|Title of Invention||
"A COMBINATION VACCINE COMPRISING A CAPSULAR POLYSACCCHARIDE ANTIGEN OF HAEMOPHILUS INFLUENZA B AND METHOD FOR PREPARING THE SAME"
|Abstract||A combination vaccine comprising a capsular polysaccharide antigen of Haemophilus influenza B conjugated to a carrier protein charaterised in that the conjugate is adsorbed onto aluminium phosphate; and an other component which can afford protection against a pathogen other than Haemophilus influenza b selected from the group of antigens which afford protection against one of Hepatitis A, diphtheria, tetanus, pertussis and Polio.|
|Full Text||The present invention relates to new vaccine formulations, comprising a conjugated polysaccharide antigen linked to a carrier protein. In particular the invention relates to a vaccine formulation for the prevention of Haemophilus Influenzae Type B (Hib) infections and where the antigen is adsorbed on to aluminium phosphate. The invention also relates to a multivalent vaccine, that is a vaccine for the amelioration or treatment of more than one disease states. The present invention also relates to the production and use of such vaccines in medicine.
Vaccines that utilise polysaccharides are known in the art. For example a vaccine for the prevention of Haemophilus influenzae b (Hib) infections are based on the capsular polysaccharide (PRP) conjugated with a carrier protein. The polysaccharide is a polymer of ribose, ribitol and phosphate. These vaccines are typically presented as plain (ie without adjuvantation) formulations. Although in one case, (Pedvax Hib produce by Merck) a diluent containing aluminium hydroxide is utilised to reconstitute the lyophilised conjugate. Typically the carrier protein is a diphtheria or tetanus toxoid or an outer membrane protein of N.menigitidis. Examples of such conjugate vaccine antigens are disclosed in US 4 365 170, US 4 673 574, EP 208 375, EP 477508 and EP 161 188.
It is desirable to administer such conjugate vaccines with other antigens or vaccines at the same time and this can involve multiple injections. Problems associated with multiple injections include a more complicated administration procedure and a large total injection volume. This is a particularly acute problem when the vaccine is intended for infants.
It has therefore been proposed to produce combination vaccines. One well known combination vaccine provides protection against Diphtheria , tetanus and B. pertussis infections. This vaccine comprises a whole cell or an accellular pertussis component which typically consists of two or three antigens - (detoxified PT, FHA and often, but not exclusively 69kDa) although in certain circumstances other B. pertussis antigens may also be present and toxoided diphtheria and tetanus
toxins. Such vaccines are often referred to as DTPw or DTPa. Other antigens would desirable be added to such a combination vaccine for the prevention of diseases like hepatitis B. or Polio,
It would be desirable to add polysaccharide conjugate vaccines to such a combination. However we have found that simple mixing of the components results in a reduction of antibody titres to the polysaccharide component.
The present inventors have discovered that this reduction can be inhibited if the conjugate antigen is adsorbed on to aluminium phosphate. In contrast, if the antigen is adsorbed on to aluminium hydroxide, there is a complete reduction of antibody titres to the polysaccharide component.
Accordingly the present invention provides a vaccine composition comprising a polysaccharide conjugate antigen adsorbed on to aluminium phosphate. Preferably the antigen is capsular polysaccharide (PRP) from Hib conjugated with a carrier protein.
Preferably the carrier protein is either diphtheria or tetanus toxoid, Diphtheria Crm,y7 protein or an outer membrane protein from a bacteria such as N.menigitidis.
The polysaccharide conjugate may be prepared by any known coupling technique. For example the polysaccharide can be coupled via a thioether linkage. This conjugation method relies on activation of the polysaccharide with l-cyano-4-dimethylamino pyridinium tetrafluoroborate (CDAP) to form a cyanate ester. The activated polysaccharide may thus be coupled directly or via a spacer group to an amino group on the carrier protein. Preferably, the cyanate ester is coupled with hexane diamine and the amino-derivatised polysaccharide is conjugated to the carrier protein using heteroligation chemistry involving the formation of the thioether linkage. Such conjugates are described in PCT published application WO93/15760 Uniformed Services University.
The conjugates can also be prepared by direct reductive amination methods as described in US 4365170 (Jennings) and US 4673574 (Anderson). Other methods are described in EP-0-161-188, EP-208375 and EP-0-477508.
A further method involves the coupling of a cyanogen bromide activated polysaccharide derivatised with adipic acid hydrazide (ADH) to the protein carrier by carbodiimide condensation. Such conjugation is described in Chu C. et al Infec Immunity, 1983 245 256.
