Summary Background In 1975–99, only 1·1% of new therapeutic products had been developed for neglected diseases. Since then, several public and private initiatives have attempted to mitigate this ...imbalance. We analysed the research and development pipeline of drugs and vaccines for neglected diseases from 2000 to 2011. Methods We searched databases of drug regulatory authorities, WHO, and clinical trial registries for entries made between Jan 1, 2000, and Dec 31, 2011. We defined neglected diseases as malaria, tuberculosis, diarrhoeal diseases, neglected tropical diseases (NTDs; WHO definition), and other diseases of poverty according to common definitions. Findings Of the 850 new therapeutic products registered in 2000–11, 37 (4%) were indicated for neglected diseases, comprising 25 products with a new indication or formulation and eight vaccines or biological products. Only four new chemical entities were approved for neglected diseases (three for malaria, one for diarrhoeal disease), accounting for 1% of the 336 new chemical entities approved during the study period. Of 148 445 clinical trials registered in Dec 31, 2011, only 2016 (1%) were for neglected diseases. Interpretation Our findings show a persistent insufficiency in drug and vaccine development for neglected diseases. Nevertheless, these and other data show a slight improvement during the past 12 years in new therapeutics development and registration. However, for many neglected diseases, new therapeutic products urgently need to be developed and delivered to improve control and potentially achieve elimination. Funding None.
The extent to which dengue virus has been circulating globally and especially in Africa is largely unknown. Testing available blood samples from previous cross-sectional serological surveys offers a ...convenient strategy to investigate past dengue infections, as such serosurveys provide the ideal data to reconstruct the age-dependent immunity profile of the population and to estimate the average per-capita annual risk of infection: the force of infection (FOI), which is a fundamental measure of transmission intensity. In this study, we present a novel methodological approach to inform the size and age distribution of blood samples to test when samples are acquired from previous surveys. The method was used to inform SERODEN, a dengue seroprevalence survey which is currently being conducted in Ghana among other countries utilizing samples previously collected for a SARS-CoV-2 serosurvey. The method described in this paper can be employed to determine sample sizes and testing strategies for different diseases and transmission settings.
Lymphatic filariasis and onchocerciasis are neglected tropical diseases (NTDs) targeted for elimination by mass (antifilarial) drug administration. These drugs are predominantly active against the ...microfilarial progeny of adult worms. New drugs or combinations are needed to improve patient therapy and to enhance the effectiveness of interventions in persistent hotspots of transmission. Several therapies and regimens are currently in (pre-)clinical testing. Clinical trial simulators (CTSs) project patient outcomes to inform the design of clinical trials but have not been widely applied to NTDs, where their resource-saving payoffs could be highly beneficial. We demonstrate the utility of CTSs using our individual-based onchocerciasis transmission model (EPIONCHO-IBM) that projects trial outcomes of a hypothetical macrofilaricidal drug. We identify key design decisions that influence the power of clinical trials, including participant eligibility criteria and post-treatment follow-up times for measuring infection indicators. We discuss how CTSs help to inform target product profiles.
Background Onchocerciasis ("river blindness") can cause severe morbidity, including vision loss and various skin manifestations, and is targeted for elimination using ivermectin mass drug ...administration (MDA). We calculated the number of people with Onchocerca volvulus infection and onchocercal skin and eye disease as well as disability-adjusted life years (DALYs) lost from 1990 through to 2030 in areas formerly covered by the African Programme for Onchocerciasis Control. Methods Per MDA implementation unit, we collated data on the pre-control distribution of microfilariae (mf) prevalence and the history of control. Next, we predicted trends in infection and morbidity over time using the ONCHOSIM simulation model. DALY estimates were calculated using disability weights from the Global Burden of Disease Study. Results In 1990, prior to MDA implementation, the total population at risk was 79.8 million with 26.0 million (32.5%) mf-positive individuals, of whom 17.5 million (21.9%) had some form of onchocercal skin or eye disease (2.5 million DALYs lost). By 2030, the total population was predicted to increase to 236.1 million, while the number of mf-positive cases (about 6.8 million, 2.9%), people with skin or eye morbidity (4.2 million, 1.8%), and DALYs lost (0.7 million) were predicted to decline. Conclusions MDA has had a remarkable impact on the onchocerciasis burden in countries previously under the APOC mandate. In the few countries where we predict continued transmission between now and 2030, intensified MDA could be combined with local vector control efforts, or the introduction of new drugs for mopping up residual cases of infection and morbidity.
Drug-based interventions are at the heart of global efforts to reach elimination as a public health problem (trachoma, soil-transmitted helminthiases, schistosomiasis, lymphatic filariasis) or ...elimination of transmission (onchocerciasis) for five of the most prevalent neglected tropical diseases tackled via the World Health Organization preventive chemotherapy strategy. While for some of these diseases there is optimism that currently available drugs will be sufficient to achieve the proposed elimination goals, for others-particularly onchocerciasis-there is a growing consensus that novel therapeutic options will be needed. Since in this area no high return of investment is possible, minimizing wasted money and resources is essential. Here, we use illustrative results to show how mathematical modelling can guide the drug development pathway, yielding resource-saving and efficiency payoffs, from the refinement of target product profiles and intended context of use, to the design of clinical trials.
Aims
Emodepside is an anthelmintic, originally developed for veterinary use. We investigated in healthy subjects the safety, and pharmacokinetics of a liquid service formulation (LSF) and immediate ...release (IR) tablet of emodepside in 2 randomised, parallel‐group, placebo‐controlled, Phase I studies.
