Patent 6,869,925

Methods and pharmaceutical compositions are provided to prevent retroviral infections of host cells. More particularly, the invention relates to prevention of HIV infection of human cells by serine leukocyte protease inhibitor (SLPI).

Description of the Invention

BACKGROUND OF THE INVENTION

Retroviral agents have been implicated in a number of diseases, including cancer, autoimmune disease and AIDS. Human immunodeficiency virus (HIV) infection causes chronic progressive depletion of CD4⁺ T lymphocytes (CD4⁺ cells) and infection of macrophages, resulting in acquired immune deficiency syndrome. Currently zidovudine (AZT), an analogue of thymidine, is the primary anti-viral drug used in the treatment of HIV infection, although two other agents with a similar mechanism of action, dideoxyinosine (ddI) and dideoxycytosine (ddC), are also used. Colley, T. P. et al., New Engl. J. Med. (1990) 322:1340-45; Fischl, M. A., et al., New Engl. J. Med. (1987) 317:185-91. These agents are effective in inhibiting viral replication, and can stabilize the CD4⁺ cell levels, but they are unable to eliminate one of the major viral reservoirs, HIV infected macrophages. Gartner, S., et al., Science (1986) 233:215-19. Severe toxicity, particularly involving HIV host bone marrow is also associated with higher doses of AZT treatment, and the beneficial effects of the drug in AIDS patients diminishes after prolonged therapy; HIV strains resistant to AZT also have been observed in treated patients. These findings have prompted the search for alternative drugs for the treatment of HIV infection, particularly agents with a different mechanism of action.

Human immunodeficiency virus type 1 (HIV-1), a retrovirus, is the etiologic cause of AIDS. The HIV-1 envelope glycoprotein, gp120, specifically binds to the CD4 receptor on T lymphocytes and on monocytes and macrophages. Although infection of T lymphocytes requires cellular proliferation and DNA synthesis, productive infection of monocytes can occur independently of cellular DNA synthesis (Weinberg, J. B., et al, (1991) J. Exp. Med. 174:1477-82). When HIV-1 infects activated CD4⁺ lymphocytes, it is lethal, but infected monocytes are relatively resistant to destruction by the virus. Consequently, these cells, once infected with HIV-1, serve as long-lived reservoirs of the virus. Not only are these cells a source of replicating virus, but their virally-mediated dysfunction may contribute to increased susceptibility to opportunistic infections that are the hallmark of AIDS.

Because monocyte-macrophages serve as reservoirs for HIV-1, selective targeting of this population, in addition to T lymphocytes, warrants further consideration (Finberg, R. W., et al., Science 252:1703-05, 1991. Early reports from Fox's group (JADA 118:709-711, 1989) indicated that a component of human saliva blocks HIV replication. More recently, Hattori (FEBS Lett. 248:48-52, 1989) showed that an inhibitor of tryptase (a trypsin-like enzyme) can inhibit syncytia formation of T-cells induced by HIV.

In exploring various potential modulators of HIV-1 infection, we have recently identified an endogenous source of inhibitory activity which retards HIV-1 infection and/or replication.

The factor responsible for the antiviral activity is serine leukocyte protease inhibitor (SLPI). SLPI is a potent inhibitor of human leukocyte elastase, chymotrypsin, cathepsin G, and of human trypsin, and has been purified from parotid secretions (Thompson, R. C. and K. Ohlsson, (1986) Proc. Natl. Acad. Sci. USA, 83:6692-96; and U.S. Pat. No. 4,760,130, both of which are incorporated herein by reference). SLPI is now available through production by recombinant DNA techniques; U.S. patent application Ser. No. 07/712,354, filed Jun. 7, 1991, PCT application No. WO86/03519, filed. Dec. 4, 1985, and European patent application 85 905 953.7, filed Dec. 4, 1985, each of which are incorporated herein by reference).

The ability of SLPI and/or its derivatives and analogs to block HIV-1 infection and/or replication can provide the basis for therapeutic intervention in HIV-1 infection.

SUMMARY OF THE INVENTION

The present invention provides novel methods for preventing or treating retroviral infections of mammalian cells, particularly preventing infection of human cells with human immunodeficiency virus (HIV) and associated diseases, including acquired immune deficiency syndrome (AIDS).

