TREATMENT OF RETROVIRAL INFECTIONS WITH OXYPHENBUTAZONE

Abstract: The invention provides a method of treatment of a human or non-human mammal subject to combat a retroviral infection, said method comprising administering to said subject an antivirally effective amount of a compound selected from oxyphenbutazone and other substituted-phenyl phenbutazones and substituted-phenyl prodrugs for oxyphenbutazone and other substituted phenyl phenbutazones.

Description: TREATMENT OF RETROVIRAL INFECTIONS WITH OXYPHENBUTAZONE This invention relates to the use of butazones to combat viral infection, especially retroviral infection, more particularly HIV infection. HIV infection and AIDS have developed into a major global medical problem with many millions of people now infected. The majority of those infected with HIV are in the developing countries and, due to scarcity of resources in such countries, the likelihood of HIV infection progressing to full-blown AIDS and death is high. Eleven compounds have been approved for combatting HIV and AIDS. These are either reverse transcriptase inhibitors (eg. zidovudine, didanosine, zalcitabine, stavudine, lamivudine, nevirapine, and delavirdine) or protease inhibitors (eg. indinavir, ritonavir and nelfinavir) . In addition several other compounds are under development. While monotherapy (treatment using a single drug) has been tried, combination therapy using a "cocktail" of more than one of the anti-HIV/AIDS drugs has been found to be significantly more effective and is now have the "gold standard" in HIV/AIDS treatment. (See for example Goldschmidt in J. Am. Board Fam. Pract . 11:158-164 (1998) . Development of new drugs is time consuming and expensive and current AIDS/HIV treatment using the approved reverse transcriptive inhibitors and protease inhibitors and the gold standard cocktails is expensive, costing in the order of US$10,000 per year per patient. This is far beyond the financial resources of the infected populations in the developing countries. Moreover, these drugs are in general quite toxic, with severe dose-limiting side effects. Furthermore, long term treatment with enzyme inhibiting drugs runs the risk of the emergence of drug resistant variants of the HIV virus, a virus which is notable for its ability to mutate rapidly and which already exists in several forms with different geographical distributions. (See for example Carrosi in J. Biol . Homeast . Agent 12:9-14 (1998) , Groschel in Intervirology 40:400-407 (1997) , Hirsch et al in J.A.M.A. 279:1984-1989 (1998), Katzenstein et al in J. Assoc. Nurses AIDS Care J3(Suppl) : 10-17 (1997) and Erickson in Annual Rev. Pharmacol. Toxicol . 36: 545-571 (1996)). Finally, the use of combination therapy of course increases the risk of drug interactions, a risk which is particularly severe with AIDS patients who are frequently taking other drugs to combat opportunistic infections. Accordingly, there is still a need for drugs which are effective in combatting AIDS/HIV, which are safe and which can be afforded by infected and at-risk patients. The use of phenbutazone (4-butyl-l, 2-diphenyl- pyrazolidin-3 , 5-dione) for the treatment of retroviral infection, and HIV infection in particular, was proposed by Miesch in US-A-4956377. Phenbutazone is a non- steroidal anti-inflammatory drug (NSAID) which has been used for many years as an anti-inflammatory, eg. in the treatment of rheumatoid arthritis, but which has been replaced in more recent years by other NSAIDs . While administration of phenbutazone to HIV- infected patients may have some effect in combatting the viral infection, we have now found that, in vi tro, phenbutazone is ineffective against the virus. However, we have surprisingly found that the hydroxylated analog oxyphenbutazone (4-butyl-l- (4-hydroxyphenyl) -2-phenyl- pyrazolidin-3 , 5-dione) is markedly effective. Besides oxyphenbutazone, substituted-phenyl prodrugs for oxyphenbutazone and other substituted-phenyl phenbutazones may also be used. Thus viewed from one aspect the invention provides a method of treatment of a human or non-human mammal subject to combat a retroviral infection, said method comprising administering to said subject an antivirally effective amount of a compound selected from oxyphenbutazone and other substituted-phenyl phenbutazones and substituted-phenyl prodrugs for oxyphenbutazone and other substituted-phenyl phenbutazones . By substituted-phenyl phenbutazones is meant compounds in which the phenyl group in the 1 or 2 position of the pyrazolidin-3 , 5-dione carries a substituent, preferably in the 4 -position, eg. a hydroxy or other oxygen attached group, and in which the 4 -position is substituted by an optionally substituted hydrocarbyl group . Such compounds may be monomers or dimers , eg . linked via the phenyl groups. By phenyl-substituted prodrugs is meant 1, 2-diphenyl-pyrazolin-3-ones in which the phenyl group in the 1 or 2 position carries a substituent (eg as defined above) and in which the 4- position is substituted as defined above. Viewed from a further aspect, the invention provides the use of a compound selected from oxyphenbutazone and other substituted-phenyl phenbutazones and substituted- phenyl prodrugs for oxyphenbutazone and other substituted-phenyl phenbutazones for the manufacture of a medicament for use in treatment to combat retroviral