The quest to find optimal treatment strategies for Neglected Tropical Diseases (NTDs) has been ongoing for many years. In the case of Soil-Transmitted Helminthiasis (STH), which involves five different species of intestinal worms and affects more than 1 billion people worldwide, this endeavor is still a work in progress. The World Health Organization’s (WHO) 2030 Roadmap for the disease aims to eliminate it as a public health problem (with a measured prevalence below 2%) by the end of this decade. However, the current strategies might not be enough to achieve this goal.

Ivermectin and albendazole have proven effective against some intestinal worms, but only when used together can they combat the five STH species prioritized by WHO’s Roadmap. Using both medicines at the same time enhances the overall effectiveness but presents challenges, particularly with ivermectin.

“The need to weigh or measure the height of each person before administering ivermectin is a complication, making the work slower and increasing the required human resources,” notes Adriana Echazú, MD, PhD, a member of Mundo Sano and part of the STOP2030 project, with years of experience treating STH infections in Argentina, her home country.

Using ivermectin is very different from treating with albendazole, especially in the context of a mass drug administration (MDA) campaign, aimed at treating every member of a target group without testing every person for an active infection, with the goal of reducing the community’s burden. Albendazole is usually given as a fixed-dose monotherapy –one 400mg tablet for everyone. In contrast, the amount of ivermectin varies between individuals based on their weight or height, requiring MDA teams to use a scale for weighing each person or a ruler for determining height.

Dr. Echazú explains that weight- and height-adjusted administration tends to be very conservative and is prone to underdosing. This means that some population groups frequently receive lower doses than the ideal.

STOP2030 aims to simplify these mass drug administration campaigns with an important innovation: extending the fixed dosing strategy, already common with albendazole, to ivermectin.

Instead of adjusting the dose for every person’s height or weight, the project proposes a two-sizes-fit-all strategy. One tablet, with 400mg albendazole and 9mg ivermectin for the 3–14-year-old group, and one with double the ivermectin for anyone older.

This brings two advantages to the current treatment strategy. First, it facilitates the simultaneous administration of both drugs, “increasing the possibility of curing or reducing the intensity of the infection,” Dr. Echazú explains. Second, it eliminates the need to weigh each person or measure their height for dosing, “significantly simplifying the operational task.”

Another advantage Dr. Echazú highlights is the streamlining process for medication acquisition and distribution, “which will also be simpler, while the cost will most probably decrease if we buy just a single formulation,” she notes.

This fixed-dose combination strategy is new for STH but has already been successfully used to treat other diseases, such as tuberculosis, where the dosage was reduced from 8 to 12 pills a day to 3 or 4 pills. The effect of the drugs remains similar, explains Dr. Echazú, but the treatment is better tolerated. “The impact on the stomach differs significantly between taking one or four tablets on the same day”.

Dr. Echazú is optimistic about the implementation of the fixed-dose coformulation (FDC) of ivermectin and albendazole and its potential acceptance, as most affected communities are already used to deworming campaigns, and those would become simpler. She also emphasizes the importance of prioritizing water, sanitation and hygiene (WASH) measures, and proper nutrition to decrease infection risk. By addressing these factors, Dr. Echazú believes many communities can achieve significant and lasting improvements in tackling STH and improving overall public health.