more structural adjuvants, the SDV may additionally comprise one or more compounds from a second group of excipients, referred to herein as “structural excipients”. These compounds may be bulking agents. In some embodiments the structural excipients may be combined with other components of the SDV, such as the structural adjuvant or structural adjuvants, without compromising the deliverability of the SDV, for example, without reducing the compressive strength below the required level e.g. 40MPa, 60MPa or 80MPa. In some embodiments therefore an SDV comprises a water soluble or water dispersible solid matrix comprising (i) an immunogen; (ii) at least one structural adjuvant which is a polysaccharide adjuvant and (iii) at least one structural excipient.

[0074] Structural excipients include, but are not limited to polyols such as mannitol and sorbitol; polysaccharides such as dextran and carboxymethyl cellulose; mono and disaccharides, for example sucrose; amino acids such as methionine, cysteine and histidine; and synthetic polymers, such as polylactic-co-glycolic acid (PLGA), polyvinyl alcohol (PVA) and polylactic acid (PLA); or mixtures of any two or more of the above structural excipients.

[0075] In some embodiments structural excipients are selected from dextran, carboxymethyl cellulose (CMC) and mixtures of the two. In some embodiments dextran is the preferred structural excipient, and where dextran is used, lOkDa - 1 lOkDa mean molecular weight provides satisfactory results.

[0076] The quantity of structural excipient will vary dependent on the quantity of other components of the SDV. In some embodiments, for example where the quantity of structural adjuvant is high, there may be no or little structural excipient. In some embodiments the SDV may comprise up to 90%, 95% or 98% by weight of structural excipient, for example 0-90%, 95% or 98%. In some embodiments the SDV may comprise up to 85%, up to 80%, up to 70%, up to 60% or up to 50% by weight of the structural excipient. In some embodiments the SDV may comprise greater than or equal to 0, 5, 10, 15, 20, 25, 30, 35, or 40% structural excipient by weight. In some embodiments therefore the SDV may comprise 5% to 85 or 98% by weight, 10% to 85% by weight or 30% to 70% by weight of structural excipient, for example.

[0077] The SDV may comprise one or more further excipients selected from the group consisting of buffers, such as citrate or phosphate; potassium chloride, sodium chloride, sodium hydroxide, hydrochloric acid; surfactants, such as polysorbate-20, polysorbate-40, polysorbate-60, polysorbate-80; stabilisers such as albumin;, MgCh, MgSCfi. lactose-sorbitol, sorbitol-gelatine and tris-EDTA; binding agent such as starch, gelatin or alginate, lubricants, such as magnesium stearate, polyethylene glycol (PEG) and lysine; disintegrants, glidants, preservatives, sorbents and vehicles

[0078] SDVs of the present disclosure include rods, pellets, grains, granules and splinters. The cross section may be circular, substantially circular, ellipsoid, triangular, square, or polygonal or a combination of these. The three-dimensional shape of the SDVs may be cylindrical, conical or polyhedral, such as in the form of a cuboid, prism or pyramid, or a combination of these. The shape typically comprises a pointed tip e.g. with an internal angle of between 22.5° and 90° to further improve ease of delivery.

[0079] The dimensions of the SDVs disclosed herein is determined by the dose of the active material and the quantity of excipients required. Typical SDVs have a maximum diameter or width of 2mm at their widest part. In some embodiments, the width is less than 2 mm, typically approximately 0.85mm with a tolerance of ±5%. Such SDVs can be injected using a needle free injection system essentially without or with very little sensation.

[0080] Whilst the compositions may be manufactured in any length, typically the SDV is less than 10mm, less than 8mm and in some embodiments, less than 6mm, for example from 2 to 6mm, in particular about 4mm.

[0081] Generally, SDVs disclosed herein have a total weight of less than 15 mg, usually less than lOmg. They typically have a weight of at least Img at least 2mg or at least 5mg. Example ranges include, for example from 2mg to 15mg and 4mg to lOmg.

[0082] The dosage forms are substantially dry. Use of the term “substantially dry” is meant that the SDV has minimal levels of moisture in the formulation. The moisture content in the final solid dosage may be 5% (w / w) or less, preferably 3% (w / w) or less, more particularly, between 1 and 5% (w / w), between 1 and 3% (w / w), preferably between 2 and 3% (w / w), based on the total weight of the SDV.

[0083] Methods for analysing the moisture content in the final dosage form will be known to the skilled person. Suitable methods include thermogravimetric analysis (TGA), Karl Fischer (KF) titration method and infrared analysis. The moisture present in the solid dosage may be water. A substantially dry dosage form can be achieved by subjecting the SDV to convection drying, for example using a Memmert UF750 convention oven or equivalent, followed by vacuum drying, for example using a Memmert VO500 vacuum oven or equivalent. Other methods of drying will be known to the skilled person,

[0084] The moisture present is not considered an ingredient of the SDV. For this reason, moisture, or water, is not listed as an ingredient in the exemplified formulations which list only the ingredients used to prepare the SDVs.