infection. Oxyphenbutazone contains a chiral centre; however either the R or the S isomers, or mixtures thereof, e.g. the racemate, may be used. By S-oxyphenbutazone is meant oxyphenbutazone with a weight ratio of at least 75:25, preferably at least 80:20, more preferably at least 90:10, and most preferably at least 99:1 between the S and R isomers. The enantiomers may be prepared from the racemates by conventional optical isomer separation techniques, eg. crystallization from chiral solvents, crystal separation, etc. The compounds used according to the invention include compounds as disclosed in US-A-3957803 , US-A-4117232 , US-A-4036845, US-A-4139709 , US-A-3968219 , and US-A- 4169147, the contents of which are incorporated herein by reference. By way of example, the substituted-phenyl phenbutazones used according to the invention includes compounds of formula I . where R : is a C 3 . 9 hydrocarbon (eg. a linear, branched or cyclic alkyl or alkenyl group or an aryl, or aralkyl or alkaryl group) optionally substituted by oxo or interrupted by thio, sulphonyl , or suphinyl ; each R 2 is hydrogen or a group OR 3 where R 3 is hydrogen or optionally substituted C^g alkyl (eg substituted by oxo, carbonyl, alkoxy, sulphonyl-alkyloxy, etc; or one R, is a group (A) where n is an integer from 1-18, with the proviso that one R 2 is hydroxyl and the other is hydrogen or a group (A) . Non-hydrogen R 2 groups are preferably in the 4- position of the phenyl group. Ri is preferably butyl, especially n-butyl . Alkyl and alkenyl moieties, unless otherwise specified preferably contain up to 6 carbons and aryl moieties preferably are phenyl groups. Similarly by way of example, the substituted-phenyl prodrugs used according to the invention may be of formula II (where R x and R 2 are as described above and R 4 is a metabolically cleavable group, eg a group R, R 2 or CHR 4 R 5 as defined in US-A-4139709) . The substituted-phenyl compounds may be prepared as described in the patents referred to above. The compounds according to the invention, when used in solid form, are preferably in amorphous rather than crystalline form. This can be achieved by rapid precipitation, e.g. by rapid cooling. Oxyphenbutazone and the substituted-phenyl compounds may be used in monotherapy; however they are preferably used in combination therapy with at least one other anti-HIV drug, eg a reverse transcriptase inhibitor or protease inhibitor such as zidovudine, didanovine, zalcitabine, stavudine, lamivudine, nevirapine, delavirdine, indinavir, ritonavir and nelfinavir. Surprisingly, they are particularly conveniently used together with phenbutazone itself since phenbutazone appears to exert a cytoprotective effect on HIV infected cells. Viewed from a further aspect therefore, the invention provides a pharmaceutical composition comprising a compound selected from oxyphenbutazone and other substituted-phenyl phenbutazones and substituted phenyl prodrugs for oxyphenbutazone and other substituted- phenyl phenbutazones, together with a further anti-HIV drug and at least one pharmaceutical carrier or excipient . Such compositions particularly preferably contain oxyphenbutazone and phenbutazone . Similarly, the oxyphenbutazone or sibstituted phenyl compounds are advantageously used together with drugs which combat side-effects of anti-HIV therapy or which combat opportunistic infection. Such drugs are well known in the field of HIV/AIDS therapy. The oxyphenbutazone or substituted phenyl compounds are preferably administered at a dosage of 10 to 2000 mg/day, more preferably 50 to 1000 mg/day, especially 100 to 500 mg/day, preferably with administration being effected once, twice, three times or four times, most preferably twice, per day. Administration may be via any conventional administration route, eg. oral, rectal, nasal, sub-lingual, transdermal or by injection or infusion (eg. iv, im or sc) . Oral and rectal, especially oral, administration is preferred. The administration forms may be any conventional pharmaceutical administration form, eg. solutions, suspensions, dispersions, emulsions, syrups, gels, granules, creams, ointments, tablets, coated tablets, capsules, sprays, suppositories, patches, etc; however, tablets and capsules, eg. soft or hard gelatin capsules, are preferred. Controlled release formulations are especially preferred, eg. with gastric juice resistant coatings such as Eudragit (Rohm GmbH, Darmstadt, Germany) . Such administration forms may contain conventional pharmaceutical carriers, diluents and excipients, eg. water, saline, flavours, sweeteners, binders, lubricants, stabilizers, coating agents, bulking agents, pH adjusting agents, osmolality adjusting agents, release delaying agents, effervescing agents, etc. The compositions may be prepared by conventional formulation techniques, eg. tableting etc. When one or more of the active ingredients is in salt form, the counterion should of course be either physiologically tolerable (eg. sodium, organic amine, chloride, bromide, hydrogen carbonate, etc) or physiologically active in a desired manner. Oxyphenbutazone and the substituted phenyl compounds may be used to treat HIV infected patients therapeutically . They may also be used prophylactically to treat members of at-risk groups who may not be HIV-infected or who may have been exposed to infection but do not yet show up as HIV