Jonathan D. Berman

Efficacy of ketoconazole against Leishmania braziliensis panamensis cutaneous leishmaniasis

PURPOSE, PATIENTS, AND METHODS The classic agent for cutaneous leishmaniasis is pentavalent antimony. However, there are no reports of the efficacy of antimony versus placebo or of the efficacy of any alternative therapy versus either antimony or placebo. In the present report, the oral antifungal agent ketoconazole (600 mg/day for 28 days) was compared to a recommended regimen of intramuscular Pentostam (20 mg antimony/kg, with a maximum of 850 mg antimony/day, for 20 days) in a randomized study of the treatment of Panamanian cutaneous leishmaniasis due to Leishmania braziliensis panamensis. A separate group of patients with this disease was administered placebo. RESULTS Ketoconazole clinically cured 16 of 21 (76%) patients. The lesions on nine patients healed by 1 month after therapy, and the lesions healed by 3 months after therapy on the other seven patients. Side effects were limited to a 27% incidence of mild, reversible hepatocellular enzyme elevation and an asymptomatic, reversible, approximately 70% decrease in serum testosterone in all patients. Pentostam cured 13 of 19 (68%) patients; the lesions on seven patients healed by the end of therapy, and the lesions on four other patients healed by 1 month after the end of therapy. Side effects were a 47% incidence of mild, reversible hepatocellular enzyme elevation and the morbidity due to 20 intramuscular injections in almost all patients. The placebo group of 11 patients had a 0% cure rate. By 1 month after therapy, all placebo-treated patients demonstrated new lesions or one lesion that was 23% to 875% larger than before therapy. CONCLUSION Both ketoconazole and Pentostam were more effective than placebo against L. braziliensis panamensis cutaneous leishmaniasis. Oral ketoconazole is comparable in efficacy to this parenteral Pentostam regimen and can be recommended as initial treatment for this disease.

Efficacy and Toxicity of Sodium Stibogluconate for Mucosal Leishmaniasis

OBJECTIVE To determine the efficacy and toxicity of the World Health Organizations (WHO) recommended treatment for mucosal leishmaniasis: antimony, 20 mg/kg body weight per day for 28 days. DESIGN Open trial with 12-month follow-up. SETTING Inpatient unit of a regional referral hospital in a developing country. PATIENTS Twenty-nine consecutive eligible patients with culture-confirmed infection of the mucosa with Leishmania species who were otherwise healthy. Eight patients (28%) had mild to moderate disease (confined to the nasal mucosa). Twenty-one patients (72%) had severe disease (including the oropharynx as well as the nasal mucosa). INTERVENTION Antimony, 20 mg/kg body weight intravenously every day for 28 days. Patients received antimony in the form of sodium stibogluconate. MEASUREMENTS AND MAIN RESULTS Initial results of therapy were as follows: 63 of 72 lesions (88%) healed or markedly improved; all lesions were culture-negative for parasites; and 18 of 29 patients (62%) showed complete clinical and parasitologic cure of all lesions. By the 12-month follow-up examinations, however, 37 lesions had recurred, 8 new lesions had appeared, and only 8 patients (30%) showed clinical cure of all lesions. Of the 8 patients with mild to moderate disease, 6 were cured compared with only 2 of the 21 patients with severe disease. Side effects of this treatment regimen included T-wave inversion on electrocardiogram (4 patients), abnormal liver function tests (10 patients), and musculoskeletal pain (24 patients). No side effects occurred during week 1 of therapy. CONCLUSIONS The only recommended treatment for mucosal leishmaniasis is ineffective in patients with severe disease. The acceptable toxicity of the regimen suggests that longer courses of therapy with antimony, or that trials with other antileishmanial agents alone or combined with antimony be evaluated as initial therapy for this disease.

SAFETY AND EFFICACY OF HIGH-DOSE SODIUM STIBOGLUCONATE THERAPY OF AMERICAN CUTANEOUS LEISHMANIASIS

40 patients with American cutaneous leishmaniasis caused primarily by Leishmania braziliensis panamensis were treated with sodium stibogluconate in a double-blind, randomised controlled trial. Nine weeks after starting treatment, all 19 patients treated with 20 mg Sb/kg per day for twenty days were cured but 5 of 21 patients treated with 10 mg Sb/kg per day for twenty days had persistent active disease (p less than 0.05). Both treatment regimens were well tolerated and they were associated with a similar incidence of reversible toxic effects. Existing recommendations for therapy of American cutaneous leishmaniasis with sodium stibogluconate are inadequate for some patients, and higher doses are both safe and efficacious.

Antileishmanial activity of liposome-encapsulated amphotericin B in hamsters and monkeys.

