EP2007400A1

EP2007400A1 - New medicines for treatments against retroviruses

Info

Publication number: EP2007400A1
Application number: EP07731297A
Authority: EP
Inventors: Jean-Claude Yvin; Jean-Claude Chermann
Original assignee: Laboratoire de la Mer SAS
Current assignee: ASE AND BIO
Priority date: 2006-04-14
Filing date: 2007-04-13
Publication date: 2008-12-31
Also published as: WO2007119006A1; US20080269162A1; FR2899815B1; FR2899815A1

Abstract

This invention relates to the use of a sulphated or phosphated polysaccharide for the preparation of a medicine for treatments against retroviruses, more particularly against lentiviruses and oncoviruses, and particularly against HIV, including strains of these retroviruses that are resistant to known anti-retroviral agents; this medicine acts on the replication cycle of said retroviruses by inhibition of their RT.

Description

SULPHATE OR PHOSPHATE POLYSACCHARIDES FOR TREATMENTS AGAINST RETROVIRUSES

The subject of the invention is new drugs for retrovirus treatments, by acting on their replication cycle by inhibition of RT.

Retroviruses belong to a family of viruses whose genome is made of RNA. The peculiarity of retroviruses is to replicate in a host cell via DNA steps, which is made possible by the Reverse Transcriptase, or Reverse Transcriptase, designated by RT in what follows, and which is an enzyme allowing the transcription of I ¹ viral RNA into complementary DNA molecule called provirus.

The provirus is able to circularize and integrate into the genome of the host cell.

The retroviruses thus integrated into the genome of the host cell can either use the cellular machinery to multiply, or remain latent in the host cell. At latent state, their genes are transmitted to the descending cells at each mitosis and are temporarily silent; the organism carrying the retrovirus does not present any pathological sign.

The retrovirus family has three subfamilies: oncoviruses, lentiviruses and spumaviruses.

Oncoviruses are responsible for cancers and, in particular, certain leukemias. Cancer-causing oncoviruses include Roux sarcoma virus or VSR. Among those causing leukemias in humans are HTLV type I and type II (HTLV means "Human T cell Leukemia Virus"); in felines, leukemia is caused by the FTLV virus. Lentiviruses are responsible for slow-growing viral infections such as acquired immunodeficiency syndrome or AIDS. In humans, lentiviruses responsible for AIDS are part of HIV or "Human Immunodeficiency Virus" (type I, HIV-I or type II, HIV-II), or French HIV (Human Immunodeficiency Virus) ; in monkeys, these are SIV ("Simian Immunodeficiency Virus") and in FIV cat (Feline Immunodeficiency Virus).

Spumaviruses are poorly known, both in terms of their structure and the exact mode of their integration into the cellular genome. In the current state of knowledge, no disease seems to be associated with spumaviruses. However, their responsibility in triggering certain autoimmune diseases seems likely.

Pathophysiologically, oncoviruses transform the T cells they infect and cause uncontrolled proliferation of these cells; lentiviruses destroy the cells they infect.

More specifically, with regard to HIV, they attack helper T4 cells that express on their surface the CD4 molecule (as a membrane glycoprotein molecule), which is a receptor that allows HIV to penetrate inside these cells. .

HIV enters a T4 lymphocyte via an endocytosis system involving the mutual recognition and binding of the CD4 molecule expressed on the surface of the T lymphocyte to a surface glycoprotein of the retrovirus termed gp120. The expression of a membrane coreceptor present on T4 lymphocytes is also necessary for the penetration of the virus.

As indicated above, the retrovirus, here an HIV, replicates inside the host cell, here the T4 lymphocyte, under the action of the RT which intervenes in the manner indicated below.

In a first step, the nucleus or core of the virus, once it has penetrated inside the host cell, releases two copies of single-stranded RNA. These two copies of single-stranded RNA are associated with RT as well as other proteins such as protease and integrase. This synthesizes a strand of DNA complementary to the viral RNA.

Then, RT-associated RNase activity degrades the RNA strand, while a second strand of DNA is synthesized. The double-stranded DNA thus obtained is then circularized and integrated, thanks to an integrase enzyme, into the cellular genome to give a provirus.

This provirus contains 3 structural genes, namely the gag (antigen group), pol (polymerase) and env (envelope) genes; gag genes code for p24 viral proteins, pol genes for RT and its associated activities which are polymerase, RNase, integrase and protease activities, and env genes for envelope glycoproteins such as gp120.

During the viral replication phase, the provirus is transcribed into messenger RNA using the machinery of the nucleus of the host cell, which allows the production of the constitutive proteins of the retrovirus on the one hand and the replication of the viral genomic material on the other hand. go. The whole constitutes a new virus produced by budding of the membrane of the host cell.

Furthermore, fusion phenomena occur between the infected cells, which have on their surface, in particular, the gp120 protein, and the uninfected T4 lymphocytes, which comprise on their surface the CD4 molecule.

Indeed, because of the high affinity of the gp 120 protein for CD4 receptors, an infected cell can bind healthy uninfected T4 cells and form what is called a syncytium, i.e. infected and uninfected lymphocytes, which is unable to survive.

A single infected cell can cause the death of many healthy T4 cells. This results in a gradual decrease in cellular immunity which results in the development of opportunistic infections, which may be accompanied by certain types of tumors. In addition to T4 cells, other cells also have the CD4 molecule on their surface, and are therefore sensitive to HIV viruses; these include macrophage monocytes, certain cells found in the ganglia, skin and other organs, and some B cells.

On the other hand, HIV viruses can also attack certain CNS central nervous system cells: in this case, they cause neurological syndromes.

Other molecules located on the surface of the cell that normally function as receptors for chemokines have also been identified as co-receptors that allow the entry of HIV viruses into the host cell.

The retroviruses responsible for AIDS, that is to say lentiviruses and especially HIV are characterized by extreme genetic and antigenic variability.

It is generally accepted that in man there are two types of virus responsible for AIDS, designated respectively by HIV-I (or HIV-I) and HIV-II (or HIV-II).

Genetic analyzes have shown that there are three distinct groups of HIV-1 viruses; these three groups are designated respectively by M (Major), O (Outlier) and N (New).

The vast majority of HIV-1 strains belong to the group M (Major), which comprises at least ten subtypes or clades (A, B, C, D, ...); we meet these clades in various geographical areas. On the contrary, the HIV-1 strains of the O and N groups have so far been isolated only in African populations.

The high genetic variability of these HIV strains is mainly due to the high error rate of RT. Indeed, during successive replication cycles, genetic variants appear. Mutations occur in particular on the env gene and more precisely on the coding part for gp120.

This genetic variability results in the appearance of strains that become resistant to known antiretroviral agents. The treatments currently used to combat retroviruses, especially lentiviruses, and especially HIV, aim to inhibit RT and therefore block their replication cycle.

It should be noted that in the case of oncoviruses associated with certain types of cancer, RT is still essential for their replication. And when this viral enzyme is inhibited, the oncovirus can no longer replicate in the host cell.

Current anti-retroviral therapies employ three major therapeutic groups: reverse transcriptase inhibitors (RTs), protease inhibitors, and fusion and entry inhibitors.

Among the reverse transcriptase (RT) inhibitors, three subgroups of molecules are currently used clinically. These include nucleoside RT inhibitors, non-nucleoside RT inhibitors and nucleotide analogues. Among the nucleoside inhibitors of RT, mention may be made of AZT

(or 3'-azidothymidine), didanosine and stavudine (d4T, Zerit which are thymidine analogues) as well as ddC and 3TC (which are cytidine analogues). These nucleoside inhibitors compete with natural nucleosides and prevent elongation of the DNA chain; they were the first to be used as RT inhibitors, first alone and then in combination with other RT inhibitors or viral enzymes such as protease and integrase. However, their side effects are known and numerous. In particular, mutations of the reverse transcriptase confer resistance to INRTs that can be crossed between several INRTs. These compounds are all neutral or reducing, with the exception of AZT which is an oxidant; Non-nucleoside RT inhibitors act as noncompetitive antagonists by binding to a hydrophobic region adjacent to the catalytic site of RT, thereby inhibiting RT; among them, ritonavir, saquinavir, efavirenz, rescriptor, sustiva and viramune may be mentioned.

