JP7116428B2 - Infectious disease drug - Google Patents

Description

The present invention relates to compositions useful for treating or preventing infectious diseases. Specifically, a block copolymer comprising a polyethylene glycol (PEG) segment as a hydrophilic portion and a segment made of polystyrene as a hydrophobic portion, to which a cyclic nitroxide radical having a radical scavenging function is covalently bonded to the side chain of the hydrophobic portion. It comprises a polymer as an active ingredient and may be further combined with an appropriate antibacterial agent for suppressing multiple organ damage that can lead to multiple organ failure associated with highly fatal infectious diseases, and for suppressing the above infectious diseases. It relates to prophylactic or therapeutic compositions.

Various infectious diseases caused by the intrusion of pathogens such as bacteria, viruses, and parasites into the body produce a large amount of reactive oxygen species by the immune response immediately after infection, and a large amount of inflammatory cytokines are produced accordingly. It is known. As a result, it is known in the art that systemic inflammatory response syndrome (SIRS), and even multiple organ failure, complicates and kills patients with infectious diseases. At present, it is possible to treat the dysfunction of each organ individually, but when these occur simultaneously in relation to each other, there is no treatment other than dealing with each. For this reason, it is important to prevent multiple organ failure before it develops, and it is necessary to take measures at the time of SIRS, which is the preceding stage. Of course, there are antibiotic therapy and the like as traditional therapies for the treatment of severe infections such as infections and sepsis, but due to the exacerbation of inflammatory reactions due to administration of antibiotics and the limitation of the spectrum range of antibiotics themselves, all bacteria can be treated. is difficult to eradicate, and the possibility of secondary infection cannot be denied.

From this point of view, attempts have been proposed to improve the therapeutic effects of infectious diseases by administering antioxidants, and anti-oxidants (for example, N-acetylcysteine) have been proposed to reduce damage to specific organs. It has also been proposed to use a drug (deferoxamine) in combination (Non-Patent Document 1: Christiane Ritter, et al., Crit Care Med.
2004, Vol. 32, No. 2,342-349 and other non-patent references cited therein). Other non-patent literature includes tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl), α-tocopherol, allopurinol, deferoxamine, catalase, superoxide dismutase ( SOD) etc. are explained. For example, Non-Patent Document 2: Christoph Thiemermann, Crit Care Med 2003, Vol. 31, No. 1, S76-S84, unlike recombinant SOD, which is a macromolecule, tempol is biologically membrane-permeable and accumulates in the cytosol to induce circulatory shock and ischemic reperfusion injury. , has been suggested to suppress inflammation.

On the other hand, the present inventors have used polyethylene glycol (PEG) segments as hydrophilic moieties and hydrophobic proposed a block copolymer composed of polystyrene and comprising a segment to which a cyclic nitroxide radical having a radical scavenging function is covalently bonded to the side chain of the hydrophobic part (Patent Document 1: WO 2013/118783). It is also known that similar block copolymers can be used to enhance the efficacy of certain anticancer agents in place of dexamethasone, which is known to enhance the efficacy of anticancer agents (patent literature 2: JP-A-2012-067025).

However, it is unknown whether such block conjugates can be useful in preventing or treating bacterial infections, particularly severe infections such as sepsis that lead to multiple organ failure.

WO 2013/118783 JP 2012-067025

Christiane Ritter, et. al. , Crit Care Med 2004, Vol. 32, No. 2,342-349

An object of the present invention is to provide a means that can be useful in slowing, preventing or treating bacterial, viral and parasitic infections, particularly severe infections such as sepsis that lead to multiple organ failure.