[0085] In one approach a process for the preparation of a solid dose vaccine as disclosed herein, comprises combining (i) an immunogen; and (ii) one or more structural adjuvants which are polysaccharide adjuvants; and optionally one or more additional excipients, as a powder; compressing the powder to form a body and optionally drying the body to provide a solid dose vaccine as described further herein. In some embodiments an SDV formed by this process comprises a water soluble or water dispersible solid matrix comprising (i) an immunogen; and (ii) at least one structural adjuvant which is a polysaccharide adjuvant as described further herein.

[0086] In some approaches the immunogen, structural adjuvant and optionally one or more additional excipients (e.g. structural excipients and / or further excipients) are each combined to form a bulk powder, alternatively the immunogen and excipients may be combined in any suitable combination as a solution or suspension and the solution or suspension dried to provide a bulk powder, which is subsequently combined with any remaining components as a powder before compression. In one approach the structural adjuvants are optionally combined with one or more structural excipients as a solution or suspension which is dried to form a bulk powder; a solution comprising the immunogen is dried to provide a dried composition comprising the immunogen and the dried composition comprising the immunogen is combined with the bulk powder. Solutions and suspensions may be dried, for example by spray drying or freeze drying.

[0087] Typically, the powder is compressed in a die. The die itself may be elongate and / or have diameter of 0.5mm to 2mm, preferably 0.75mm to 1.2mm. More preferably, the die is about 0.85mm in diameter.

[0088] In some examples, the drying step comprises drying at approximately 25°C to 60°C, for 1 to 11 days under vacuum.

[0089] The SDVs disclosed herein are typically uncoated.

[0090] The solid dose vaccines disclosed herein may be used to prevent or treat a variety of diseases or conditions in human or animal subjects. These may be infectious diseases or conditions caused by infection with an infectious agent such as a virus a bacterium a fungus or a protozoan, for example, by delivering to the subject an immunogen of the infectious agent; or they may be endogenous diseases of conditions in which targeting of an endogenous antigen or neoantigen is advantageous, for example in cancer.

[0091] The SDVs of this disclosure may be used to prevent or treat infection by viruses including one or more of human papilloma viruses (HPV), herpes simplex virus (HSV-1 and HSV-2) influenza virus (types A, B and C), parainfluenza viruses, polio virus, RSV virus, rhinoviruses, rotaviruses, hepatitis (A, B, C, D and E) virus, Norwalk virus, enteroviruses, measles virus, mumps virus, rubella virus, Japanese encephalitis virus, varicella-zoster virus, cytomegalovirus, Epstein-Barr virus, adenoviruses, human T- cell lymphoma type I virus (HTLV-I), dengue virus, yellow fever virus, rabies virus, Chikungunya virus, Lassa virus, West Nile virus, Ebola virus, Marburg virus, Lassa fever, Zika virus, Rift Valley Fever virus, henipaviruses (such as Nipah virus, Hendra virus, Kumasi virus, Cedar virus, and Angavokely virus.), variola virus, corona viruses, Crimean-Congo hemorrhagic fever virus, and poxviruses.

[0092] The SDVs of this disclosure may be used to prevent or treat infection by bacteria including one or more of tuberculosis, anthrax, tetanus, leptospirosi, pnenumonia, cholera, botulism, Pseudomonas, MRSA, E. Coli, meningitis, gonorrhea, Yersinia and syphilis.

[0093] The SDVs of this disclosure may also be used to prevent or treat infection by parasites for example Plasmodium, Trypanosoma, Leishmania, Babesia and Toxocara

[0094] The vaccine may further be used to provide a suitable immune response against numerous veterinary diseases, such as foot and mouth disease (including serotypes O, A, C, SAT-1, SAT-2, SAT-3 and Asia- 1), coronavirus, bluetongue, feline leukaemia virus, avian influenza, hendra and nipah virus, pestivirus, canine parvovirus and bovine viral diarrhea virus.

[0095] Non limiting examples of diseases against which a subject may be vaccinated include yellow fever, rabies, diphtheria, tetanus, haemophilus influenza type B (Hib), pertussis, pneumococcal diseases, meningococcal diseases, diseases and conditions caused by human papilloma viruses (HPV), HSV- II / HSV-I, influenza (types A, B and C), parainfluenza, polio, RSV, rhinoviruses, rotaviruses, hepatitis A, acquired immunodeficiency syndrome (AIDS), anthrax, gastroenteritis, enterovirus diseases, measles, mumps, varicella zoster, glandular fever, respiratory diseases, rubella, human T-cell lymphoma type I (HTLV-I), hepatitis B, hepatitis C, hepatitis D, poxvirus diseases, cholera, Japanese encephalitis, zika, chikungunya, bat lyssavirus, Q fever, rift valley fever, hendra virus, tularaemia, nipah virus, lassa fever, typhoid fever, Crimean-Congo haemorrhagic fever, ebola, plague, Middle East respiratory syndrome (MERS, Severe acute respiratory syndrome (SARS), COVID- 19 and shigella; or against veterinary diseases, such as foot and mouth disease (including serotypes O, A, C, SAT-1, SAT- 2, SAT-3 and Asia-1), coronavirus, bluetongue, feline leukaemia virus, avian influenza, hendra and nipah virus, pestivirus, canine parvovirus and bovine viral diarrhoea virus. In some embodiments, the SDV is for use in the treatment or prevention of a cancer associated or attributable to the Human Papilloma Virus (HPV), by vaccination of a subject with an immunogen of the HPV. Such cancers include anal cancer, oropharyngeal cancer; cervical, vulvar and vaginal cancer in women and penile cancer in men.

