Determination of the Optimal Single Dose Treatment for Acoziborole, a Novel Drug for the Treatment of Human African Trypanosomiasis: First-in-Human Study.

BACKGROUND AND OBJECTIVES: Acoziborole is a novel boron-containing candidate developed as an oral drug for the treatment of human African trypanosomiasis (HAT). Results from preclinical studies allowed progression to Phase 1 trials. We aimed to determine the best dose regimen for all stages of HAT. METHODS: Acoziborole was assessed in 128 healthy adult males of sub-Saharan African origin living in France. The study included a single oral administration of a 20- to 1200-mg dose in a randomised double-blind study in cohorts of 8 (6 active, 2 placebo) to assess safety, tolerability, and pharmacokinetics. In three additional open cohorts of 6 participants, the effect of activated charcoal was evaluated, bioequivalence of capsules versus tablets was assessed, and safety in the 960-mg tablet cohorts was monitored. RESULTS: Acoziborole was well tolerated at all doses tested; no dose-related adverse events were observed. The drug appeared rapidly in plasma (at 1 h), reached tmax between 24 and 72 h, and remained stable for up to 96 h, after which a slow decrease was quantifiable until 14 weeks after dosing. Charcoal had little impact on the enterohepatic recirculation effect, except for the 20-mg dose. Bioequivalence between capsule and tablet formulations was demonstrated. The therapeutic single dose for administration under fasted conditions was fixed to 960 mg. The maximum administered dose was 1200 mg. CONCLUSIONS: This study showed that acoziborole could be safely assessed in patients as a potential single-dose oral cure for both stages of gambiense HAT. TRIAL REGISTRATION: The study was registered with ClinicalTrials.gov: NCT01533961.

Safety and efficacy of oral fexinidazole in children with gambiense human African trypanosomiasis: a multicentre, single-arm, open-label, phase 2-3 trial.

BACKGROUND: Fexinidazole has been reported as an effective oral monotherapy against non-severe gambiense human African trypanosomiasis in a recent trial in adults. We aimed to assess the safety and efficacy of fexinidazole in children across all disease stages of gambiense human African trypanosomiasis. METHODS: We did a multicentre, single-arm, open-label, phase 2-3 trial at eight district hospitals in the Democratic Republic of the Congo. We recruited children with a Karnofsky score of more than 50, those aged 6 years to younger than 15 years, weighing 20 kg or more, and with confirmed gambiense human African trypanosomiasis (any stage). Children weighing 20 kg or more and less than 35 kg received oral fexinidazole of 1200 mg (two × 600 mg tablets) once per day for 4 days (days 1-4) followed by 600 mg (one × 600 mg tablet) once per day for 6 days (days 5-10). Children weighing 35 kg or more received oral fexinidazole of 1800 mg (three × 600 mg tablets) once per day for 4 days (days 1-4), followed by 1200 mg (two × 600 mg tablets) once per day for 6 days (days 5-10). The primary endpoint was fexinidazole treatment success rate 12 months after end of treatment. A rate greater than 80% was deemed acceptable and a target value of 92% was aimed for. Safety was assessed through routine monitoring. This study is completed and registered with ClinicalTrials.gov, number NCT02184689. FINDINGS: Between May 3, 2014, and Nov 22, 2016, we screened a total of 130 paediatric patients, of whom 125 (96%) received at least one dose of fexinidazole. All 125 patients (69 [55%] patients with stage 1, 19 [15%] with early stage 2, and 37 [30%] with late stage 2 gambiense human African trypanosomiasis) completed the 10-day treatment. Treatment success rate at 12 months was 97·6% (95% CI 93·1-99·5; 122 of 125 patients). The primary endpoint was met and the targeted value of 92% was exceeded. Treatment success at 12 months was elevated across all disease stages: 98·6% (95% CI 92·2-99·9; 68 of 69 patients) in stage 1, 94·7% (74·0-99·9; 18 of 19 patients) in early stage 2, and 97·3% (85·8-99·9; 36 of 37 patients) in late stage 2 gambiense human African trypanosomiasis. No new safety issues were observed beyond those found in adult trials. Overall, 116 (93%) of 125 patients reported 586 treatment-emergent adverse events, mainly mild or moderate. The most frequently reported treatment-emergent adverse events of interest during hospital admission were vomiting (86 [69%] of 125) and headache (41 [33%]). Seven (6%) of 125 patients had severe malaria, which was often accompanied by anaemia that was unrelated to fexinidazole. One patient died following dyspnoea and injury due to traumatic aggression 172 days after end of treatment, which was considered unrelated to fexinidazole or gambiense human African trypanosomiasis. INTERPRETATION: Oral fexinidazole is a safe and effective first-line treatment option across all gambiense human African trypanosomiasis disease stages in paediatric patients. FUNDING: Through the Drugs for Neglected Diseases initiative: the Bill & Melinda Gates Foundation (USA), the Republic and Canton of Geneva (Switzerland), the Dutch Ministry of Foreign Affairs (Netherlands), the Norwegian Agency for Development Cooperation (Norway), the Federal Ministry of Education and Research through KfW (Germany), the Brian Mercer Charitable Trust (UK), and other private foundations and individuals from the human African trypanosomiasis campaign. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.