Visceral leishmaniasis (kala-azar) results from parasitization of the macrophages of the liver, spleen, and the rest of the visceral reticuloendothelial system with Leishmania donovani. Pentavalent antimony is the drug of choice for leishmaniasis chemotherapy; amphotericin B (AmB) is active but is rarely used, because of drug toxicity. AmB encapsulated within macrophage-directed carriers (liposomes) has been used to treat humans with systemic mycoses complicating neoplastic diseases; dosages of up to 5 mg of encapsulated AmB per kg per day for greater than 14 days are without apparent kidney or liver toxicity. In the present work, greater than 99% of L. donovani parasites were eliminated from the liver and spleen of infected hamsters by one administration of 1.5 to 11 mg of liposome-encapsulated AmB (L-Amb) per kg. A total of 98 to 99% of hepatosplenic parasites were eliminated from squirrel monkeys by three administrations of 4 mg of L-AmB per kg. L-AmB was 170 to 750 times as active as antimony in hamsters, and approximately 60 times as active as antimony in monkeys. The demonstration that apparently nontoxic human dosages of L-AmB eliminate essentially all hepatosplenic parasites in hamster and primate models suggests that this preparation should be considered for clinical trial against kala-azar.

Once Weekly Azithromycin Therapy for Prevention of Mycobacterium avium Complex Infection in Patients with AIDS: A Randomized, Double-Blind, Placebo-Controlled Multicenter Trial

We conducted a randomized, double-blind, placebo-controlled multicenter trial of azithromycin (1,200 mg once weekly) for the prevention of Mycobacterium avium complex (MAC) infection in patients with AIDS and a CD4 cell count of < 100/mm3. In an intent-to-treat analysis through the end of therapy plus 30 days, nine (10.6%) of 85 azithromycin recipients and 22 (24.7%) of 89 placebo recipients developed MAC infection (hazard ratio, 0.34; P = .004). There was no difference in the ranges of minimal inhibitory concentrations of either clarithromycin or azithromycin for the five breakthrough (first) MAC isolates from the azithromycin group and the 18 breakthrough MAC isolates from the placebo group. Of the 76 patients who died during the study, four (10.5%) of 38 azithromycin recipients and 12 (31.6%) of 38 placebo recipients had a MAC infection followed by death (P = .025). For deaths due to all causes, there was no difference in time to death or number of deaths between the two groups. Episodes of non-MAC bacterial infection per 100 patient years occurred in 43 azithromycin recipients and 88 placebo recipients (relative risk, 0.49; 95% confidence interval, 0.33-0.73). The most common toxic effect noted during the study was gastrointestinal, reported by 78.9% of azithromycin recipients and 27.5% of placebo recipients. Azithromycin given once weekly is safe and effective in preventing disseminated MAC infection, death due to MAC infection, and respiratory tract infections in patients with AIDS and CD4 cell counts of < 100/mm3.

Effects of ketoconazole on sterol biosynthesis by Leishmania mexicana mexicana amastigotes in murine macrophage tumor cells.

Murine macrophage tumor cells infected with Leishmania mexicana mexicana were exposed to the antimycotic drug ketoconazole and to [2-14C]mevalonate, then the amastigotes were isolated, collected, purified, and their free sterols were analyzed by chromatographic and mass spectrometric methods. Control amastigotes contained as products of de novo biosynthesis C28 4-desmethyl sterols (episterol, 5-dehydroepisterol), C29 4-desmethyl sterols (stigmasta-7,24 (28)-dien-3 beta-ol, stigmasta-5,7,24(28)-trien-3 beta-ol), 4-methyl sterols (4 alpha, 14 alpha-dimethylzymosterol, obtusifoliol) and a 4,4-dimethyl sterol (lanosterol). Present also were macrophage sterols (cholesterol, desmosterol) and a putative product of the C-24 alkylation of desmosterol by amastigotes (24-methylenecholesterol). Amastigotes from macrophages exposed to ketoconazole showed notable changes in the proportions, concentrations and specific activities of their free sterols; increased for 4 alpha, 14 alpha-dimethylzymosterol and decreased for the endogenous C28 and C29 4-desmethyl sterols. Such changes were observed at a ketoconazole concentration as low as 0.01 microgram ml-1. By contrast, uninfected macrophages accumulated only small amounts of lanosterol of high specific activity at a ketoconazole concentration of 10 micrograms ml-1. the ketoconazole-induced alterations in amastigote sterols parallel those previously reported in fungi and L. m. mexicana promastigotes, and suggest a biochemical mechanism for the anti-leishmanial activity of the drug in which changes in sterol composition are linked to disturbances of cell membrane structure and function, and hence to cytotoxicity.