[0096] In some embodiments, the vaccine is a multivalent or combination vaccine. For example, the invention may be used to treat or prevent infection by two or more different types of disease or virus, such as measles, mumps and rubella (e.g. MMR vaccine).

[0097] In some embodiments the vaccine is selected from an attenuated (live) vaccine, an inactivated vaccine, a toxoid vaccine, a subunit or purified antigen vaccine, a conjugate vaccine, a neoantigen vaccine, or a DNA vaccine. DNA vaccines include DNA vector vaccines, such as adenovirus, measles virus, vaccinia virus, poxvirus, alphavirus, vesicular stomatitis virus (VSV) and lentivirus vectors, as well as plasmid vaccines “doggy-bone” DNA and selfassembling, virus-like particles.

[0098] Thus this disclosure provides a method of treating or preventing a condition, disease or disorder, said method comprising administering to a subject in need thereof, a therapeutically effective amount of an SDV as described herein. The disclosure also provides the use of SDVs as disclosed herein in the prevention or treatment of such conditions diseases and disorders and the preparation of medicaments, such as vaccines for use in treating or preventing such conditions, diseases and disorders.

[0099] For example an immune response may be elicited towards an immunogen in a subject by delivering to the subject a solid dose vaccine as described herein comprising the immunogen.

[0100] The disclosure also relates to a method of vaccinating a subject against an infection caused by organism comprising delivering to the subject a solid dose vaccine, comprising an immunogen of (or derived from) the organism as disclosed further herein.

[0101] The disclosure also relates to a method of vaccinating a subject against a cancer comprising delivering to the subject an SDV as described herein comprising an immunogen of the cancer. Such immunogens of the cancer include, for example, neo antigens.

[0102] Also provided are SDVs as described herein for use as a medicament, particularly as a vaccine, in the treatment or prevention of a condition, disease or disorder as described further herein. Also provided are immunogens as described herein for use in vaccinating a subject in the treatment or prevention of a condition, disease or disorder; wherein the immunogen is delivered in the form of an SDV as described herein. Also provided is a solid dose vaccine as described herein, for use in the vaccination of a subject against an infectious disease, and a solid dose vaccine as described herein, for use in the vaccination of a subject against a cancer.

[0103] Also provide is an immunogen as described herein for use in the manufacture of a medicament, particularly a vaccine, for use in the treatment or prevention of a condition, disease or disorder; wherein the immunogen is delivered in the form of an SDV as described herein.

[0104] The solid dose vaccines described herein particularly find use in a method of needle-free vaccination. In this approach, the SDV is delivered to the subject at low velocity, the low velocity being sufficient to drive the SDV through the skin of the subject such that it is deposited completely below the surface of the skin, but does not proceed to deeper tissues. Devices for achieving the delivery are described in, for example, W02006 / 082439, WO2012 / 098356, WO2016 / 124903 and WO2021 / 123736.

[0105] A further aspect of the disclosure relates to SDVs as described herein for use in the manufacture of a medicament, particularly a vaccine, for use in the treatment or prevention of a condition, disease or disorder.

[0106] The SDV may be delivered by a variety of routes including by dermal, intradermal, transdermal, subcutaneous or intramuscular administration, but may also be delivered orally, mucosally or intraperitoneally.

[0107] Figures

[0108] Figure 1 is a graph illustrating the results of an rHA antigen dose finding study carried out in rabbits. See example 1. LoQ = limit of quantification.

[0109] Figure 2 illustrates the development of antibody response to the rHA immunogen in NZW rabbits. 5pg of rHA antigen was presented in 7mg SDVs incorporating various combinations of structural adjuvants according to a Design of Experiment protocol derived using JMP DoE software. See Example 2. LoQ = limit of quantification.

[0110] Figure 3 illustrates the development of antibody response in NZW rabbits in response to varying quantities of rHA antigen. Antigen was presented in either 7 mg SDVs comprising either (i) a combination of structural adjuvants [DEAE-dextran (10.7%), cyclodextrin (14.3%), inulin (14.3%) chitosan (5.7%) ESDV]; or (ii) a base SDV comprising no structural adjuvants; or liquid intramuscular vaccines comprising the same dose of antigen. LoQ = limit of quantification. A - 30ng rHA, B - 90ng rHA, C - 270ng rHA, D - 8 lOng rHA and E - 2500ng rHA.

[0111] Figure 4 illustrates the development of functional antibodies to rHA (A) and development of total IgG titre (B) following immunization with either a liquid intramuscular injection of 2500ng of rHA antigen; base SDV comprising 2500ng of rHA antigen; or experimental SDV (ESDV) comprising a combination of structural adjuvants [DEAE-dextran (10.7%), cyclodextrin (14.3%), inulin (14.3%) chitosan (5.7%)] and 2500ng of rHA antigen. Data for days 21 and day 28 are presented. LoQ = limit of quantification.

[0112] Figure 5 illustrates the compressive strength of 4.2mg SDVs formulated according to Table 8.

