PAROMOMYCIN OR DERIVATIVES THEREOF FOR PARENTERAL TREATMENT OF HUMAN PARASITIC DISEASES

Abstract: A compound of formula (I), wherein R1 is a hydroxy group or an amino group optionally substituted with a C1-C4 alkyl or phenyl-(C1-C4)alkyl group, R2 is hydrogen or a hydroxy group, R3 is hydrogen or chlorine, R4 is hydrogen or a hydroxy or amino group, R5 is hydrogen or a hydroxy group, and R6 is hydrogen or a hydroxy group, or a non-toxic acid addition salt thereof, is useful in the parenteral treatment of visceral leishmaniasis or malaria, and a synergistic composition comprising a compound of formula (I) or a non-toxic acid addition salt thereof and sodium stibogluconate is useful in the treatment of visceral leishmaniasis.

Description: PAROMOMYCIN OR ITS DERIVATIVES OR SALTS THEREOF FOR PARENTERAL TREATMENT OF HUMAN PARASITIC DISEASES The present invention relates to the use of paromomycin or a derivative or non-toxic acid addition salt thereof for use in the manufacture of a medicament for the parenteral treatment of certain diseases. Both Malaria and Leishmaniasis are included by W.H.O. among the six major tropical diseases against which a special programme was launched in 1974. Malaria is still one of the major parasitic diseases in the world. It is distributed nowadays in about one hundred different countries (W.H.O., Wkly Epid. Rec:, 62:157, 1987), with acute clinical manifestations affecting some 90 to 100 million people per year, according to W.H.O. estimates; in addition, more than 40 percent of the world population live in zones where malaria is endemic and are therefore at risk of infection (World Health Statistical Quarterly, 37:130, 1984). Human malaria is caused by four species of Plasmodium, namely P. falciparum, P. vivax, P. malariae and P. ovale, each of which present a diverse and characteristic clinical entity (COOK G.C., Prevention and treatment of malaria, Lancet, 1:32, 1988). In most endemic zones of the world, the prevailing parasite is P. falciparum, which causes the most severe form of the disease which is often fatal in children (Cohen S. and Lambert P.H. in Immunology of Parasitic Infection, S. Cohen and K. Warren Eds, Blackwell Oxford, pag. 422, 1982). In spite of the availability of different antimalarial drugs, serious problems concerning chemoprophylaxis and chemotherapy are arising due to the emergence of a P. falciparum strain resistant to the major antimalarial drugs and for this reason new effective drugs are necessary (W.H.O., Advances in Malaria Chemotherapy, Techn. Rep. Ser. 711, 1984). The leishmaniases Human leishmaniasis is caused by at least 14 different species and subspecies of genus Leishmania, a flagellate protozoan parasite. The clinical manifestations of the disease depend on the infecting Leishmania organism and fall into three major forms: visceral, mucocutaneous and cutaneous. (Seveneh Programme Report of Tropical Diseases Research, Chapter 7, The Leishmaniases - UNDP/World Bank, W.H.O. 1985). Visceral Lieshmaniasis, in which the parasite invades internal organs such as the spleen, liver or bone marrow, is often fatal. The visceral disease, caused by L. donovani, L. donovani infantum and L. chagasi, is endemic in several parts of Africa, the Indian subcontinent and Latin America, and it occurs sporadically in China, the flediterranean basin, South-West Asia and the Southern regions of the Soviet Union. Few drugs are available for the treatment of Leishmaniases and those which are have been known for some time, namely pentavalent antimonials, considered as first-line drugs, and pentamidine or Amphoterian B, considered as second-line drugs (McGreevy P.B. and Marsden P.D.: American Trypanosomiasis and Leishmaniasis, in chemotherapy of Parasitic Diseases, Campbell W.C. and Rew R.S. Eds, Plenum Press, New York and London, 1986). However, these drugs are fairly toxic and their activity is variable. Sodium stibogluconate, used on its own in the treatment of visceral leishmaniasis, may give a cure rate of about 80% when administered parenterally in doses of 20 mg/kg body weight over 30 days. However, difficult cases due to primary unresponsiveness and/or relapse require additional treatment with allopurinol and the sodium stibogluconate for at least a further 30 days. This treatment requires prolonged hospitalisation. Paromomycin I (Aminosidine) sulphate is an aminoglycoside antibiotic which