Effectiveness of Nifurtimox Eflornithine Combination Therapy (NECT) in T. b. gambiense second stage sleeping sickness patients in the Democratic Republic of Congo: Report from a field study.

BACKGROUND: Nifurtimox-eflornithine combination therapy (NECT) for the treatment of second stage gambiense human African trypanosomiasis (HAT) was added to the World Health Organization's Essential Medicines List in 2009 after demonstration of its non-inferior efficacy compared to eflornithine therapy. A study of NECT use in the field showed acceptable safety and high efficacy until hospital discharge in a wide population, including children, pregnant and breastfeeding women, and patients with a HAT treatment history. We present here the effectiveness results after the 24-month follow-up visit. METHODOLOGY/PRINCIPAL FINDINGS: In a multicenter, open label, single arm phase IIIb study, second stage gambiense HAT patients were treated with NECT in the Democratic Republic of Congo. Clinical cure was defined 24 months after treatment as survival without clinical and/or parasitological signs of HAT. Of the 629 included patients, 619 (98.4%) were discharged alive after treatment and were examined for the presence of trypanosomes, white blood cell count in cerebro-spinal fluid, and disease symptoms. The clinical cure rate of 94.1% was comparable for all subpopulations analyzed at the 24-month follow-up visit. Self-reported adverse events during follow-up were few and concerned mainly nervous system disorders, infections, and gastro-intestinal disorders. Overall, 28 patients (4.3%) died during the course of the trial. The death of 16 of the 18 patients who died during the follow-up period was assessed as unlikely or not related to NECT. Within 24 months, eight patients (1.3%) relapsed and received rescue treatment. Sixteen patients were completely lost to follow-up. CONCLUSIONS/SIGNIFICANCE: NECT treatment administered under field conditions was effective and sufficiently well tolerated, no major concern arose for children or pregnant or breastfeeding women. Patients with a previous HAT treatment history had the same response as those who were naïve. In conclusion, NECT was confirmed as effective and appropriate for use in a broad population, including vulnerable subpopulations. TRIAL REGISTRATION: The trial is registered at ClinicalTrials.gov, number NCT00906880.

Oral fexinidazole for stage 1 or early stage 2 African Trypanosoma brucei gambiense trypanosomiasis: a prospective, multicentre, open-label, cohort study.