[0113] Figure 6 illustrates the proportion of structural excipients that provide maximum antibody response with 82MPa compressive strength. This represents the optimal proportions for unsieved excipients. D = DEAE-dextran, Cd = cyclodextrin, I = inulin, Ct = chitosan. The X axis is the ratio of structural adjuvant weight to total weight of the SDV. The Y axis is the predicted structural strength of the SDV (MPa).

[0114] Figure 7. illustrates the development of antibody response following immunisation with 5ug of rHA antigen presented in SDVs comprising combinations of structural adjuvants formulated according to Table 8. Each of graphs A, B and C illustrates 6 SDV formulations, shown compared to the development of antibody response to rHA antigen presented in base (control) SDV, intramuscular liquid injection (IM) and subcutaneous liquid injection (SC) of 5ug of rHA antigen. Note: Values below the limit of quantification (1:400) were assigned a nominal value three-fold lower (1: 133). LoQ = limit of quantification.

[0115] Figure 8 is a composite illustrating the modelled antibody response obtainable by using structural adjuvants individually D = DEAE-dextran, Cd = cyclodextrin, I = inulin, Ct = chitosan. Separate graphs are given for the response at day 21 and following boost. Data for Days 28, 35, 42 and 49 are combined and presented as post boost. The X axis is the ratio of structural adjuvant weight to total weight of the SDV. The Y axis is the predicted antibody response to the SDV according to the model.

[0116] Figure 9. illustrates the compressive strength of 4.2mg SDVs formulated according to Table 8 using structural adjuvants that have been subjected to grinding and subsequently sieved through a 200pm mesh sieve to provide uniform particle size.

[0117] Figure 10. illustrates the compressive strength of 4.2mg SDVs of formulation 4 according to Table 8 and compares the effect of sieving (200pm mesh) and spray drying structural adjuvants.

[0118] Figure 11 is a composite that illustrates antibody production (Log fold dilution) pre and post boost for one optimised composition of structural adjuvants DEAD dextran-600pg: cyclodextrin lOOOpg: inulin 750pg and chitosan 805pg to give a compressive strength of 80MPa. The X axis is the ratio of structural adjuvant weight to total weight of the SDV.

[0119] Figure 12 illustrates the effect of structural adjuvants on antibody response in mice and rats. Antibodies were determined in serum obtained from 28 day blood samples by serial 3x dilution to endpoint in each case. Values are geometric means of n=6 (rats) and n=8 (mice). Values for animals treated with experimental SDVs (ESDVs) are significantly higher than for the base SDV with no structural adjuvant in each case. (P= <0.05 using 2-tailed Mann-Whitney test). Values above each histogram give the fold difference.

[0120] Figure 13 illustrates the effect of structural adjuvants on antibody titre following treatment of rabbits with a tetanus toxoid immunogen delivered as an SDV. BSDV= base SDV comprising no structural adjuvant; ESDV= experimental SDV comprising structural adjuvants (15.75% DEAE-dextran; 14.7% cyclodextrin; 18.9% inulin; 12.6% chitosan) 4.0mg SDV. “A” compares antibody titre over a 45 day period of a prime boost regimen using 1 IU antigen. Boost was at day 21. “B” shows the fold difference at each time point for rabbits treated with ESDV compared to Base SDV.

[0121] “C” and “D” illustrate the same data using 4 IU of tetanus toxoid immunogen.

[0122] Datapoints are geometric means of n=5 rabbits + / - standard deviation.

[0123] Examples

[0124] Example 1: Dose Ranging Study.

[0125] This study was carried out to guide appropriate quantities of antigen (recombinant influenza hemagglutinin (rHA) for use in further studies. a. Preparation of solid dose vaccine doses.

[0126] A “pre-lyo” solution was formulated, comprising a phosphate buffer system, mannitol and the appropriate amount of immunogen to provide 5 (0.71%), 15 (2.14%) or 45 micrograms (6.43%) of vaccine in the final freeze dried matrix (FDM see below) after lyophilisation. In formulations with lower dose of vaccine, an additional amount of mannitol was included to quantum satis 100%.

[0127] The FDM was combined with spray dried dextran 70 (S-dextran) and magnesium stearate (Sigma Aldrich) in the following weight ratios: 89% S-dextran, 1% magnesium stearate, 10% freeze dried matrix to provide a bulk powder (or powder blend). To prepare the SDV, bulk powder was compressed in a 1.2 mm diameter punch and die set producing 7 mg rod shaped SDVs in which each tablet contained either 5, 15 or 45pg of vaccine. Doses were then dried under vacuum to produce the SDV. b. Treatment

[0128] Rabbits (Female New Zealand White; 3 per group) were immunised subcutaneously with SDVs containing 5 pg, 15 pg or 45 pg of rHA vaccine using a needle and trocar on day 0 and again on day 21. Anti-rHA antibody was measured in serum (collected at Day 0, Day 14, Day 21, Day 28, and Day 35) by ELISA in serial 3 -fold dilutions to identify the end point titre (determined as the last serum dilution that gives a positive colour reaction significantly greater than negative control serum). The results are presented in Figure 1. The 5 pg dose was selected for further use.

