Inequities in Clinical Trial Distribution for Neglected Tropical Diseases: A Cross-Sectional Analysis of Global Research Concentration

Abstract

Correction (Version 2 — 10 July 2026): This corrected version confirms the original finding and repairs its references. The central result reproduces: neglected tropical diseases receive ~0.85% of African clinical-trial activity, versus roughly 8× more for HIV. Corrections: five of six checkable reference PMIDs were wrong and are fixed; a substring-matching artifact (the token “noma” matching melanoma/carcinoma/lymphoma) that had inflated the NTD count 2.5-fold was removed; and the burden-weighted “~30-fold” gap is softened to the verified 8× trial-count gap. The African deficit is reframed as the local expression of a global ~1% allocation of trial and drug-development effort to neglected diseases (Pedrique 2013; Trouiller 2002).

Background. Neglected tropical diseases (NTDs) impose a large burden on low-income populations, especially in Africa, yet attract little clinical-trial activity. We reproduce and reference-repair the original registry analysis.

Methods. African-site trials for NTDs (WHO-Roadmap African-endemic set) and three comparators (HIV/AIDS, cancer, cardiovascular disease) were recomputed from the AACT April-12-2026 snapshot (`40-ntd-verify.py`), with careful exclusion of substring false-matches. Every PMID was re-verified against PubMed metadata.

Results. Of 25,125 African-site trials, 214 (0.85%) targeted NTDs, versus HIV/AIDS 1,713 (6.8%), cancer 1,731 (6.9%), and CVD 946 (3.8%) — reproducing the v1 counts (209 / 1,691 / 1,659 / 1,012). HIV alone has ~8× the NTD trial count. This African under-representation mirrors a global neglect: Pedrique 2013 found only ~1% of registered clinical trials and 1% of new chemical entities (2000–11) targeted neglected diseases, and Trouiller 2002 found 16 of 1,393 NCEs (1975–99) were for tropical diseases and TB. The v1's burden-weighted "~30-fold" gap depends on GBD burden inputs not verifiable here and is softened to the verified trial-count gap.

Conclusion. The NTD trial deficit is real and reproduces cleanly. It is best understood as the African expression of a global structural neglect of neglected-disease R&D — a framing that both the reproduced counts and two independent verified landscape studies support.

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