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

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.

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.

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%).

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.