PLoS Neglected Tropical Diseases (Apr 2022)

Effect of a single dose of 8 mg moxidectin or 150 μg/kg ivermectin on O. volvulus skin microfilariae in a randomized trial: Differences between areas in the Democratic Republic of the Congo, Liberia and Ghana and impact of intensity of infection.

  • Didier Bakajika,
  • Eric M Kanza,
  • Nicholas O Opoku,
  • Hayford M Howard,
  • Germain L Mambandu,
  • Amos Nyathirombo,
  • Maurice M Nigo,
  • Kambale Kasonia Kennedy,
  • Safari L Masembe,
  • Mupenzi Mumbere,
  • Kambale Kataliko,
  • Kpehe M Bolay,
  • Simon K Attah,
  • George Olipoh,
  • Sampson Asare,
  • Michel Vaillant,
  • Christine M Halleux,
  • Annette C Kuesel

DOI
https://doi.org/10.1371/journal.pntd.0010079
Journal volume & issue
Vol. 16, no. 4
p. e0010079

Abstract

Read online

BackgroundOur study in CDTI-naïve areas in Nord Kivu and Ituri (Democratic Republic of the Congo, DRC), Lofa County (Liberia) and Nkwanta district (Ghana) showed that a single 8 mg moxidectin dose reduced skin microfilariae density (microfilariae/mg skin, SmfD) better and for longer than a single 150μg/kg ivermectin dose. We now analysed efficacy by study area and pre-treatment SmfD (intensity of infection, IoI).Methodology/principal findingsFour and three IoI categories were defined for across-study and by-study area analyses, respectively. We used a general linear model to analyse SmfD 1, 6, 12 and 18 months post-treatment, a logistic model to determine the odds of undetectable SmfD from month 1 to month 6 (UD1-6), month 12 (UD1-12) and month 18 (UD1-18), and descriptive statistics to quantitate inter-interindividual response differences. Twelve months post-treatment, treatment differences (difference in adjusted geometric mean SmfD after moxidectin and ivermectin in percentage of the adjusted geometric mean SmfD after ivermectin treatment) were 92.9%, 90.1%, 86.8% and 84.5% in Nord Kivu, Ituri, Lofa and Nkwanta, and 74.1%, 84.2%, 90.0% and 95.4% for participants with SmfD 10-20, ≥20-40% of pre-treatment SmfD) occurred in 0%, 0.3%, 1.6% and 3.9% of moxidectin and 12.1%, 23.7%, 10.8% and 28.0% of ivermectin treated participants in Nord Kivu, Ituri, Lofa and Nkwanta, respectively.Conclusions/significanceThe benefit of moxidectin vs ivermectin treatment increased with pre-treatment IoI. The possibility that parasite populations in different areas have different drug susceptibility without prior ivermectin selection pressure needs to be considered and further investigated.Clinical trial registrationRegistered on 14 November 2008 in Clinicaltrials.gov (ID: NCT00790998).