Pharmacological therapies for neglected tropical diseases: a systematic review and evidence gap mapping

Abstract

Background: Neglected tropical diseases (NTDs) comprise 21 endemic infections that affect over one billion people worldwide. This study mapped and identified evidence gaps regarding pharmacological therapies for all WHO-recognized NTDs. Methods: We systematically searched PubMed for systematic reviews (SRs) and randomized controlled trials (RCTs), and the ClinicalTrials. gov database for ongoing RCTs. Methodological quality was assessed using the AMSTAR-2 for SRs and the Cochrane Risk of Bias tool for RCTs. Data were synthesized into evidence and gap maps, and the distribution of evidence was analyzed according to quality. Results: Twenty-four maps were developed, including 74 SRs, 500 RCTs, and 70 ongoing clinical trials; of these, only seven SRs and 17 RCTs were rated as high quality or as having a low risk of bias, respectively. Trachoma exhibited the highest number of evidence gaps, while Buruli ulcer had the lowest. Taeniasis/cysticercosis presented the highest proportion (31.8%) of high-quality SRs, whereas Chagas disease showed the highest proportion of RCTs with a low risk of bias (18.4%). Conclusions: Significant gaps remain in the evidence regarding the efficacy and safety of pharmacological treatments for WHO-recognized NTDs. The currently available evidence is predominantly of low methodological quality and is often insufficient to support robust therapeutic conclusions, highlighting the urgent need for rigorously designed clinical trials.