[0129] Example 2: Effect of potential structural adjuvants on antibody response

[0130] The following experiment was designed according to a 2 level Design of Experiment (DoE) design using JMP DoE software (JMP, Carey NC USA). a. SI) I7preparation

[0131] Seven milligram SDVs comprising 5 pg of rHA immunogen were prepared according to Example 1 with the proportion of S-dextran adjusted to take account of the addition of candidate structural adjuvants. Table 3 gives the composition (in micrograms) of each constituent to prepare a 7mg SDV. Table 4 gives the proportion of each component as %wt. Animal group 1 was treated with IM liquid vaccine comprising 5ug rHA formulated in PBS buffer. b. Determination of Antibody Response

[0132] Ten groups of rabbits (Female NZW; 3 per group) received an SDV on day 0 and day 21 delivered subcutaneously to the back as per example 1. Group 1 (Formulation 1, n=3) received an intramuscular dose of 5 pg vaccine in PBS buffer. Group 12 received a base SDV comprising rHA antigen and dextran but no structural adjuvant. Anti -rHA antibody was measured in serum collected at Day 0, Day 21, Day 28, and Day 35 by ELISA, as per Example 1.

[0133] Table 3 Figure 2 illustrates the development of antibody response to the rHA immunogen. Table 5 shows the fold difference in antibody response over the IM liquid vaccine at days 21, 28 and 35. Formulations 1 to 11 refer to the animal groups of Table 3 above. Table 6 shows the same data expressed as fold difference over base (control) SDV. Table 4

[0134] S-dextran = spray dried dextran; FDM = freeze dried matrix

[0135] Table 5

[0136] JMP software was used to de-convolute antibody data and infer the effect of individual components and combination of components on antibody response. Both chitosan and cyclodextrin had significant positive effects on antibody titre at day 21. DEAE-dextran had a small positive effect, however, inulin on its own did not have an effect at day 21. At day 35, cyclodextrin and chitosan had significant positive effects on antibody titre.

[0137] Table 6

[0138] Example 3: Effect of immunogen dose.

[0139] In this trial, the dose response to rHA formulated at doses between 30ng and 2,500ng in 3-fold steps when incorporated into base SDVs (no structural adjuvant) or SDVs comprising a combination of selected structural adjuvants at a single dose ratio, based on Formulation group 4 in Example 2 (see Table 7) were compared. A liquid vaccine given intramuscularly was used as a comparator. a. Vaccine preparation

[0140] A “pre-lyo” solution was formulated, comprising a phosphate buffer system and mannitol, into which the appropriate vaccine quantity was dissolved. The pre-lyo solution was then lyophilised to provide a freeze-dried matrix (FDM). For base SDVs, FDM containing lOng, 30ng, 90ng, 270ng, 810ng or 2500ng of vaccine was combined with spray dried dextran 70 (Pharmacosmos) and magnesium stearate (Sigma Aldrich) in the following weight ratio: 89% S-dextran, 1% magnesium stearate, 10% freeze dried matrix to provide a bulk powder (or powder blend) targeting manufacture of 7mg solid doses containing immunogen dose as presented in Table 7 below.

[0141] For the Experimental SDVs (ESDVs), freeze dried matrix containing the respective amount of vaccine was combined with DEAE-dextran (10.7%) (Sigma Aldrich), Cyclodextrin (14.3%) (Sigma Aldrich), Inulin (14.3%) (Sigma Aldrich), Chitosan (5.7%) (Sigma Aldrich), spray dried dextran 70 (44%) (Pharmacosmos) and magnesium stearate (1%) (Sigma Aldrich) and 10% freeze dried matrix to provide a bulk powder (or powder blend) targeting manufacture of solid doses containing immunogen dose as presented in Table 7 below. Structural adjuvants were used in powder form without further refinement. For Intra-muscular liquid formulations, the appropriate amount of rHA vaccine was diluted in phosphate buffered saline to provide the same respective doses. Individual unit SDVs were prepared according to Example 1.

[0142] Table 7 b. Vaccination

[0143] Rabbits (Female, New Zealand White) were vaccinated with either (a) a liquid vaccine delivered IM in the back; (b) a control SDV or (c) an ESDV, delivered subcutaneously to the back in the manner of example 1. In each case vaccines were provided in three-fold increments between 30ng and 2,500ng. Each treatment was carried out on 5 rabbits. Two vaccinations were carried out in each rabbit, one on day 0 (prime) and another on day 21 (boost). Blood samples (6-8mL) were taken from the lateral ear vein on day 0 and on days 7, 14, 21, 28, 35, 42 and 49. Anti-rHA antibody was measured according to example 1. For 2500ng doses functional antibodies were measured using haemagglutination inhibition assay using a modified WHO method (reference:https: / / www.who.int / publications / m / item / serological- detection-of-avian-influenza-a(h7n9)-vims-infections-by-modified-horse-red-blood-cells- haemagglutination-inhibition-assay)

[0144] Figures 3A-E illustrate the development of IgG titre over time in each of liquid IM, base SDV SC and experimental SDV (ESDV) SC formulations. In each case and at every time point the experimental SDV provides a higher dose of antibodies that either the base SDV SC or the liquid IM injection. Figure 4 A and B compare the IgG response to functional anti rHA antibodies on days 21 and 28. Example 4: Determination of the optimum ranges of excipient composition

[0145] In this trial, a full-scale, response surface model DOE-led determination of the optimum concentration ranges of selected excipients for the enhanced induction of an immune response while retaining SDV compressive strength was conducted. a. Vaccine preparation

[0146] A “pre-lyo” solution was formulated, comprising a phosphate buffer system and mannitol, into which vaccine was dissolved to provide 5 pg of rHA in each SDV. The pre-lyo solution was then lyophilised to provide a freeze-dried matrix (FDM) Other SDV components are shown in Table 8.