BACKGROUND: Staging and treatment of human African trypanosomiasis caused by Trypanosoma brucei gambiense (g-HAT) required lumbar puncture to assess cerebrospinal fluid (CSF) and intravenous drugs that cross the blood-brain barrier for late-stage infection. These procedures are inconvenient in rural health systems of disease-endemic countries. A pivotal study established fexinidazole as the first oral monotherapy to be effective against non-severe stage 2 g-HAT. We aimed to assess the safety and efficacy of fexinidazole in early g-HAT. METHODS: In this prospective, multicentre, open-label, single-arm cohort study, patients with stage 1 or early stage 2 g-HAT were recruited from eight treatment centres in the Democratic Republic of the Congo. Primary inclusion criteria included being older than 15 years, being able to ingest at least one complete meal per day (or at least one sachet of Plumpy'Nut®), a Karnofsky score higher than 50, evidence of trypanosomes in the blood or lymph but no evidence of trypanosomes in the CSF, willingness to be admitted to hospital to receive treatment, having a permanent address, and being able to comply with the follow-up visit schedule. Exclusion criteria included severe malnutrition, inability to take medication orally, pregnant or breastfeeding women, any clinically important medical condition that could jeopardise patient safety or participation in the study, severely deteriorated general status, any contraindication to imidazole drugs, HAT treatment in the past 2 years, previous enrolment in the study or previous intake of fexinidazole, abnormalities on electrocardiogram that did not return to normal in pretreatment repeated assessments or were considered clinically important, QT interval corrected using Fridericia's formula of at least 450 ms, and patients not tested for malaria or not having received appropriate treatment for malaria or for soil-transmitted helminthiasis. Patients were classified into stage 1 or early stage 2 g-HAT groups following evidence of trypanosomes in the blood, lymph, and absence in CSF, and using white-blood-cell count in CSF. Patients received 1800 mg fexinidazole once per day on days 1-4 then 1200 mg fexinidazole on days 5-10. Patients were observed for approximately 19 months in total. Study participants were followed up on day 5 and day 8 during treatment, at end of treatment on day 11, at end of hospitalisation on days 11-18, at week 9 for a subset of patients, and after 6 months, 12 months, and 18 months. The primary endpoint was treatment success at 12 months. Safety was assessed through routine monitoring. Analyses were done in the intention-to-treat population. The acceptable success rate was defined as treatment efficacy in more than 80% of patients. This study is completed and registered with ClinicalTrials.gov (NCT02169557). FINDINGS: Patients were enrolled between April 30, 2014, and April 25, 2017. 238 patients were recruited: 195 (82%) patients with stage 1 g-HAT and 43 (18%) with early stage 2 g-HAT. 189 (97%) of 195 patients with stage 1 g-HAT and 41 (95%) of 43 patients with early stage 2 g-HAT were finally included and completed the 10 day treatment period. Three patients with stage 1 g-HAT died after the 10 day treatment period and before the 12 month primary follow-up visit, considered as treatment failure and were withdrawn from the study. Treatment was effective at 12 months for 227 (99%) of 230 patients (95% CI 96·2-99·7): 186 (98%) of 189 patients (95·4-99·7) with stage 1 and 41 (100%) of 41 patients (91·4-100·0) with early stage 2, indicating that the primary study endpoint was met. No new safety issues were observed. The most frequent adverse events were headache and vomiting. In total, 214 (93%) of 230 patients had treatment-emergent adverse events, mainly common-terminology criteria for adverse events grades 1 to 3. None led to treatment discontinuation. INTERPRETATION: Fexinidazole is a valuable first-line treatment option in the early stages of g-HAT. FUNDING: Through the Drugs for Neglected Diseases initiative: the Bill & Melinda Gates Foundation, the Republic and Canton of Geneva (Switzerland), the Dutch Ministry of Foreign Affairs (also known as DGIS; Netherlands), the Norwegian Agency for Development Cooperation (also known as Norad; Norway), the Federal Ministry of Education and Research (also known as BMBF) through KfW (Germany), the Brian Mercer Charitable Trust (UK), and other private foundations and individuals from the HAT campaign. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.

Low antileishmanial drug exposure in HIV-positive visceral leishmaniasis patients on antiretrovirals: an Ethiopian cohort study.

BACKGROUND: Despite high HIV co-infection prevalence in Ethiopian visceral leishmaniasis (VL) patients, the adequacy of antileishmanial drug exposure in this population and effect of HIV-VL co-morbidity on pharmacokinetics of antileishmanial and antiretroviral (ARV) drugs is still unknown. METHODS: HIV-VL co-infected patients received the recommended liposomal amphotericin B (LAmB) monotherapy (total dose 40 mg/kg over 24 days) or combination therapy of LAmB (total dose 30 mg/kg over 11 days) plus 28 days 100 mg/day miltefosine, with possibility to extend treatment for another cycle. Miltefosine, total amphotericin B and ARV concentrations were determined in dried blood spots or plasma using LC-MS/MS. RESULTS: Median (IQR) amphotericin B Cmax on Day 1 was 24.6 µg/mL (17.0-34.9 µg/mL), which increased to 40.9 (25.4-53.1) and 33.2 (29.0-46.6) µg/mL on the last day of combination and monotherapy, respectively. Day 28 miltefosine concentration was 18.7 (15.4-22.5) µg/mL. Miltefosine exposure correlated with amphotericin B accumulation. ARV concentrations were generally stable during antileishmanial treatment, although efavirenz Cmin was below the 1 µg/mL therapeutic target for many patients. CONCLUSIONS: This study demonstrates that antileishmanial drug exposure was low in this cohort of HIV co-infected VL patients. Amphotericin B Cmax was 2-fold lower than previously observed in non-VL patients. Miltefosine exposure in HIV-VL co-infected patients was 35% lower compared with adult VL patients in Eastern Africa, only partially explained by a 19% lower dose, possibly warranting a dose adjustment. Adequate drug exposure in these HIV-VL co-infected patients is especially important given the high proportion of relapses.