became commercially available in the sixties. It is mainly used in humans by the oral route to treat diarrhoeal diseases, in the management of hepatic coma or preoperatively for bowel preparation. It is also used in the treatment of the infection of various tapeworms. Being also directly amebicidal, Paromomycin I sulphate is also used as above and with other drugs to treat, by the oral route, asymptomatic as well as acute and chronic intestinal amebiasis. Due to its broad spectrum antibacterial activity it can also be used by the parenteral route (Gabbromycin (Trade mark of Farmitalia Carlo Erba)) to treat infections caused by susceptible bacteria. EP-A-90,587 describes a topical composition containing paromomycin sulphate, dimethylsulphoxide and/or quaternary ammonium salts for the treatment of cutaneous leishmaniasis. It has now surprisingly been found that parenteral administration of paromomycin or certain derivatives thereof gives an effective treatment against symptomatic and asymptomatic malaria by Plasmodium falciparum and also against visceral leishmaniasis, especially in humans. The present invention therefore provides use of a compound of formula (I): EMI4.1 wherein: R1 is a hydroxy group or an amino group optionally substituted with a C1 -C4 alkyl or phenyl (C1 -C4) alkyl group, R2 is hydrogen or a hydroxy group, R3 is hydrogen or chlorine, R4 is hydrogen or a hydroxy or amino group, R5 is hydrogen or a hydroxy group, and R6 is hydrogen or a hydroxy group, or a non-toxic acid addition salt thereof in the manufacture of a medicament for the parenteral treatment or prophylaxis of visceral leishmaniasis. The present invention also provides use of a compound of formula (I) or a non-toxic acid addition salt thereof in the manufacture of a medicament for the parenteral treatment or prophylaxis of malaria. The present invention further provides a compound of formula (I) or a non-toxic acid addition salt thereof for the parenteral treatment or prophylaxis of visceral leishmaniasis. The present invention also provides a compound of formula (I) or a non-toxic acid addition salt thereof for the parenteral treatment or prophylaxis of malaria. The compounds of formula (I) and salts thereof are agents for treating malaria or visceral leishmaniasis. They may be used to alleviate the condition of a patient, typically a human patient, suffering from malaria or visceral leishmaniasis. In formula (I) examples of suitable groups represented by R1 are ethylamino and phenylpropylamino groups. Preferred compounds are shown in the following Table, after which the references previously describing them are also given. These references are herein incorporated by reference. EMI6.1 <tb> Name <SEP> R1 <SEP> R2 <SEP> R3 <SEP> R4 <SEP> R5 <SEP> R6 <SEP> Ref. <tb> 1) <SEP> PAROMOMYCIN <SEP> I <SEP> -NH2 <SEP> -OH <SEP> -H <SEP> -OH <SEP> -OH <SEP> -OH <SEP> 1.2 <tb> 2) <SEP> 2'-N-ETHYL <SEP> -NH-CH2CH3 <SEP> -OH <SEP> -H <SEP> -OH <SEP> -OH <SEP> -OH <SEP> 3 <tb> <SEP> PAROMOMYCIN <tb> 3) <SEP> 2'-N-(3-PHENYL) <tb> <SEP> PAROMOMYCIN <SEP> I <SEP> -NH-CH2-CH2-CH2-PH <SEP> -OH <SEP> -H <SEP> -OH <SEP> -OH <SEP> -OH <SEP> 3 <tb> 4) <SEP> 6'-DEOXY <tb> <SEP> PAROMOMYCIN <SEP> I <SEP> -NH2 <SEP> -OH <SEP> -H <SEP> -H <SEP> -OH <SEP> -OH <SEP> 4 <tb> 5) <SEP> 6',5"-DIDEOXY <tb> <SEP> -PAROMOMYCIN <SEP> I <SEP> -NH2 <SEP> -OH <SEP> -H <SEP> -H <SEP> -H <SEP> -OH <SEP> 4 <tb> 6) <SEP> COMPOUND <SEP> 224 <SEP> -OH <SEP> -OH <SEP> -H <SEP> -NH2 <SEP> -OH <SEP> -OH <SEP> 5 <tb> <SEP> 4-0-(6-amino <tb> <SEP> -6-deoxy-&alpha; ;-D- <tb> <SEP> -glucopyranosyl) <tb> <SEP> -5-0-[3-0-(2,6 <tb> <SEP> -diamino-2,6 <tb> <SEP> -dideoxy-ss-L-ido <tb> <SEP> pyranosyl)-ss-D <tb> <SEP> -ribofuranosyl] <tb> <SEP> -2-deoxy <SEP> strepta <tb> <SEP> mina <tb> 7) <SEP> 4'-DEOXYPAROMOMY- <SEP> -NH2 <SEP> -H <SEP> -H <SEP> -OH <SEP> -OH <SEP> -OH <SEP> 6 <tb> <SEP> CIN <SEP> I <tb> 8) <SEP> 4'-DEOXY-4' <tb> <SEP> -EPICHLORO <tb> <SEP> -PAROMOMYCIN <SEP> I <SEP> -NH2 <SEP> -H <SEP> -Cl <SEP> -OH <SEP> -OH <SEP> -OH <SEP> 6 <tb> 9) <SEP> 4'-4"-DIDEOXY <tb> <SEP> PAROMOMYCIN <SEP> I <SEP> -NH2 <SEP> -H <SEP> -H <SEP> -OH <SEP> -OH <SEP> -H <SEP> 7 <tb> 1. Frohardt et al. US-A-2,916,485 2. Arcamone et al. US-A-3,065,147 3. F. Arcamone and G. Cassinelli, US-A-4,021,601 (May 3, 1977) 4. F. Arcamone and G. Cassinelli, GB-A-1,464,684 (June 15, 1977) 5. F. Arcamone and G. Cassinelli, US-A-4,125,707 (Nov. 