The second therapeutic group is constituted by protease inhibitors (PIs). They are powerful anti-retroviral agents that inhibit the proteolytic activity of the viral protease; for example, amprenavir, tipranavir, indinavir, saquinavir, lopinavir, posanprenavir, ritonavir, atazanavir and nelfinavir.

Finally, the third therapeutic group corresponds to the fusion and entry inhibitors, of which several molecules are under study. Only enfuvirtide is currently on the market. It acts at the first stage of virus replication by preventing fusion between virus / cell by competitive inhibition.

The emergence and transmission, especially in industrialized countries, of HIV strains resistant to known antiretroviral agents has placed the medical world in the grip of a serious public health problem. Failures encountered in the treatment of patients with

AIDS is mainly due to viral resistance phenomena, although other factors such as the toxicity of the agents used as well as some side effects also affect the effectiveness of treatments, although to a lesser extent. It is to cope with this situation that much research has been and is being conducted to discover novel antiretroviral agents capable of inhibiting RT, particularly among polysaccharides.

European Patent Application 0 240 098 recommends the use as antiretroviral agents of synthetic or natural sulfated polysaccharides via connector groups. EP 0240 098 particularly described sulphates of chondroitin, dermatan, keratan, hyaluronic acid, carrageenan, fucoidan, heparin and dextran.

The patent application EP 0 464 759 also describes sulfated polysaccharides via a specific group intended for the long-term prophylaxis of diseases caused by viruses. These two patent applications, EP 0 240 098 and EP 0 464 759, have the major disadvantage of providing complex oligosaccharides to be synthesized due to the presence of an intermediate group necessary for sulfation. Japanese Patent Application Publication 01-103601 describes the antiviral activity, especially with regard to HIV, lentinan sulfate, certain β-1, 3 glucans such as curdlan, pachymane, and those of the cell walls of yeast and those of cellulose.

In an article published in November 1987 in Jpn. J. Cancer Res / Gann No. 78, pp. 1164-1168, Hideki Nakajima et al. Disclose the inhibitory effect on HIV infectivity and replication of certain sulfated polysaccharides such as dextran, xylofuranan and ribofuranan sulfates as well as inhibition by these products of HIV RT.

The published Japanese patent application 03-145 425 describes the antiviral activity, with respect to HIV, of certain sulphated laminarioligosaccharides and in particular of sulphated laminaripentaose.

However, the work described in these documents has not led to any practical application, especially since the described oligosaccharides, even if they possess a potential antiretroviral activity, show a strong anticoagulant activity, for example the dextran and dextran sulphates. heparin, rendering them unusable in vivo as part of therapy.

The problem to be addressed by the present invention is therefore the availability to the medical profession of new antiretroviral drugs with a high therapeutic index, particularly active against lentiviruses and oncoviruses, especially against HIV, as well as against strains resistant to certain antiretroviral agents already known, and having a low anticoagulant activity in vivo.

Surprisingly and unexpectedly, this problem was solved by the applicant company, which could determine that sulfated or phosphated polysaccharides of formula (I), as described below, had a strong antiretroviral activity, in particular against lentiviruses and oncoviruses, in particular against HIV, and against the strains of these retroviruses resistant to antiretroviral agents already known to inhibit RT, and did not possess anticoagulant activity incompatible with in vivo administration.

The subject of the present invention is therefore the use, for the manufacture of a medicament for the treatment of retroviral diseases, of a polysaccharide of formula (I)

G) in which

- R ¹ represents either a hydrogen atom, a sulfate group or a phosphate group, or a sulfated or phosphate glucose preferably linked by a β-type bond (1 → 6) to the saccharide structure,

- R ² represents a hydrogen atom, a sulfate group or a phosphate group, R ¹ and R ² can not simultaneously represent a hydrogen atom, X and Y represent, each independently, an OH group, a glucose, a sulfated or phosphated glucose, a mannitol, or a sulfated or phosphated mannitol,

n represents an integer from 11 to 30, preferably from 20 to 30, more preferably from 25 to 30, said polysaccharide having a degree of sulfation greater than 2, preferably from 2.2 to 2.4, or a degree of phosphatation greater than 1, preferably from 1.5 to 2.5.

According to another embodiment, the polysaccharide used is a polysaccharide of formula (I) in which R ₁ and R ₂ may be identical and then represent a sulfate or phosphate group, or different from each other, Ri representing then a sulfated or phosphated glucose unit preferably linked by a β-1 β-bond to the saccharide structure, X and / or Y representing a mannitol group and n an integer of 11 to 30, more particularly of 25 to 30.

According to the invention, the drug manufactured using a polysaccharide of formula (I) acts on the retrovirus replication cycle by inhibiting the RT of the latter.

For the purposes of the present invention, the term "sulfation degree" means the average number, per saccharide unit, of sulphated OH groups. A degree of sulfation greater than 2 means that, on average, over the entire polysaccharide, more than 2 OH groups per saccharide unit are sulfated.

For the purposes of the present invention, the term "degree of phosphatation" means the average number, per saccharide unit, of phosphate-containing OH groups. A degree of phosphatation greater than 1 means that, on average, over the entire polysaccharide, more than 1 OH group per saccharide unit is phosphated.

For the purposes of the invention, the term "sulfate group" means a group of the type (-SO ₃ H). For the purposes of the invention, the term "phosphate group" means a group of the type (-PO3H2).

Another subject of the invention is the use of one of the polysaccharides defined above for the implementation of a method for treating retroviral diseases.

For the purposes of the invention, the retroviral diseases are preferably chosen from those caused by lentiviruses and oncoviruses, more particularly by HIV, and by the strains of these retroviruses resistant to anti-retroviral RT inhibitors agents already known. In the case of lentiviruses and in particular HIV type I and II, the drug obtained by use according to the invention of a polysaccharide of formula (I) makes it possible to treat the acquired immunodeficiency syndrome in humans. Thus, in a particular embodiment, a retroviral disease within the meaning of the invention is the acquired immunodeficiency syndrome or AIDS in humans.

The polysaccharides of formula (I) as used according to the invention are also particularly active against oncoviruses, in particular against HTLV type I and II viruses. Thus, in a particular embodiment, the use according to the invention of a polysaccharide of formula (I) makes it possible to treat the cancers associated with these retroviruses.

In a particular embodiment of the invention, the polysaccharide of formula (I) is a sulfated laminarine having a degree of polymerization of 11 to 28.

Preferably, the polysaccharide of formula (I) is a laminarine of degree of sulfation equal to about 2.3, called "laminarin PS3".

For the purposes of the invention, the term "degree of polymerization" is intended to mean the number of monosaccharide units bonded to each other by β (1-> 3) -type bonds constituting the main linear chain. A degree of polymerization of 11 to 28 means a polysaccharide composed of 11 to 28 saccharide units, in particular glucose, bound together by β (1-> 3) type bonds. This degree of polymerization does not take into account glucose units bound in β (1 → 6) to the main chain of the polysaccharide. Thus, the degree of polymerization is equal to n + 2 when X and Y simultaneously represent OH, to n + 3 if only one of X or Y represents OH, and at n + 4 neither X nor Y represents OH.

Surprisingly and surprisingly, the Applicant has been able to demonstrate that sulphated laminarine, having a degree of sulphation greater than 2, preferably of 2.2 to 2.4, and a degree of polymerization of 11 to 28, was particularly effective for the treatment of retroviral diseases, preferably selected from those caused by lentivirus and oncovirus, more particularly by HIV, and by strains of these retroviruses resistant to anti-retroviral agents RT inhibitors already known, particularly I ¹ AZT . This sulphated laminarine also had a low anticoagulant activity, thus confirming its great interest in the manufacture of a medicament intended for human or animal administration.