positive, eg. intravenous drug users, prostitutes, homosexuals, medical and paramedical staff exposed to patients' blood or to surgical instruments, partners of HIV infected individuals, etc. Such prophylactic use of phenbutazone itself is novel and forms a further aspect of this invention. Besides HIV, oxyphenbutazone and the substituted phenyl compounds may also be used to combat other viral infections, especially retroviral infections but also infections by togaviridea, reoviridea, picornaviridae, hantavirus, orthomyxoviridae, paramyxoviridae, mononegaviralis, viral hepatitis, haemorrhagic fevers, flaviviridae, viral encephalitis, coronaviridae, calciviridae, adenoviridae, papovaviridae, arboviridae, pox virus, rhabdoviridae, herpes virus, and arenaviridae . Oxyphenbutazone and the substituted phenyl compounds may also be used to combat and viral infections of CD4 cells, e.g. HIV-1, HIV-2, HTLV-I, HTLV-II and herpes viruses, for example to combat AIDS, T-cell tumours (e.g. Sezary Syndrome, mycosis fungoides, and T-cell lymphoma) , tropic spastic paraparesis, and Karposi's sarcoma. Such uses form further aspects of the invention. By way of example oxyphenbutazone may be formulated for oral administration in tablets containing 100 mg oxyphenbutazone as described in USP 23, pages 1140-1141. Oxyphenbutazone, as available commercially, may be used in this regard. It is especially preferred to use oxyphenbutazone that has been stored for at least some hours after preparation and purification. The invention will now be illustrated further by the following non-limiting Example and with reference to the accompanying figures in which: Figure 1 is a graph showing the potentiation of HIV replication suppression by the combination of oxyphenbutazone and indinavir. Example 1 Oral Suspension Gram oxyphenbutazone hydrate 10 carboxymethyl cellulose 1.5 sorbitol 200 sodium benzoate 1.0 orange essence 0.3 apricot essence 0.7 ethanol 50 water 236.5 Carboxymethyl cellulose, sorbitol and sodium benzoate are dissolved in water with stirring for 2 hours. A solution of the essences in ethanol is added. Oxyphenbutazone hydrate is milled, screened through a 0.15 mm sieve and dispersed in the solution under vigorous stirring. The suspension (10 gram) is filled in a 20 ml tube. Each tube contains 200 mg active compound . Example 2 Capsules oxyphenbutazone hydrate 50 mg amylum maydis q.s. Oxyphenbutazone hydrate (USP 23) is mixed with amylum maydis and filled into hard gelatin capsules. Each capsule contains 50 mg of oxyphenbutazone hydrate. The capsules are administered orally in doses of 50 to 500 mg daily to prevent/treat HIV- infection/AIDS . Example 3 Enteric Coated Tablets Gram oxyphenbutazone hydrate 500 hydroxypropylmethyl 120 cellulose lactose 45 povidone 30 magnesium stearate 5 cellulose acetate phthalate q.s Oxyphenbutazone hydrate, hydroxypropylmethyl-cellulose and lactose are mixed together for 20 minutes and granulated with a solution of povidone, magnesium stearate is added and the mixture is compressed into tablets. The tablet diameter is 13 mm. The tablets are coated by spray drying with a solution of cellulose acetate phthalate. Tablet weight is 700 mg and each tablet contains 500 mg oxyphenbutazone. The tablets are administered orally in doses of 250 mg to 2.5 g daily to prevent/treat HIV-infection/AIDS . Polyvinyl acetate phthalate or acrylates (e.g. Eudragit ® ) may be used in place of the cellulose acetate phthalate as the enteric coating material. Example 4 Combination therapy with oxyphenbutazone and indinavir 162 mg oxyphenbutazone (OPB) , 19 g homogenized rat liver (LH) and 20 ml acetate buffer were incubated for 14 hours at 37°C at a pH below 6. After one night incubation, dimethylformamide (DMF) was added to the reaction mixture to obtain a final concentration of DMF of 50% and a concentration of OPB of 10 mM. The mixture was prefiltered and sterile filtered twice. Indinavir (Crixivan ® ) , extracted from tablets, was dissolved in water at a concentration of ImM and sterile filtered. Indinavir and OPB were added to wells in a culture plate at concentrations of 0 to 100 μM. The isotonicity was corrected for wells receiving 100 μM. 60000 growing MT4 cells were seeded per well. The wells were also seeded with HIV at a concentration of about 1/3 viral particles per cell. The cell contents were brought to room temperature after 48 hours and soon after tested for development of HIV antigen using the Abbott's HIV antigen test. Dispersion of normal cell clamping from zero to complete at 48 hours (on a scale of 0 to 4) was as set out in Table 1 below. Table 1 Antigen development (E* dilution) was as set forth in Table 2 below: Table 2 The mean is geometrical mean of two parallels and the control without any addition is the mean of 4 values. There was observed an effect of LH (liver homogenate) treated OPB on the replication of HIV. When using indinavir there was observed an increased effect on inhibition of HIV replication by the use of LH treated OPB. The effect oxyphenbutazone (OPB) treated with rat liver homogenate (OPB-LH) for 14 hours at 37°C at pH <6 on HIV replication (E=extinction multiplied with dilution of sample) is shown in Figure 1 of the accompanying drawings. There is a good effect at 100 μM. The effect of indinavir on HIV replication is appreciably increased by LH-OPB concentrations as low as lμM.