14, 1978) 6. C. Battistini, G. Cassinelli et al, US-A-4,337,248 (June 29, 1982) 7. C. Battistini, G. Cassinelli et al, GB-A-2,068,367 (Aug. 12, 1981). The other derivatives may be prepared by obvious modifications of the synthetic methods described in these references. The preferred compound of formula (I) is paromomycin, and the preferred salt is the sulphate. The most preferred compound is paromomycin sulphate. The parenteral administration may be, for example, intramuscular or intravenous administration. The present invention also provides a composition for or suitable for parenteral administration for the treatment or prophylaxis of malaria, which comprises a compound of formula (I) or a non-toxic acid addition salt thereof and a pharmaceutically acceptable diluent. The present invention also provides a composition for the parenteral treatment or prophylaxis of visceral leishmaniasis which comprises a compound of formula (1) or a non-toxic acid addition salt thereof and a pharmaceutically acceptable diluent. Conventional diluents such as Water for Injections may be used. The composition may be formulated and administered in a manner conventionally employed in the art. The composition may also comprise other agents effective in the parenteral treatment or prophylaxis of malaria or visceral leishmaniasis. It is surprisingly possible to treat successfully a greater proportion of subjects suffering from visceral leishmaniasis with a mixture of the compound of formula (I) and sodium stibogluconate than with either compound separately. The present invention therefore provides a composition for parenteral administration for the treatment or prophylaxis of visceral leishmaniasis which comprises a compound of formula (I) or a non-toxic acid addiction salt thereof, sodium stibogluconate and a pharmaceutically acceptable diluent. The compound of formula (I) or salt thereof and the sodium stibogluconate are generally administered in a weight ratio from 1:9 to 9:1, preferably 3:7 to 7:3, more preferably 4:6 to 6:4. An especially preferred weight ratio is about 4:5, such that the compound of formula (I) or salt thereof may be administered in an amount of about 16 mg/kg body weight/day and the sodium stibogluconate may be administered in an amount of about 20 mg/kg body weight/day. The compound of formula (I) or salt thereof and the sodium stibogluconate may be administered together in the same composition or separately simultaneously or sequentially. The present invention provides a composition suitable for parenteral administration for the treatment or prophylaxis of visceral leishmaniasis, which composition comprises a compound of formula (I) or a non-toxic acid addition salt thereof, sodium stibogluconate and a pharmaceutically acceptable diluent, the weight ratio of the compound of formula (I) or salt thereof to the sodium stibogluconate being from 1:9 to 9:1. The composition may be prepared by simply mixing together all the components. A suitable method of treatment of visceral leishmaniasis comprises administering to a subject suffering or liable to suffer therefrom an effective amount of a compound of formula (I) or a non-toxic acid addition salt thereof by a parenteral route. A further suitable method of treatment of visceral leishmaniasis comprises administering to a subject suffering or liable to suffer therefrom an effective amount of a compound of formula (I) or a non-toxic acid addition salt thereof and sodium stibogluconate by parenteral routes. A suitable method of treatment of malaria comprises administering to a subject suffering or liable to suffer therefrom an effective amount of a compound of formula (I) or a non-toxic acid addition salt thereof by a parenteral route. A suitable dosage range for the parenteral route is from 1 to 50 mg/kg body weight/day, preferably 10 to 20 mg/kg body weight/day, more preferably about 14 to 16 mg/kg body weight/day, of the compound of formula (I) or salt thereof for the treatment of visceral leishmaniasis or malaria. The sodium stibogluconate may be administered parenterally in amounts conventially used, for example about 20 mg/kg body weight/day. The present invention also provides a process for preparing pharmaceutical compositions containing a compound of formula (I) or a non-toxic acid addition salt thereof as active agent, characterized in that the active agent, which has been prepared in