Included within the scope of this invention are pharmaceutical compositions for treating retroviral infections, particularly HIV infections in a human, comprising serine leukocyte protease inhibitor (SLPI), or an analog or derivative thereof, and a pharmaceutically acceptable carrier.

The invention also includes a method for treating HIV infections in a human cell comprising administering thereto an effective amount of SLPI or an analog or derivative thereof.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides methods for preventing retrovirus, particularly HIV infection of mammalian cells, particularly human cells, and associated diseases, including acquired immune deficiency syndrome (AIDS).

The term "pharmaceutically acceptable carrier" as used herein means a non-toxic, generally inert vehicle for the active ingredient, which does not adversely affect the ingredient or the patient to whom the formulation is administered.

The term "effective amount" as used herein means a pre-determined amount of SLPI, or an analog or derivative thereof, sufficient to be effective against HIV in vivo.

According to the present invention, retroviral infections are treated by administering anti-retroviral agents in doses sufficient to diminish the effects of such infection. Retroviral infections are implicated in a number of diseases, including but not limited to cancer, autoimmune disease, and acquired immune deficiency syndrome. Human immunodeficiency virus infection is of particular interest according to the present invention.

A variety of anti-retroviral agents are known in the art. Most of these inhibit the activity of retroviral reverse transcriptase and include zidovudine (AZT), an analogue of thymidine, dideoxyinosine (ddI), and dideoxycytosine (ddC). Zidovudine is the primary anti-viral drug used in the treatment of HIV infection. Anti-retroviral agents are generally efficacious in a dose ranging from about 50 mg/day to about 1000 mg/day, more particularly from about 100 mg/day to about 500 mg/day, and in the case of zidovudine, specifically about 300 mg/day to about 500 mg/day. These agents are generally administered in oral formulations.

The protease inhibitors used in this invention can be prepared by means well known to those skilled in the art (see, e.g., U.S. Pat. No. 4,760,130; European patent application 85 905 953.7, PCT application WO86/03519, and U.S. patent application Ser. No. 07/712,354, supra). The disclosed protease inhibitors include secretory protease inhibitors comprising the amino acid sequence of naturally-occurring secretory leukocyte protease inhibitor or a substitution analog comprising the amino acid sequence (SEQ ID NO:4):

R1-Gly-Lys-Ser-Phe-Lys-Ala-Gly-Val-Cys-Pro-Pro-Lys- Lys-Ser-Ala-Gln-Cys-Leu-R2-Tyr-Lys-Lys-Pro-Glu-Cys- Gln-Ser-Asp-Trp-Gln-Cys-Pro-Gly-Lys-Lys-Arg-Cys-Cys-Pro-Asp-Thr-Cys-Gly-Il e-Lys-Cys-Leu-Asp-Pro-Val-Asp- Thr-Pro-Asn-Pro-Thr-Arg-Arg-Lys-Pro-Gly-Lys-Cys-Pro- Val-Thr-Tyr-Gly-Gln-Cys-R8-R3-R9-Asn-Pro-Pro-Asn- Phe-Cys-Glu-R4-Asp-Gly-Gln-Cys-Lys-Arg-Asp-Leu-Lys- Cys-Cys-R5-Gly-R6-Cys-Gly-Lys-Ser-Cys-Val-Ser-Pro- Val-Lys-R7

wherein

R1 and R7 are the same or different and are selected from the group consisting of a substituted or unsubstituted amino acid residue or derivatives thereof; and

R2, R3, R4, R5, R6, R8 and R9 are the same or different and are selected from the group consisting of methionine, valine, alanine, phenylalanine, tyrosine, tryptophan, lysine, glycine and arginine.

It is believed that minor alterations to the amino acid sequence at the C- and N-termini will not significantly alter the activity of the disclosed protease inhibitors. Specifically, substitution at the C- or N-terminus with a cyclized amino acid, for example, proline, is believed to result in a protease inhibitor having the desired serine protease inhibiting activity. Also, analogs of the disclosed protease inhibitors which have alterations at the C- or N-terminus, which alterations do not destroy the serine protease inhibitor properties of the analog, are included within the scope of the present invention.