According to another embodiment, the invention relates to the use of a polysaccharide, obtained from sulphated laminarine with a degree of sulphation greater than 2 and preferably from 2.2 to 2.4, of degree of polymerization of 11 to 28, for the preparation of a medicament for the treatment of retroviral diseases, preferably chosen from those caused by lentiviruses and oncoviruses, more particularly by HIV, and by the strains of these retroviruses resistant to antiretroviral agents already known RT inhibitors. In another particular embodiment of the invention, the polysaccharide of formula (I) is a phosphatized laminarine having a degree of polymerization of 11 to 28. The laminarin phosphate according to the invention has a degree of phosphatation greater than 1 and preferably from 1.5 to 2.5 and is particularly suitable for the treatment of retroviral diseases, preferably chosen from those caused by lentiviruses and oncoviruses, more particularly by HIV, and by strains of these retroviruses resistant to anti-retroviral RT inhibitors already known.

According to another embodiment, the invention relates to the use of a polysaccharide obtained from laminarine phosphate with a degree of phosphatation greater than 1 and preferably from 1.5 to 2.5, with a degree of polymerization of 11. at 28, for the preparation of a medicament for the treatment of retroviral diseases, preferably chosen from those caused by lentiviruses and oncoviruses, more particularly by HIV, and by the strains of these retroviruses resistant to inhibitory antiretroviral agents of the RT already known.

A particular embodiment of the invention relates to the use of a sulfated laminarine, characterized in that it has a degree of sulfation greater than 2, preferably from 2.2 to 2.4, and a degree of polymerization. from 11 to 28 for the manufacture of a medicament for the treatment of retroviral diseases.

Another particular embodiment of the invention relates to the use of a sulfated laminarine, characterized in that it has a degree of sulfation greater than 2, preferably from 2.2 to 2.4, and a degree of polymerization from 11 to 28, for the implementation of a method for treating retroviral diseases.

Another particular embodiment of the invention relates to the use of a phosphatized laminarine, characterized in that it has a degree of phosphatation greater than 1, preferably from 1.5 to 2.5, and a degree of polymerization from 11 to 28, for the manufacture of a medicament for the treatment of retroviral diseases.

Yet another particular embodiment of the invention relates to the use of a phosphatized laminarin, characterized in that it has a degree of phosphatation greater than 1, preferably from 1.5 to 2.5, and a degree of polymerization from 11 to 28, for the implementation of a method for treating retroviral diseases. It is known to administer to patients with AIDS in particular, in the context of treatments designated by the term "multi-therapies" not only two or even three antiretroviral agents, but also other pharmacological agents intended to fight against the associated pathogenesis. The use of these numerous drugs represents a considerable bond for patients. To remedy this drawback and according to another advantageous embodiment, the subject of the invention is also a combination product comprising an effective quantity

a polysaccharide of formula (I) in which R ¹ represents either a hydrogen atom, a sulphate group or a phosphate group, or a sulphated or phosphatic glucose bonded, preferably, by a β-type bond (1- 6) to the saccharide structure, R ² represents a hydrogen atom, a sulfate group or a phosphate group, X and Y represent, each independently, an OH group, a glucose, a sulfated or phosphated glucose, a mannitol, or a sulfated or phosphated mannitol, n represents an integer from 11 to 30, preferably from 20 to 30, more preferably from 25 to 30, said polysaccharide having a degree of sulfation greater than 2, preferably from 2.2 to 2.4, or a degree of phosphatation greater than 1, preferably from 1.5 to 2.5,

at least one antiretroviral agent chosen from the group comprising:

• nucleoside reverse transcriptase inhibitors (NRTIs), including I ¹ AZT, ddI, ddC, d4T, 3TC and ABC,

• non-nucleoside reverse transcriptase inhibitors (NNRTIs), including Viramune and Sustiva,

• protease inhibitors, including Agenerase and Kaletra, • fusion inhibitors, including enfuvirtide (Fuzeon),

Input inhibitors, including, in particular, AMD-3100 and, optionally, at least one pharmacological agent chosen from the group comprising anti-nausea agents, anti-diarrheal agents, anti-hyperbilirubinemia agents, agents anti-pain agents for dermatological treatments, anti-nephrotoxic agents, for simultaneous, separate or spread over time. Indeed, the skilled person is able to define the best adapted administration to obtain the best therapeutic index for the patient. Each active substance in HAART can be administered sequentially, on different routes, or at the same time. For the purposes of the invention, the term "effective amount" means an amount of active substance that is sufficient to obtain a therapeutic effect on a patient.

The subject of the invention is also the use of an effective amount of a polysaccharide of formula (I) as described above,

at least one antiretroviral agent chosen from the group comprising:

Input inhibitors, including, in particular, AMD-3100 and, optionally, at least one pharmacological agent chosen from the group comprising anti-nausea agents, anti-diarrheal agents, anti-hyperbilirubinemia agents, agents anti-pain agents for dermatological treatments, anti-nephrotoxic agents, for the manufacture of a medicament for the treatment of retroviral diseases, preferably caused by lentiviruses and oncoviruses, more preferably by HIV, in particular by the strains of these retroviruses resistant to antiretroviral agents already known.

Another object of the present invention is the use of an effective amount

a polysaccharide of formula (I) as described above,

at least one antiretroviral agent chosen from the group comprising:

• nucleoside reverse transcriptase inhibitors (INRTs), including AZT, ddl, ddC, d4T,

3TC and ABC,

• non-nucleoside reverse transcriptase inhibitors (NNRTIs), including Viramune and Sustiva, • protease inhibitors, including Agenerase and Kaletra,

• fusion inhibitors, including enfuvirtide (Fuzeon),

• input inhibitors, including the AMD-3100 and possibly at least one pharmacological agent chosen from the group comprising anti-nausea agents, anti-diarrheal agents, anti-hyperbilirubinemia agents, anti-pain agents, agents for dermatological treatments, anti-nephrotoxic agents, the implementation of a method for treating retroviral diseases, preferably caused by lentiviruses and oncoviruses, more preferably by HIV, in particular by the strains of these retroviruses resistant to antiretroviral agents already known.

The present invention also relates to a method for treating a retroviral disease, preferably caused by lentiviruses and oncoviruses, more preferably by HIV, in particular by the strains of these retroviruses resistant to antiretroviral agents already known, comprising administering, in a patient affected by said retroviral disease, an effective amount of a medicament comprising as active agent at least one polysaccharide of formula (I) as previously described; or a combination product as described above.

For the purposes of the present invention, the term "patient" means any warm-blooded animal, particularly mammals and especially humans.

The present invention also relates to a treatment method as defined above, in which the polysaccharide of formula (I) is a sulfated laminarine, characterized in that it has a degree of sulfation greater than 2, preferably 2, 2 to 2.4, and a degree of polymerization of 11 to 28.

The subject of the present invention is also a treatment method as defined above, in which the polysaccharide of formula (I) is a phosphatized laminarine, characterized in that it has a degree of phosphatation greater than 1, preferably of 1, 5 to 2.5, and a degree of polymerization of 11 to 28. To prepare a polysaccharide of formula (I) sulfated in the sense of the invention, a sulfation step is carried out preferably following the protocol described by Alban S, Kraus J, and Franz G in "Synthesis of laminarin sulfates with anticoagulant activity" , Artzneim.Forsch./drug Res (1992) 42; 1005-1008. This process was perfected in the thesis of Susanne Alban, defended in 1993 at the University of Regensburg and entitled "Synthesis und physiologische Testung neuartiger Heparinoide". These processes are adaptable to the sulphation of the polysaccharides of formula (I) of the invention and make it possible to obtain a highly substituted sulphated polysaccharide, without degradation, and with good reproducibility, in a simple and inexpensive manner.