a known way, is admixed with a pharmaceutically acceptable diluent and then transformed to a pharmaceutical preparation suitable for treating visceral leishmaniasis or malaria. The efficacy of Paromomycin I sulphate for parenteral treatment of human parasitic diseases, has been demonstrated by the comparative clinical trials in the following Examples. The drug used was Gabbromycin supplied by Farmitalia Carlo Erba, comprising: (a) Vial containing Paromomycin I sulphate 500 mg (b) Ampoule containing Water for Injections 4 ml EXAMPLE 1 Study in asymptomatic human carriers of Plasmodium falciparum The results, reported in Table 1, show that in asymptomatic school children, living in an area of hyperendemicity, a 16mg/kg single dose of aminosidine sulphate (maximum 1 gram) administered by the intramuscular route, cleared 100% of the treated patients from parasites, while lower percentages of cleared patients were obtained upon conventional oral treatment with chloroquine and metakelfin, two primary antimalarial chemotherapeutic agents. TABLE 1 - H@@@@@cin I sulphate in asymptomatic human carriers of P.falciparum EMI12.1 DRUG <SEP> AND <SEP> ROUTE <SEP> NUMBER <SEP> OF <SEP> AGE <SEP> DOSAGE <SEP> PARASITE <SEP> COUNT <SEP> (MEAN)/ml <SEP> PATIENTS <SEP> % <SEP> OF <SEP> PATIENTS <tb> OF <SEP> ADMINISTRATION <SEP> PATIENTS <SEP> RANGE <SEP> SCHEDULE <SEP> INITIAL <SEP> POST <SEP> POST <SEP> CLEARED <SEP> CLEARED <tb> THERAPY <SEP> THERAPY <SEP> (NUMBER) <tb> Placebo <SEP> i.m. <tb> (saline <SEP> solution) <SEP> 13 <SEP> 10-17 <SEP> 5 <SEP> ml <SEP> 2080 <SEP> 96 <SEP> 216 <SEP> 8 <SEP> 61.5 <tb> single <SEP> dose <tb> Chloroquine <tb> p.o. <SEP> 11 <SEP> 12-16 <SEP> 25 <SEP> mg/kg <SEP> b.w. <SEP> 3600 <SEP> 8 <SEP> 24 <SEP> 10 <SEP> 91 <tb> in <SEP> 3 <SEP> days <tb> Metakelfin <tb> p.o. <SEP> 14 <SEP> 7-10 <SEP> 17.5 <SEP> mg/kg <SEP> 2400 <SEP> 128 <SEP> 8 <SEP> 13 <SEP> 93 <tb> b.w. <SEP> single <tb> dose <tb> (Max <SEP> 1050 <SEP> mg) <tb> GABBROMYCIN <SEP> i.m. <SEP> 43 <SEP> 8-17 <SEP> 16 <SEP> mg/kg <SEP> 3520 <SEP> 96 <SEP> 0 <SEP> 43 <SEP> 100 <tb> b.w. <SEP> single <tb> dose <tb> (Max <SEP> 1000 <SEP> mg) <tb> EXAMPLE 2 Study in human symptomatic malaria by Plasmodium falciparum The results, reported in Table 2, show that, in symptomatic malaria by Plasmodium falciparum, the efficacy of a 16 mg/kg single dose treatment (maximum 1 gram) of Paromomycin I sulphate by the intramuscular route is, in treated patients, higher that of chloroquine, and what is more, a complete cure was also achieved in patients previously and unsuccessfully treated with chloroquine, sulphamethoxypyrazine (Metakelfin (Trade Mark)) and pyrimethamine-sulphodoxime (Fansidar (Trade Mark)), the most commonly used antimalarial drugs. These results indicate that Paromomycin I sulphate administered by the parenteral route is highly effective in the treatment of malaria by P. falciparum strains resistant to primary antimalarial drugs. TABLE 2 - Paromomycin I sulphate in human symptomatic malaria by P. falciparum EMI14.1 CATEGORY <SEP> OF <SEP> NUMBER <SEP> AGE <SEP> DOSAGE <SEP> PARASITE <SEP> COUNT/ml <SEP> (MEAN) <SEP> NO. <SEP> OF <SEP> PATIENTS <SEP> % <SEP> OF <SEP> PATIENTS <tb> PATIENTS <SEP> AND <SEP> OF <SEP> RANGE <SEP> SCHEDULE <SEP> AND <SEP> CURED <SEP> CURED <tb> DRUG <SEP> PATIENTS <SEP> ROUTE <SEP> OF <SEP> BEFORE <SEP> 48HRS <tb> ADMINISTRATION <SEP> THERAPY <SEP> POST <SEP> THERAPY <tb> Chloroquine <SEP> 9 <SEP> 2-44 <SEP> 25 <SEP> mg/kg <SEP> b.w. <SEP> 4880 <SEP> 48 <SEP> 7 <SEP> 78 <tb> in <SEP> previously <SEP> in <SEP> 3 <SEP> days <tb> untreated <SEP> (Max <SEP> 1.5 <SEP> mg)p.o. <tb> patients <tb> Gabbromycin <SEP> 8 <SEP> 1-54 <SEP> 16 <SEP> mg/kg <SEP> b.w. <SEP> 5440 <SEP> 0 <SEP> 8 <SEP> 100 <tb> previously <SEP> single <SEP> dose <tb> untreated <SEP> (Max <SEP> 1 <SEP> g) <SEP> i.m. <tb> patients <tb> Gabbromycin <SEP> 6 <SEP> 9-34 <SEP> as <SEP> above <SEP> 4960 <SEP> 0 <SEP> 6 <SEP> 100 <tb> patients <tb> previously <tb> treated <SEP> with <tb> chloroquine <tb> Gabbromycin <SEP> 1 <SEP> 28 <SEP> as <SEP> above <SEP> 3520 <SEP> 0 <SEP> 1 <SEP> 100 <tb> patients <tb> previously <tb> treated <SEP> with <tb> Metakelfin <tb> Gabbromycin <tb> patients <tb> previously <SEP> treated <tb> with <SEP> Fansidar <SEP> 2 <SEP> 15-36 <SEP> as <SEP> above <SEP> 5680 <SEP> 0 <SEP> 2 <SEP> 100 <tb> EXAMPLE 3 Studies in human leishmaniasis Studies in human