In a preferred embodiment of the invention the ratio of PRP polysaccharide to carrier protein is reduced from a typical 1:3 to 1:0.3 to 1:2. Such low ratio conjugates are advantageous, since even in an unadjuvanted state, they do not suffer from interference problems.
In a preferred embodiment of the invention the formulation preferably contains at least one other component selected from antigens which afford protection against one or more of the following: Hepatitis A virus (HAV), diphtheria, tetanus, pertussis, Hepatitis B and polio.
Particular combination vaccines within the scope of the invention include a DTPa (diphthena-tetanus-accellular pertussis) -Hib combination vaccine formulation, an Hib-Hepatitis B vaccine formulation, a DTPa-Hib-Hepatitis B vaccine formulation and an IPV (inactivated polio vaccine) -DTPa-Hib-Hepatitis B vaccine formulation.
The above combinations may optionally include a component which is protective against Hepatitis A.
Suitable components for use in such vaccines are already commercially available and details may be obtained from the World Health Organisation. For example the IPV component may be the Salk inactivated polio vaccine. The Diphtheria, Tetanus and Pertussis vaccine may comprise an acellular product such as Infanrix DTPa (SmithKline Beecham Biologicals) . The component affording protection against Hepatitis A is preferably the product known as 'Havrix' (SmithKline Beecham Biologicals) which is a killed attenuated vaccine derived from the HM-175 strain of HAV [see 'Inactivated Candidate Vaccines for Hepatitis A' by F.E. Andre, A Hepburn and E.D'Hondt, Prog Med. Virol. Vol 37, pages 72-95 (1990) and the product monograph 'Havrix' published by SmithKline Beecham Biologicals (1991)|. The Hepatitis B component may comprise the 'S' antigen as in 'Engerix-B'.
Advantageously the Haemophilias Influenzae B or combination vaccine according to the invention is a paediatric vaccine.
Vaccine preparation is generally described in Vaccine Design - The Subunit and adjuvant approach Ed Powell and Newman; Pellum Press. Encapsulation within liposomes is described, for example, by Fullerton, US Patent 4,235,877. Conjugation of proteins to macromolecules is disclosed, for example, by Likhite, US Patent 4,372,945 and by Armor et al., US Patent 4,474,757.
The amount of conjugate antigen in each vaccine dose is selected as an amount which induces an immunoprotective response without significant, adverse side effects in typical vaccinees. Such amount will vary depending on which specific immunogens are employed. Generally it is expected that each dose will comprise l-1000ug of total immunogen, preferably 2-100ug, most preferably 4-40ug. An optimal amount for a particular vaccine can be ascertained by standard studies involving observation of antibody litres and other responses in subjects. Following an initial vaccination, subjects may receive one or two booster injections at about 4 weeks intervals.
In a further aspect according to the invention, there is provided a method of producing the vaccine comprising adsorbing the conjugate antigen on to aluminium phosphate. The adsorbing is preferably done at a pH of between 5 and 6, preferably at about 5.4. In an embodiment the vaccine is freeze dried after standing for more than 24 hours. Alternatively, the vaccine of the invention may be combined with other antigens in a liquid form.
The invention further provides the first medical use of such a vaccine.
In a further embodiment the invention provides a method of preventing or ameliorating Heamophilus Influenzae B infections, the method comprising the administration of a non toxic, effective amount of the vaccine of the invention.
The following examples illustrate the invention.
Vaccine formulation comprising HiB polysaccharide conjugated on Tetanus toxoid adsorbed on to Aluminium phosphate.
Synthesis of Haemophilus influenzae type B capsular polysaccharide (PRP) Tetanus toxoid (TT) conjugate
1 .a Cyanogen Bromide Coupling
The covalent binding of PRP and TT is carried out by a coupling chemistry developed at the NIH (Chu C. et al (1983), further studies on the immunogenicity of Haemophilus influenzae type b and pneumococcal type 6A polysaccharide protein conjugates. Infec. Immunity, 245-256). The PRP is activated under controlled conditions by cyanogen bromide and derivatised with an adipic hydrazide spacer.
After derivatisation, the activated polysaccharide (PRP-AH) is purified by diafiltration. The coupling of the two purified components (PRP-AH and TT) is effected by carbodiimide condensation. The conjugate is then purified by ultrafiltration and gel filtration to remove the reagent and unconjugated PRP and TT.