In order to achieve effective sulfation of the polysaccharide without degradation of the polysaccharide chains, the sulfation reaction is advantageously carried out under conditions corresponding to an absolute absence of water. Before sulfation, the polysaccharide is therefore preferably dried, for example on phosphorus pentoxide (P ₂ O ₅ ) and then dissolved in dimethylformamide or DMF. By its alternative effects on the polysaccharide, DMF has an activating influence by substitution. Indeed, the association of the polar DMF with the OH groups leads to the cleavage of intra- and inter-molecular hydrogen bonds and to the disintegration of the higher structures.

To carry out the sulfation reaction, the SO ₃ -pyridine complex can advantageously be used.

As a result of the coordination of the electron acceptor SO ₃ with the pyridine electron donor, the difficultly controllable reactivity of the SO _3, which results in highly exothermic reactions leading to degradation, is reduced. The Sθ ₃ -pyridine complex has, compared to other complexes, the advantage of being neither too reactive nor too stable, that is to say, too slowly from the reaction point of view. Due to the fact that the degree of sulfation obtained is proportional to the molar excess of sulfation reagent and since it is sought to obtain a degree of substitution greater than 2, it is advantageously implemented a concentration of 6 moles of SO ₃ - pyridine per mole of glucose.

Advantageously, to ensure the absence of water, one can work under an argon atmosphere.

Preferably, from the beginning of the reaction, pyridine is added to the sulfation reagent in an equimolar amount, in order to directly capture the sulfuric acid that may be formed by reaction of the complex Sθ ₃ -pyridine with water . The concentration of the polysaccharide as that of the sulfation reagent should preferably be as high as possible, the solubility of the polysaccharide and sulfation reagent limiting the degree of final sulfation. In order to avoid cooling of the mixture at the beginning of the reaction which could lead to solubility problems and to obtain the most regular substitution possible, the solution of the Sθ3-pyridine complex in DMF could not be added all at once but in a manner continue for a period of 4 hours.

The sulfation reaction can be carried out at a temperature of 20 to 60 ^° C., preferably of approximately 40 ^° C. Higher temperatures result in a more efficient substitution but also a degradation of the chains.

After the addition of the sulfation reagent, the mixture is preferably stirred for several hours around 60 ^° C. At this temperature, an additional substitution occurs without degradation of the chains.

The supernatant of the mixture is then advantageously separated by decantation. The residue is dissolved, preferably in NaOH, and then mixed with 10 times its volume of ethanol. The precipitate which occurs at a temperature of 4-8 ° C overnight is isolated and then preferentially dissolved in dilute sodium hydroxide (pH solution of about 9). The solution is dialysed to remove salts and low weight molecules molecularly then advantageously brought to a pH of 7.0 by addition of NaOH and then lyophilized. The resulting sulfated polysaccharide is in the form of the sodium salt.

The degree of sulphation is preferably determined by conductimetric titration of the free acid of the sulphated polysaccharide, or alternatively by ion chromatography after hydrolysis using an HPLC type system. The first method has the advantage of being also suitable for stability research (the consumption of soda increases when sulphate groups are eliminated) whereas the HPLC method requires less substance and can be automated. As a control, it is possible to determine the sulfur content by elemental analysis.

It is furthermore possible to control the homogeneity of the sulfation and the distribution of the sulfate groups at the different positions in the glucose molecule by a modified form of the methylation analysis followed by a GC-MS examination (ie chromatography Gas, Mass Spectrometry).

The degree of sulfation obtained by proceeding as indicated above is greater than 2, more precisely from 2 to 2.5 and especially from 2.2 to 2.4.

According to an advantageous embodiment, the polysaccharide of formula (I), and preferably sulphated laminarine, are used for the preparation of a medicament for retrovirus treatments intended for general administration and preferably for oral, rectal, pulmonary topical (including transdermal, oral and sublingual) and parenteral (including subcutaneous intramuscular, intravenous, intradermal and intravitreous).

The daily dose is generally from 0.01 to 250 mg per kilogram of weight of the patient and preferably from 0.10 to 100 mg, more preferentially still from 0.5 to 30 mg, and more particularly from 1.0 to 20 mg.

These daily doses apply in particular in the case of laminarin sulphate; for the other salts and esters according to formula (I), the daily doses are adapted to each case.

The daily dose can be administered per unit dose in one, two, three, four, five or six times or more at different times of the day.

The unit doses can comprise from 10 to 1000 mg, from 50 to 400 mg, and preferably from 50 to 100 mg of active substance.

The medicaments obtained according to the invention, using at least one of the polysaccharides of formula (I), comprise the conventional formulation ingredients and optionally one or more other therapeutic agents. In addition, as mentioned above, the polysaccharide of the invention can be advantageously combined with other active substances. Their mode of administration can be simultaneous or sequential. They can also be administered by different routes as previously described.

The present invention will be better understood on reading the following nonlimiting examples.

EXAMPLE 1 Preparation of a Laminarine Sulfate PS3 Laminarine was extracted from a raw material constituted by brown algae and then the sulphating of the laminarine thus extracted was carried out, following the protocol described in Patent FR 92 08387. .

Once the laminarine was extracted, sulfation was carried out following the protocol described by Alban S, Kraus J, and Franz G in Synthesis of Laminarin Sulfates with Anticoagulant Activity,

Artzneim.Forsch./drug Res (1992) 42; 1005-1008, perfected by the Susanne Alban's thesis, defended in 1993 at the University of Regensburg and entitled "Synthesis und physiologische Testung neuartiger Heparinoide".

The laminarine was first dried over phosphorus pentoxide (P2O5) and then dissolved in dimethylformamide or DMF.

Then, to implement the sulfation reaction, was used to Sθ complex ₃ pyridine under an argon atmosphere was added at once but continuously over a period of 4 hours of the Sθ ₃ -pyridine in DMF in equimolar amount. The sulphation reaction was carried out at a temperature of 40 ^° C. After the addition of the sulphation reagent, the mixture was stirred for 6 hours at 60 ^° C.

The supernatant was then decanted from the mixture, the residue dissolved in 2.5 M NaOH, and then mixed with 10 times its volume of 99% ethanol. The resulting solution was then placed at a temperature of 4-8 ° C overnight and a precipitate was obtained which was isolated and then dissolved in dilute sodium hydroxide (pH solution of about 9). The solution was then dialyzed using a 1000 D cutoff Spectrapor membrane and then brought to pH 7.0 by the addition of NaOH. Finally, the solution thus dialysed was lyophilized. A laminarin sulphate in the form of a sodium salt was obtained.

The degree of sulfation by conductimetric titration of the free acid of the sulfated polysaccharide was then determined using 0.1 N sodium hydroxide. The degree of sulfation of the laminarine obtained was 2.3. The degree of polymerization of the laminarin sulphate thus obtained was 23 to 28.

This sulphated polysaccharide was called "laminarine PS3" or "PS3".

EXAMPLE 2 Anti-Retroviral Activity of Sulphated Laminarine PS3 The action of sulphated laminarin PS3 on the retrovirus replication cycle was determined by inhibition of RT, which inhibition of RT was appreciated.

- or by observation, depending on the amount of sulfated polysaccharides used and the timing of this implementation that can take place before, during or after infection or permanently, the decrease in the number of syncitia , appearing in a culture of MT ₄ cells following infection with an HIV retrovirus, (Example 2A) - either by evaluation as a function of the amount of sulfated polysaccharides used and the moment of this implementation that can take place before, during or after infection, or permanently throughout the infection, inhibition of RT, which results in a measurable decrease in RT activity, and which reflects the slowing down of the replication of the infecting virus in a culture of CEM cells infected with an HIV retrovirus, (Example 2B) it being understood that for comparison purposes the same experiments were carried out using as comparison products on the one hand the dextran ulfate and on the other hand 3'-azidothymidine or AZT. The above-mentioned MT ₄ and CEM cells are human lymphoblastic lines transformed by HTLV-1.

The retroviruses that have been implemented are constituted by

- laboratory strains BRU (clade B) and NDK (clade D),

the RTMC virus (clade B) known to be resistant to the AZT antiviral agent,

primary isolates RW92009 (clade A) and UG92029 (clade A), and

an isolate (PIC CH, clade B) derived from a patient resistant to several antiviral agents known as d4T and Zerit.

