Manica Balasegaram

Miltefosine: a review of its pharmacology and therapeutic efficacy in the treatment of leishmaniasis

Miltefosine is an alkylphosphocholine drug with demonstrated activity against various parasite species and cancer cells as well as some pathogenic bacteria and fungi. For 10 years it has been licensed in India for the treatment of visceral leishmaniasis (VL), a fatal neglected parasitic disease. It is the first and still the only oral drug that can be used to treat VL and cutaneous leishmaniasis (CL). The standard 28 day miltefosine monotherapy regimen is well tolerated, except for mild gastrointestinal side effects, although its teratogenic potential severely hampers its general use in the clinic and roll-out in national elimination programmes. The pharmacokinetics of miltefosine are mainly characterized by its long residence time in the body, resulting in extensive drug accumulation during treatment and long elimination half-lives. At the moment, different combination therapy strategies encompassing miltefosine are being tested in multiple controlled clinical trials in various geographical areas of endemicity, both in South Asia and East Africa. We here review the most salient pre-clinical and clinical pharmacological aspects of miltefosine, its mechanism of action against Leishmania parasites and other pathogens, and provide a systematic overview of the efficacy and safety data from all clinical trials of miltefosine, either alone or in combination, in the treatment of VL and CL.

Comparison of short-course multidrug treatment with standard therapy for visceral leishmaniasis in India: an open-label, non-inferiority, randomised controlled trial

BACKGROUND Improved treatment approaches are needed for visceral leishmaniasis. We assessed the efficacy and safety of three potential short-course combination treatments compared with the standard monotherapy in India. METHODS Standard treatment (1 mg/kg amphotericin B infusion on alternate days for 30 days, total dose 15 mg/kg) was compared with three drug combinations (single injection of 5 mg/kg liposomal amphotericin B and 7-day 50 mg oral miltefosine or single 10-day 11 mg/kg intramuscular paromomycin; or 10 days each of miltefosine and paromomycin) in an open-label, parallel-group, non-inferiority, randomised controlled trial in two hospital sites in Bihar, India. Patients aged 5-60 years with parasitologically confirmed visceral leishmaniasis were randomly assigned one of the four treatments by the trial statistician by use of a computer-generated list. Clinical assessments were done at the end of treatment (15 days on combination treatment; 31 days for standard treatment) and after 45 days and 6 months. The primary endpoint was definitive cure (defined as no sign or symptom of visceral leishmaniasis and parasitologically cured to the last follow-up). Analyses were done both by intention to treat and per protocol. This trial is registered with ClinicalTrials.gov, number NCT00696969. FINDINGS Between June, 2008, and July, 2009, 634 patients were assigned amphotericin B (n=157), liposomal amphotericin B with miltefosine (n=160) or paromomycin (n=158), or miltefosine and paromomycin (n=159). 618 patients were in the per-protocol population. There were two relapses in each group. The numbers with definitive cure at 6 months for the intention-to-treat population were 146 (cure rate 93·0%; CI 87·5-96·3) for amphotericin B, 156 (97·5%; 93·3-99·2) for liposomal amphotericin B and miltefosine, 154 (97·5%; 93·24-99·2) for liposomal amphotericin B and paromomycin, and 157 (98·7%; 95·1-99·8) for miltefosine and paromomycin. All combinations were non-inferior to the standard treatment, in both the intention-to-treat and per-protocol populations. Patients in the combination groups had fewer adverse events than did those assigned standard treatment. INTERPRETATION Combination treatments for visceral leishmaniasis are efficacious and safe, and decrease the duration of therapy, thereby encouraging adherence and reducing emergence of drug-resistant parasites. FUNDING Drugs for Neglected Diseases initiative and the Indian Council of Medical Research.