Synthesis of PRP-TT Conjugates
l.b CDAP coupling
30mg of native Hib PRP were dissolved in 6ml 2M NaCl. 225mcl of CDAP (1 cyano-4-dimethylamino-pyridinum tetrafluoroborate) was added to the polysaccharide solution (from a 100 mg/ml stock solution in acetonitrile). 90 seconds later, 450 mcl of 0.2 M triethylamine was added. The activation was performed at pH 10.0 during 1 minute on ice and minute at room temperature.
90 mg of tetanus toxoid (initial PS/protein ratio of 1/3) were added to the activated polysaccharide and the coupling reaction was performed at room
temperature for 1 hour. Then, the reaction was quenched with 3 ml of 1M glycine solution, pH 5.0 for 30 minutes at room temperature and overnight at 4°C.
The conjugate was purified by gel filtration on a sephacryl HR 500 column equilibrated in 0.2M NaCl. The carbohydrate and protein content was determined in each fraction. The conjugate was pooled and sterile filtered (membrane Minisart
0 0.222 ym).
Adsorption on to aluminium phosphate
1 .c To 0.15rng of aluminium phosphate was added 12.5 meg of the polysaccharide
conjugate of example l(a). This was stirred for two hours the pH is adjusted to
5.1. The mixture was left to stand for one day at room temperature and the
adsorbed conjugate then left for a further 9 days at 2 to 8 o C. To prepare a freeze
dried product the adsorbed product is diluted in lactose (15.75mg) to give a final
composition of 25mcg polysaccharide/ml and 0.4mg Al/ml and the resulting
composition was filled into 0.5ml vials and freezed dried.
To prepare a liquid product the adsorbed conjugate is diluted in water for injection with 150mM NaCl and 5mg/ml phenoxy ethanol to give a final composition of 20 meg polysaccharide/ml and 0.32 mgAl/ml.
1 ,d Formulation of a Diphtheria Tetanus and Pertussis (acellular) vaccine with and without hepatitis B was done in accordance to the methods of WO 93/24148 (SmithKline Beecham Biologicals).
l.e Preparation of a 'low ratio' PRP-TT aluminium phosphate pre-adsorbed conjugate.
The conjugate was prepared in an analogous manner to the example of la, but with reduced amount of Tetanus used (30mcg, 60mcg) to give a product with Polysaccharide:Protein ratio of 1:1 or 1:2. The conjugate is then adsorbed on to aluminium phosphate according to the method of example Ic. The final freeze
dried preparation contains 12.5/xg of conjugate, 0.15mg ALPO4, 15.75 mg lactose. This is reconstituted in 0.5ml water for injection prior to use at a pH of 0.1 +/-0.1.
Example 2: Immunogenicity of PRP-TT conjugate preadsorbed on aluminium phosphate and combined with DTPa or DTPa-HB
The Hib conjugate of example la), either plain or pre-adsorbed on Al PO4 (both vaccines were lyophilized) was mixed with DTPa or DTPa HB no more than 1 hour before injection and the combination was injected in baby rats (1 week of age) by the subcutaneous route at a dose corresponding to l/20th a human dose (0.5 jig of PRP), The rats were boosted 2 weeks and 4 weeks later and the serum was collected was collected after each immunization to measure anti-PRP antibodies. Controls included the Hib vaccines (adsorbed or not on Al PO4) reconstituted in saline.
Groups of 10 randomized baby rats (1 week of ago-OFA strain) were immunized 3 times subcutaneously at 0-14-28 days with l/20th human dose of Hib vaccine, alone or combined with DTPa or DTPa HB (l/20th a human dose). The reconstitution of the lyophilised Hib vaccine with saline or combinations (DTPa or DTPa HB) was done less than 1 hour before immunization.
The rats were bled under anesthesia at 14-28-42 and 56 days. The anti-PRP antibodies were measured by ELISA in individual sera and the liters were expressed in y/ml using a calibrated reference. The GMT was calculated for each group and for each time point. The 95% confidence limits were calculated for the tilers obtained after that third immunization.
As shown in table 1, the adsorption of Hib conjugate on Al PO4 does not modify its immunogenicity: some anti-PS were produced after the second dose and a good booster effect is shown after the third dose as seen in human babies. The mixing of Hib vaccine with DTPa or DTPa HB reduces by 3 to 8 fold the anti-PRP response and, in the case of DTPa-HB, this decrease is significant In conlrast, the
pre-adsorption of the Hib vaccine on Al PO4 restores the anti-PRP response to a level at least equivalent to that obtained with the plain vaccine.
The Hib/aluminium phosphate formulation has thus the potential to solve the compatibility problem encountered when mixing Hib with other peadiatric combinations.