Strains RTMC, RW92009 and UG92029 were obtained from the AIDS Research and Reference Reagent Program, Division of AIDS, NIAID-NIH (USA). MT ₄ and CEM cells were cultured in RPMI medium

(from Cambrex) supplemented with 10% fetal calf serum

(Cambrex source), 1% Penicillin-Streptomycin (from Life

Technologies), 2 mM glutamine (from Invitrogen), 2 μg / ml polybrene (Sigma origin).

Sulfated laminar PS3 in freeze-dried form obtained by the method as described in Example 1 was used, which was dissolved in PBS at a concentration of 12 mg / ml to provide a stock solution. On the other hand, dextran sulphate (from

Sigma, D4911) in PBS at the concentration of 41.6 mg / ml (stock solution).

PTA ₁ at the concentrations indicated below was also diluted with AZT (Sigma origin A2169), widely known to be an inhibitor of RT.

Example 2A: Measuring the number of syncitia

The action of laminarin PS3 and syncitia comparison products in a MT ₄ cell culture infected with one of the retroviruses indicated above was evaluated by the following procedure.

Were first preincubated MT ₄ cells (3.10 ⁵ cells in 50 .mu.l) for 1 hour at 37 ^C C. in a humid atmosphere of 5% CO ₂ with serial dilutions of sulfated laminarin PS3 (50 .mu.l) and Comparison products, 96-well V-bottom microplate. Each concentration of sulfated laminarin PS3 and comparison product is tested in duplicate.

The cells were then infected by adding to each well, except those corresponding to the cell controls, 50 .mu.l of viral dilution previously titrated. After a further hour of incubation, the plate was centrifuged and the supernatants containing the residual virus removed.

Two rinses were performed, then the cell pellets were transferred to a 24-well plate or the cells were cultured at a concentration of 3.10 ⁵ cells / ml in the presence of Laminarin PS3 or the comparison product.

After 3 days of culture, the cells were diluted to half and the syncytia were observed under the inverted microscope from day 3 to day 7 after resuspension. As already stated above, four series of experiments have been carried out in order to specify the effect of sulphated laminar PS3 as a function of the moment at which it is used in cell culture, that is to say

- before infection - during infection

- after infection and

- throughout the infection.

In the first case, the sulfated laminarin PS3 and the comparison products were brought into contact with the cells for one hour, then the cells were washed twice to eliminate the products used and finally the infection was carried out. of MT ₄ cell culture.

In the second case, the sulfated laminarin PS3 was contacted with the comparison products at the time when the cells were infected. The culture thus treated was kept as it was for one hour, followed by two washes, which resulted in the removal of the sulfated laminarin PS3 and comparison products as well as viruses that did not penetrated into the cells.

In the third case, were preincubated culture of MT ₄ cells for one hour at 37 ⁰ C and then proceeded to the infection of the cells, and subjected to all incubation for one hour at 37 ⁰ C followed by centrifugation with elimination of the supernatant containing the viruses having no not penetrated into the cells. The cell pellet was then rinsed twice and then transferred to a 24-well plate and then cultured at a concentration of 3.10 ⁵ cells / ml simultaneously with the introduction into the same wells of the sulfated laminar PS3 and the products of comparison to selected concentrations.

In the fourth case, the sulfated laminar PS3 and the comparison products were first contacted with the cells for one hour at 37 ° C, then the culture was infected for one hour at 37 ° C. . Then two washes were made, which led to the elimination of viruses that did not penetrate the cells. The cell pellets were then transferred to 24-well plates at 3.10 ⁵ cells / ml per well in the presence of the sulfated laminarin PS3 and comparison products at the selected concentrations.

Washes and rinses were performed with RPMI culture medium without fetal calf serum.

In the case of each of the four types of experiments which have just been described and as already indicated above, the cells were diluted half a day after three days of culture and then the syncytia were observed under the inverted microscope from day D3 to D7. . The result of these observations is illustrated by Figures 1 to 3, it being understood that

- Figure 1 shows an uninfected cell culture Ci: Ci cells remain distinct from each other; there is no syncytia;

FIG. 2 shows an infected cell culture in which certain Ci cells agglutinate in syncytia identified by S, and

FIG. 3 shows, at a larger magnification, a culture of infected Ci cells, some of the Ci cells being agglutinated in syncytia identified by S.

In the experiments described in more detail below, the absence of syncytia is noted by a sign - and the signs (+), +, ++, ++ T indicate an increasing amount of syncitia in each well. The indication T reflects the death of the cells.

In a first series of experiments, AZT was used as a comparison product at a concentration of 0.01 μm, and sulphated laminarin PS3 was used at two concentrations of 5 and 10 μg / ml, respectively.

The BRU (clade B) virus was used for the infection of MT ₄ cells at a viral dilution of 10 ⁵ which corresponds to the amount of virus particles that can infect 80% of the MT4 cultures (Tissue Culture Infections Dose 80% TCID ₈ %). The results observed from day D3 to day D4 in the four types of experiments previously defined are shown in Table A.

TABLE A

The results summarized in Table A make it possible to make the following observations.

After 6 days from infection with the BRU viral strain, MT ₄ cell cultures do not form syncitia when treated continuously, as soon as they are cultured (before, during and after infection), with concentrations of 10 μg / ml of PS3.

MT ₄ cell cultures do not form syncitia when treated with concentrations of 10 and 5 μg / ml PS3 after infection with the BRU viral strain. The effect is observed from the ^3rd day after the viral infection.

It is important to note that no inhibition effect is observed when MT ₄ cells are treated before or during infection with the viral strain.

It also follows from Table A that the PS3 is as effective as I ¹ AZT.

In view of these results, it appears that in the case of PS3 it is a specific effect on the replication of the virus and not an aspecific effect, due to the anionic nature of PS3, on the entry of the virus. in the cell (there is no action when the PS3 is brought into contact only before infection).

In a second series of experiments, ΔZT and dextran sulphate were used as comparison products respectively at concentrations of 0.4 μM and 10 μg / ml, the latter concentration also being that of PS3.

The NDK virus (clade D) used was used at the viral dilution of 2.5 × 10 ^-5, which corresponds to the amount of viral particles that can infect 80% of the MT4 cultures (Tissue Culture Infections Dose 80% TCID ₈₀ % The results observed from D3 to D6 are collated in Table B. TABLE B

The findings that can be made from the results in Table B are as follows.

On day 5, after 5 days from infection with the NDK viral strain, MT ₄ cell cultures do not form syncitia when treated continuously, during and after infection, with a concentration of 10. μg / ml of PS3.

However, no inhibition effect is observed when MT ₄ cells are treated only before infection.

Dextran sulphate, on the other hand, has an optimal effect when the cells are treated before viral infection (2 out of 2 wells inhibited).

It also appears, and as in the series of experiments illustrated in Table A, that the activity of PS3 is comparable to that of I ¹ AZT.

The general conclusions given in the results presented in Table A apply here.

Example 2B: Measurement of inhibition of RT activity

To evaluate the action of laminarine PS3 and comparison products on the replication of the infecting virus by measuring the RT activity in a cell culture constituted this time by CEM cells, the following procedure was followed.

The number of viruses present in the culture was demonstrated by measuring RT activity in the culture supernatant, the detected amount of RT activity being proportional to the number of viruses produced.

The same experimental protocol as that used in Example 2A was used on MT ₄ cells, except that the CEM cells were incubated with the sulphated laminarin PS3 or the comparison product and then cultured at the same time. concentration of 0.5 × 10 ⁶ cells / ml. Every three days, the cells were counted and the cultures were diluted for culture at 0.5. 10 ⁶ cells / ml; the RT activity was assayed according to a protocol comprising:

the release in the culture samples of the viral enzymes and in particular of the RT,

reacting the samples with a reaction mixture comprising ³ H dTTp (thymidine) radioactive,

the isolation of the DNA synthesized as a result of the replication of the retrovirus, the measurement of the radioactivity of the synthesized DNA, this radioactivity being proportional to the amount of tritiated thymidine incorporated in said synthesized DNA, which itself is proportional to the RT activity and therefore to the number of viruses produced by replication.