The above-mentioned block copolymer is an infectious disease that is not necessarily effectively treated with antibacterial agents such as antibiotics, and causes sepsis, etc., and may cause multiple organ failure, leading to death of the patient. It has now been found that in listeriosis or Listeria infection, multiple organ damage that can lead to multiple organ failure can be suppressed and malaria or an infection model of malaria (Plasmodium spp.) can be significantly prolonged. rice field. Furthermore, in the infectious disease, in a manner that can suppress multiple organ damage, when combined with the antibacterial agent that is block-copolymerized with respect to the infectious agent of the infectious disease, therapy with an antibacterial agent It has also been found that even those infections that cannot be effectively prevented or treated by the method can be effectively prevented or treated.

Such effects of the block copolymers were equally found in the prevention or treatment of infectious diseases that can produce a large amount of cytokines and reactive oxygen species immediately after infection, like listeriosis or malaria.

Therefore, the problems of the present invention can be solved mainly by providing inventions having the following aspects or features.

Aspect 1: A composition for suppressing multiple organ failure accompanying highly lethal infectious diseases, which may lead to multiple organ failure, comprising a block copolymer represented by the following formula (I) as an active ingredient: .

During the ceremony,
A represents unsubstituted or substituted C ₁ -C ₁₂ alkoxy and the substituent, if substituted, represents a formyl group, a group of formula ^{R′R ″} CH—wherein R ^′ and R ^″ are independently and C ₁ -C ₄ alkoxy or R ^′ and R ^″ together represent —OCH ₂ CH ₂ O—, —O(CH ₂ ) ₃ O— or —O(CH ₂ ) ₄ O—,
L ₁ is a direct bond or a divalent linking group, e.g.

or the divalent linking group L ₁ has the formula -(CH ₂ ) _b S-, -CO(CH ₂ ) _b S-, -(CH ₂ ) _b NH—, —(CH ₂ ) _b selected from groups represented by CO—, —CO—, —OCOO—, and —CONH— ;
X represents L ₂ -R ₁ or chloro or bromo or hydroxyl and L ₂ is -(C
H ₂ ) _a —O—(CH ₂ ) _a — and R ₁ is 2,2,6,6-tetramethylpiperidine-
1-oxyl-4-yl, 2,2,5,5-tetramethylpyrrolidin-1-oxyl-3-yl, 2,2,5,5-tetramethylpyrrolin-1-oxyl-3-yl, 2, 4,4-trimethyl-1,3-oxazolidin-3-oxyl-2-yl, 2,4,4-trimethyl-1,3-thiazolidin-3-oxyl-2-yl, 2,4,4-trimethyl- is selected from imidazolidin-3-oxyl-2-yl, and at least 50% of the n Xs are L ₂ -R ₁ ;
each a is independently an integer from 0 to 5;
b is an integer from 1 to 5,
m represents an integer from 2 to 10,000,
n represents an integer of 3 to 100,
Z is H, SH or S(C=S)-Ph, Ph represents phenyl optionally substituted with 1 or 2 methyl or methoxy.

Aspect 2: A composition for the prevention or treatment of highly lethal infectious diseases, wherein a block copolymer represented by the following formula (I) and an antibacterial agent having antibacterial activity against pathogens of the infectious diseases are effective A composition comprising as an ingredient.

During the ceremony,
A represents unsubstituted or substituted C ₁ -C ₁₂ alkoxy and the substituent, if substituted, represents a formyl group, a group of formula ^{R′R ″} CH—wherein R ^′ and R ^″ are independently and C ₁ -C ₄ alkoxy or R ^′ and R ^″ together represent —OCH ₂ CH ₂ O—, —O(CH ₂ ) ₃ O— or —O(CH ₂ ) ₄ O—,
L ₁ is a direct bond or a divalent linking group, such as the formula

