Prophylaxis against streptococcus pneumoniae infections

Abstract

The present invention relates to a vaccine composition for prophylactic use against Streptococcus pneumoniae infections. This composition contains inactivated bacteria of Escherichia coli, Morganella morganii, Proteus mirabilis, Klebsiella pneumoniae and Enterococcus faecalis and preferably dextran and an aluminum compound as adjuvant.

Description

[0001] Prophylaxis against infections caused by Streptococcus pneumoniae

[0002] The present invention relates to a vaccine composition for prophylactic use against infections caused by Streptococcus pneumoniae (S. pneumoniae). S. pneumoniae is one of the most common causes of pneumonia. In addition, S. pneumoniae can also cause other serious illnesses such as otitis media, sinusitis, meningitis, or sepsis. Numerous preparations for the prophylaxis of S. pneumoniae infections are marketed, these vaccine compositions typically containing polysaccharides derived from S. pneumoniae. These polysaccharides are either derived from the bacterial capsule (subunit vaccines) or from the bacterial cell wall, where they are conjugated to carrier proteins (conjugate vaccines). The marketed products thus lead to homologous immunity against S. pneumoniae, which is directed against a specific number of serotypes contained in the vaccine.

[0003] It has now been found that effective immunoprophylaxis against S. pneumoniae can be achieved with a vaccine composition that does not contain antigens derived from S. pneumoniae (heterologous immunity). This vaccine composition for prophylactic use against S. pneumoniae infections contains inactivated bacteria of the following species: Escherichia coli, Morganella morganii, Proteus mirabilis, Klebsiella pneumoniae, and Enterococcus faecalis. An injectable suspension containing these inactivated bacteria is marketed under the trade name StroVac® for the treatment and prophylaxis of recurrent urinary tract infections of bacterial origin. StroVac® is a drug kit consisting of a lyophilisate containing, in addition to the aforementioned inactivated bacteria, dextran 40 for injection, various salts, sucrose, and thiomersal, and a base suspension consisting of aluminum phosphate and water.

[0004] Dextran is a mixture of α,6-glucan polysaccharides. Dextrans serve as storage substances for yeasts and bacteria and consist exclusively of glucose units. The dextran fractions used in medicine are usually obtained by hydrolysis of natural dextrans and subsequent fractionation of the polymer mixture. The natural dextrans typically originate from the bacterial strain Leuconostoc mesenteroides NRRL B-512 or its substrains, e.g., B-512(F). The dextran fractions used in medicine are characterized by their average molecular weight. The dextran fractions 40, 60, and 70, approved for the manufacture of parenteral preparations, have average molecular weights of approximately 40,000, 60,000, and 70,000 g / mol, respectively.

[0005] Bacteria are classified as Gram-positive or Gram-negative based on the structure of their cell wall. The supporting skeleton of the bacterial cell wall consists of the peptidoglycan murein. Peptidoglycans are composed of the sugar derivative molecules N-acetylglucosamine and N-acetylmuramic acid. In contrast to Gram-positive bacteria, the murein layer of Gram-negative bacteria is covered by a characteristic outer membrane made of lipopolysaccharides. The lipopolysaccharides have a three-part structure: attached to the murein layer is lipid A, followed by the core polysaccharide, which connects lipid A to the O-specific side chain, the so-called O-antigen. The O-antigen consists of repeating oligosaccharide subunits made up of three to five sugars. These O-antigens are directed away from the nucleus into the surrounding environment. For E. coli, Gamian et al. (Eur. J. Biochem., 1994, 225, 1211-1220) detect terminal D-glucose.

[0006] In addition, many bacteria can synthesize extracellular polymers. When these polymers are deposited on the bacterial cell wall and firmly attached to it, they form a capsule or glycocalyx. This glycocalyx protects the bacterium from desiccation and also from phagocytosis. It consists of oligosaccharides, with sugar residues including glucose, fructose, and mannose. A large number of Gram-positive bacteria contain teichoic acid, which can be covalently bound to the peptidoglycans of the cell wall. For the bacterium Enterococcus faecalis, Theilacker et al. (Carbohydr. Res., 2012, 354, 106-109) postulate a structure in which a D-glucose unit is bound to the repeat structure of teichoic acid. Oliver et al. (J. Biol. Chem., 2013, 288{3), 21945-21954) found in their investigations on S. pneumoniae that the glycocalyx consists predominantly of glucose-containing repeating units.

[0007] Dextran is immunologically active. The use of dextran as an immunological enhancer, i.e., as an adjuvant to boost the immune response to a vaccine, has been described. Furthermore, the use of dextran as a component of a conjugated vaccine, whose immunological efficacy is primarily based on the antigen conjugated to dextran, was known. The use of dextran as an adjuvant or as a component of a conjugated vaccine against HIV is described in US 6,287,568.