The culture samples were made in a protected P3 laboratory.

The contents of each well (1 ml) were centrifuged for 5 min at 1500 rpm (Jouan GR 422 centrifuge), and then ultracentrifuged the culture supernatant thus obtained at ^{40 °} C., 95000 rpm (Beckman TL100 ultracentrifuge) to obtain the viral pellet. . The viral pellet was then taken up in a test tube containing 10 μl of NTE buffer supplemented with 0.1% triton, which releases the viral enzymes and in particular the RT; the tube was then vortexed, capped with parafilm and kept for 10 minutes at 4 ^° C. and then frozen at -20 ^° C.

The reaction mixture previously discussed in the biochemistry laboratory was prepared and this mixture comprises for a 5 mL test tube.

• 5X base pad 10.0 μl

• Poly rA 1 OD / ml (RNA) 12.5 μl

• Oligo dT 1 OD / ml (primer) 12.5 μl • Distilled water 2.5 μl

• ³ H dTTp (thymidine) 1 mCi / ml 2.5 ul total 40.0 μl

The composition of the aforesaid 5X base buffer is as follows

Final concentration

- TRIS 1M pH 7.8 1, 25 ml 0.25 M

MgCl ₂ 0.5 M 1, 00 ml 0.10 M

- KCl 1 M 0.50 ml 0.10 M

- DTT IOO mM 0.50 ml 10 Mm

- H ₂ O 1, 75 ml

As many test tubes containing this reaction mixture were prepared as samples to be tested. In the biochemistry laboratory, these 10 .mu.l samples prepared as indicated above, which contain the 0.1% triton-lysed virus, were introduced into as many tubes each containing 40 .mu.l of reaction mixture.

The tubes in question were held for one hour in a water bath at 37 ° C with stirring every 15 minutes. The reaction was then stopped by introducing into each tube 1 ml of 0.1 M NaP (sodium pyrophosphate) prepared in trichloroacetic acid or 5% TCA.

Then, the synthesized DNA contained in the mixture was precipitated at 4 ° C. by addition of 3.5 ml / tube of 20% trichloroacetic acid and then filtered through 0.45 μ Millipore nitrocellulose filters. To do this, the contents of the tubes were poured into the corresponding wells of a sample collector (Millipore), and the tubes and wells were rinsed three times with 5% TCA.

The filters were then dehydrated with 70% alcohol before being dried in the oven at 80 ^° C. for 20 minutes. After cooling, the filters were individually placed in flasks containing a scintillation or scintillating agent sold under the tradename Emulsifier Safe cat. N ^{0 6013389} by Perkin Elmer Company. The count was then carried out using a liquid scintillation analyzer marketed under the trademark "PACKARD 2100T", the results of which are expressed in dpm / ml (disintegration per minute and per ml of supernatant).

The amount of radioactivity measured is proportional to the RT activity present and, consequently, to the number of viruses produced by replication.

In a first series of experiments, the sulphated laminarine PS3 was tested at concentrations of 5 and 10 μg / ml and the comparison product of AZT at the concentration of 0.1 μM.

The RTMC virus (clade B) was used for the infection of the CEM cells, which has the particularity of being resistant to AZT and which has been used at a dilution of 5.10 ^-4 .

The results recorded on days 3, 7 and 10 are collated in Table C. These results include, for each experiment, the RT activity expressed in dpm / ml and the number of cells expressed in 10 ⁶ cells / ml.

TABLE C

To better show the action of sulphated laminarin PS3, we have transposed on the graph of FIG. 4 and from the results in Table C ₁ the evolution of the RT activity expressed in dpm / ml as a function of time (days D3 to D10) for the cells treated respectively at the two concentrations of PS3 and with I ¹ AZT and than

For the control cells (without agent) the viral dilution being 5.10 ^-4 .

Examination of Table C and FIG. 4 makes it possible to conclude that at a concentration of 10 μg / ml, PS3 makes it possible to obtain a 100% inhibition of the RMTC virus at the viral concentration of 5.10 ^-4 .

It is thus demonstrated that the PS3 is effective on the virus RMTC

Which is resistant to AZT, a known inhibitor of RT. Example 3 Study of the action of the sulphated PS3 as a function of the moment of its setting in ouyre.

The action of sulphated Laminarine PS3 was studied as a function of the time of its implementation (continuously, before infection, during infection and after infection).

The procedure was carried out as indicated above with respect to the experiments carried out on MT ₄ cells, that is to say as in Example 2A.

Again, PS3 was tested at concentrations of 5 and 10 μg / ml and I ¹ AZT at a concentration of 0.1 μM, the virus used being, this time, the NKD virus (clade D) at dilution. 2.5.10 ^"5 .

The results of the measurements carried out on days 3 and 7 are combined in Table D, as regards the RT activity expressed in dpm / ml and the number of cells expressed in 10 ⁶ cells / ml.

TABLE D

In FIG. 5, which illustrates Table D, the RT activity expressed in dpm / ml measured at day 7 in the case of I ¹ AZT and the two concentrations of PS3, as well as in the case of the cells, was plotted on a graph. control not having been treated with an antiretroviral agent, for the four experiments corresponding to the administration of the antiretroviral agent continuously, before, during and after the infection with the NDK virus at a dilution of 2.5.10 ^"5 .

On examining Table D and Figure 5, it appears that the PS3 at the concentration of 10 μg / ml has no action when it is incubated before the infection, that it is most effective when it is present throughout the experiment and that it has an action when it is implemented during and after the infection.

Still at a concentration of 10 μg / ml, its higher activity compared to AZT appears clearly.

Example 4: Direct Inhibitory Action of PS3

A number of additional experiments were also conducted to investigate the direct inhibitory action of PS3 on the RT of RW92009, UG92029P, PIC CH and NDK viruses. For this purpose, the RT activity of the four virus strains just identified and placed in the presence of PS3, as well as, in certain cases, dextran sulphate as a comparison product, was measured.

To perform these measurements, the procedure described in detail in the foregoing (Example 2) was carried out.

The results recorded at the end of these measurements are reported on graphs which are shown in FIGS. 6 to 9; in these graphs, the ordinate axis corresponds to the percentage inhibition of the RT activity (this activity is expressed in dpm / ml) measured for different concentrations of PS3 or dextran sulphate which are indicated on the abscissa axis, these concentrations being expressed in μg / ml.

For the RW92009 virus, a viral concentration corresponding to an RT activity of 75,000 dpm was used; the results obtained appear on the graph of FIG. 6 for which it was found that PS3 at a concentration of 1.5 μg / ml causes an inhibition of RT of 45%.

For the virus UG92029, a viral concentration corresponding to a RT activity of 220,000 dpm was used; the results obtained appear on the graph of FIG. 7, the examination of which shows that PS3 at the concentration of 2.5 μg / ml causes an inhibition of RT of 35%, whereas dextran sulfate does not inhibit RT than 6% at the same concentration.

Note also that at the concentration of 3 μg / ml is obtained a 74% inhibition for PS3 against 8% for dextran sulfate.

For the PIC CH virus, a viral concentration corresponding to a RT activity of 105 000 dpm was used; the results obtained appear on the graph of FIG. 8; on the basis of this graph, it can be seen that PS3 at a concentration of 0.6 μg / ml causes an inhibition of RT of 46%, whereas dextran sulphate does not cause any inhibition at the same concentration; at a concentration of 0.8 μg / ml, a 65% inhibition is obtained in the case of PS3, whereas dextran sulphate still does not cause any inhibition.

For the NDK virus, a viral concentration corresponding to a RT activity of 81,000 dpm was used; the results obtained appear on the graph of FIG. 9, the examination of which shows that at the concentration of 0.6 μg / ml, the PS3 causes an inhibition of the RT of 43% compared to only 11% in the case of the sulphate of dextran; to the concentration of 0.8 μg / ml is obtained 57% inhibition respectively in the case of PS3 against 18% in the case of dextran sulfate.