The present invention relates to protease inhibitors which have been isolated in a purified form. Preferably, the serine protease inhibitors of the present invention are single-polypeptide-chain proteins which are substantially homologous to, and most preferably biologically equivalent to, the native serine protease inhibitor isolated from human parotid secretions. The native serine protease inhibitor is also referred to as the native parotid inhibitor. By "biologically equivalent" as used throughout the specification and claims, is meant that the compositions are capable of inhibiting the monocyte-derived or T-cell derived protease that is inhibited by SLPI, but not necessarily to the same degree. By "derivatives" as used throughout the ensuing specification and claims, is meant a degree of amino acid homology to the native parotid inhibitor, preferably in excess of 40%, most preferably in excess of 50%, with a particularly preferred group of proteins being in excess of 60% homologous with the native parotid inhibitor. The percentage homology, as above described, is calculated as the percentage of the components found in the smaller of the two sequences that may also be found in the larger of the two sequences, a component being understood as a sequence of four, contiguous amino acids.

One useful SLPI derivative is CLPI, a truncated SLPI molecule having only the last 60 amino acids of the native parotid inhibitor. These 60 amino acids are:

Leu Asp Pro Val Asp Thr Pro Asn Pro Thr Arg Arg Lys
Pro Gly Lys Cys Pro Val Thr Tyr Gly Gln Cys Leu Met
Leu Asn Pro Pro Asn Phe Cys Glu Met Asp Gly Gln Cys
Lys Arg Asp Leu Lys Cys Cys Met Gly Met Cys Gly Lys
Ser Cys Val Ser Pro Val Lys Ala. (SEQ. ID. NO.: 1)

The following nucleotide sequence has been used to encode the above 60 amino acid molecule:

CTG GAT CCT GTT GAC ACC CCA ACA CCA ACA AGG AGG AAG
CCT GGG AAG TGC CCA GTG ACT TAT GGC CAA TGT TTG ATG
CCT AAC CCC CCC AAT TTC TGT GAG ATG GAT GGC CAG TGC
AAG CGT GAC TTG AAG TGT TGC ATG GGC ATG TGT GGG AAA
TCC TGC GTT TCC CCT GTG AAA GCT. (SEQ. ID. NO.: 2)

CLPI has been constructed by deleting from the SLPI gene the signal sequence and the nucleotides corresponding to the first 47 amino acids of the mature SLPI protein as described in U.S. patent application Ser. No. 07/712,354. CLPI can also be made by the method of Example 8 described in both PCT application WO86/03519 and European patent application 85 905 953.7. Although Example 8 in these two applications recites a method of making SLPI, this method can also be used to make CLPI. CLPI can be used to generate antibodies useful in purifying SLPI. Antibodies can be produced, for example, by the methods discussed in E. Harlow & D. Lane, Antibodies: A Laboratory Manual, pp. 92-114 (Cold Springs Harbor Laboratory, 1988).

By "analogs" as used herein, is meant any compound, including, for example, small organic compounds, that are functionally biologically equivalent to SLPI in inhibiting HIV infection. Such derivatives and analogs can be isolated by means well known to those skilled in the art, including using monocyte cells or T cells to screen for compounds that prevent SLPI from binding thereto. Analogs may also include specific SLPI muteins that have at least equivalent, and in some cases, greater activity than the native protein. Particularly useful SLPI muteins include substitution of the following amino acids at the residue position enumerated: Gly 20, Gly 72, Val 72, and Phe 72.