or the divalent linking group L ₁ has the formula -(CH ₂ ) _b S-, -CO(CH ₂ ) _b S-, -(CH ₂ ) _b NH—, —(CH ₂ ) _b selected from groups represented by CO—, —CO—, —OCOO—, and —CONH— ;
X represents L ₂ -R ₁ or chloro or bromo or hydroxyl and L ₂ is -(C
H ₂ ) _a —O—(CH ₂ ) _a — and R ₁ is 2,2,6,6-tetramethylpiperidine-
1-oxyl-4-yl, 2,2,5,5-tetramethylpyrrolidin-1-oxyl-3-yl, 2,2,5,5-tetramethylpyrrolin-1-oxyl-3-yl, 2, 4,4-trimethyl-1,3-oxazolidin-3-oxyl-2-yl, 2,4,4-trimethyl-1,3-thiazolidin-3-oxyl-2-yl, 2,4,4-trimethyl- is selected from imidazolidin-3-oxyl-2-yl, and at least 50% of the n Xs are L ₂ -R ₁ ;
each a is independently an integer from 0 to 5;
b is an integer from 1 to 5,
m represents an integer from 2 to 10,000,
n represents an integer of 3 to 100,
Z is H, SH or S(C=S)-Ph, Ph represents phenyl optionally substituted with 1 or 2 methyl or methoxy.

Embodiment 3: R ₁ is the formula

wherein R' is methyl
The composition according to aspect 1 or 2, which is any of

Aspect 4: The composition according to aspect 1 or 2, wherein L ₁ is --CH ₂ CH ₂ S-- or para-xylylene or meta-xylylene and L ₂ is --O--.

Aspect 5: A composition according to aspect 1 or 2, wherein the highly fatal infection is selected from Listeria infection, malaria, cholera, Zika fever, dengue fever, salmonella infection, Ebola hemorrhagic fever.

Aspect 6: The composition of aspect 2, wherein the highly fatal infection is a Listeria infection and the block copolymer is administered prior to administration of an antimicrobial agent to the patient.

Aspect 7: The highly lethal infectious disease is malaria, and Plasmodium
spp. 3. The composition according to aspect 2, wherein the block copolymer is administered to the patient before or after infection with ).

According to the present invention, the block copolymer represented by the formula (I) is included as an active ingredient for suppressing multiple organ damage that can lead to multiple organ failure accompanying highly fatal infectious diseases. A composition that can provide a composition and that effectively prevents or treats the infectious disease by using such a block copolymer in combination with an antibacterial agent that has been used for severe infectious diseases can provide. The effect of the copolymer, which is the active ingredient of such a composition, is due to the fact that the low-molecular-weight compound tempol described in Non-Patent Document 2 is permeable to biological membranes, unlike recombinant SOD, which is a polymer. This is unexpected in light of the suggestion that it effectively suppresses sexual shock, ischemic reperfusion injury, and inflammation.

Schematic diagram of a typical block copolymer according to the present invention and redox nanoparticles (RNPs) prepared therefrom. In Test Example 1, L. Shows inhibitory action on liver injury by monocytogenes. In Test Example 1, L. Shows inhibitory action on lung damage caused by monocytogenes. In Test Example 1, L. Fig. 4 shows inhibitory action on splenic damage caused by monocytogenes. The infection and treatment program implemented in Test Example 2 are shown. 4 is a graph showing the results of Test Example 2. FIG. The infection and treatment program implemented in Test Example 3 are shown. 4 is a graph showing the results of Test Example 3. FIG. The infection and its treatment program implemented in Test Example 4 are shown. 4 shows a growth curve after infection with malaria parasite in Test Example 4. FIG. FIG. 10 shows survival curves of model animals treated with RNP for malaria infection in Test Example 4. FIG. FIG. 10 shows a photograph in place of a drawing showing the results of observing the model animal on day 6 of the test in Test Example 4. FIG.

Detailed description of the invention

Unless otherwise defined or explained, the terms used in connection with the present invention are understood to have the meanings commonly used in the relevant technical fields.