The results of the experiments illustrated in Figures 6-9 confirm that PS3 is an inhibitor of RT on various strains of HIV, which reflects the early inhibition of the replication cycle of these strains.

PS3 is particularly effective on the RT of the CH CH virus (clade B) which is resistant to several antiviral agents, as well as on the NDK virus (clade D).

EXAMPLE 5 Measurement of the Anti-Coaqlating Activity of Sulfated Laminarine PS3

It has been shown that the anticoagulant activity of sulphated laminarin PS3 is sufficiently low compared to that of heparin to be no disadvantage in the context of the use according to the invention and that it is not cytotoxic. at the highest concentrations likely to be used.

For this, the anticoagulant activity of the laminar sulfate PS3 obtained in Example 1 was determined as a function of its concentration in comparison with that of heparin in conventional APTT coagulation tests or "Partial Activator Thromboplastin-Zeit", the duration of prothrombin, the test called "HEPTEST" and the duration of thrombin. The APTT reflects an interaction with the intrinsic coagulation system while the prothrombin time reflects an interaction with extrinsic coagulation; the so-called "HEPTEST" test is the standard test for the measurement of heparin inhibitory activity with respect to factor Xa and the duration of thrombin corresponds to the last stage of coagulation, namely the formation of fibrins induced by thrombin. It has been found that unlike heparin, the activity of laminar sulfate PS3 in the test called "HEPTEST" is more than 20 times lower. Similarly, in relation to the duration of prothrombin sulfate laminarine PS3 showed no pronounced anticoagulant effect, as in the case of heparin. The specific activity (ILJ / mg) in the APTT represents 30% of the activity of heparin and in the case of the thrombin time 60%. In order to completely prevent coagulation, the concentration of APTT was 4 times higher and, in the case of thrombin time, 20 times higher.

In the specific anti-factor Xa and anti-thrombin tests using chromogenic substrates, it has been found that laminar sulfate PS3, unlike heparin, does not exhibit either a significant anti-thrombin-dependent anti-factor Xa activity. an anti-thrombin activity. The effect in the case of thrombin time may be considered to be due to heparin cofactor II-dependent thrombin inhibition. Because of the lower specific activity on the one hand, and the concentration-dependent profile on the other, and further research on the mechanism of action, it is possible to consider that in the case of of laminarin sulphate PS3, the risk of bleeding is significantly lower than in the case of heparin. It follows that the inhibitory properties of RT of laminarin sulfate PS3 can be advantageously exploited without fear of undesirable side effects on coagulation.

EXAMPLE 6 Measurement of the In Vitro Chemical Toxin of PS3 Sulphated Laminarin

The in vitro cytotoxicity of the sulfated laminar PS3 obtained in Example 1 was determined simultaneously with that of a comparison product.

To do this, 24-well plate CEM cells were cultured in 1 ml of RPMI supplemented with 10% fetal serum and calf, 1% Penicillin-Streptomycin, 2 mM glutamine, 2 μg / ml polybrene and different concentrations of sulphated laminarine PS3 and the comparison product consisting of dextran sulphate.

Four different concentrations of sulphated laminarine PS3 were tested: 125 μg / ml, 250 μg / ml, 500 μg / ml and 1000 μg / ml. The lowest of these concentrations is already much higher than the concentration of 10 μg / ml, the effectiveness of which has been shown by the foregoing experiments.

All tests were done in duplicate.

The cells were counted daily and the increase in number was compared to that of a control culture consisting of cultured CEM cells in the absence of sulphated PO3 laminarin or dextran sulfate (Oμg / ml).

In Table E, the results recorded at the first, second and third days of the experiment, that is, the number of cells counted in each culture, were combined.

In light of these results in Table E, it appears that PS3 shows no cytotoxicity up to very high concentrations, in this case 1 mg / ml.

TABLE E

EXAMPLE 7 Measurement of the In Vivo Toxicity of PS3 Sulphated Laminarin

In vivo toxicity of the sulfated laminar PS3 used according to the invention has been investigated. This study was conducted on New Zealand white rabbits and Sprague Dawley rats.

The white rabbits were tested on the one hand for ocular irritation and on the other hand for the primary skin irritation test. The outcome of the first of these tests led to the conclusion that the action was slightly irritating and in the second to a non-irritating action.

The rats were then subjected to an acute dermal toxicity test and to an acute oral toxicity study.

In the first case, the dermal lethal dose 50 is greater than 2 g / kg of body weight, which makes it possible to affirm that the product is not toxic.

In the second case, the acute oral toxicity may be considered greater than 2 g / kg of body weight which again allows the product to be classified as nontoxic.

The experiments that led to these conclusions were carried out under the direction of Dr. R. SHRIVASTA VA at the Toxicology Department of the establishment named

Scientific breeding of Dombes (ESD)

ROMANS 01400 CHATILLON ON CHALARONNE

in accordance with OECD Guidelines 404 and 405 of 24 February 1987 as far as the studies on white rabbits and OECD Guidelines No. 401 is 402 (1987) and EEC Guideline B-1 92/69 (1992) as far as studies on Sprague Dawley rats are concerned.

EXAMPLE 8 Composition of a Sulphated Laminarine Cream PS3 A sulphated laminarin cream PS3 having the following composition was produced:

Demineralized water 69.7%

Glycerin 5.0%

Laminarine sulphate PS3 1, 0%

PEG 100 stearate 4.0%

Cetearyl alcohol 2.0%

Conservative 1, 0%

PEG 40 stearate 3.0%

0.5% vitamin E acetate

C - 12-15 alkyl benzoate 6.5%

Caprylic / capric triglycerides 5.5%

0.1 N NaOH, 8%

100%

It is possible to provide 2 to 5 applications per day.

Example 9 Composition of an Aerosol Solution Based on Sulphated Laminarine PS3

An aerosol solution based on sulfated laminarine PS3 having the following composition was produced:

2.5% laminarine sulphate PS3

Sodium Chloride 9.0% Demineralized Water European Pharmacopoeia 88.5% It is possible to administer a daily quantity of aerosol corresponding to a quantity of 1000 to 10 000 μg of active substance.

EXAMPLE 10 Composition of a suppository based on a sulfate of 3 1-3 qlucan

A suppository based on sulfate of a β 1-3 glucan having the following composition:

Potassium salt of β 1-3 glucan sulfate

(DP = 22-24, Sulfation Level 2.4) 5.0% Solid Semisynthetic Glycerines 95.0%

It is advisable to administer 1 or 2 daily.

Example 11 Composition of a Laminaritol Sulphate Injectable Solution An injectable solution based on laminaritol sulphate having the following composition was prepared:

Sodium salt of laminaritol sulphate

(DP20 and sulfation degree of 2.4) 5.0%

Sodium bicarbonate 3.0% Water ppi 92.0%

Over a period of 24 hours it is possible to administer 1000 to 3000 ml of the injectable solution.

Example 12 Composition of a Vaginal Solution Based on a β 1-3 Glucan Sulfate

A vaginal solution based on β 1-3 glucan sulfate having the following composition was produced:

Sodium salt of β 1-3 glucan sulfate

(DP22 and sulfation degree of 2.4) 0.1% Sodium chloride 9.0%

95% ethyl alcohol 5.0% Rose aroma 0,2%

Purified water 84.7%

Preservatives (benzalkonium chloride) 0.2%

Sodium edetate 0.3% Polysorbate 20 0.5%

100% It is possible to make one or two applications a day.

In view of all the experimental results described in the foregoing, it is possible to conclude that the polysaccharides of formula (I), and more particularly sulphated laminarin, exhibit significant anti-retroviral activity, in particular on the replication cycle of the HIV.

The time of implementation at which sulfate laminar PS3 is effective demonstrates a specific action on the early events of the replication cycle of the virus.

No toxicity on the cells was observed at the inhibitory doses tested and even at 1 mg / ml.