CLPI muteins are also within the scope of the invention. CLPI muteins which correspond to the SLPI muteins Gly 72, Val 72, and Phe 72 are herein referred to as Gly 25, Val 25, and Phe 25. Some contemplated CLPI muteins have the following amino acid sequence:

Leu Asp Pro Val Asp Thr Pro Asn Pro Thr Arg Arg Lys
Pro Gly Lys Cys Pro Val Thr Tyr Gly Gln Cys R₈ R₃ R₉ Asn Pro Pro Asn Phe Cys Glu R₄ Asp Gly Gln Cys
Lys Arg Asp Leu Lys Cys Cys R₅ Gly R₆ Cys Gly Lys
Ser Cys Val Ser Pro Val Lys R₇

wherein R7 is alanine, and R3, R4, R5, R6, and R8 are the same or different amino acids and one or more of R3, R4, R5, R6, and R8 may be methionine, valine, alanine, phenylalanine, tyrosine, tryptophan, lysine, glycine, or arginine. (SEQ. ID. NO.: 3) Analogs also include, for example, PEGylated forms of SLPI or CLPI which may have improved therapeutic characteristics over the native SLPI protein. Muteins which may be suitable for PEGylation include those having a cysteine residue at positions 13, 23, 52, 58, 68, and/or 75 of SLPI and at the corresponding sites 5, 11, 21, and 28 in CLPI. Preparation of cysteine muteins for PEGylation is described in PCT application WO 92/16221, filed Mar. 13, 1992, which is specifically incorporated herein by reference. A useful step in mutein production can include a refolding step in which cysteine is added to the solution containing the protein. The cysteine can aid in refolding and can bond to the substituted free cysteine in the mutein. One may also isolate from monocytes or T cells the SLPI inhibitable protein (SIP) from human monocyte cells or human T cells using standard biochemical techniques well known to those skilled in the art and purify proteins having proteolytic activity which is inhibited by SLPI. After purifying the protein (and, if necessary, sequencing it, cloning its gene, and expressing it in host cells, i.e., recombinantly producing SIP), one can screen for inhibitors of SIP by means well known to those skilled in the art. Alternatively, one can determine its structure and design inhibitors therefrom, also by means well known to those skilled in the art.

When SLPI, or an analog or derivative thereof (collectively, the "compounds"), is used to combat HIV infections in a mammal, the compound can be administered orally, parenterally, or locally, in a vehicle comprising one or more pharmaceutically acceptable carriers, the proportion of which is determined by the solubility and chemical nature of the compound, chosen route of administration and standard biological practice.

Pharmaceutical compositions containing the compounds of the present invention can be prepared. These compounds can be in a pharmaceutically-acceptable carrier to form the pharmaceutical compositions of the present invention. The term "pharmaceutically acceptable carrier" as used herein means a non-toxic, generally inert vehicle for the active ingredient, which does not adversely affect the ingredient or the patient to whom the composition is administered. Suitable vehicles or carriers can be found in standard pharmaceutical texts, for example, in Remington's Pharmaceutical Sciences, 16th ed., Mack Publishing Co., Easton, Pa. (1980), incorporated herein by reference. Such carriers include, for example, aqueous solutions such as bicarbonate buffers, phosphate buffers, Ringer's solution and physiological saline. In addition, the carrier can contain other pharmaceutically-acceptable excipients for modifying or maintaining the pH, osmolarity, viscosity, clarity, color, sterility, stability, rate of dissolution, or odor of the formulation.

The pharmaceutical compositions can be prepared by methods known in the art, including, by way of an example, the simple mixing of reagents. Those skilled in the art will know that the choice of the pharmaceutical carrier and the appropriate preparation of the composition depend on the intended use and mode of administration.

In one embodiment, it is envisioned that the compound and pharmaceutically acceptable carrier constitute a physiologically-compatible, slow-release formulation. The primary solvent in such a carrier can be either aqueous or non-aqueous in nature. In addition, the carrier can contain other pharmacologically-acceptable excipients for modifying or maintaining the pH, osmolarity, viscosity, clarity, color, sterility, stability, rate of dissolution, or odor of the formulation. Similarly, the carrier can contain still other pharmacologically-acceptable excipients for modifying or maintaining the stability, rate of dissolution, release, or absorption of the compound. Such excipients are those substances usually and customarily employed to formulate dosages for oral, parenteral or local administration in either unit dose or multi-dose form.

Once the pharmaceutical composition has been formulated, it can be stored in sterile vials as a solution, suspension, gel, emulsion, solid, or dehydrated or lyophilized powder. Such formulations can be stored either in a ready to use form or requiring reconstitution immediately prior to administration.