Host transcriptomic signature as alternative test-of-cure in visceral leishmaniasis patients co-infected with HIV.

BACKGROUND: Visceral leishmaniasis (VL) treatment in HIV patients very often fails and is followed by high relapse and case-fatality rates. Hence, treatment efficacy assessment is imperative but based on invasive organ aspiration for parasite detection. In the search of a less-invasive alternative and because the host immune response is pivotal for treatment outcome in immunocompromised VL patients, we studied changes in the whole blood transcriptional profile of VL-HIV patients during treatment. METHODS: Embedded in a clinical trial in Northwest Ethiopia, RNA-Seq was performed on whole blood samples of 28 VL-HIV patients before and after completion of a 29-day treatment regimen of AmBisome or AmBisome/miltefosine. Pathway analyses were combined with a machine learning approach to establish a clinically-useful 4-gene set. FINDINGS: Distinct signatures of differentially expressed genes between D0 and D29 were identified for patients who failed treatment and were successfully treated. Pathway analyses in the latter highlighted a downregulation of genes associated with host cellular activity and immunity, and upregulation of antimicrobial peptide activity in phagolysosomes. No signs of disease remission nor pathway enrichment were observed in treatment failure patients. Next, we identified a 4-gene pre-post signature (PRSS33, IL10, SLFN14, HRH4) that could accurately discriminate treatment outcome at end of treatment (D29), displaying an average area-under-the-ROC-curve of 0.95 (CI: 0.75-1.00). INTERPRETATION: A simple blood-based signature thus holds significant promise to facilitate treatment efficacy monitoring and provide an alternative test-of-cure to guide patient management in VL-HIV patients. FUNDING: Project funding was provided by the AfricoLeish project, supported by the European Union Seventh Framework Programme (EU FP7).

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.

A randomized trial of AmBisome monotherapy and AmBisome and miltefosine combination to treat visceral leishmaniasis in HIV co-infected patients in Ethiopia.

BACKGROUND: Visceral leishmaniasis (VL) in human immunodeficiency virus (HIV) co-infected patients requires special case management. AmBisome monotherapy at 40 mg/kg is recommended by the World Health Organization. The objective of the study was to assess if a combination of a lower dose of AmBisome with miltefosine would show acceptable efficacy at the end of treatment. METHODOLOGY/PRINCIPAL FINDINGS: An open-label, non-comparative randomized trial of AmBisome (30 mg/kg) with miltefosine (100 mg/day for 28 days), and AmBisome monotherapy (40 mg/kg) was conducted in Ethiopian VL patients co-infected with HIV (NCT02011958). A sequential design was used with a triangular continuation region. The primary outcome was parasite clearance at day 29, after the first round of treatment. Patients with clinical improvement but without parasite clearance at day 29 received a second round of the allocated treatment. Efficacy was evaluated again at day 58, after completion of treatment. Recruitment was stopped after inclusion of 19 and 39 patients in monotherapy and combination arms respectively, as per pre-specified stopping rules. At D29, intention-to-treat efficacy in the AmBisome arm was 70% (95% CI 45-87%) in the unadjusted analysis, and 50% (95% CI 27-73%) in the adjusted analysis, while in the combination arm, it was 81% (95% CI 67-90%) and 67% (95% CI 48-82%) respectively. At D58, the adjusted efficacy was 55% (95% CI 32-78%) in the monotherapy arm, and 88% (95% CI 79-98%) in the combination arm. No major safety concerns related to the study medication were identified. Ten SAEs were observed within the treatment period, and 4 deaths unrelated to the study medication. CONCLUSIONS/SIGNIFICANCE: The extended treatment strategy with the combination regimen showed the highest documented efficacy in HIV-VL patients; these results support a recommendation of this regimen as first-line treatment strategy for HIV-VL patients in eastern Africa. TRIAL REGISTRATION NUMBER: www.clinicaltrials.gov NCT02011958.

Recent Development of Visceral Leishmaniasis Treatments: Successes, Pitfalls, and Perspectives.