patients have been carried out in respect of visceral leishmaniasis. A comparative trial, carried out in patients affected by visceral leishmaniasis with sodium stibogluconate (Pentostam (Trade Mark)) alone (20 mg/kg b.w./die for more than 20 days), Gabbromycin alone (16 mg/kg b.w./die for 20 days maximum 1 g per day) or a combination of the two drugs for 14 days administered by the intramuscular route, has given the following results (shown in Table 3): Pentostam alone cured 10/13 patients, but 3/10 of patients cured had a relapse within 2 months after the end of the therapy. Gabbromycin alone cured 10/12 patients without any relapses among the cured patients. The combination cured 16/16 patients with one relapse in a patient treated for only 11 days but the patient was definitely cured after a second cycle of treatment. TABLE 3 - Paromomycin I sulphate in visceral leishmaniasis EMI16.1 DRUG <SEP> NUMBER <SEP> OF <SEP> DOSAGE <SEP> DAYS <SEP> OF <SEP> NUMBER <SEP> OF <SEP> % <SEP> PATIENTS <SEP> NUMBER <SEP> OF <tb> PATIENTS <SEP> SCHEDULE <SEP> TREATMENT <SEP> PATIENTS <SEP> CURED <SEP> CURED <SEP> RELAPSES <tb> PENTOSTAM <SEP> 13 <SEP> 20 <SEP> mg/kg/day <SEP> 20 <SEP> 10 <SEP> 77 <SEP> 3 <SEP> (30%) <tb> i.m. <tb> GABBROMYCIN <SEP> 12 <SEP> 16 <SEP> mg/kg/day <SEP> 20 <SEP> 10 <SEP> 84 <SEP> 0 <tb> i.m. <tb> Maximum: <SEP> 1 <SEP> g <tb> PENTOSTAM <SEP> 16 <SEP> 20 <SEP> mg/kg/day <SEP> 14 <SEP> 16 <SEP> 100 <SEP> 1* <tb> + <SEP> + <tb> GABBROMYCIN <SEP> 16 <SEP> mg/kg/day <tb> i.m. <tb> * Patient treated only for 11 days and cured definitively after a second complete cycle of therapy EXAMPLE 4 Studies in human leishmaniasis Patients newly diagnosed with visceral leishmaniasis, confirmed by the presence of leishmaniasis amastigotes in spleen aspirates, were allocated randomly to groups subjected to the following treatments: 1) IV/IM sodium stibogluconate (SbV) 20 mg/kg body weight once per day; 2) IM paromomycin sulphate (PM) 14-16 mg/kg body weight once per day; 3) IV/IM sodium stibogluconate 20 mg/kg body weight once per day and paromomycin sulphate 14-16 mg/kg body weight once per day. All treatments were administered until the first negative spleen aspirate was obtained, or for 20 consecutive days regardless of aspirate findings. Exclusion criteria were: age 3 years; known allergy to aminoglycoside comounds: pregnancy; haemoglobin assay below 40 g/l; abnormal prothrombin time; impaired liver or renal function; major concurrent infection; previous drug treatment for leishmaniasis; and a spleen smear-parasite grading of less than 4+. The following procedures were conducted for patient assessment at intake and at suitable intervals during and after treatment: clinical history writeup: physical examination: body weight: chest X-ray: ECG tracing: liver and kidney function tests: blood picture and blood smears (to rule out malaria): complete urinalysis: stool examination: prothrombin time: and spleen aspirate smear examination by the method of Chulay & Bryceson, Quantitations of amastigotes of leishmania donovani in smears of splenic aspirates from patients with visceral leishmaniasis, American Journal of Tropical Medicine and Hygiene, 32, 1983, 475-479. Follow-up examinations were given 2 and 6 months after termination of treatment, since relapses after this period were found to be rare (Manson Bahr, East Africa kala-azar with special reference to the pathology, prophylaxis and treatment, Transactions of the Royal Society of Tropical Medicine and Hygiene, 53, 1956, 123-137, and Oster, Advances in clinical diagnosis and chemotherapy of leishmaniasis in Kenya, Insect Science Applications, 7, 1968, 235-240). Treatment of effectiveness was graded under the following headings Clinical cure: complete abatement of initial symptoms with marked reduction of spleen size; Partial cure: persistence of low parasite counts in terminal spleen aspirates; Apparent cure: negative spleen aspirate smears at termination of treatment; Relapse: reappearance of leishmanial parasites after an apparent cure; Definite cure: persisting clinical cure with negative spleen aspirates 6 months after termination of treatment; Failures: partial cures and relapses. Drug safety was assessed for each treatment regime in terms of incidence of drug-related signs and symptoms and of laboratory test results return abnormalities. The assembled data were processed statistically