The manner of administering the formulations containing the compounds for systemic delivery can be via subcutaneous, intramuscular, intravenous, oral, intranasal, or vaginal or rectal suppository. Administration of the formulations containing the compounds for local delivery includes via intraarticular, intratracheal, or instillation or inhalations to the respiratory tract. Local administration via vaginal or rectal suppository or topical application is also contemplated. In addition it may be desirable to administer the compounds to specified portions of the alimentary canal either by oral administration of the compounds in an appropriate formulation or device.

For oral administration, the compound can be formulated in unit dosage forms such as capsules or tablets each containing a predetermined amount of the active ingredient, ranging from about 10 to 1000 mg, more preferably 10-200 mg per day per patient, even more preferably 20-200 mg per day per patient, in a pharmaceutically acceptable carrier. The compound can be formulated with or without pharmaceutically-acceptable carriers customarily used in the compounding of solid dosage forms. Preferably, the capsule or tablet is designed so that the active portion of the formulation is released at that point in the gastro-intestinal tract when bioavailability is maximized and pre-systemic degradation is minimized. Additional excipients can be included to facilitate absorption of the compound. Diluents, flavorings, low melting point waxes, vegetable oils, lubricants, suspending agents, tablet disintegrating agents, and binders can also be employed.

For parenteral administration, the compound is administered by either intravenous, subcutaneous or intramuscular injection, in compositions with pharmaceutically acceptable vehicles or carriers. For administration by injection, it is preferred to use the compound in solution in a sterile aqueous vehicle which may also contain other solutes such as buffers or preservatives as well as sufficient quantities of pharmaceutically acceptable salts or of glucose to make the solution isotonic. Subcutaneous injection is the preferred route of administration. Dosages are essentially the same as those set forth above for oral administration.

For local administration, the compound is preferably formulated to maximize the availability of the compound at the intended site of administration. Local administration of the compound at known or expected sites of entry or release of retrovirus into and from the body is particularly contemplated. For example, in consideration of the variety of mammalian sexual practices, topical administration of the compound to all orifices and interior or exterior genitalia is desirable. In addition, topical application to skin surfaces, and in particular to any skin interruptions such as cuts, abrasions, lesions, blisters and the like, is believed useful in preventing the exchange of retrovirus from one host to another.

In one particularly useful embodiment, gloves containing the compounds formulated for local administration are prepared for those who come into contact with hosts or bodily fluids. Preferred dosages for local administration include those for which a local compound concentration of 1-10 .mu.g/ml is achieved.

In the case of systemic administration, the specific dose is typically calculated according to the approximate body weight of the patient. On the other hand, for local administration, the specific dose is typically not a function of the patient's body weight. Other factors in determining the appropriate dosage can include the disease or condition to be treated or prevented, route of administration and the age, sex and medical condition of the patient. Generally, treatment is initiated with small dosages substantially less than the optimum dose of the compound. Thereafter, the dosage is increased by small increments until the optimum effect under the circumstances is reached.

In general, the compound is most desirably administered at a concentration level that will generally afford antivirally effective results without causing any harmful or deleterious side effects. It is desirable to maintain a blood level of the compound at a level sufficient to inhibit retrovirus infection of the host cell. This can be estimated by assaying the amount of compound that is effective in preventing retroviral infection of host cells, e.g., HIV into monocytes, in vitro, and then, using standard pharmacokinetic techniques, determining the amount of compound required to keep plasma level at the same inhibitory level, or up to 10-100 times more. In certain embodiments, the dosage and administration is designed to create a preselected concentration range of the compound in the patient's blood stream. Further refinement of the calculations necessary to determine the appropriate dosage for treatment involving each of the above mentioned formulations is routinely made by those of ordinary skill in the art and is within the ambit of tasks routinely performed by them without undue experimentation, especially in light of the dosage information and assays disclosed herein. These dosages may be ascertained through use of the established assays for determining dosages utilized in conjunction with appropriate dose-response data.