Treatment of New World cutaneous and mucosal leishmaniases

The most extensive investigations of treatment of New World cutaneous leishmaniasis have been performed against L. panamensis disease in Colombia, and the relative value of regimens shown there may be instructive for disease from other areas. In Colombia, a 90-95% cure rate was achieved with three different drug regimens: The standard regimen of pentavalent antimony (20 mg/ kg/day for 20 days parenterally) A short course of pentamidine (3 mg/kg every other day for four injections intramuscularly The marketed combination of topical paromomycin (15%)-MBCl (12%) for 10 days, plus antimony (20 mg/kg/day parenterally) for 7 days. My view is that all these regimens could be chosen as first-line therapy for cutaneous disease in Colombia. The antimony regimen has the advantage of established use; the disadvantages are cost, requirement for injections each day for 20 days, and considerable morbidity in the last two weeks of therapy. The pentamidine regimen has the advantage of a short time course; the disadvantages are lack of experience with this new regimen and frequent, although moderate, morbidity. The combined topical-parenteral regimen has the advantage of requiring few and nontoxic injections; the primary disadvantage is that the regimen is novel and its efficacy has not been confirmed. It would be expected that cases of lesions in other areas caused by L. braziliensis complex would respond in a similar manner to these regimens. To date, however, only the efficacy of the standard antimonial regimen has been confirmed. In certain regions of Central America, other regimens may be effective. Thus, ketoconazole appears to be effective for the more rapidly self-curing forms of disease (cutaneous disease caused by L. mexicana and L. panamensis from Central America), and a short course of antimony may be effective against L. braziliensis in Guatemala.

Effects of ketoconazole on growth and sterol biosynthesis of Leishmania mexicana promastigotes in culture

Ketoconazole, a clinically effective antimycotic agent active in vitro against the amastigote stage of Leishmania mexicana Walter Reed 227 in human monocyte-derived macrophages, was found to inhibit growth and impair sterol biosynthesis of the cultured promastigote stage by approx. 50% at a concentration of approx. 10(-8)M. Sterol biosynthesis was interfered with at the level of the removal of the 14 alpha-methyl group of lanosterol, as judged by changes in the distribution of [2-14C]mevalonate radioactivity among desmethyl sterol and methyl sterol thin-layer chromatography fractions, by the loss of 4-desmethyl sterols (mainly 5-dehydroepisterol), and by the accumulation of 14 alpha-methyl sterols. The growth inhibition and sterol changes were evident in promastigotes cultured in a cholesterol-rich medium and in a cholesterol-poor medium, even though promastigotes incorporated cholesterol. The mechanism of action of ketoconazole against promastigotes may be that postulated for Candida albicans: interference with membrane permeability secondary to loss of desmethyl sterols and accumulation of 14 alpha-methyl sterols.

Noninvasive Management of Indian Visceral Leishmaniasis: Clinical Application of Diagnosis by K39 Antigen Strip Testing at a Kala-azar Referral Unit

Firm diagnosis of visceral leishmaniasis (kala-azar) requires organ aspiration and microscopic examination of tissue specimens. To determine the usefulness of noninvasive diagnosis by strip test detection of anti-K39 immunoglobulin (Ig) G antibody in blood specimens obtained by fingerstick, 143 Indian patients with suspected kala-azar (fever, splenomegaly, anemia) were studied. Of 120 strip test-positive subjects (subjects with presumed kala-azar [group A]), amphotericin B treatment induced clinical cure in 119. Of 23 strip test-negative subjects (subjects presumed to have other diseases [group B]), 16 had other disorders diagnosed at entry, 4 responded to empiric antimalarial therapy, 2 were proven to have kala-azar, and 1 died elsewhere after undergoing splenic aspiration. Six months after treatment ended, all 120 patients in group A and the 18 assessable patients in group B were healthy. In a region in India where visceral infection is prevalent, strip test detection of anti-K39 IgG is a clinically promising diagnostic guide in persons with suspected kala-azar.

Causal prophylactic efficacy of atovaquone-proguanil (MalaroneTM) in a human challenge model

Plasmodia infect the liver for about 7 days before subsequently infecting the blood. Present prophylaxis against Plasmodium falciparum malaria employs agents that primarily kill blood stages and must be continued for 28 days after the last exposure. Atovaquone-proguanil (Malarone) is a new antimalarial agent that is licensed in 35 countries as treatment against blood-stage infection, but its components (atovaquone and proguanil) have separately been shown to be active also against liver stages. To determine whether atovaquone-proguanil is sufficiently active against liver stages to be discontinued 7 days after exposure, we challenged 16 volunteers with P. falciparum via infected mosquitoes. Twelve volunteers received atovaquone-proguanil (1 tablet daily) on the day prior to challenge, on the day of challenge, and for the next 6 days; 4 volunteers received matching placebo. All placebo volunteers demonstrated parasitaemia and malarial symptoms beginning on days 11-12 after challenge. No atovaquone-proguanil volunteer acquired malaria. Atovaquone-proguanil is the first licensed antimalarial agent that kills P. falciparum in the liver and that may be discontinued 7 days after the last exposure.