[0008] In WO 2017 / 129699, the use of dextran as a vaccine for the prophylactic treatment of recurrent bacterial and viral infections such as urinary tract and respiratory tract infections is described. A randomized, double-blind, placebo-controlled, parallel-group study on the efficacy and tolerability of StroVac® in patients with recurrent bacterial urinary tract infections found that the actual placebo, which differed from the StroVac® injection suspension only in that it did not contain inactivated bacteria, showed no statistically significant differences in efficacy compared to the established StroVac® vaccination.The incidence of bacterial urinary tract infections (UTIs) was reduced from an average of 5.4 times in the 12 months prior to study enrollment to 1.3 UTIs in 13.5 months by administering the placebo (StroVac®: 5.5 to 1.2 UTIs in 13.5 months). Conversely, significantly fewer adverse reactions to the vaccine occurred in the placebo group than in the treatment group. Therefore, dextran can be effectively used in the prophylactic treatment of local infections, such as recurrent bacterial UTIs, but also in recurrent furunculosis caused by Staphylococcus aureus.

[0009] US 2006 / 0019926 discloses the use of dextran for the prevention of mastitis. The annual cycle of a dairy cow is characterized by a lactation period of approximately 305 days and a dry period of approximately 60 days, during which the mammary glands regenerate. During the onset of the dry period, the mammary glands are highly susceptible to infection because, in the first few days, they are not yet sealed with a keratin plug to protect against germs. US 2006 / 0019926 proposes the administration of a dextran-containing depot formulation, which is injected into the udder and slowly releases dextran, providing a sustained stimulus to the immune system.

[0010] WO 2019 / 01 1514 describes the use of dextran as a vaccine for the prophylactic treatment of bacterial or viral systemic infections. It was demonstrated that both StroVac® and a formulation identical except for the presence of inactivated pathogens protect against peritonitis and sepsis caused by Escherichia coli. US 11,672,857 describes the use of β-glucan in combination with lipid A and aluminum hydroxide to generate an immune response against fungi and bacteria, particularly Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa. It is postulated that the generated immune response is based on a sustained enhancement of the innate immune response.

[0011] The vaccine composition for prophylactic use against infection by S. pneumoniae according to the present invention contains, in addition to the inactive bacteria Escherichia coli, Morganella morganii, Proteus mirabilis, Klebsiella pneumoniae and Enterococcus faecalis, preferably dextran and optionally an adjuvant.

[0012] Preferably, the vaccine composition contains an adjuvant, in particular an aluminum compound. Aluminum hydroxide and aluminum phosphate are examples of suitable aluminum compounds. The mechanism of action of aluminum compounds as adjuvants in immunology is well-established (Springer Plus 2015, 4:181; Scientific Reports 2015, 5, Article No. 13146). Aluminum compounds, such as aluminum hydroxide and aluminum phosphate, increase the uptake of antigens by antigen-presenting cells due to the local inflammatory response triggered by the aluminum injection. The immature dendritic cells attracted to the injection site take up soluble antigens administered with the aluminum compound and migrate to the lymph nodes, where they initiate the activation of B cells. Thus, aluminum compounds increase the uptake of antigens by antigen-presenting cells.

[0013] In a preferred embodiment of the present invention, the vaccine composition is an injectable suspension, which is particularly suitable for intramuscular injection. For example, a vaccine composition according to the invention is a dextran-containing lyophilisate containing the inactivated pathogens, which is resuspended with an aqueous aluminum phosphate suspension.

[0014] Furthermore, the present invention relates to a pharmaceutical kit for the preparation of a vaccine composition for prophylactic use against infection by S. pneumoniae, wherein a first composition contains the inactivated bacteria and optionally dextran, and a second composition contains the adjuvant. Preferably, the first composition is in the form of a dry substance and the second composition is in the form of an aqueous suspension.

[0015] The average molecular weight of the dextran used in the intended application is typically in the range of 10,000–200,000 g / mol, preferably 20,000–120,000 g / mol, more preferably 30,000–100,000 g / mol, and most preferably 40,000–80,000 g / mol. Dextran can be considered to be, in particular, the dextrans listed in the European Pharmacopoeia (Ph. Eur. 9th Edition, Basic Work 2017) for the manufacture of parenteral preparations, i.e., dextran 40, 60, and 70 for injection with an average molecular weight of approximately 40,000, 60,000, and 70,000 g / mol, respectively.

[0016] Furthermore, the present invention relates to a vaccine composition for prophylactic use against infections caused by S. pneumoniae, wherein the composition contains dextran and an aluminum compound, preferably aluminum hydroxide or aluminum phosphate. It is expected that the combination of dextran and an aluminum compound can induce an immune response against S. pneumoniae even in the absence of the inactivated bacterial species according to the invention. Consequently, dextran, as the only vaccine, can be used together with the aluminum compound as an adjuvant for immunoprophylaxis against S. pneumoniae. The vaccine compositions described above are intended for prophylactic use against infections caused by S. pneumoniae, in particular for the prevention of pneumonia, otitis media, sinusitis, meningitis, or sepsis.