by the Fishes exact test (chi-square) and Pearson's correlation coefficient. Results A total of 56 patients were entered. Of these, two died during the follow-up period, one from fulminating oral thrush and one from trauma, and one patient failed to report. This left 53 assessable patients, namely 37 males and 16 females, age range 3-36 years, mean age 18. Clinical manifestations at intake were fever, weakness, enlarged liver and spleen, pallor, and tachycardia in all patients; plus malnutrition in 95%, cough in 62%, jaundice in 25% and ankle oedema in 14%. Complicating factors present at intake or emerging in the course of treatment included epistaxis, pneumonia, uveltis throat infection, and chest pain, as reported in Chung et al., Complications of kala-azar and its treatment in Kenya, East African Medical Journal, 61, 1984, 120-127. Fever was the first symptom to abate, usually after 24 to 60 hours of starting treatment; splenomegaly was the last. At 2 and 6 month follow-up examination, the spleen was still moderately enlarged respectively in 20 and 5% of treated patients. Body weight tended to drop in the first 10 days of treatment and pick up later, to return to normal by the first (2 month) re-check (Table 4). Ankle oedema abated in the first 10 days of treatment. The incidence of epistaxis was significantly reduced by treatment with vitamin K (10 mg daily for 5 days) in patients with low initial haemoglobin as says and prolonged prothrombin time readings. Uveitis with ocular pain and blurred vision was present at intake in 22.5% of the patients; it abated without specific treatment as visceral leishmaniasis was cured. Bouts of pneumonia developed in 9 cases (-17%). Of these, 5 were on SbV alone and required antibiotic treatment; the remaining 4 were receiving PM and did not need additional antibiotic medication. Initial hematologic disorders (Table 4) consisted for the most part of depressed hematopolesis (WHO Expert Committee on Leishmaniasis, Technical Report Series 70, 1984) and pancytopenia (Kasli, Haematological abnormalities in visceral leishmaniasis, East African Medical Journal, 57, 1980, 634-640; Wasunna et al., Haematological changes in patients with visceral leishmaniasis, Proceedings of the 12th International Congress of Tropical Medicine and Malaria, Abstract ThP 5-3, page 270); both features showed improvement as the underlying leishmaniasis was cured. All patients had zero eosinophil counts at intake; the reappearance of peripheral blood was taken to connote a good prognosis (Lyerly et al., Eosinophilis as prognostic indicator in East African kala-azar., Proceedings of the 2nd Annual Medical Scientific Conference, KEMRI/KETRI, 1981, 54-81). Blood biochemistry (Table 5) was not much altered at intake. With treatment, total blood bilirubin and BUN assays fell gradually, and serum albumin increased likewise. Table 6 displays patient characteristics, drug effectiveness and drug safety data for the 3 treatment groups. The initial spleen parasite grading averaged 5+ in all three groups. At termination, all three groups yielded 100% clinical cures. Some partial cures occurred in patients treated with PM alone or SbV alone; even in those, however, spleen parasite gradings never exceeded 1+. All patients treated with PM + SbV made apparent cures. The least incidence of relapses was seen in the PM treatment group, rising in the PM + SbV group and further in the SbV group; the difference between PM and SbV was highly significant (P < 0.01). The highest proportion of definite cures was seen in the PM + SbV treatment group, followed by the PM and SbV groups in that order. The cure rate at 6 months follow up examination was significantly higher in the PM and PM + SbV treatment groups than in the SbV group (P < 0.01 for both differences). EXPERIMENTAL DISCUSSION All three drug regimes resulted in the complete abatement of signs and symptoms (clinical cure) in all patients, with no detectable differences between treatment groups. Conversely, some important differences emerged in terms of parasitologic cures. Here the superiority of PM alone or combined with pentavalent antimonium is apparent. Treatment with SbV alone proved by far the least effective of all, with fully 45.5% failures. in the same experimental conditions PM alone or combined with SbV afforded the best results (Table 6). With the same treatment duration PM alone contributed