[0147] Table 8

[0148] Each of the experimental SDVs contain 10% FDM and 1% magnesium stearate, structural adjuvants were incorporated in proportions determined using JMP DoE software and dextran 70 (Pharmacosmos) quantum satis to 100% as shown in Table 8. Structural adjuvants were used in powder form without further refinement. Each SDV was 4.2mg in weight and comprised 5pg of immunogen. Table 9 provides the same data but shown as percent dry weight of the SDV. SA = structural adjuvant. FDM = freeze dried matrix.

[0149] Table 9 The powder blend was compacted to form 4.2mg SDVs in a 0.89 mm diameter punch and die set and SDVs were then dried under vacuum at 25°C. Control liquid vaccine was diluted in PBS (pH 7.2). Compression testing was carried out as described above.

[0150] Rabbits (Female NZW) were vaccinated with either (a) a liquid vaccine delivered IM in the back, (b) a liquid vaccine delivered subcutaneously (SC) in the back, (c) an SDV comprising a combination of structural adjuvants; or (d) a base SDV comprising no structural adjuvant. SDVs were delivered subcutaneously to the back using a needle and trocar. Each treatment was carried out on a group of 5 rabbits. Two vaccinations were carried out in each rabbit, one on day 0 (prime) and another on day 21 (boost). a. Compressive strength Results of the compressive strength (CS) trial are shown in Figure 5. By way of example only, Table 10. sets out the proportion of structural adjuvant required to provide compressive strength greater than or equal to 80MPa (wt%) when structural adjuvant powders are used individually and without further refinement. The data is, obtained by deconvolution of the CS DoE data. Compressive strength of the base SDV, with all structural adjuvants absent was 90MPa.

[0151] Table 10

[0152] All formulations provided an SDV having a compressive strength greater than or equal to 40MPa. Effect of refining powders by size and size distribution is examined in Example 5. b. Antibody titre

[0153] Blood samples (6-8 mL) were taken from the lateral ear vein on day 0 and on days 7, 14, 21, 28, 35, 42 and 49. Anti-rHA antibody was measured by ELISA in serum diluted 3-fold to end point titre; determined as the last dilution that gives positive results above the negative control. Results are illustrated in figures 7 A-C.

[0154] All compositions with the exception of Fl 8 (25 pg of each structural adjuvant) showed a markedly increased antibody response when compared to the base SDV.

[0155] Antibody data was deconvoluted to provide the minimum quantity of each structural adjuvant (when used alone) that is required to provide an immune response greater than the base SDV (calculated as the quantity required to provide an antibody response greater than 1 std. dev. above that for the base SDV). This data is given in Table 11 below. The model for post boost is derived from pooled 28, 35, 42 and 49 days. “Combination” is a combined dose that would be suitable for providing both prime and boost. The deconvoluted model for each structural adjuvant is represented graphically in Figure 8 for both prime and boost. Table 11

[0156] *Inulin had no effect on Ab response over the dose range tested for the 21day (prime) time point.

[0157] Example 5: SDV formulations with improved compressive strength

[0158] By reducing particle size and improving size uniformity of the structural adjuvant powders, compressive strength of the formulations can be improved.

[0159] Structural adjuvant powders (DEAE-dextran, cyclodextrin and chitosan) were processed by grinding in a mortar and pestle followed by passage through a sieve (200pm mesh) and the resultant powder used to prepare sample SDVs according to Example 4, with formulations according to Tables 8 and 9. Compressive strength was determined according to Example 4 (figure 9). Formulation 4 was also prepared using structural adjuvants that had been spray dried and results compared to those obtained using sieving (figure 10). Table 12 shows the proportion of structural adjuvants required to provide compressive strength (CS) greater than or equal to 80MPa when used alone following sieving of the powders. Following sieving, the proportions of cyclodextrin and chitosan that can be incorporated and still achieve high compressive strength is increased. It was also noted that cyclodextrin levels could be increased further, to 40.7%wt, and still achieve a compressive strength of 80MPa if cyclodextrin was combined with 10.6%wt inulin.

[0160] Table 12. Following sieving optimised levels of structural adjuvants were determined to provide maximal antibody response whilst maintaining a compressive strength of at least 80MPa (Table 13) in the 4.2mg SDV.

[0161] Table 13

[0162] CS = compressive strength.

[0163] Example 6: Treatment of Mice and Rats with rHA vaccines delivered as an SDV. a. SDV preparation

[0164] 4.2 mg SDVs comprising rHA immunogen (H7N9) were prepared according to Example 1.

[0165] A “pre-lyo” solution was formulated, comprising a phosphate buffer system and mannitol, into which immunogen was dissolved to provide the appropriate amount of rHA in 50mg of FDM to target 0.035ug of rHA immunogen / 4.2mg SDV for mice and 0.135ug / 4.2mg SDV for rats. The pre-lyo solution was then lyophilised to provide a freeze-dried matrix (FDM)

[0166] Other SDV components are shown in Table 14.