Methods
Seventy‐nine subjects in 10 cohorts in the single ascending dose study and 24 subjects in 3 ascending‐dose cohorts in the multiple ascending dose study were enrolled. Emodepside as LSF was administered orally as single 1–40‐mg doses and for 10 days as 5 or 10 mg once daily and 10‐mg twice daily doses, respectively. Pharmacokinetics and safety were assessed up to 21 and 30 days, respectively. In addition, IR tablets containing 5 or 20 mg emodepside were tested in the single ascending dose study.
Results
Emodepside as LSF was rapidly absorbed under fasting conditions, with dose‐proportional increase in plasma concentrations at doses from 1 to 40 mg. Terminal half‐life was > 500 hours. In the fed state, emodepside was absorbed more slowly but overall plasma exposure was not significantly affected. Compared to the LSF, the rate and extent of absorption was significantly lower with the tablets.
Conclusions
Overall, emodepside had acceptable safety and tolerability profiles, no major safety concerns, after single oral administration of 20 mg as LSF and after multiple oral administration over 10 days at 5 and 10 mg OD and at 10 mg twice daily. For further clinical trials, the development of a tablet formulation overcoming the limitations observed in the present study with the IR tablet formulation is considered.
Abstract
Background
Onchocerciasis elimination through mass drug administration (MDA) is hampered by coendemicity of Loa loa, as people with high L. loa microfilariae (mf) density can develop serious ...adverse events (SAEs) after ivermectin treatment. We assessed the geographical overlap of onchocerciasis and loiasis prevalence and estimated the number of coinfected individuals at risk of post-ivermectin SAEs in West and Central Africa from 1995 to 2025.
Methods
Focusing on regions with suspected loiasis transmission in 14 countries, we overlaid precontrol maps of loiasis and onchocerciasis prevalence to calculate precontrol prevalence of coinfection by 5 km2 × 5 km2 pixel, distinguishing different categories of L. loa mf intensity. Using statistical and mathematical models, we predicted prevalence of both infections and coinfection for 2015 and 2025, accounting for the impact of MDA with ivermectin.
Results
The number of people infected with onchocerciasis was predicted to decline from almost 19 million in 1995 to 4 million in 2025. Of these, 137 000 people were estimated to also have L. loa hypermicrofilaremia (≥20 000 L. loa mf/mL) in 1995, declining to 31 000 in 2025. In 2025, 92.8% of coinfected cases with loiasis hypermicrofilaremia are predicted to live in hypoendemic areas currently not targeted for MDA.
Conclusions
Loiasis coinfection is a major concern for onchocerciasis elimination in Africa. We predict that under current strategies, at least 31 000 coinfected people still require treatment for onchocerciasis in 2025 while being at risk of SAEs, justifying continued efforts in research and development for safer drugs and control strategies.
Onchocerciasis elimination using
mass drug administration with ivermectin is jeopardized in areas with Loa loa coendemicity. We estimate the number of people at risk of serious adverse events due to ivermectin in onchocerciasis– loiasis coendemic areas in Africa between 1995 and 2025.
Background Onchocerciasis (river-blindness) in Africa is targeted for elimination through mass drug administration (MDA) with ivermectin. Onchocerciasis may cause various types of skin and eye ...disease. Predicting the impact of MDA on onchocercal morbidity is useful for future policy development. Here, we introduce a new disease module within the established ONCHOSIM model to predict trends over time in prevalence of onchocercal morbidity. Methods We developed novel generic model concepts for development of symptoms due to cumulative exposure to dead microfilariae, accommodating both reversible (acute) and irreversible (chronic) symptoms. The model was calibrated to reproduce pre-control age patterns and associations between prevalences of infection, eye disease, and various types of skin disease as observed in a large set of population-based studies. We then used the new disease module to predict the impact of MDA on morbidity prevalence over a 30-year time frame for various scenarios. Results ONCHOSIM reproduced observed age-patterns in disease and community-level associations between infection and disease reasonably well. For highly endemic settings with 30 years of annual MDA at 60% coverage, the model predicted a 70% to 89% reduction in prevalence of chronic morbidity. This relative decline was similar with higher MDA coverage and only somewhat higher for settings with lower pre-control endemicity. The decline in prevalence was lowest for mild depigmentation and visual impairment. The prevalence of acute clinical manifestations (severe itch, reactive skin disease) declined by 95% to 100% after 30 years of annual MDA, regardless of pre-control endemicity. Conclusion We present generic model concepts for predicting trends in acute and chronic symptoms due to history of exposure to parasitic worm infections, and apply this to onchocerciasis. Our predictions suggest that onchocercal morbidity, in particular chronic manifestations, will remain a public health concern in many epidemiological settings in Africa, even after 30 years of MDA.
Lymphatic filariasis is a tropical disease that affects about 70 million people worldwide.1 It is caused by infection with the parasitic nematodes Wuchereria bancrofti, Brugia malayi, or Brugia ...timori and is transmitted through mosquitoes. Chronic infection causes lymphatic dysfunction, resulting in progressive, irreversible swelling of the limbs and genitals (box 1). Filarial induced lymphoedema is the second leading cause of disability in the world, accounting for about 2 million disability adjusted life years lost.1 The associated social stigma often causes mental health problems and poverty because of loss of employment.1
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