A highly lethal infection means an infection that is associated with a high probability of causing multiple organ failure, which can lead to sepsis or multiple organ failure, resulting in death of the patient. Infectious agents of such infectious diseases are not limited as long as they cause the above-defined infectious diseases. Plasmodium ssp., which is an infectious agent, Vibrio cholerae, which is an infectious agent of cholera, Zika virus, which is an infectious agent of Zika fever, and an infectious agent of dengue fever A certain dengue virus, Salmonella enterica which is an infectious agent of salmonella infection, Ebola virus which is an infectious agent of Ebola hemorrhagic fever, and the like can be mentioned.

Multiple organs referred to as multiple organ failure are organs essential for sustaining life, particularly liver, lung, spleen, and kidney. Disorders that occur in more than one of these organs are multiorgan disorders that are intended to be inhibited by the present invention. Such damage is measured by the thiobarbiturate reaction product (MDA), which measures malondialdehyde (MDA), a key marker that occurs during the process of lipid peroxidation, a known mechanism of cell or organ damage in animals. TBARS: Thiobarbituric acid Reactive Substances) assay (for example, TBARS is also mentioned in Non-Patent Document 1 above). Therefore, a person skilled in the art would understand that the composition for suppressing multiple organ damage that can lead to multiple organ failure accompanying a highly fatal infectious disease, as referred to in the present invention, is the block copolymer of formula (I) above. It can be easily confirmed in light of the definition of coalescence. Administration of the above block copolymer to an individual (or patient) for suppression may cause new infection or expand (enhancement) the area of infection even before or after infection. is done if there is The route of administration is selected by parenteral, parenteral (other than passage through the gastrointestinal tract or lungs), intravenous, subcutaneous, intramuscular, intramedullary, intraperitoneal injection, and the like.

Compositions for the prevention or treatment of highly lethal infectious diseases comprise the block copolymer represented by formula (I) above and, if appropriate, antibacterial or antiprotozoal activity against pathogens of said infectious diseases. Antibacterial agents or antiprotozoal vaccines with antimicrobial agents are included as active ingredients. The antibacterial activity referred to here does not require an activity that completely kills pathogens, but together with the inhibitory action or effect of the above-mentioned block copolymer on multiple organ damage, recovers patients with infectious diseases, Any substance can be used as long as it acts to significantly increase the survival rate. Such antibacterial agents cannot be specified because they vary depending on the pathogen, but in general, various antibacterial agents or antiviral agents that are commonly used to treat infections and sepsis, such as aminoglycoside anti-antibiotics, Antifungal agents, carbapenem antibiotics, penicillin antibiotics, cephalosporin antibiotics, fluoroquinolone antibiotics, macrolide antibiotics, tetracycline antibiotics, antiviral agents, and the like.

Said prophylactic or therapeutic composition comprises said block copolymer and, if appropriate, an antibacterial agent or a vaccine against pathogens, administered either simultaneously or one after the other. Since it can contain, it does not mean only to contain as a mixture. Preferably, in the composition, the block copolymer is contained in a form that can be administered before infection or even after infection at a time when new infection may occur or the area of infection may expand. On the other hand, the antibacterial agent is contained in such a manner that it is administered simultaneously with, before, or after the administration of the block copolymer. In order to improve the efficacy of the antibacterial agent, it is desirable to administer the antibacterial agent after the administration of the block copolymer, particularly after the state in which multi-organ damage can be suppressed has been achieved. The route of administration of antibacterial agents is not limited to parenteral administration.

When each linking group in the block copolymer represented by the above formula (I) changes depending on the bonding directionality, it means that the bonding is performed with the stated directionality.