Claims: Claims 1. A method of treatment of a human or non-human mammal subject to combat a retroviral infection, said method comprising administering to said subject an antivirally effective amount of a compound selected from oxyphenbutazone and other substituted-phenyl phenbutazones and substituted-phenyl prodrugs for oxyphenbutazone and other substituted phenyl phenbutazones . 2. A method as claimed in claim 1 wherein said compound is oxyphenbutazone. 3. A method as claimed in claim 2 wherein oxyphenbutazone is administered orally in an amorphous form. 4. A method as claimed in either of claims 2 and 3 wherein oxyphenbutazone is administered orally in a delayed release dosage form. 5. A method as claimed in any one of claims 1 to 4 wherein there is also administered an antivirally effective amount of a further antiviral compound. 6. A method as claimed in claim 5 wherein said further compound is an anti-HIV agent. 7. A method as claimed in claim 6 wherein said anti- HIV agent is selected from reverse transcriptase inhibitors and protease inhibitors. 8. A method as claimed in claim 6 wherein said anti- HIV agent is indinavir. 9. A method as claimed in any one of claims 1 to 8 wherein phenbutazone is also administered. 10. A method as claimed in any one of the preceding claims for the treatment of viral infections other than HIV. 11. The use of a compound selected from oxyphenbutazone and other substituted-phenyl phenbutazones and substituted-phenyl prodrugs for oxyphenbutazone and other substituted phenyl phenbutazones for the manufacture of a medicament for use in treatment to combat retroviral infection. 12. Use as claimed in claim 11 of oxyphenbutazone. 13. Use as claimed in claim 12 of oxyphenbutazone and phenbutazone for the manufacture of said medicament. 14. Use as claimed in either of claims 12 and 13 of oxyphenbutazone and an anti-HIV agent for the manufacture of said medicament. 15. Use as claimed in claim 14 of oxyphenbutazone and indinavir. 16. Use as claimed in any one of claims 12 to 15 for the manufacture of said medicament in a form adapted for oral administration. 17. Use as claimed in claim 16 of amorphous oxyphenbutazone . 18. Use as claimed in either of claims 16 and 17 for the manufacture of a delayed release dosage form. 19. A pharmaceutical composition comprising a compound selected from oxyphenbutazone and substituted-phenyl phenbutazones and substituted-phenyl prodrugs for oxyphenbutazone and other substituted phenyl phenbutazones together with a further anti-HIV drug and at least one pharmaceutical carrier or excipient. 20. A composition as claimed in claim 19 comprising oxyphenbutazone and a reverse transcriptase inhibitor and/or a protease inhibitor. 21. A composition as claimed in claim 20 comprising at least one of zidovudine, didanovine, zalcitabine, stavudine, lamivudine, nevirapine, delavirdine, indinavir, ritonavir and nelfinavir. 22. A composition as claimed in claim 21 comprising oxyphenbutazone and indinavir. 23. A composition as claimed in any one of claims 19 to 22 comprising oxyphenbutazone and phenbutazone. 24. A method of prophylaxis of a human or non-human mammal subject to combat a retroviral infection, said method comprising administering to said subject an antivirally effective amount of phenbutazone. 25. The use of phenbutazone for the manufacture of a medicament for use in prophylactic treatment to combat retroviral infection.

Inventors: KLAVENESS JO, TJOETTA ENOK, KLAVENESS, JO, TJOETTA, ENOK
Applicants: COCKBAIN JULIAN, KLAVENESS JO, TJOETTA ENOK, VIRAL AS A, A-VIRAL AS, COCKBAIN, JULIAN, KLAVENESS, JO, TJOETTA, ENOK
Application year: 1999
Main classification: A61K31
IPC codes: A61K31, A61K45, A61P31, C07D231