Combination therapy for visceral leishmaniasis

Combination therapy for the treatment of visceral leishmaniasis has increasingly been advocated as a way to increase treatment efficacy and tolerance, reduce treatment duration and cost, and limit the emergence of drug resistance. We reviewed the evidence and potential for combination therapy, and the criteria for the choice of drugs in such regimens. The first phase 2 results of combination regimens are promising, and have identified effective and safe regimens as short as 8 days. Several phase 3 trials are underway or planned in the Indian subcontinent and east Africa. The limited data available suggest that combination therapy is more cost-effective and reduces indirect costs for patients. Additional advantages are reduced treatment duration (8-17 days), with potentially better patient compliance and lesser burden on the health system. Only limited data are available on how best to prevent acquired resistance. Patients who are coinfected with visceral leishmaniasis and HIV could be a reservoir for development and spread of drug-resistant strains, calling for special precautions. The identification of a short, cheap, well-tolerated combination regimen that can be given in ambulatory care and needs minimal clinical monitoring will most likely have important public health implications. Effective monitoring systems and close regulations and policy will be needed to ensure effective implementation. Whether combination therapy could indeed help delay resistance, and how this is best achieved, will only be known in the long term.

Three Drug Combinations for Late-Stage Trypanosoma brucei gambiense Sleeping Sickness: A Randomized Clinical Trial in Uganda

Objectives: Our objective was to compare the efficacy and safety of three drug combinations for the treatment of late-stage human African trypanosomiasis caused by Trypanosoma brucei gambiense. Design: This trial was a randomized, open-label, active control, parallel clinical trial comparing three arms. Setting: The study took place at the Sleeping Sickness Treatment Center run by Médecins Sans Frontières at Omugo, Arua District, Uganda Participants: Stage 2 patients diagnosed in Northern Uganda were screened for inclusion and a total of 54 selected. Interventions: Three drug combinations were given to randomly assigned patients: melarsoprol-nifurtimox (M+N), melarsoprol-eflornithine (M+E), and nifurtimox-eflornithine (N+E). Dosages were uniform: intravenous (IV) melarsoprol 1.8 mg/kg/d, daily for 10 d; IV eflornithine 400 mg/kg/d, every 6 h for 7 d; oral nifurtimox 15 (adults) or 20 (children <15 y) mg/kg/d, every 8 h for 10 d. Patients were followed up for 24 mo. Outcome Measures: Outcomes were cure rates and adverse events attributable to treatment. Results: Randomization was performed on 54 patients before enrollment was suspended due to unacceptable toxicity in one of the three arms. Cure rates obtained with the intention to treat analysis were M+N 44.4%, M+E 78.9%, and N+E 94.1%, and were significantly higher with N+E (p = 0.003) and M+E (p = 0.045) than with M+N. Adverse events were less frequent and less severe with N+E, resulting in fewer treatment interruptions and no fatalities. Four patients died who were taking melarsoprol-nifurtimox and one who was taking melarsoprol-eflornithine. Conclusions: The N+E combination appears to be a promising first-line therapy that may improve treatment of sleeping sickness, although the results from this interrupted study do not permit conclusive interpretations. Larger studies are needed to continue the evaluation of this drug combination in the treatment of T. b. gambiense sleeping sickness.

Cost-Effectiveness Analysis of Combination Therapies for Visceral Leishmaniasis in the Indian Subcontinent

Background Visceral leishmaniasis is a systemic parasitic disease that is fatal unless treated. We assessed the cost and cost-effectiveness of alternative strategies for the treatment of visceral leishmaniasis in the Indian subcontinent. In particular we examined whether combination therapies are a cost-effective alternative compared to monotherapies. Methods and Findings We assessed the cost-effectiveness of all possible mono- and combination therapies for the treatment of visceral leishmaniasis in the Indian subcontinent (India, Nepal and Bangladesh) from a societal perspective using a decision analytical model based on a decision tree. Primary data collected in each country was combined with data from the literature and an expert poll (Delphi method). The cost per patient treated and average and incremental cost-effectiveness ratios expressed as cost per death averted were calculated. Extensive sensitivity analysis was done to evaluate the robustness of our estimations and conclusions. With a cost of US