Although the formulations disclosed hereinabove are effective and relatively safe medications for treating HIV infections, the possible concurrent administration of these formulations with antibacterial or other antiviral medications or agents to obtain beneficial results is not excluded. Such other antiviral medications or agents include soluble CD4, zidovudine, dideoxycytidine, phosphonoformate, ribavarin, antiviral interferons (e.g. alpha-interferon or interleukin-2) or aerosol pentamidine. Particularly useful antibacterial agents include those which target sexually-transmitted pathogens or the opportunistic pathogens often associated with retroviral infection.

It should be noted that the compound formulations described herein may be used for veterinary as well as human applications and that the term "patient" should not be construed in a limiting manner. In the case of veterinary applications, the dosage ranges should be the same as specified above.

It is also possible to utilize the nucleic acid sequences for SLPI themselves as therapeutic agents. For example, gene transfer methodologies can be employed to transfer a coding sequence for SLPI or an analog thereof to the patient where the gene can be replicated and expressed in vivo. Particularly useful gene therapy methods are discussed in the published international application WO 93/00051, which is specifically incorporated herein by reference.

Compositions containing the compounds useful for storing or treating instruments, devices, or the like which contact hosts or bodily fluids are also within the scope of the invention. Nonlimiting examples of such instruments, devices, or the like include needles, speculums, scalpels, surgical clips, or other articles which might penetrate a host or contact bodily fluids. Preferably, the compositions neither adversely affect the activity of the compounds contained therein nor adversely react with the articles to be treated or stored. Such compositions can be prepared by methods known in the art particularly in light of the information contained herein.

The invention also includes a method for inhibiting retrovirus infection by blocking the function of a host cell enzyme, which enzyme function is necessary for retrovirus infection of the cell. As stated above, SLPI is a potent inhibitor of elastase, trypsin, cathepsin G, and chymotrypsin.

The host cell enzyme can be an elastase-like enzyme. The term "elastase-like enzyme" as used herein means a protease which cleaves at the carboxy-terminal side of amino acids with small to medium sized hydrophobic side chains such as leucine, isoleucine, valine, and alanine.

The host cell enzyme can also be a chymotrypsin-like enzyme. As used herein, the term "chymotrypsin-like enzyme" means a protease which cleaves at the carboxy-terminal side of amino acids with medium to large hydrophobic side chains, including for example, phenylalanine, tyrosine, trytophan, leucine, and isoleucine.

A trypsin-like enzyme can also be a host cell enzyme. The term "trypsin-like" enzyme as used herein means a protease which cleaves at the carboxy-terminal side of basic amino acids including, for example, lysine and arginine.

In addition, cathepsin G can also be a host cell enzyme.

Claim 1 of 22 Claims

What is claimed is:

1. A method for the inhibition of viral proliferation which comprises treating a patient with a composition containing an antiviral effective amount of a serine protease inhibitor comprising the amino acid sequence set forth in SEQ ID NO:4:

R1-Gly-Lys-Ser-Phe-Lys-Ala-Gly-Val-Cys-Pro-Pro- Lys-Lys-Ser-Ala-Gln-Cys-Leu-R2-Tyr-Lys-Lys-Pro- Glu-Cys-Gln-Ser-Asp-Trp-Gln-Cys-Pro-Gly-Lys-Lys- Arg-Cys-Cys-Pro-Asp-Thr-Cys-Gly-Ile-Lys-Cys-Leu- Asp-Pro-Val-Asp-Thr-Pro-Asn-Pro-Thr-Arg-Arg-Lys- Pro-Gly-Lys-Cys-Pro-Val-Thr-Tyr-Gly-Gln-Cys-R8- R3-R9-Asn-Pro-Pro-Asn-Phe-Cys-Glu-R4-Asp-Gly- Gln-Cys-Lys-Arg-Asp-Leu-Lys-Cys-Cys-R5-Gly-R6 Cys-Gly-Lys-Ser-Cys-Val-Ser-Pro-Val-Lys-R7

wherein

R1 and R7 are the same or different and are an amino acid residue;

R2, R3, R4, R5 and R6 are the same or different and are selected from the group consisting of methionine, valine, alanine, phenylalanine, tyrosine, tryptophan, lysine, glycine and arginine; and

R8 and R9 are the same or different and are selected from the group consisting of methionine, valine, alanine, phenylalanine, tyrosine, tryptophan, lysine, glycine, leucine and arginine.

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