In the block copolymer represented by formula (I), the divalent linking group defined for L ₁ is a poly(ethylene glycol) (hereinafter sometimes abbreviated as PEG) segment and a cyclic nitroxide as a side chain. There is no limitation as long as the function of the segment to which the radical is bound meets the purpose of the present invention. However, divalent linking groups generally refer to groups containing up to 34, preferably 18, more preferably up to 10 carbons and optionally oxygen and nitrogen atoms. Specific examples of such a linking group include the following groups represented by the following formulae:

or —(CH ₂ ) _b S—, —CO(CH ₂ ) _b S—, —(CH ₂ ) _b NH—, —(CH ₂ ) _b CO—, —CO is selected from the group consisting of -, -OCOO-, and -CONH-, and each b is independently an integer of 1 to 5;

L ₁ in formula (I) is represented by the formula

When the block copolymer is selected from the linking groups represented by WO 2016/0524
63 A1, and the --(CH ₂ ) ₂ --OL ₁ -- moiety is a bond, --(CH ₂ ) _b S--, --CO(CH ₂ ) _b S--, --(CH ₂ ) _b NH-, -(CH ₂ ) _b CO-, -CO-
, —OCOO—, and —CONH—, the block copolymer in which the linking group is selected from the group consisting of is described in Patent Document 1 or Patent Document 2, or can be obtained by the method described. Divalent linking groups other than these can also be obtained by methods well known in the art with reference to the methods described in the above literature.

These block copolymers are composed of polystyrene in aqueous media, including physiological saline, phosphate-buffered saline, water for injection, etc., as described in both documents, respectively. It is possible to form a so-called core-shell polymer micelle, in which the core is the hydrophobic part of the segment in which the cyclic nitroxide radical having a radical scavenging function is covalently bonded to the chain, and the hydrophilic part of the polyethylene glycol (PEG) segment is the shell. can. Such polymeric micelles are provided as particles having an average size of several nm to several hundreds of nm, preferably 10 nm to 400 nm, more preferably 15 nm to 100 nm, by dynamic light scattering (DLS) measurement in an aqueous solution. can. Such particles are sometimes referred to herein as RNPs or RNP-O or RNP(O). In such RNPs, a cyclic nitroxide radical moiety having a redox function essential for exerting the action of the present invention is present in the hydrophobic core portion, and the surrounding portion exhibits high mobility in an aqueous environment. Although it is presumed to be covered by a shell of known PEG segments, the desired effects of the present invention are exerted in localized areas where multiple organ damage occurs due to infections.

In block copolymers suitable for use in the present invention, a in formula (I) is the integer zero. n is an integer of 5-80, preferably 5-60, more preferably 5-50. m is an integer of 12-5000, preferably 15-2000, more preferably 40-500. At least 50%, preferably 70%, more preferably 80%, and most preferably 100% of the n X's are L ₂ -R ₁ .

The block copolymer is preferably administered to the patient as such, preferably in the form of RNP, in a dosage form suitable for the above administration routes. Prior to use, RNPs may be provided as a lyophilized preparation, which may include mono- or disaccharides, polyvinylpyrrolidone, polyethylene glycol, and the like. The dose of the block copolymer or RNP can be determined according to the judgment of a specialist, etc., after confirming the dose capable of suppressing multiple organ damage due to infection by the TBARS assay using a model animal described later. On the other hand, the antibacterial agent can be determined according to the judgment of a specialist, etc., with reference to doses that have already been used for the treatment of infectious diseases to be treated.

The present invention will be described in more detail below using specific examples, but the present invention is not meant to be limited to these.

Production Example 1: Synthesis of poly(ethylene glycol)-block-poly(chloromethylstyrene) (PEG-b-PCMS) diblock copolymer and introduction of TEMPO PEG-b-PCMS is synthesized according to the following synthesis scheme 1 did:

Dehydration was carried out by evacuating methoxypolyethylene glycol (PEG-OH) (Mn: 5000; 3 mmol, 15 g) having a terminal hydroxy group at 110°C for 12 hours. After that, a nitrogen atmosphere was established, and 60 mL of tetrahydrofuran (THF) was added. n-Butyllithium (BuLi) (0.384 g, 6 mmol) was added thereto. Further, α,α'-dichloroparaxylene (5.25 g, 30 mmol) was added to synthesize polyethylene glycol-chloroparaxylene (PEG-Cl). Purification work-up was performed by precipitation against isopropyl alcohol (yield 13.77 g, 91.8% yield). Carbon disulfide (0.974 g, 12.8 mmol) and benzomagnesium bromide (polyethylene glycol with a chain initiator at the end (PEG-CTA) were recovered (7.76 g, 97% yield). PEG-CTA ( Mn: 5000; 0.7 mmol, 3.5 g) was added to the reaction vessel.Next, after the reaction vessel was evacuated, the operation of blowing nitrogen gas into the reaction vessel was repeated three times to create a nitrogen atmosphere in the reaction vessel. 1-Azobisisobutyronitrile (AIBN) (114.9 mg, 0.7 mmol) and chloromethylstyrene (21 mmol, 3 mL) were added to the reaction vessel, heated to 60° C., and stirred for 24 hours. After washing three times with diethyl ether, which is a good solvent for polychloroethylstyrene homopolymer, and freeze-drying with benzene, a skin-colored powder was obtained. The synthesis of styrene (having a degree of polymerization m of about 18) was completed and the yield was 4.45 g (72% yield).The target polystyrene was obtained by size exclusion chromatography (SEC) column It can be confirmed by the separation spectrum and the NMR spectrum.

10 g of the PEG-b-PCMS thus obtained was dissolved in 150 mL of dimethylformamide (DMF) and the separately prepared 4-hydroxy-TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) 19 .7 g Li compound was added and allowed to react for 2 days at room temperature. The reaction mixture was precipitated in 500 mL of cold 2-propanol, centrifuged (4° C., 9000 rpm, 2 minutes), and dried under reduced pressure. A product (PEG-b-PMOT) in which 80% of the PCMS moieties were replaced with TEMPO was thus obtained.

Production Example 2: Preparation of redox nanoparticles RNP from PEG-b-PMOT obtained in Production Example 1 300 mg of the TEMPO-introduced compound synthesized in Production Example 1 above is placed in a glass container, dissolved in 2 mL of DMF, and fractionated. It was dialyzed against 2 L of water with a 3,000 molecular weight hollow fiber dialysis module (mPES Midikros® Modules 3 kD IC 0.5 mm D06-E003-05-N). The light scattering spectrum of the resulting particles yielded RNPs (also described as RNP-O or RNP(O)) with a narrow distribution range and an average particle size of about 20 nm. FIG. 1 shows a conceptual diagram of RNP preparation.

Test Example 1: Effect of RNP on Multiple Organ Damage in Listeria Infection Model Animals Listeria monocytogenes (obtained from ATCC) (10 ¹² CFU/mL) was added to Balb/c mice (7 weeks old, body weight 20 g). 200 μL of RNP was administered intraperitoneally (200 mg/kg) at the same time. One day later, various organs were collected and analyzed for degree of organ damage by TBARS assay (reagent purchased from Tokyo Kasei Kogyo Co., Ltd.). In this test, 4 animals per group were used. Results observed in liver, lung and spleen are shown in Figures 2, 3 and 4, respectively. From these, malondialdehyde (MDA) levels, which are major markers produced in the process of lipid peroxidation, which is known as a mechanism of organ damage, in the liver, lung and spleen, respectively, were It turns out that it decreases significantly. This indicates that the block copolymer according to the present invention effectively suppresses multiple organ damage caused by Listeria monocytogenes.

Test Example 2 Improving Effect of RNP on Survival Rate and Body Weight Change in Listeria-Infected Mice RNP was administered to Listeria-infected mice according to the procedure (infection and treatment program) shown in FIG. 5, and the survival rate and body weight change were analyzed. For comparison, hydroxy-TEMPO, a small-molecule antioxidant, was administered to compare the effects. Each test was performed on 5 mice per group.