the highest share of partial cures but also the smallest share of relapses, so that the total incidence of failures was only 21%. The combined PM + SbV regime resulted in materially earlier clearing of spleen parasites and produced the least failure rate (13% between partial cures and relapses). Thus the two drugs seem to act synergistically. The optimal duration of SbV treatment is still the object of debate, apparently changing from one area to another and from one patient to another (WHO Expert Committee on Leishmaniasis, 1984 supra). In India, the duration of SbV treatment has been shown to correlate positively with the cure rate; in a comparative trial the best results (only 8% failures) were obtained with 20 mg SbV/kg daily administered for 40 days (Thakur et al, Rationalization of regimens of treatment of Kala-azar with sodium stibogluconate in India: a randomized study, British Medical Journal, 296, 1988, 1557-1559). Obviously a treatment period of that length would create compliance problems in the prevalent condition of tropical countries. In our own study the combined PM + SbV regime gave the best results (13% failure) when administered for an average 14 days. This, plus the low rate of relapses seen with PM administered alone for 19 days, suggests that the incidence of relapses with the PM + SbV regime might show further reduction by adding a few extra days of treatment. The difference in terms of cure rates between SbV and PM alone or combined was highly significant (P < 0.01). The choice between drug regimes may be based on cost and side effects considerations. PM is an inexpensive drug and caused no side effects in our study. SbV is expensive, more so for the PM + SbV combination where full dosage of both drugs are used. Furthermore, SbV produces distinctly more side effects. The synergism of action between PM and SbV makes it possible to obtain equally good therapeutic results with suitably reduced dosages, with obvious gains in terms of lower cost and fewer side effects. Additionally, the rate of definite cures might show further improvement with somewhat longer treatment periods, still materially shorter than those recommended for SbV therapy. TABLE 4 - Changes in the mean values of parametric indices during treatment and followup Eosinophil Hemoglobin Weight Temp Heart rate Spleen Parasite count/cu mm assay g/d1 kg C /minute size(cm) grading Sbv Day 0 0 7.6 33.2 38.5 112 14.5 5 Day 20 1 8.9 27.3 36.2 92 7 1 Day 75 1 11.6 36.7 36.9 80 5 1 PM Day 0 0 7.1 34.0 38.3 105 15.5 5 Day 20 2 10.0 37.0 36.1 84 8.4 1 Day 75 1 12.3 39.1 36.1 82 4.3 1 PM + SbV Day 0 0 7.4 36.2 38.0 106 13.4 5 Day 20 2 8.7 33.3 36.3 92 6.5 0 Day 75 2 10.7 40.2 36.3 80 4.1 1 TABLE 5 - Blood biochemistry data during the various treatments ASAT ALAT ALP Bilirubin BUN assay Creatinine Albumin I.U./1 I.U./1 I.U./1 umol/1 Sbv Day 0 20.2 25.4 87.6 6.4 8.2 73.6 31.3 Day 10 19.2 24.0 79.1 4.1 8.1 68.0 30.3 Day 20 21.0 22.0 71.0 3.8 4.0 53.0 29.5 Day 75 25.5 25.3 83.7 4.5 3.8 73.5 36.6 Day 195 22.0 23.0 84.0 4.0 4.0 78.9 40.0 PM Day 0 17.8 21.0 75.3 9.7 6.20 71.1 29.3 Day 10 19.9 23.4 76.7 8.3 4.0 59.5 32.1 Day 20 21.2 23.3 84.8 4.5 4.0 64.2 32.5 Day 75 18.0 26.0 66.0 3.0 4.8 85.0 37.0 Day 195 21.5 22.0 85.0 3.6 3.5 82.2 42.0 PM + Sbv Day 0 21.8 26.8 84.3 9.0 8.3 73.3 32.9 Day 10 21.0 26.0 85.8 3.3 4.4 99.2 33.9 Day 20 15.0 23.0 82.0 3.8 3.9 109.0 36.0 Day 75 17.0 23.7 73.7 3.2 4.9 72.2 37.0 Day 195 20.2 23.0 89.0 4.0 4.5 80.0 50.0 ASAT e Aspartate aminotransferase; ALAT - Alanine aminotransferase = Alkaline phosphatase TABLE 6 - Patient characteristics, clinical results and parasitologic returns in the various treatment groups TREATMENT GROUPS SbV PM PM + SbV Mean age, years 16.8 18.7 18.7 (Range) (4-48) (5-49) (3-63) Male 10 12 15 Female 1 7 8 Totals 11 19 23 Mean treatment duration, days 17 19 14 Parasitic grading at intake 5+ 5+ 5+ Clinical cures, No. (%) 11(100) 19(100) 23(100) Partial cures, No. (%) 1(9.1) 3(15.8) 0(0) Apparent cures, No. (%) 10(90.9) 16(84.2) 23(100) Relapses, No. (%) 4(36.4) 1(5.2) 3(13) Failures, No. (%) 5(45.5) 4(21) 3(13) Definite cures, No. (%) 6(54.5) 15(79) 20(87) Adverse effects, No.(%) 3(27) 0(0) 5(2)

