Pentamidine isethionate as treatment and secondary prophylaxis for disseminated cutaneous leishmaniasis during HIV infection: case report

Long term outcomes and prognostics of visceral leishmaniasis in HIV infected patients with use of pentamidine as secondary prophylaxis based on CD4 level: a prospective cohort study in Ethiopia

Background

The long-term treatment outcome of visceral leishmaniasis (VL) patients with HIV co-infection is complicated by a high rate of relapse, especially when the CD4 count is low. Although use of secondary prophylaxis is recommended, it is not routinely practiced and data on its effectiveness and safety are limited.

Methods

A prospective cohort study was conducted in Northwest Ethiopia from August 2014 to August 2017 (NCT02011958). HIV-VL patients were followed for up to 12 months. Patients with CD4 cell counts below 200/μL at the end of VL treatment received pentamidine prophylaxis starting one month after parasitological cure, while those with CD4 count ≥200 cells/μL were followed without secondary prophylaxis. Compliance, safety and relapse-free survival, using Kaplan-Meier analysis methods to account for variable time at risk, were summarised. Risk factors for relapse or death were analysed.

Results

Fifty-four HIV patients were followed. The probability of relapse-free survival at one year was 50% (95% confidence interval [CI]: 35–63%): 53% (30–71%) in 22 patients with CD4 ≥200 cells/μL without pentamidine prophylaxis and 46% (26–63%) in 29 with CD4 <200 cells/μL who started pentamidine. Three patients with CD4 <200 cells/μL did not start pentamidine. Amongst those with CD4 ≥200 cells/μL, VL relapse was an independent risk factor for subsequent relapse or death (adjusted rate ratio: 5.42, 95% CI: 1.1–25.8). Except for one case of renal failure which was considered possibly related to pentamidine, there were no drug-related safety concerns.

Conclusion

The relapse-free survival rate for VL patients with HIV was low. Relapse-free survival of patients with CD4 count <200cells/μL given pentamidine secondary prophylaxis appeared to be comparable to patients with a CD4 count ≥200 cells/μL not given prophylaxis. Patients with relapsed VL are at higher risk for subsequent relapse and should be considered a priority for secondary prophylaxis, irrespective of their CD4 count.

Achieving parasitological cure at the end of visceral leishmaniasis (VL) treatment in HIV co-infected patients does not assure definitive cure, as the disease will recur within a year in many patients. In this cohort study, the probability of relapse-free survival at one-year was 50% in all patients. The use of monthly pentamidine infusion for those with lower CD4 counts (<200 cells/μL) at the time of VL cure appeared to result in a comparable relapse-free survival rate to those patients with higher CD4 count (≥200 cells/μL) who did not receive secondary prophylaxis. On the other hand, patients with a history of previous VL treatment (VL relapse) remained at high risk of relapse despite achieving CD4 count ≥200 cells/μL at the end of the VL treatment. While all VL patients with HIV co-infection may benefit from secondary prophylaxis, those with CD4 <200 cells/μL and previous history of treatment should be prioritized for secondary prophylaxis. New modalities for prevention of VL relapse in HIV patients should also be explored.

Use of Pentamidine As Secondary Prophylaxis to Prevent Visceral Leishmaniasis Relapse in HIV Infected Patients, the First Twelve Months of a Prospective Cohort Study

Background

Visceral leishmaniasis (VL) has become an important opportunistic infection in persons with HIV-infection in VL-endemic areas. The co-infection leads to profound immunosuppression and high rate of annual VL recurrence. This study assessed the effectiveness, safety and feasibility of monthly pentamidine infusions to prevent recurrence of VL in HIV co-infected patients.

Methods

A single-arm, open-label trial was conducted at two leishmaniasis treatment centers in northwest Ethiopia. HIV-infected patients with a VL episode were included after parasitological cure. Monthly infusions of 4mg/kg pentamidine-isethionate diluted in normal-saline were started for 12months. All received antiretroviral therapy (ART). Time-to-relapse or death was the primary end point.