1 and 2: Balb/c mice (7 weeks old, body weight 20 g) were given Listeria monocytogenes (10 ¹² CFU/mL) bacterial solution (physiological saline + L. monocytogenes) (200 μL) or physiological control Saline was administered (day 1).
3: Amoxicillin (ip 15 mg/kg) was administered for five days starting one day after administration of Listeria monocytogenes (10 ¹² CFU/mL) bacterial solution (200 μL).
4: One day after administering hydroxy TEMPO (ip 60 mg/kg), administering Listeria monocytogenes (10 ¹² CFU/mL) fungal solution (200 μL), over five days from the day after Amoxicillin (ip 15 mg/kg) was administered.
5: One day after administering RNP(O) (i.p. 200 mg/kg), administer Listeria monocytogenes (10 ¹² CFU/mL) bacterial solution (200 μL), and one day later, administer 5 Amoxicillin (ip 15 mg/kg) was administered for days.

The results of these tests are shown in FIG. The data in these figures confirmed a significant improvement in survival rate in the RNP-administered group, while a small-molecule antioxidant (hydroxy-TEMPO) did not show a significant improvement effect. Furthermore, it was confirmed that the surviving mice (4 out of 5) recovered their lost body weight. These results indicate that administration of RNP in the early stages of Listeria infection inhibits multiple organ damage leading to death and effectively treats Listeria infection.

Test Example 3: Improving effect of RNP (post-infection administration) on survival rate in Listeria-infected mice
was administered and the survival rate and body weight change were analyzed. For comparison, only amoxicillin was administered to compare the effects. Each test was performed on 5 mice per group.

1 and 2: Balb/c mice (7 weeks old, body weight 20 g) were given Listeria monocytogenes (10 ¹² CFU/mL) bacterial solution (physiological saline + L. monocytogenes) (200 μL) or physiological control Saline was administered (day 0).
3: Amoxicillin (ip 15 mg/kg) was administered for five days starting one day after administration of Listeria monocytogenes (10 ¹² CFU/mL) bacterial solution (200 μL).
4: RNP (O) (ip 200 mg/kg) was administered on the day of administration of Listeria monocytogenes (10 ¹² CFU/mL) bacterial solution (200 μL) and one day after administration, and further after administration Amoxicillin (ip 15 mg/kg) was administered for five days starting one day later.

The results of these tests are shown in FIG. From the data in these figures, it was confirmed that amoxicillin did not show a significant improvement effect, while the RNP administration group showed a significant improvement in survival rate. These results indicate that administration of RNP after Listeria infection inhibits multiple organ damage leading to death and effectively treats Listeria infection.

Test Example 4: Effect of RNP in malaria-infected model animals The infection and its treatment performed in this test followed the procedure shown in FIG. Briefly, female C57BL/6 mice (8 weeks old, body weight about 20 g) were intraperitoneally injected with 0.2 mL of a malaria parasite (virulent strain Plasmodium berghel (Pb): obtained from MR4) solution (10 ⁶ Pb ANKA). dosed. One day after administration of the protozoa, RNP (200 mg/kg) prepared as described above was intraperitoneally administered daily. In this test, 3 animals per group were used.

The results of observing the growth of malaria parasites and the survival of model animals after infection with malaria parasites are graphically represented in FIGS. 10 and 11, respectively. In addition, FIG. 12 shows a photograph as a substitute for a diagram showing the observation results of the model animal on day 6 of the test. Although no significant difference was observed between the RNP-treated group and the non-treated group in the rate of proliferation of malaria parasites, the RNP-treated group was found to have a life-prolonging effect.

Claims (5)

A highly fatal infection selected from Listeria infection, malaria, cholera, Zika fever, dengue fever, salmonella infection, and Ebola hemorrhagic fever, comprising a block copolymer represented by the following formula (I) as an active ingredient A composition for inhibiting multiple organ damage that accompanies disease and can lead to multiple organ failure.