Claims: CLAIMS 1. Use of a compound of formula (I): EMI28.1 wherein: R1 is a hydroxy group or an amino group optionally substituted with a C-C4 alkyl or phenyl-(C1-C4)alkyl group, R2 is hydrogen or a hydroxy group, R3 is hydrogen or chlorine, R4 is hydrogen or a hydroxy or amino group, R5 is hydrogen or a hydroxy group, and R6 is hy rogen or a hydroxy group, or a non-toxic acid addition salt thereof in the manufacture of a medicament for the parenteral treatment or prophylaxis of visceral leishmaniasis. 2e Use according to claim 1 wherein the compound of formula (I) is one in which: (a) Rl is -NH2, -NH-CH2CH3 or -NH-CH2CH2CH2-C6H5, R2, R4, R5 and R6 are each -OH and R3 is -H; (b) R1 is -NH2, R2 and R6 are each -OH, R3 and R4 are each -H and R5 is -OH or -H; (c) Rl, R2, R5 and R 6 are each -OH, R3 is -H and R4 is -NH2; (d) Rl is -NH2, R2 is -H, R3 is -H or -Cl and R4, R5 and R6 are each -OH; or (e) R1 is -NH2, R2, R3 and R6 are each -H and R4 and R5 are each -OH; or a non-toxic acid addition salt thereof. 3. Use according to claim 1 wherein the compound of formula (I) is paromomycin or a non-toxic acid addition salt thereof. 4. Use according to claim 1 wherein the acid addition salt is the sulphate. 5. Use according to claim 1 wherein the medicament also comprises sodium stibogluconate. 6. Use according to claim 5 wherein the weight ratio of the compound of formula (I) or salt thereof to the sodium stibogluconate is from 1:9 to 9:1. 7. Use according to claim 6 wherein the weight ratio is from 4:6 to 6:4. 8. Use according to claim 7 wherein the weight ratio is about 4:5 such as to provide a medicament adapted to be administered to a subject in an amount of about 16 mg/kg body weight/day of the compound of formula (I) or salt thereof and about 20 mg/kg body weight/day of sodium stibogluconate. 9. Use of a compound of formula (I) or a non-toxic acid addition salt thereof as defined in claim 1 in the manufacture of a medicament for the parenteral treatment or prophylaxis of malaria 10. A composition suitable for parenteral administration for the treatment or prophylaxis of visceral leishmaniasis, which composition comprises a compound of formula (I) or a non-toxic acid addition salt thereof as defined in claim l, sodium stibogluconate and a pharmaceutically acceptable diluent, the weight ratio of the compound of formula (1) or salt thereof to the sodium stibogluconate being from 1:9 to 9:1. lle A composition according to claim 10 wherein the weight ratio is from 4:6 to 6:4. 12. A process for preparing a composition as defined in claim 10 which comprises mixing together the compound of formula (I) or non-toxic acid addition salt thereof, the sodium stibogluconate and the pharmaceutically acceptable diluent. 13. A method of treatment of visceral leishmaniasis which comprises administering parenterally to a subject suffering or liable to suffer therefrom an effective amount of a compound of formula (I) or a non-toxic acid addition salt thereof as defined in claim 1. 14. A method treatment of visceral leishmaniasis which comprises administering parenterally to a subject suffering or liable to suffer therefrom synergistically effective amounts of a compound of formula (I) or a non-toxic acid addition salt thereof as defined in claim 1 and sodium stibogluconate. 15. A method of treatment of malaria which comprises administering parenterally to a subject suffering or liable to suffer therefrom an effective amount of a compound of formula (I) or a non-toxic acid addition salt thereof as defined in claim 1. 16. A composition for the parenteral treatment or prophylaxis of visceral leishmaniasis which comprises a compound of formula (I) or a non-toxic acid addition salt thereof as defined in claim 1 and a pharmaceutically acceptable diluent. 17. A composition according to claim 16 which also comprises sodium stibogluconate. 18. A composition for the parenteral treatment or prophylaxis of malaria which comprises a compound of formula (I) or a non-toxic acid addition salt thereof as defined in claim 1 and a pharmaceutically acceptable diluent. 19. A compound of formula (I) or a non-toxic acid addition salt thereof as defined in claim 1 for the parenteral treatment or prophylaxis of visceral leishmaniasis. 20. A compound of formula (I) or a non-toxic acid addition salt thereof as defined in claim 1 for the parenteral treatment or prophylaxis of malaria.

Inventors: CASSINELLI GIUSEPPE, DONNO LUIGI, CASSINELLI, GIUSEPPE, DONNO, LUIGI
Applicants: ERBA CARLO SPA, FARMITALIA CARLO ERBA S.R.L.
Application year: 1989
Main classification: A61K31
IPC codes: A61K31, A61K33, A61P33, C07H15