[0167] Table 14

[0168] The composition of Base SDV (no structural adjuvant) is given in Table 15 Table 15

[0169] The powder blend was compacted to form 4.2mg SDVs in a 0.89 mm diameter punch and die set and SDVs were then dried under vacuum at 25°C. b. Determination of Antibody Response groups of 8 BALB / c mice (female 7-9 weeks) and 2 groups of Wistar Han rats (female 7-9 weeks) received a 4.2mg SDV delivered subcutaneously to the flank by needle and trocar on day 0 and day 21. On each occasion, each Group 1 (n=6) received a base SDV comprising rHA antigen and dextran but no structural adjuvant. Each Group 2 (n=6) received a experimental SDV (ESDV) comprising rHA antigen and a combination of structural adjuvants according to Table 14.

[0170] Anti -rHA antibody was measured in serum by ELISA, as per Example 1. Results are illustrated in figure 12.

[0171] Example 7. Treatment of Rabbits with tetanus vaccine delivered as an SDV

[0172] 4 milligram SDVs comprising either 1 international unit (IU) or 4 IU of Tetanus toxoid immunogen (Bulbio Ltd Bulgaria) were prepared according to Example 4 with the proportion of S -dextran adjusted to take account of the addition of structural adjuvants. A combination of structural adjuvants (628pg DEAE-dextran; 588 pg cyclodextrin; 756pg inulin and 04 pg chitosan equivalent to 15.75%, 14.7% 18.9%; and 12.6% respectively, by weight, per 4mg SDV) was used in each case. Rabbits (Female NZW) were vaccinated with either a base SDV comprising no structural adjuvant or an SDV comprising a combination of structural adjuvants (ESDV). SDVs were delivered subcutaneously to the back using a needle and trocar. Each treatment was carried out on a group of 5 rabbits. Two vaccinations were carried out in each rabbit, one on day 0 (prime) and another on day 21 (boost).

[0173] Blood samples (6-8 mL) were taken from the lateral ear vein on day 0 and on days 7, 14, 21, 28, 35 and 42. Anti-Tet. antibody was measured by ELISA in serum diluted 3-fold to end point titre; determined as the last dilution that gives positive results above the negative control. Results are illustrated in figures 13 A-D.

Claims

CLAIMS1. A solid dose vaccine comprising:(i) an immunogen; and(ii) one or more structural adjuvants which are polysaccharide adjuvants.

2. A solid dose vaccine according to claim 1, comprising a water soluble or water dispersible solid matrix comprising(i) an immunogen; and(ii) one or more structural adjuvants which are polysaccharide adjuvants.

3. A solid dose vaccine according to claim 1 or claim 2, wherein the one or more structural adjuvants are selected from the group consisting of chitosan, DEAE-dextran, inulin, and cyclodextrin.

4. A solid dose vaccine according to any of claims 1 to 3, wherein the structural adjuvant consists of chitosan and optionally at least one additional structural adjuvant selected from DEAE-dextran, inulin and cyclodextrin.

5. A solid dose vaccine according to any of claims 1 to 3, wherein the structural adjuvant consists of DEAE-dextran and optionally at least one additional structural adjuvant selected from chitosan, inulin and cyclodextrin.

6. A solid dose vaccine according to any of claims 1 to 3, wherein the structural adjuvant consists of inulin and optionally at least one additional structural adjuvant selected from DEAE-dextran, chitosan and cyclodextrin.

7. A solid dose vaccine according to any of claims 1 to 3, wherein the structural adjuvant consists of cyclodextrin and optionally at least one additional structural adjuvant selected from DEAE-dextran, chitosan and inulin.

8. A solid dose vaccine according to any of claims 1 to 7, comprising greater than or equal to 3.2wt% of total structural adjuvant; optionally between 3.2wt% and 99.9wt% of total structural adjuvants.

9. A solid dose vaccine according to any of claims 1 to 7, comprising greater than or equal to 134pg of total structural adjuvant; optionally between 134pg and 4158pg of total structural adjuvants.

10. A composition according to any of claims 1 to 7, wherein the structural adjuvant consists of a combination of two or more of chitosan, DEAE-dextran, cyclodextrin and inulin and at least 10% ofthe total weight of structural adjuvant is chitosan, or at least 10% of the total weight of the structural adjuvant is DEAE-dextran, or at least 10% of the total weight of the structural adjuvant is inulin, or at least 10% of the total weight of structural adjuvant is cyclodextrin.

11. A solid dose vaccine according to any of claims 1 to 10, in which the structural adjuvant consists of either 3.2wt% or greater of DEAE-dextran, or 23.8wt% or greater of cyclodextrin or 22.5wt% or greater of chitosan.

12. A solid dose vaccine according to any of claims 1 to 10, in which the structural adjuvant consists of either 945 jag or greater of chitosan, or 134 .g or greater of DEAE-dextran, lOOOpg or greater of cyclodextrin.

13. A solid dose vaccine according to any of claims I to 10, in which the structural adjuvant consists of either 4.5wt% or greater of DEAE-dextran, 23.8wt% or greater of cyclodextrin, 14.3wt% or greater of inulin or 6.8wt% or greater of chitosan.

