Tackling Soil-Transmitted Helminths with New Drug Combinations
Alejandro Krolewiecki, MD, discussed testing a combination of albendazole and ivermectin to improve treatments for neglected tropical diseases.
Alejandro Krolewiecki, MD, director of innovation at Mundo Sano and principal investigator of the STOP2030 project, is leading a project to develop more effective tools for controlling neglected tropical diseases (NTDs), specifically soil-transmitted helminths (STH) in northwestern Argentina. The team is testing a combination of albendazole and ivermectin, which shows better efficacy against several STH species, including those resistant to standard treatments.
The focus of the project is to create a broad-spectrum treatment for STH, a group of parasites that affect millions of people in tropical and subtropical regions. Albendazole and mebendazole are commonly used in mass drug administration (MDA) programs, but some STH species, like Strongyloides stercoralis and Trichuris trichiura (whipworm), are less responsive to these drugs. The combination of albendazole and ivermectin has shown better results in addressing these species and others.
Albendazole and mebendazole are commonly used to treat these parasites, but some species have developed resistance to these medications. Krolewiecki explains the reasoning behind testing the two-drug combination, “We were working in an area endemic for a specific species of STH, Strongyloides stercoralis. This species is not susceptible to the standard drugs like albendazole or mebendazole, which are commonly distributed through WHO programs. However, it is susceptible to ivermectin. That was our starting point—recognizing that we needed two different drugs to cover the full spectrum of medically relevant soil-transmitted helminths.”
Additionally, the team found that Trichuris trichiura did not respond well to albendazole and mebendazole but responded better to ivermectin, prompting them to combine both drugs to improve treatment outcomes, as Krolewiecki states, “When combined, ivermectin and albendazole had a much superior efficacy for either curing or reducing the burden of these diseases.” One of the main challenges the team faced was the difference in dosing between the two drugs. Albendazole is typically given in a fixed dose (400 mg for all individuals aged two and older), while ivermectin is dosed based on weight or height, which made it difficult to combine the two drugs in a single treatment.
To test this, the team conducted a preliminary trial in Horace, Argentina, using a combination of albendazole and a higher dose of ivermectin, “We tested this through a preliminary clinical trial in Horace, where we treated children infected with Trichuris using a combination of albendazole and 600 micrograms per kilogram of ivermectin. The safety was maintained in this higher dose regimen.”
Although ivermectin is widely available in veterinary medicine, it is not as accessible in human medicine, which could be an obstacle to implementing large-scale treatment programs. Krolewiecki points out, “The next challenge we faced was the availability of ivermectin. While it’s widely available in veterinary medicine, it’s less readily accessible for human use, which can be a logistical hurdle in implementing large-scale treatment campaigns.”
Despite challenges related to drug availability, the combination of albendazole and ivermectin shows promise as a more effective treatment for soil-transmitted helminths in endemic regions like northwestern Argentina. The team, in collaboration with institutions such as the University of Salta, is continuing its clinical trials to further assess the efficacy and safety of the treatment. Stay tuned for part 2 of our interview soon.