Immunogenicity in a baby rat model of PRP-TT conjugate pre adsorbed on AIP04 and combined with DTPa or DTPa-HB (Table Removed)
1. A combination vaccine comprising:
i) a capsular polysaccharide antigen of Haemophilus influenza B conjugated to a carrier protein charaterised in that the conjugate is adsorbed onto aluminium phosphate; and
ii) an other component which can afford protection against a pathogen other than Haemophilus influenza b selected from the group of antigens which afford protection against one of Hepatitis A, diphtheria, tetanus, pertussis and Polio.
2. A combination vaccine as claimed in claim 1 wherein the carrier protein is selected from the group consisting of; Diphtheria toxoid, Diphtheria CRM197 protein and Meningococcal outer membrane protein.
3. A combination vaccine as claimed in claim 1 wherein the carrier protein conjugated to the capsular polysaccharide of Haemophilus influenzae B is tetanus toxoid.
4. A combination vaccine as claimed in any one of claims 1 to 3 wherein the ratio of the
Haemophilus influenzae B polysaccharide to carrier protein is from 1:0:3 to 1:2
5. A combination vaccine as claimed in any one of claims 1 to 4 wherein the adsorbed
conjugate has been freeze dried prior to its combination with the other antigens.
6. A method of producing a vaccine as claimed in claims 1 to 5 comprising: conjugating
a Haemophilus influenzae type B capsular polysaccharide antigen to a protein earner, adsorbing said conjugate onto aluminium phosphate and mixing with the other component which can afford protection against a pathogen other than
Haemophilus influenza b, wherein the adsorption step is done at a pH of between 5 and
7. The method as claimed in claim 6 wherein the other component is selected from the
of antigens which afford protection against one of Hepatitis A, diphtheria, tetanus. pertussis and Polio.
8. A combination vaccine as claimed in claim 1 comprising:
i) a capsular polysaccharide of Haemophilus influenzae B conjugated to a
carrier protein characterised in that the conjugare is adsorbed onto aluminium phosphate; and
ii) other antigens which afford protection against diphtheria, tetanus and
9. A combination vaccine as claimed in claim 8 wherein the conjugate is admixed
with one or more other antigens which afford protection against a disease selected from the group consisting of; Hepatitis A, Hepatitis B and Polio.
10. A combination vaccine as claimed in claim 8 or 9 wherein the carrier protein is
selected from the group consisting of: Diphtheria toxoid. Diphtheria CRM197 protein and Meningococcal outer membrane protein.
11. A combination vaccine as claimed in any one of claims 8 or 9 wherein the carrier protein
conjugated to the capsular polysaccharide of Haemophilus influenzae B is tetanus
12. A combination vaccine as claimed in any one of claims 8 to 11 wherein the ratio of
the Haemophilus influenzae B polysaccharide to carrier protein is from 1:0:3 to 1:2 (w:w).
13. A combination vaccine as claimed in any one of claims 8 to 12 wherein the
adsorbed conjugate has been freeze dried prior to its combination with the other antigens.
14. A kit for making a combination vaccine comprising a container of a freeze-dried
vaccine comprising a capsular polysaccharide of Haemophilus influenzae R conjugated to a carrier protein and adsorbed onto aluminium phosphate, and a second container with a vaccine which affords protection against diphtheria, tetanus and pertussis disease.
15. A method of producing a vaccine as claimed in claims 8 to 13 comprising
conjugating a Haemophilus influenzae type B capsular polysaccharide antigen to a protein carrier, adsorbing said conjugate onto aluminium phosphate, and mixing with said other antigens.
16. The method of claim 15 wherein the adsorption step is done at a pH of between 5 and 6.
17. The method of claim 15 or 16 wherein said other antigens afford protection against
a disease selected from the group consisting of: Hepatitis A, diphtheria, tetanus, pertussis, Hepatitis B and polio.
18. The combination vaccine of claim 1 or 9 wherein the capsular polysaccharide of
Haemophilus influenzae B is conjugated to tetanus toxoid, and wherein the vaccine comprises the following antigens: diphtheria toxoid, tetanus toxoid, acellular pertussis antigens, Hepatitis B surface antigen and Inactivated Polio Vaccine.
|Indian Patent Application Number||1375/DEL/1996|
|PG Journal Number||40/2008|
|Date of Filing||21-Jun-1996|
|Name of Patentee||SMITHKLINE BEECHAM BIOLOGICALS S.A.|
|Applicant Address||RUE DE 1'INSTITUT 89, B-1330 RIXENSART, BELGIUM.|
|PCT International Classification Number||A61K 39/02|
|PCT International Application Number||N/A|
|PCT International Filing date|