In addition, the absence of toxicity of laminarin sulphate, even at 1 mg / ml on the EMC cells, indicates a therapeutic index greater than 200.

The anti-retroviral activity of the polysaccharides of formula (I), in particular that of sulphated laminarine, is not only better than that of the products previously used, but, moreover, it is exerted even on viruses resistant to known inhibitors. of the RT, which is resistant to d4T and Zerit and CHT virus that is resistant to AZT. The polysaccharides of formula (I), and especially sulfated laminarine, inhibit the RT of isolated viruses, which seems to rule out the hypothesis of a mechanism of action related to the simple anionic nature of the sulfated polysaccharides of the invention.

Claims

1. Use of a polysaccharide of formula (I)

(I) in which

R ¹ represents either a hydrogen atom, a sulfate group or a phosphate group, or a sulphated or phosphated glucose bonded preferably by a β (1-> 6) type bond to the saccharide structure,

- R ² represents a hydrogen atom, a sulfate group or a phosphate group, R ¹ and R ² can not simultaneously represent a hydrogen atom,

X and Y represent, each independently, an OH group, a glucose, a sulfated or phosphated glucose, a mannitol, or a sulfated or phosphated mannitol,

n represents an integer from 11 to 30, preferably from 20 to 30, more preferably from 25 to 30, said polysaccharide having a degree of sulfation greater than 2, preferably from 2.2 to 2.4, or a degree of phosphatation greater than 1, preferably from 1.5 to 2.5, for the manufacture of a medicament for the treatment of retroviral diseases.

2. Use of a polysaccharide of formula (I)

(I) in which

R ¹ represents either a hydrogen atom, a sulfate group or a phosphate group, or a sulphated or phosphated glucose bonded, preferably by a bond of the type? (1-> 6) to the saccharide structure,

n represents an integer from 11 to 30, preferably from 20 to 30, more preferably from 25 to 30, said polysaccharide having a degree of sulfation greater than 2, preferably from 2.2 to 2.4, or a degree of phosphatation greater than 1, preferably from 1.5 to 2.5, for the implementation of a method for treating retroviral diseases.

3. Use according to claim 1 or claim 2, characterized in that the polysaccharide of formula (I) is a sulfated laminarine having a degree of polymerization of 11 to 28.

4. Use according to claim 1 or claim 2, characterized in that the polysaccharide of formula (I) is a phosphatized laminarine having a degree of polymerization of 11 to 28.

5. Use according to any one of claims 1 to 4, characterized in that the retroviral diseases are preferentially chosen from those caused by lentiviruses and oncoviruses, more particularly by HIV, and by the strains of these agents resistant retroviruses. antiretrovirals already known.

6. Use according to any one of claims 1 to 5, characterized in that the retroviral disease is the acquired immunodeficiency syndrome or AIDS in humans.

7. Use according to any one of claims 1 to 5, characterized in that the retroviral diseases are cancers associated with oncoviruses.

8. Combination product comprising an effective amount of a polysaccharide of formula (I) in which R ¹ represents either a hydrogen atom, a sulfate group or a phosphate group, or a sulfated or phosphated glucose bound, preferably by a β (1-> 6) bond to the saccharide structure, R ² represents a hydrogen atom, a sulfate group or a phosphate group, X and Y represent, each independently, an OH group, a glucose, a sulfated or phosphated glucose, a mannitol, or a sulfated or phosphated mannitol, n represents an integer from 11 to 30, preferably from 20 to 30, more preferably from 25 to 30, said polysaccharide having a degree of sulfation greater than 2, preferentially from 2.2 to 2.4, or a degree of phosphatation greater than

1, preferably from 1.5 to 2.5, at least one antiretroviral agent chosen from the group comprising:

• nucleoside reverse transcriptase inhibitors (INRTs), including ¹ AZT ₁ ddl, ddC, d4T, 3TC and ABC,

• protease inhibitors, including Agenerase and Kaletra,

• fusion inhibitors, including enfuvirtide (Fuzeon),

Input inhibitors, including, in particular, AMD-3100 and, optionally, at least one pharmacological agent chosen from the group comprising anti-nausea agents, anti-diarrheal agents, anti-hyperbilirubinemia agents, agents anti-pain agents for dermatological treatments, anti-nephrotoxic agents, for simultaneous, separate or spread over time.

9. Use of an effective quantity

at least one antiretroviral agent chosen from the group comprising: nucleoside reverse transcriptase inhibitors

(INRT), including AZT, ddl, ddC, d4T, 3TC and ABC,

• protease inhibitors, including Agenerase and Kaletra,

• fusion inhibitors, including enfuvirtide (Fuzeon), "inhibitors of entry, including AMD-3100 and possibly

at least one pharmacological agent chosen from the group comprising anti-nausea agents, anti-diarrheal agents, anti-hyperbilirubinemia agents, anti-pain agents, agents for dermatological treatments, anti-nephrotoxic agents, the manufacture of a medicament for the treatment of retroviral diseases, preferably caused by lentiviruses and oncoviruses, more preferably by HIV, in particular by the strains of these retroviruses resistant to antiretroviral agents already known.

10. Use of an effective quantity

a polysaccharide of formula (I) in which R ¹ represents either a hydrogen atom, a sulphate group or a phosphate group, or a sulphated or phosphated glucose bonded, preferably, by a β-type bond (1 → 6) to the saccharide structure, R ² represents a hydrogen atom, a sulfate group or a phosphate group, X and Y represent, each independently, an OH group, a glucose, a sulfated or phosphated glucose, a mannitol, or a sulfated or phosphated mannitol, n represents an integer from 11 to 30, preferably from 20 to 30, more preferably from 25 to 30, said polysaccharide having a degree of sulfation greater than 2, preferably of 2.2 to 2.4, or a degree of phosphatation greater than 1, preferably of 1.5 to 2.5,

(INRT), including I ¹ AZT, ddl, ddC, d4T, 3TC and ABC,

• protease inhibitors, including Agenerase and Kaletra,

• fusion inhibitors, including enfuvirtide (Fuzeon), • input inhibitors, including AMD-3100 and, possibly,

at least one pharmacological agent chosen from the group comprising anti-nausea agents, anti-diarrheal agents, anti-hyperbilirubinemia agents, anti-pain agents, agents for dermatological treatments, anti-nephrotoxic agents, the implementation of a method for treating retroviral diseases, preferably caused by lentiviruses and oncoviruses, more preferably by HIV, in particular by the strains of these retroviruses resistant to antiretroviral agents already known.

11. A method of treating a retroviral disease, preferably caused by lentiviruses and oncoviruses, more preferably by HIV, especially by the strains of these retroviruses resistant to antiretroviral agents already known, including the administration, in a patient suffering from said retroviral disease, an effective amount of a medicament comprising as active agent at least one polysaccharide of formula (I)

(I) in which R ¹ represents either a hydrogen atom, a sulfate group or a phosphate group, or a sulphated or phosphated glucose bonded, preferably, by a β (1-> 6) type bond to the saccharide structure , R ² represents a hydrogen atom, a sulfate group or a phosphate group, X and Y represent, each independently, an OH group, a glucose, a sulphated or phosphated glucose, a mannitol, or a sulphated or phosphated mannitol, n represents an integer from 11 to 30, preferably from 20 to 30, more preferably from 25 to 30, said polysaccharide having a degree of sulfation greater than 2, preferably from 2.2 to 2.4, or a degree of phosphatation greater than 1, preferably from 1.5 to 2.5; or a combination product as claimed in claim 8.

12. Method of treatment according to claim 11, in which the polysaccharide of formula (I) is a sulfated laminarine, characterized in that it has a degree of sulfation greater than 2, preferably 2.2 to 2.4, and a degree of polymerization of 11 to 28.

13. The treatment method as claimed in claim 11, in which the polysaccharide of formula (I) is a phosphatized laminarine, characterized in that it has a degree of phosphatation greater than 1, preferably from 1.5 to 2.5, and a degree of polymerization of 11 to 28.