Research in visceral leishmaniasis in the last decade has been focused on how better to use the existing medicines as monotherapy or in combination. Systematic research by geographical regions has shown that a universal treatment is far from today's reality. Substantial progress has been made in the elimination of kala-azar in South Asia, with a clear strategy on first- and second-line therapy options of single-dose liposomal amphotericin B and a combination of paromomycin and miltefosine, respectively, among other interventions. In Eastern Africa, sodium stibogluconate (SSG) and paromomycin in combination offer an advantage compared to the previous SSG monotherapy, although not exempted of limitations, as this therapy requires 17 days of painful double injections and bears the risk of SSG-related cardiotoxicity. In this region, attempts to improve the combination therapy have been unsuccessful. However, pharmacokinetic studies have led to a better understanding of underlying mechanisms, like the underexposure of children to miltefosine treatment, and an improved regimen using an allometric dosage. Given this global scenario of progress and pitfalls, we here review what steps need to be taken with existing medicines and highlight the urgent need for oral drugs. Furthermore, it should be noted that six candidates belonging to five new chemical classes are reaching phase I, ensuring an optimistic near future.

Oral fexinidazole for late-stage African Trypanosoma brucei gambiense trypanosomiasis: a pivotal multicentre, randomised, non-inferiority trial.

BACKGROUND: Few therapeutic options are available to treat the late-stage of human African trypanosomiasis, a neglected tropical disease, caused by Trypanosoma brucei gambiense (g-HAT). The firstline treatment is a combination therapy of oral nifurtimox and intravenous eflornithine that needs to be administered in a hospital setting by trained personnel, which is not optimal given that patients often live in remote areas with few health resources. Therefore, we aimed to assess the safety and efficacy of an oral regimen of fexinidazole (a 2-substituted 5-nitroimidazole with proven trypanocidal activity) versus nifurtimox eflornithine combination therapy in patients with late-stage g-HAT. METHODS: In this randomised, phase 2/3, open-label, non-inferiority trial, we recruited patients aged 15 years and older with late-stage g-HAT from g-HAT treatment centres in the Democratic Republic of the Congo (n=9) and the Central African Republic (n=1). Patients were randomly assigned (2:1) to receive either fexinidazole or nifurtimox eflornithine combination therapy according to a predefined randomisation list (block size six). The funder, data management personnel, and study statisticians were masked to treatment. Oral fexinidazole was given once a day (days 1-4: 1800 mg, days 5-10: 1200 mg). Oral nifurtimox was given three times a day (days 1-10: 15 mg/kg per day) with eflornithine twice a day as 2 h infusions (days 1-7: 400 mg/kg per day). The primary endpoint was success at 18 months (ie, deemed as patients being alive, having no evidence of trypanosomes in any body fluid, not requiring rescue medication, and having a cerebrospinal fluid white blood cell count ≤20 cells per µL). Safety was assessed through routine monitoring. Primary efficacy analysis was done in the modified intention-to-treat population and safety analyses in the intention-to-treat population. The acceptable margin for the difference in success rates was defined as 13%. This study has been completed and is registered with ClinicalTrials.gov, number NCT01685827. FINDINGS: Between October, 2012, and November, 2016, 419 patients were pre-screened. Of the 409 eligible patients, 14 were not included because they did not meet all inclusion criteria (n=12) or for another reason (n=2). Therefore, 394 patients were randomly assigned, 264 to receive fexinidazole and 130 to receive nifurtimox eflornithine combination therapy. Success at 18 months was recorded in 239 (91%) patients given fexinidazole and 124 (98%) patients given nifurtimox eflornithine combination therapy, within the margin of acceptable difference of -6·4% (97·06% CI -11·2 to -1·6; p=0·0029). We noted no difference in the proportion of patients who experienced treatment-related adverse events (215 [81%] in the fexinidazole group vs 102 [79%] in the nifurtimox eflornithine combination therapy group). Treatment discontinuations were unrelated to treatment (n=2 [1%] in the fexinidazole group). Temporary nifurtimox eflornithine combination therapy interruption occurred in three (2%) patients. 11 patients died during the study (nine [3%] in the fexinidazole group vs two [2%] in the nifurtimox eflornithine combination therapy group). INTERPRETATION: Our findings show that oral fexinidazole is effective and safe for the treatment of T b gambiense infection compared with nifurtimox eflornithine combination therapy in late-stage HAT patients. Fexinidazole could be a key asset in the elimination of this fatal neglected disease. FUNDING: Drugs for Neglected Diseases initiative.