During the ceremony,
A represents unsubstituted or substituted C ₁ -C ₁₂ alkoxy and the substituent, if substituted, represents a formyl group, a group of formula ^{R′R ″} CH—wherein R ^′ and R ^″ are independently and C ₁ -C ₄ alkoxy or R ^′ and R ^″ together represent —OCH ₂ CH ₂ O—, —O(CH ₂ ) ₃ O— or —O(CH ₂ ) ₄ O—,
L ₁ represents a direct bond or a divalent linking group,
X represents L ₂ -R ₁ or chloro or bromo or hydroxyl and L ₂ is -(C
H ₂ ) _a —O—(CH ₂ ) _a — and R ₁ is 2,2,6,6-tetramethylpiperidine-
1-oxyl-4-yl, 2,2,5,5-tetramethylpyrrolidin-1-oxyl-3-yl, 2,2,5,5-tetramethylpyrrolin-1-oxyl-3-yl, 2, 4,4-trimethyl-1,3-oxazolidin-3-oxyl-2-yl, 2,4,4-trimethyl-1,3-thiazolidin-3-oxyl-2-yl, 2,4,4-trimethyl- is selected from imidazolidin-3-oxyl-2-yl, and at least 50% of the n Xs are L ₂ -R ₁ ;
each a is independently an integer from 0 to 5;
m represents an integer from 2 to 10,000,
n represents an integer of 3 to 100,
Z is H, SH or S(C=S)-Ph, Ph represents phenyl optionally substituted with 1 or 2 methyl or methoxy. Listeria infection, malaria, cholera, Zika fever, dengue fever, salmonella infection, Ebola hemorrhagic fever. A composition comprising, as active ingredients, a block copolymer and an antibacterial agent having antibacterial activity against pathogens of the infectious diseases.

During the ceremony,
A represents unsubstituted or substituted C ₁ -C ₁₂ alkoxy and the substituent, if substituted, represents a formyl group, a group of formula ^{R′R ″} CH—wherein R ^′ and R ^″ are independently and C ₁ -C ₄ alkoxy or R ^′ and R ^″ together represent —OCH ₂ CH ₂ O—, —O(CH ₂ ) ₃ O— or —O(CH ₂ ) ₄ O—,
L ₁ represents a direct bond or a divalent linking group,
X represents L ₂ -R ₁ or chloro or bromo or hydroxyl and L ₂ is -(C
H ₂ ) _a —O—(CH ₂ ) _a — and R ₁ is 2,2,6,6-tetramethylpiperidine-
1-oxyl-4-yl, 2,2,5,5-tetramethylpyrrolidin-1-oxyl-3-yl, 2,2,5,5-tetramethylpyrrolin-1-oxyl-3-yl, 2, 4,4-trimethyl-1,3-oxazolidin-3-oxyl-2-yl, 2,4,4-trimethyl-1,3-thiazolidin-3-oxyl-2-yl, 2,4,4-trimethyl- is selected from imidazolidin-3-oxyl-2-yl, and at least 50% of the n Xs are L ₂ -R ₁ ;
each a is independently an integer from 0 to 5;
m represents an integer from 2 to 10,000,
n represents an integer of 3 to 100,
Z is H, SH or S(C=S)-Ph, Ph represents phenyl optionally substituted with 1 or 2 methyl or methoxy. R ₁ has the formula

wherein R' is methyl
is either
3. A composition according to claim 1 or 2. A divalent linking group has the formula

, -(CH ₂ ) _b S-, -CO(CH ₂ ) _b S-, -(CH ₂ ) _b NH-, -(CH ₂ ) _b CO-, -CO-, -OCOO- , -CONH- is selected from the group consisting of the groups represented , wherein each b is an integer from 1 to 5 ;
3. A composition according to claim 1 or 2. 3. The composition according to claim 2, wherein the highly fatal infectious disease is Listeria infectious disease, and the block copolymer is administered before, after or simultaneously with the administration of the antibacterial agent.

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