Geographical Variation in the Response of Visceral Leishmaniasis to Paromomycin in East Africa: A Multicentre, Open-Label, Randomized Trial

92 per death averted, the combination miltefosine-paromomycin was the most cost-effective treatment strategy. The next best alternative was a combination of liposomal amphotericin B with paromomycin with an incremental cost-effectiveness of

Developments in the treatment of visceral leishmaniasis

652 per death averted. All other strategies were dominated with the exception of a single dose of 10mg per kg of liposomal amphotericin B. While strategies based on liposomal amphotericin B (AmBisome) were found to be the most effective, its current drug cost of US

Sodium Stibogluconate (SSG) & Paromomycin Combination Compared to SSG for Visceral Leishmaniasis in East Africa: A Randomised Controlled Trial

20 per vial resulted in a higher average cost-effectiveness. Sensitivity analysis showed the conclusion to be robust to variations in the input parameters over their plausible range. Conclusions Combination treatments are a cost-effective alternative to current monotherapy for VL. Given their expected impact on the emergence of drug resistance, a switch to combination therapy should be considered once final results from clinical trials are available.

Effectiveness of melarsoprol and eflornithine as first-line regimens for gambiense sleeping sickness in nine Médecins Sans Frontières programmes

Background Visceral leishmaniasis (VL) is a major health problem in developing countries. The untreated disease is fatal, available treatment is expensive and often toxic, and drug resistance is increasing. Improved treatment options are needed. Paromomycin was shown to be an efficacious first-line treatment with low toxicity in India. Methods This was a 3-arm multicentre, open-label, randomized, controlled clinical trial to compare three treatment regimens for VL in East Africa: paromomycin sulphate (PM) at 15 mg/kg/day for 21 days versus sodium stibogluconate (SSG) at 20 mg/kg/day for 30 days; and the combination of both dose regimens for 17 days. The primary efficacy endpoint was cure based on parasite-free tissue aspirates taken 6 months after treatment. Findings Overall, 135 patients per arm were enrolled at five centres in Sudan (2 sites), Kenya (1) and Ethiopia (2), when the PM arm had to be discontinued due to poor efficacy. The trial has continued with the higher dose of PM as well as the combination of PM and SSG arms. These results will be reported later. Baseline patient characteristics were similar among treatment arms. The overall cure with PM was significantly inferior to that with SSG (63.8% versus 92.2%; difference 28.5%, 95%CI 18.8% to 38.8%, p<0.001). The efficacy of PM varied among centres and was significantly lower in Sudan (14.3% and 46.7%) than in Kenya (80.0%) and Ethiopia (75.0% and 96.6%). No major safety issues with PM were identified. Conclusion The efficacy of PM at 15 mg/kg/day for 21 days was inadequate, particularly in Sudan. The efficacy of higher doses and the combination treatment warrant further studies.

Efficacy of three artemisinin combination therapies for the treatmentof uncomplicated Plasmodium falciparum malaria in the Republic of Congo

Background: Visceral leishmaniasis (VL) is one of the most neglected parasitic diseases causing large scale mortality and morbidity among the poorest of the poor in the Indian subcontinent and Africa. Objective: This review aims to describe the potential and the (lack of) current impact of newly developed treatments on the control of VL. It describes how the problem of an empty research pipeline is addressed, and discusses the emerging threat of incurable HIV/VL coinfection. Methods: The literature was searched for drugs used in VL. Conclusion: Research and development of VL drugs has received a financial boost but no new drugs are expected in the next 5 years. Only three new and highly effective treatments have been licensed in the past 10 years. These remain, however, largely inaccessible as VL control programs in the developing world are lacking. This is deserving of immediate and urgent attention, especially in the context of the rapidly expanding HIV/VL coinfection.