Results

Seventy-four patients were included. The probability of relapse-free survival at 6months and at 12 months was 79% and 71% respectively. Renal failure, a possible drug-related serious adverse event, occurred in two patients with severe pneumonia. Forty-one patients completed the regimen taking at least 11 of the 12 doses. Main reasons to discontinue were: 15 relapsed, five died and seven became lost to follow-up. More patients failed among those with a CD4+cell count ≤ 50cells/μl, 5/7 (71.4%) than those with counts above 200 cells/μl, 2/12 (16.7%), (p = 0.005).

Conclusion

Pentamidine secondary prophylaxis led to a 29% failure rate within one year, much lower than reported in historical controls (50%-100%). Patients with low CD4+cell counts are at increased risk of relapse despite effective initial VL treatment, ART and secondary prophylaxis. VL should be detected and treated early enough in patients with HIV infection before profound immune deficiency installs.

Relapse of visceral leishmaniasis (VL) among HIV co-infected patients occurs universally. Evidence on the use of secondary prophylaxis especially in anthroponotic transmission regions was lacking. It was found out now that secondary prophylaxis in addition to antiretroviral therapy for VL in people with HIV infection is useful to decrease the relapse rate. However, this intervention is more effective when started before profound immune deficiency. Patients with low CD4 cell counts continued to relapse significantly despite the use of secondary prophylaxis as compared to those with high CD4 cell counts. Earlier VL case detection and management is crucial. This is the first adequately powered trial that has addressed the use of secondary prophylaxis for prevention of VL relapse in HIV co-infected patients.

Visceral Leishmaniasis and HIV coinfection in East Africa

Visceral Leishmaniasis (VL) is an important protozoan opportunistic disease in HIV patients in endemic areas. East Africa is second to the Indian subcontinent in the global VL caseload and first in VL-HIV coinfection rate. Because of the alteration in the disease course, the diagnostic challenges, and the poor treatment responses, VL with HIV coinfection has become a very serious challenge in East Africa today. Field experience with the use of liposomal amphotericin B in combination with miltefosine, followed by secondary prophylaxis and antiretroviral drugs, looks promising. However, this needs to be confirmed through clinical trials. Better diagnostic and follow-up methods for relapse and prediction of relapse should also be looked for. Basic research to understand the immunological interaction of the two infections may ultimately help to improve the management of the coinfection.

Antimalarial and antileishmanial activities of histone deacetylase inhibitors with triazole-linked cap group

Histone deacetylase inhibitors (HDACi) are endowed with plethora of biological functions including anti-proliferative, anti-inflammatory, anti-parasitic, and cognition-enhancing activities. Parsing the structure-activity relationship (SAR) for each disease condition is vital for long-term therapeutic applications of HDACi. We report in the present study specific cap group substitution patterns and spacer-group chain lengths that enhance the antimalarial and antileishmanial activity of aryltriazolylhydroxamates-based HDACi. We identified many compounds that are several folds selectively cytotoxic to the plasmodium parasites compared to standard HDACi. Also, a few of these compounds have antileishmanial activity that rivals that of miltefosine, the only currently available oral agent against visceral leishmaniasis. The anti-parasite properties of several of these compounds tracked well with their anti-HDAC activities. The results presented here provide further evidence on the suitability of HDAC inhibition as a viable therapeutic option to curb infections caused by apicomplexan protozoans and trypanosomatids.