[0017] Examples

[0018] 1. Example wording

[0019] Description and composition of an invention according to the drug kit (Stro Vac®):

[0020] One vial of lyophilisate (dry substance vial) contains:

[0021] 10 9 Inactivated germs of the following type and quantity: Escherichia coli 7.5 * 10 8 , Morganella morganii 3.75 * 10 7 , Proteus mirabilis 3.75 * 10 7 , Klebsiella pneumoniae

[0022] 1.5 x 10 8 and Enterococcus faecalis 2.5 *

[0023] Sucrose Ph.Eur.* 12.9 - 14.375 mg

[0024] Dextran 40 for injection Ph.Eur.* 12.9 - 14.375 mg

[0025] NaCl Ph.Eur.* 2.5 - 2.79 mg

[0026] Na2HPO4x 2 H2O Ph.Eur.* 0.36 - 0.41 mg

[0027] HisNaiOiöP Ph.Eur.* 0.24 - 0.275 mg

[0028] KH2PO4 Ph.Eur.* 0.30 - 0.33 mg

[0029] Thiomersal Ph.Eur.* 0.030 - 0.033 mg

[0030] * Ph. Eur. 8th edition

[0031] The substances used have the following functions: Sucrose and Dextran 40 serve as protective and stabilizing substances during lyophilization.

[0032] Sodium chloride, disodium monohydrogen phosphate dihydrate, disodium hydrogen phosphate dodecahydrate and potassium dihydrogen phosphate are components of the phosphate-buffered saline solution (PBS buffer), thiomersal is used as a preservative.

[0033] One ampoule of suspension (base suspension) contains:

[0034] Aluminum Phosphate Company spec. 1.0 mg

[0035] Water for injection Ph.Eur.* 500.0 mg

[0036] * Ph. Eur. 8th edition

[0037] 2. Mouse protection test

[0038] The efficacy of StroVac® injection suspension was determined in a mouse protection test. The ready-to-use vaccine dilution was prepared on the day of immunization of the test animals. For this purpose, 0.5 ml of the base suspension was added to the vial of the lyophilisate using a syringe and resuspended.

[0039] Five-week-old NMRI mice received three intraperitoneal injections of 0.3 ml StroVac® at weekly intervals. Age-matched control mice received three injections of 0.3 ml 0.9% NaCl. One week after the third injection, the mice received two doses of 10 mg StroVac® to evaluate homologous immunity. 7 Colony-forming units (CFU) of Escherichia coli or for the detection of heterologous immunity five times 10 4Intraperitoneal colony-forming units (CFU) of S. pneumoniae were used. Survival and symptom-free survival of vaccinated and control mice were compared using the two-sided log-rank test, and overall mortality was compared using the two-sided Fisher's Exact test. Results: StroVac® protected 100% of mice after homologous infection with Escherichia coli, while 78% of control mice died (p < 0.0001).

[0040] Following heterologous infection with S. pneumoniae, 9 out of 16 mice died in the StroVac* vaccinated group, compared to 15 out of 16 mice in the control group.

[0041] (p < 0.0001 for both survival and symptom-free survival, log-rank test; p = 0.037, Fisher's exact test). At the time of euthanasia (for ethical reasons, severely ill mice are euthanized immediately), the concentration of S. pneumoniae in blood and spleen was lower in StroVac*-vaccinated mice than in control mice (p = 0.04 and 0.02, U-test).

[0042] According to this, StroVac® induced both strong homologous immunity and a somewhat weaker heterologous immunity against S. pneumoniae, which was nevertheless clearly detectable.

Claims

AMENDED CLAIMS received by the International Bureau on 6 November 2025 (06.11.2025) 1. Vaccine composition for prophylactic use against infections caused by Streptococcus pneumoniae, wherein the composition contains inactivated bacteria of the following species: - Escherichia coli - Morganella morganii - Proteus mirabilis - Klebsiella pneumoniae - Enterococcus faecalis.

2. Vaccine composition for use according to claim 1, wherein the composition contains dextran.

3. Vaccine composition for use according to claim 1 or 2, wherein the composition contains an aluminium compound as an adjuvant.

4. Vaccine composition for use according to claim 3, wherein the aluminium compound is aluminium hydroxide or aluminium phosphate.

5. Vaccine composition for use according to any one of claims 1 to 4, wherein the vaccine composition is in the form of an injectable suspension.

6. Vaccine composition for use according to claim 5, wherein the injectable suspension is prepared for intramuscular injection.

7. Drug kit for the manufacture of a vaccine composition for use according to any one of claims 1 to 6, wherein a first composition contains the inactivated bacteria and optionally dextran and a second composition contains the adjuvant. AMENDED SHEET (ARTICLE 19) 8. Drug kit for use according to claim 7, wherein the first composition is a dry substance and the second composition is an aqueous suspension.

9. Vaccine composition or drug kit for use according to any one of the preceding claims, wherein the infection is pneumonia, otitis media, sinusitis, meningitis, or sepsis. AMENDED SHEET (ARTICLE 19)