A DBS method for quantitation of the new oral trypanocidal drug fexinidazole and its active metabolites.

AIM: Fexinidazole (FEX) is a nitroimidazole being developed as a new trypanocide treatment for human African trypanosomiasis/sleeping sickness. Its main metabolites, fexinidazole sulfoxide (M1) and fexinidazole sulfone (M2), show the same in vitro pharmacological activity as FEX. METHODS & RESULTS: An LC-MS/MS assay was developed for quantitation of FEX in DBS, collected via finger-prick from healthy subjects. The DBS assay was specific, accurate and reproducible for FEX, M1 and M2 when validated against the current plasma assay. DBS samples were stable for 24 h at 37°C with 95% relative humidity, and 58 weeks desiccated at room temperature. CONCLUSION: DBS finger-prick sampling offers a simple, practical method for determining FEX, M1 and M2 concentrations in clinical studies in Africa.

Improving the Quality of Host Country Ethical Oversight of International Research: The Use of a Collaborative 'Pre-Review' Mechanism for a Study of Fexinidazole for Human African Trypanosomiasis.

Developing countries face numerous barriers to conducting effective and efficient ethics reviews of international collaborative research. In addition to potentially overlooking important scientific and ethical considerations, inadequate or insufficiently trained ethics committees may insist on unwarranted changes to protocols that can impair a study's scientific or ethical validity. Moreover, poorly functioning review systems can impose substantial delays on the commencement of research, which needlessly undermine the development of new interventions for urgent medical needs. In response to these concerns, the Drugs for Neglected Diseases Initiative (DNDi), an independent nonprofit organization founded by a coalition of public sector and international organizations, developed a mechanism to facilitate more effective and efficient host country ethics review for a study of the use of fexinidazole for the treatment of late stage African Trypanosomiasis (HAT). The project involved the implementation of a novel 'pre-review' process of ethical oversight, conducted by an ad hoc committee of ethics committee representatives from African and European countries, in collaboration with internationally recognized scientific experts. This article examines the process and outcomes of this collaborative process.

Determination of an optimal dosing regimen for fexinidazole, a novel oral drug for the treatment of human African trypanosomiasis: first-in-human studies.

BACKGROUND AND OBJECTIVES: Fexinidazole is a 5-nitroimidazole recently included in a clinical efficacy trial as an oral drug for the treatment of human African trypanosomiasis (HAT). Preclinical studies showed it acts as a pharmacologically active pro-drug with two key active metabolites: sulfoxide and sulfone (the most active metabolite). The present studies aimed to determine the best dose regimen for the treatment of stage 2 sleeping sickness patients, which could eventually also treat stage 1 patients. METHODS: Fexinidazole was assessed in 154 healthy adult male subjects of sub-Saharan African origin. Three initial first-in-human studies and two additional studies assessed a single ascending dose and multiple ascending doses (both under fasted conditions), tablet versus suspension formulation and food effect (fasted vs. high-fat meal and field-adapted food), and multiple ascending doses with a loading dose regimen under fed conditions. RESULTS: Fexinidazole was well-tolerated in a single dose from 100 to 3,600 mg, with quick absorption of the parent drug and rapid metabolism into sulfoxide [time to maximum concentration (t max) 2-5 h] and sulfone (t max 18-24 h). The tablet formulation was approximately 25 % less bioavailable than the suspension, and food intake increased drug absorption and plasma concentrations of fexinidazole and its two metabolites by approximately 200 %. Fourteen-day multiple ascending dosing administered up to 3,600 mg/day in fasted conditions showed that fexinidazole was generally well-tolerated (mild to moderate, spontaneously reversible drug-related adverse events). Following the high-fat food effect finding, another study was conducted to evaluate the impact of a low-fat regimen closer to that of the target population, showing that the type of meal does not influence fexinidazole absorption. The last study showed that a loading dose of 1,800 mg/day for 4 days followed by a 1,200 mg/day regimen for 6 days with a normal meal provided the desired exposure of fexinidazole and its metabolites, particularly sulfone, with good tolerability. Based on preclinical evidence from a chronic infection mouse model, systemic drug concentrations obtained are expected to be clinically effective in stage 2 HAT. CONCLUSIONS: These studies show that fexinidazole can be safely assessed in patients as a potential oral cure for both stages of HAT.