14. A solid dose vaccine according to any of claims 1 to 10, in which the structural adjuvant consists of either 189pg or greater of DEAE-dextran; lOOOpg or greater of cyclodextrin; 600pg or greater of inulin or 286pg or greater of chitosan.

15. A solid dose vaccine according to any of claims I to 10, in which the structural adjuvant consists of either DEAE-dextran at a rate of 4.5wt% or greater, cyclodextrin at a rate of 23.8wt% or greater, inulin at a rate of 14.3wt% or greater or chitosan at a rate of 22.5wt% or greater.

16. A solid dose vaccine according to any of claims I to 10, in which the structural adjuvant consists of either DEAE-dextran at a rate of 189pg or greater; cyclodextrin at a rate of 1 OOOpg or greater; inulin at a rate of 600pg or greater or chitosan at a rate of 945 jag or greater.

17. A solid dose vaccine according to any of claims 1 to 10, wherein the structural adjuvant consists of DEAE-dextran; or consists of inulin; or consists of cyclodextrin at a rate of less than or equal to 26.2wt%; or consists of chitosan at a rate of less than or equal to 31 ,2wt%.

18. A solid dose vaccine according to any of claims 1 to 10, wherein the structural adjuvant consists of DEAE-dextran; or consists of inulin; or consists of cyclodextrin at a rate of less than or equal to 69wt%; or consists of chitosan at a rate of less than or equal to 82.6wt%.

19. A solid dose vaccine according to any preceding claim, which additionally comprises one or more structural excipients; optionally wherein the structural excipients are selected from one or more of a polyols, polysaccharides, disaccharides, monosaccharides, amino acids, and synthetic polymers.

20. A solid dose vaccine according to any preceding claim comprising a water soluble or water dispersible solid matrix comprising (i) an immunogen; (ii) at least one structural adjuvant which is a polysaccharide adjuvant and (iii) at least one structural excipient.

21. A solid dose vaccine according to claim 20, wherein the structural adjuvant is selected from the group consisting of Chitosan, DEAE-dextran, Inulin and cyclodextrin.

22. A solid dose vaccine according to any of claims 19 to 21, wherein the structural excipient is selected from dextran, carboxymethyl cellulose or a combination of the two; particularly dextran.

23. A solid dose vaccine according any of claims 19 to 22, wherein the SDV comprises up to 96.7% of the structural excipient.

24. A solid dose vaccine comprising:(i) an immunogen; and(ii) between 3.2% and 99.9wt% DEAE-dextran; and optionally one or more structural adjuvants selected from chitosan, inulin and cyclodextrin.

25. A solid dose vaccine comprising:(i) an immunogen; and(ii) between 134pg and 4196pg of DEAE-dextran; and optionally one or more structural adjuvants selected from chitosan, inulin and cyclodextrin.

26. A solid dose vaccine according to any preceding claim, having a compressive strength of at least 40MPa; preferably at least 60MPa; preferably at least 70MPa, preferably at least 80MPa.

27. A solid dose vaccine according to any preceding claim, which is alum free.

28. A solid dose vaccine according to any preceding claim, which elicits seroconversion in 7 days or less.

29. A solid dose vaccine according to any preceding claim, wherein the quantity of immunogen is less than 10% of that used in a base SDV providing the same level of antibody response.

30. A solid dose vaccine according to any preceding claim, which is delivered fully under the surface of the skin.

31. A solid dose vaccine according to any preceding claim, wherein the immunogen is selected from an attenuated vaccine immunogen, an inactivated vaccine immunogen, a toxoid vaccine immunogen, a subunit or purified antigen vaccine immunogen, a conjugate vaccine immunogen, aneoantigen vaccine immunogen, an RNA vaccine, a DNA vaccine, a heterologous prime-boost vaccine immunogen, a homologous vaccine immunogen and a recombinant vector vaccine.

32. A method of eliciting an immune response towards an immunogen in a subject comprising delivering to the subject a solid dose vaccine according to any of claims 1 to 31, comprising the immunogen; optionally wherein the solid dose vaccine is delivered by dermal, intradermal, transdermal, subcutaneous, oral, mucosal intraperitoneal or intramuscular administration.

33. A method of vaccinating a subject against an infection caused by an organism comprising delivering to the subject a solid dose vaccine according to any of claims 1 to 31, comprising an immunogen of the organism.

34. A method of vaccinating a subject against a cancer comprising delivering to the subject a solid dose vaccine according to any of claims 1 to 31, comprising an immunogen of the cancer.

35. A solid dose vaccine according to any of claims 1 to 31, for use in a method of needle-free vaccination.

36. A solid dose vaccine according to any of claims 1 to 31, for use in the vaccination of a subject against an infectious disease.

37. A solid dose vaccine according to any of claims 1 to 31, for use in the vaccination of a subject against a cancer.

38. A process for the preparation of a solid dose vaccine according to any of claims 1 to 31 comprising combining the components of the solid dose vaccine as a powder; compressing the powder to form a body and optionally drying the body to provide a solid dose vaccine having a compressive strength of at least 40, 60, 70 or 80MPa.

39. A process according to claim 38, wherein the powder is compressed in a die.

40. A process according to claim 38 or 39, wherein the step of combining the components as a powder comprises spray drying or freeze drying a solution or suspension of the combined components.