Using the zebrafish lateral line to screen for ototoxicity

The zebrafish is a valuable model for studying hair cell development, structure, genetics, and behavior. Zebrafish and other aquatic vertebrates have hair cells on their body surface organized into a sensory system called the lateral line. These hair cells are highly accessible and easily visualized using fluorescent dyes. Morphological and functional similarities to mammalian hair cells of the inner ear make the zebrafish a powerful preparation for studying hair cell toxicity. The ototoxic potential of drugs has historically been uncovered by anecdotal reports that have led to more formal investigation. Currently, no standard screen for ototoxicity exists in drug development. Thus, for the vast majority of Food and Drug Association (FDA)-approved drugs, the ototoxic potential remains unknown. In this study, we used 5-day-old zebrafish larvae to screen a library of 1,040 FDA-approved drugs and bioactives (NINDS Custom Collection II) for ototoxic effects in hair cells of the lateral line. Hair cell nuclei were selectively labeled using a fluorescent vital dye. For the initial screen, fish were exposed to drugs from the library at a 100-muM concentration for 1 h in 96-well tissue culture plates. Hair cell viability was assessed in vivo using fluorescence microscopy. One thousand forty drugs were rapidly screened for ototoxic effects. Seven known ototoxic drugs included in the library, including neomycin and cisplatin, were positively identified using these methods, as proof of concept. Fourteen compounds without previously known ototoxicity were discovered to be selectively toxic to hair cells. Dose-response curves for all 21 ototoxic compounds were determined by quantifying hair cell survival as a function of drug concentration. Dose-response relationships in the mammalian inner ear for two of the compounds without known ototoxicity, pentamidine isethionate and propantheline bromide, were then examined using in vitro preparations of the adult mouse utricle. Significant dose-dependent hair cell loss in the mouse utricle was demonstrated for both compounds. This study represents an important step in validating the use of the zebrafish lateral line as a screening tool for the identification of potentially ototoxic drugs.

Parasitic central nervous system infections in immunocompromised hosts: malaria, microsporidiosis, leishmaniasis, and African trypanosomiasis

Immunosuppression associated with HIV infection or following transplantation increases susceptibility to central nervous system (CNS) infections. Because of increasing international travel, parasites that were previously limited to tropical regions pose an increasing infectious threat to populations at risk for acquiring opportunistic infection, especially people with HIV infection or individuals who have received a solid organ or bone marrow transplant. Although long-term immunosuppression caused by medications such as prednisone likely also increases the risk for acquiring infection and for developing CNS manifestations, little published information is available to support this hypothesis. In an earlier article published in Clinical Infectious Diseases, we described the neurologic manifestations of some of the more common parasitic CNS infections. This review will discuss the presentation, diagnosis, and treatment of the following additional parasitic CNS infections: malaria, microsporidiosis, leishmaniasis, and African trypanosomiasis.

Chemotherapy of leishmaniasis part II: synthesis and bioevaluation of substituted arylketene dithioacetals as antileishmanial agents

Some novel aryl substituted ketene dithioacetals have been synthesized using novel synthetic methods. The compounds were screened against Leishmania donovani in hamsters for their activity profile. Some of the compounds inhibited 50-65% parasite growth at 50 mg kg(-1) x 5 days.

Synthesis and antileishmanial profile of some novel terpenyl pyrimidines

Some novel terpenyl pyrimidine derivatives 2(a-d) and 6(a-b) have been synthesised from alpha/beta-ionone keteneacetals 1 and 5. The terpenyl pyrimidine 2e has been synthesised from beta-ionone 3 in two steps in quantitative yield. The pyrimidine derivatives were screened for in-vivo antilesihmanial activity. The compounds 2d, 2e, 6a and 6b showed promising in-vivo antileishmanial activity.

In vitro antiproliferative effects of several diaryl derivatives on Leishmania spp

In a previous works searching for new drugs with high efficiency, we reported the in vitro and in vivo antileishmanial activity of a series of diarylheptanoid structurally related to curcumin against L. amazonensis. This work describes the in vitro antileishmanial activity of a new series of diarylheptanoids and diarylpentanoids derivatives. These drugs were assayed against Leishmania amazonensis, L. braziliensis and L. chagasi promastigotes containing a high percentage of metacyclic forms and the axenic amastigote form of L. amazonensis and using Pentamidine Isethionate as reference drug. Parasites in the log late phase culture were incubated with several concentrations of the drugs solubilized in dimethyl sulphoxide (DMSO) and then counted in a Neubauer's chamber. Controls without the drugs and with DMSO were done in parallel. The results showed that all diarylheptanoids and diarylpentanoids had a very good antileishmanial activity.