In-hospital safety in field conditions of nifurtimox eflornithine combination therapy (NECT) for T. b. gambiense sleeping sickness.

BACKGROUND: Trypanosoma brucei (T.b.) gambiense Human African trypanosomiasis (HAT; sleeping sickness) is a fatal disease. Until 2009, available treatments for 2(nd) stage HAT were complicated to use, expensive (eflornithine monotherapy), or toxic, and insufficiently effective in certain areas (melarsoprol). Recently, nifurtimox-eflornithine combination therapy (NECT) demonstrated good safety and efficacy in a randomised controlled trial (RCT) and was added to the World Health Organisation (WHO) essential medicines list (EML). Documentation of its safety profile in field conditions will support its wider use. METHODOLOGY: In a multicentre, open label, single arm, phase IIIb study of the use of NECT for 2(nd) stage T.b. gambiense HAT, all patients admitted to the trial centres who fulfilled inclusion criteria were treated with NECT. The primary outcome was the proportion of patients discharged alive from hospital. Safety was further assessed based on treatment emergent adverse events (AEs) occurring during hospitalisation. PRINCIPAL FINDINGS: 629 patients were treated in six HAT treatment facilities in the Democratic Republic of the Congo (DRC), including 100 children under 12, 14 pregnant and 33 breastfeeding women. The proportion of patients discharged alive after treatment completion was 98.4% (619/629; 95%CI [97.1%; 99.1%]). Of the 10 patients who died during hospitalisation, 8 presented in a bad or very bad health condition at baseline; one death was assessed as unlikely related to treatment. No major or unexpected safety concerns arose in any patient group. Most common AEs were gastro-intestinal (61%), general (46%), nervous system (mostly central; 34%) and metabolic disorders (26%). The overall safety profile was similar to previously published findings. CONCLUSIONS/SIGNIFICANCE: In field conditions and in a wider population, including children, NECT displayed a similar tolerability profile to that described in more stringent clinical trial conditions. The in-hospital safety was comparable to published results, and long term efficacy will be confirmed after 24 months follow-up. REGISTRATION: The trial is registered at ClinicalTrials.gov, number NCT00906880.

The anti-angiogenic activity of IL-12 is increased in iNOS-/- mice and involves NK cells.

We have previously reported that the in vivo transfer of murine interleukin-12 (IL-12) gene using a Semliki Forest virus vector induced tumor regression through inhibition of tumor blood vessel formation. To examine whether IL-12 anti-angiogenic activity interferes with the NO pathway, we used inducible nitric oxide synthase-deficient mice (iNOS-/-) and demonstrated that the anti-tumor effect of IL-12 is more pronounced in these mice. In addition, despite the increased level of intratumoral VEGF in iNOS-/- mice, IL-12 induced a stronger inhibition of blood vessel formation. Histological analysis of SFV-IL-12-treated tumors showed an increase in natural killer (NK) perivascular infiltration in iNOS-/- as compared to control mice. In vitro IL-12-stimulated murine splenic NK cells displayed significant killing activity towards established murine endothelial cells used as targets. These studies indicate that the anti-angiogenic activity of IL-12 interferes with iNOS pathway and involves NK cell recruitment.

Analysis of the mechanisms of human cytotoxic T lymphocyte response inhibition by NO.

NO is a potent cellular mediator which has been shown to modulate several immune mechanisms. Using human T lymphocytes as responder cells in a primary mixed lymphocyte reaction, we demonstrated that, at the initiation of the culture, exogenously provided NO via sodium nitroprusside, in non-toxic concentrations, inhibited both allogeneic proliferative and primary cytotoxic responses in a dose-dependent manner. In contrast, it had no effect on the cytotoxic activity of established human TCR (alpha)beta and TCR (gamma)delta cytotoxic T lymphocyte (CTL) clones. The NO inhibitory effect on primary cytotoxic T cell response correlates with inhibition of T cell blastogenesis. Furthermore, under our stimulation conditions, NO induced an inhibition of IL-2 production, an alteration of IL-2R(alpha) expression, and a down-regulation of NF-AT translocation in CD4(+) and CD8(+)allostimulated T cells. Furthermore, we demonstrate that the inhibition of allospecific CTL activity by the NO donor was at least in part related to an inhibition of granzyme B and Fas ligand transcription as revealed respectively by RNase protection and RT-PCR analysis. These results suggest that NO may function to fine tune human CD3(+) T cell activation and subsequent CTL generation.